[john e. moore] field hydrogeology- a guide for si(bookfi.org)

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A Guide forSite Investigationsand Report Preparation

HYDROGEOLOGYFIELD JOHN E. MOORE

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Moore, John E. (John Ezra) 1931-Field hydrogeology : a guide for site investigations and report preparation / John E. Moore.

p. cm.Includes bibliographical references (p. ).ISBN 1-56670-587-8 (alk. paper)1. Hydrogeology--Field work. I. Title.

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L1587 Front Matter Page 2 Thursday, June 6, 2002 10:53 AM

The Author

John E. Moore, Ph.D.

, is an internationally recog-nized hydrologist. He is currently a hydrogeologistwith the U.S. Environmental Protection Agency(EPA) Office of Drinking Water and an adjunct pro-fessor of hydrology at Metro State College in Denver,Colorado. He has more than 40 years of experienceas a research scientist, teacher, technical advisor andsenior hydrologist with the Water Resources Divisionof the U.S. Geological Survey (USGS) and EPA.At the USGS, he planned and directed hydrologic

investigations, supervised test well drilling, designed aquifer tests, investi-gated contamination, designed hydrogeologic models, supervised writingand review of 1500 reports per year, and presented short courses on projectplanning and management, report writing, and hydrogeology.

Moore has served as an advisor to the EPA, Department of Energy,Department of Defense, U.S. Congress, and the state of Colorado. He is apast president of the American Institute of Hydrology (AIH) and the Inter-national Association of Hydrogeologists (IAH), and he is an associate editorof

Environmental Geology

and the

Hydrogeology Journal

.Dr. Moore received the Department of Interior Meritorious Service

Award, AIH Founders’ Award and IAH Honorary Member Award. He is theauthor of the

Glossary of Hydrology and Groundwater

,

A Primer

published bythe American Geological Institute.


Preface

This book was prepared as a practical guide for field hydrogeologists. It differsfrom other field guides because the American Society for Testing and Mate-rials (ASTM) and U.S. Geological Survey (USGS) technique manuals andEnvironmental Protection Agency manuals were used in its preparation andare referenced extensively. I wrote this guide in part to expose hydrogeologiststo these detailed and useful standard operating procedures (SOPs). I becameinterested in SOPs when I was an electronics officer in the U.S. Air Force(USAF) and a teaching assistant at the University of Illinois. As an electronicsofficer in the USAF, I wrote SOPs for using electronic testing instruments.At the university, I prepared standard procedures for sedimentary petrologylaboratory analyses. As a staff hydrologist with the USGS and as a seniorhydrogeologist for an environmental consulting firm, I prepared many stan-dard hydrogeologic field procedures. I feel these procedures are an essentialpart of an investigation because they standardize data collection, provideguidance to beginning hydrogeologists, and serve as reminders to experiencedhydrologists. I visited an environmental consulting firm recently and askedtheir senior hydrogeologist what he thought about ASTM guides and stan-dards. He felt some were too stringent and some inhibited creative thinking,but he believed that overall they have improved the quality and consistencyof field data.

The USGS took the lead in establishing standards for collecting hydro-logic data when they published the water supply papers in the 1940s. In the1960s, the USGS started the publication of the series

Techniques of WaterResources Investigation

. These technique manuals describe procedures forplanning and specialized work in water resources investigation. Key hydro-geologic technique manuals are listed in this preface. USGS books on rec-ommended methods for collecting hydrologic data established standards fordata collection. ASTM standards and guides are based in part on these books.

ASTM is 103 years old. It has grown into one of the largest voluntarystandards systems in the world and currently has more than 33,000 members.More than 9500 standards are published annually. It provides a forum forproducers, users, consumers, and those having a common interest, such asrepresentatives of government and academia, where they can write standards


for materials, products, and services. ASTM standards are incorporated intocontracts. Scientists and engineers use them in laboratories, designers usethem for specifications and plans, and government agencies reference themin codes, regulations and laws. ASTM standards are developed voluntarilyand used voluntarily. They become legally binding only when a governmentbody references them in regulations or when they are cited in a contract.Major ASTM committees dealing with water problems are Soil and Rock,Water, Waste Management, Biological Effects and Environmental Fate, andAssessment. There are more than 100 hydrogeology standards. It is the obli-gation of every hydrogeologist to evaluate each standard for validity andutility before using them.

Some key ASTM hydrogeology standards and guides

ASTM, 1996, ASTM Standards on Analysis of Hydrologic Parameters and Ground WaterModeling, 144 p.

ASTM, 1996a, ASTM Design and Planning for Ground Water and Vadose Zone Investigations,126 p.

ASTM, 1999, ASTM Standards on Design, Planning and Reporting of Ground Water andVadose Zone Investigations (2nd ed.), 600 p.

ASTM, 1999a, ASTM Standards on Determining Subsurface Hydraulic Properties and GroundWater Modeling (2nd ed.), 320 p

ASTM, 1996, ASTM Standards on Ground Water and Vadose Zone Investigations: Drilling,Sampling, Well Installation and Abandonment Procedures, 247 p.

ASTM, 1997, ASTM Standards Relating to Environmental Site Characterization, 1410 p.

Some key USGS publications in hydrogeology

Buchanan, T.J. and Somers, W.P., 1969, Discharge measurements at gaging stations. In

USGSTechniques of Water-Resources Investigations

, TWRI Book 3, Chapter A8, 65 p. Keys, W.S., 1989, Borehole geophysics applied to ground water investigations. In

USGS Tech-niques of Water-Resources Investigations

, TWRI Book 2, Chapter E2. Heath, R.C., 1984,

Basic Ground-Water Hydrology

, U.S. Geological Survey Water-Supply Paper2220, 84 p.

Hem, J.D., 1985,

Study and Interpretation of the Chemical Characteristics of Natural Water

, U.S.Geological Survey Water Supply Paper 2254, 263 p.

Stallman, R.W., 1971, Aquifer-test, design, observations, and data analysis. In

USGS Techniquesof Water-Resources Investigations

, TWRI Book 3, Chapter B1, 26 p. Wood, W.W., 1976, Guidelines for collection and field analysis of groundwater samples for

selected unstable constituents:

USGS Techniques of Water-Resources Investigations

,TWRI, Chapter D2, 53 p.

Zody, A.A.R. et al., 1974, Application of surface geophysics to ground-water investigations. In

USGS Techniques of Water-Resources Investigations

, TWRI Book 2, Chapter D1, 116 p.

Some key USEPA publications in hydrogeology

EPA, 1985,

Practical Guide for Ground-Water Sampling

, EPA/600/2- 85/104.EPA, 1991,

Site Characterization for Subsurface Remediation

, EPA/625/4-91/026.EPA, 1993,

Subsurface Characterization and Monitoring Techniques — A Desk Reference Guide,Volume I: Solids and Ground Water

, Appendices: A and B.


Acknowledgments

I would like to thank the hydrologists that provided me with guidance in thepreparation of this book. I am grateful to Joe Downey and Edwin D. Gutentagwho gave me the material they used in the courses they taught for ASTMand strongly encouraged me to write this guide.

Many hydrologists gener-ously contributed their expertise and time in the development of this book.My special thanks go to Bozidar Biondic, Phil E. LaMoreaux, A. Ivan Johnson,Chester Zenone, Patrick Tucci, F. L. Doyle, and James R. Lundy who providedoutstanding editorial and technical reviews. I appreciate the support of theInternational Association of Hydrogeologists (Commission on Educationand Training), Lewis Publishers, my hydrology students at Metro State Col-lege and attendees at field hydrogeology short courses in Albuquerque, St.Paul, and Munich. I also want to thank Jack Sharp, Van Brahana, MikeWireman and J. Joel Carrillo-Rivera who provided chapters for this book. Icould not have completed this work without the support of my wife, Dr.Unetta T. Moore, my daughter Pamela, and my son Sean.


Contents

1

Introduction

1.1 Hydrogeologic Concepts 11.2 Aquifer Materials 51.3 Groundwater Movement 71.4 Recharge and Discharge 81.5 Source of Water to a Well 91.6 Locating Groundwater 111.7 Groundwater Key Facts 12References 12

2

Responsibilities of Hydrogeologists

2.1 Rules for Professional Conduct 152.2 Field Notebook 16Reference 16

3

Planning a Field Investigation

3.1 Project Planning 19Project Definition 20Sound Planning 21Types of Projects 23Project Proposal 24Summary of Project Planning 25

3.2 Project Management 26Technical Progress 30Progress Evaluation and Troubleshooting 31Project Completion 33Checklist for Client Correspondence 36Summary of Project Management 37

3.3 Types of Investigations 38Actions taken in the 1980s 40Actions recommended in 2002 40

3.4 Objectives of Investigations 40


3.5 Sources of Hydrologic Data 413.6 Hydrologic Web Sites 433.7 Geographic Information Systems 44References 44

4

Field Investigations

4.1 Conceptual Model 474.2 Preliminary Site Reconnaissance 49

Suggestions for Planning a Field Investigation 49Site Visit 50Springs Investigation 50Hazardous Waste Site Investigation 56

4.3 Geophysical Survey Methods 58References 60

5

Subsurface Investigations

5.1 Geologic Mapping 635.2 Well Inventory 645.3 Monitor Wells 645.4 Test Drilling and Examination of Drill Cuttings 675.5 Water-Quality Sampling and Field Measurements 685.6 Water Level Measurements 69

Wetted Steel Tape 70Electrical Tape 71Pressure Transducer 72

5.7 Tracing Techniques 72Natural Tracers 73

Stable Isotopes 73Radioactive Isotopes 74

Artificial Tracers 74Salts 74Organic Dyes 75

Field Methods 75Isotopes 76Organic Dyes 76

References 78

6

Aquifer Evaluation

6.1 Determination of Hydraulic Conductivity (K) 79Grain Size 79Laboratory Measurements 80


6.2 Design of Aquifer Tests 806.3 Types of Tests 82

Specific Capacity Test 82Step-Drawdown Test 82Slug Test 83

6.4 Analysis of Aquifer Test Data 84Theis Equation 84Cooper-Jacob Straight Line Method 84

6.5 A Computer Program to Design an Aquifer Test 856.6 Construction of Hydrogeologic Maps 87References 87

7

Stream Flow Measurements

7.1 Basic Equipment 917.2 Measurement Procedure 917.3 Methods To Determine Stream–Aquifer Relations 92References 93

8

Hydrogeologic Reports

8.1 Report Planning 95Report Work Plan 96Report Writing Guides 97General Report Outline 98Report Organization 98

8.2 Report Writing 99Overcoming Writer’s Block 99Title 99Executive Summary or Abstract 100Introduction 101Purpose and Scope 101Study Area Description 102Methods of Study 102Approach 102Previous Studies 103Body of Report 103Summary, Conclusions, and/or Recommendations 103

8.3 Report Review 104Peer Reviewers 105Review Methods 106Editorial Review 106

Text 107


Illustrations 107Maps 108Cross-sections 108Tables 108

Peer/Technical Review 109References 113

9

Case Studies

9.1 Central Valley, California 1179.2 Chicago, Illinois 1189.3 Las Vegas Valley, Nevada 1199.4 Tucson and Phoenix, Arizona 120References 121

Further Reading 123

Glossary 125

Appendix: “The Ideal Project — Its Planning and Supervision” 181

Introduction 181Characteristics of the Ideal Project 182Project Planning 183Project Supervision 186

Index 191


1

1

Chapter

Introduction

This book is a practical guide for field personnel evaluating commonlyencountered problems in field hydrogeologic investigations, and it usesa practical “how to” rather than a textbook approach. The focus ofhydrogeologic investigations has changed in the past 15 years fromresource evaluations to contamination investigations. Therefore, thisguide emphasizes that aspect of field studies. It discusses hydrogeo-logic principles; conceptual models of hydrogeologic systems; sourcesof hydrologic information; geophysical methods; surface investiga-tions; subsurface investigations; well inventory; aquifer tests design;streamflow measurements; report planning; report writing and review.This guide also provides field case studies, a glossary, and referencesfor additional study. It presents current standards, methods, and guidesfor planning and undertaking field investigations. These methods applyto most site investigations. The book stresses field methods for deter-mining hydrogeologic characteristics and collection of samples forfurther analysis. Major source references for this guide were of U.S.Geological Survey techniques of water-resources investigations man-uals and ASTM standards and guides for soil, rock, and groundwater.

The following section is a basic review of hydrogeologic funda-mentals and concepts.

1.1 Hydrogeologic Concepts

Groundwater is one of the nation’s most important natural resources.It is the principal source of drinking water for about 50% of the U.S.population, providing approximately 96% of the water used for domes-

L1587_Frame_C01 Page 1 Tuesday, May 21, 2002 9:15 AM

2 Field Hydrogeology

tic supplies and 40% of the water used for public supplies (Solley etal., 1998). Groundwater is a significant source component of U.S.surface-water resources, and much of the flow in streams and waterin lakes and wetlands is sustained by groundwater discharge.

Groundwater is difficult to visualize. Some people believe thatgroundwater collects in underground lakes or rivers. In fact, ground-water is simply the subsurface water that fully saturates pores or cracksin soils and rocks. Such conditions may exist in cavernous limestoneor lava rock, but they are relatively uncommon. Most groundwater iscontained in and moves through the pore spaces between rock particlesor in fractures and fissures in rocks. When the pore spaces in sand andgravel become saturated with water, the water is called groundwater.

Groundwater is replenished by precipitation and, depending onthe local climate and geology, is unevenly distributed in both quantityand quality (Figure 1.1).When it rains, some of the water runs offto streams, some evaporates, and some recharges aquifers (Moore etal., 1995).

Groundwater occurs nearly everywhere in the world at depthsranging from land surface to about 2000 ft below the land surface.Below that depth, most pores and cracks are closed because of theweight of overlying rocks. Most groundwater is present within 300 ftof the land surface.

After the water requirements for plants and soil are satisfied, anyexcess water will infiltrate the water table, which is the top of the zonebelow which the openings in rocks are saturated. Below the watertable, all the openings in the rocks are full of water that moves throughthe aquifer to streams, springs, or wells.

FIGURE 1.1

Hydrologic cycle.

Water table

Aquifer

Precipitation

Ocean

EvaporationEvaporation

Transpiration

Recharge

OverlandFlow

LakeStorage

StreamFlow


Introduction 3

Groundwater is stored and transmitted by aquifers. One simpledefinition of an aquifer is a formation, or part of a formation, thatcontains sufficient saturated permeable material to yield significantquantities of water to wells and springs. The word

aquifer

comes fromtwo Latin words:

aqua,

which means water, and

ferre,

to bear or carry.Aquifers literally carry water underground. An aquifer may be a layerof gravel or sand, sandstone, limestone, lava flow, or fractured granite.

The major productive aquifers in the world are unconsolidatedsand and gravel, limestone, dolomite, basalt, and sandstone. The loca-tion and yield of aquifers are dependent on geologic conditions, suchas the size and sorting of grains in unconsolidated deposits and fault-ing, solution openings and fracturing in consolidated rocks (limestone,granite, lava, volcanic ash).

Two properties of aquifers that affect the storage and flow of ground-water are porosity and hydraulic conductivity. Methods for determiningthese properties are described in Freeze and Cherry (1979).

The quantity of water that a given type of soil, sediment, or rockwill hold depends on the porosity of the formation. Porosity is a measureof pore space between the grains of the rock or of cracks in the rockthat can fill with water. All rocks and soils contain pore spaces. Thepercentage of the total volume of the soil or rock that consists of poresis porosity. If the porosity of sand is 30%, then 30% of the total volumeof a quantity of sand is pore space, and 70% is solid material. Theporosity of rocks varies widely. In granite, the porosity is typically lessthan 1%. In unconsolidated sand and gravel, it may be as great as 30%.

Porosity is either primary or secondary (Moore et al., 1955), and itdefines the storage capacity of an aquifer. Primary porosity, such as poresbetween sand grains, is created when rocks are formed (Figure 1.2). The

FIGURE 1.2

Aquifer pore spaces.

Pores in unconsolidatedsedimentarydeposits

Caverns inlimestoneand dolomite

Fractures inintrusiveigneous rocks

Rubble zoneand coolingfractures inextrusiveigneous rocks



shape, sorting, and packing of grains control primary porosity. Sedimentis poorly sorted when the grains are not all the same size, and thus thespaces between the larger grains are filled with smaller grains. When thepores are not connected and dead-end pores exist, there is no groundwaterflow. This condition is analogous to water in a sponge. On the other hand,effective porosity refers to pores that are interconnected. Cementation ofsand may isolate pores and thereby reduce the sand’s effective porosity.Clays have many pores but do not yield water readily. Secondary porosity,such as joints, fractures, solution openings, and openings created byplants and animals, develops after rocks are formed. The number andarrangement of fracture openings and the degree to which they are filledby finer grained material control secondary porosity.

If water is to move through rock, the pores must be connected toone another. If the pore spaces are connected and large enough thatwater can move freely through them, the rock is said to be permeable.Permeability and hydraulic conductivity are the measure of an aqui-fer’s ability to transmit water. An aquifer with large hydraulic conduc-tivity is highly permeable can easily transmit water, and will yield alarge volume of water to wells or springs.

Permeability and hydraulic gradient determine the rate of flowof water. The hydraulic gradient is the change in head (decrease inwater level) per unit distance. The greater the permeability, the lessthe resistance to flow. In volcanic or crystalline rocks and in somecarbonate rocks permeability depends on the size of the opening andhow well the cracks or fractures are interconnected. In sand andgravel aquifers, permeability depends partly on pore size;coarse-grained materials, such as coarse sand and gravel, have greaterpermeability than fine-grained materials, such as fine sand or clay.Therefore, rocks and unconsolidated sediments with high permeabil-ity make the best aquifers.

Because geologic processes (sedimentation or glacial action) donot deposit sand and gravel uniformly, aquifers commonly differ intheir hydraulic properties at different locations. A sandstone aquiferthat contains different amounts of clay from place to place, and thusdifferent hydraulic properties (porosity and permeability), is hetero-geneous. An aquifer with the same properties at all locations wouldbe called homogeneous.

Geologic depositional (sedimentation) patterns and materials canaffect groundwater movement. Alluvial aquifers commonly show apronounced difference, or anisotropy, between horizontal and verticalpermeability. Horizontal permeability is usually much greater thanvertical permeability (100 to 1) because of the vertical alternation of


Introduction 5

sand and clay lenses (stratification). Fractured-rock permeability isanisotropic (inhomogeneous) because both vertically and horizontallyit is completely governed by the orientations of fractures. An aquiferthat has the same properties in every direction is isotropic (homoge-neous). However, this type of aquifer is rare.

Aquifers are classified as unconfined and confined The watertable is the upper boundary of an unconfined aquifer. Recharge tounconfined aquifers is primarily by downward seepage through theunsaturated zone. The water table in an unconfined aquifer rises ordeclines in response to rainfall and changes in the stage of surfacewater to which the aquifer discharges. When a well that taps anunconfined aquifer is pumped, the water level drops, gravity causeswater to flow to the well, and sediments near the well are dewatered.Unconfined aquifers are usually the uppermost aquifers and, there-fore, are more susceptible to contamination from activities occurringat the land surface.

A confined, or artesian, aquifer contains water under pressuregreater than atmospheric pressure. Rocks or sediment of lower per-meability (such as clay or shale) overlie a confined aquifer. Theoverlying low-permeability layer is called a confining bed, whichhas very low permeability and is poorly transmissive to groundwater.It thus restricts the movement of groundwater either into or out ofthe aquifer. Because the water in a confined aquifer is under pressure,water levels in wells that tap a confined aquifer rise above the topof the aquifer. If the water level in a well tapping a confined aquiferis above the land surface, the well is called a flowing artesian well.After entering the aquifer, water moves down gradient and eventuallyis discharged from the aquifer by springs, seeps, lakes, or streams.An example of unconfined and confined aquifer flow is shown inFigure 1.3.

1.2 Aquifer Materials

Sand and gravel aquifers produce most of the groundwater pumped inmany parts of the world, including North America, the Netherlands,France, Spain, and China. Such aquifers are common near large tomoderately sized streams and were formed by rivers or the melt-waterstreams from glaciers (Moore et al. 1995).

Sand grains with silica or calcium carbonate cement form sand-stone aquifers. Their porosity ranges from 5 to 30%. Their permeability



is a function of grain packing, grain size, and amount of cement (clay,calcite, and quartz). Sandstone is an important source of groundwaterin Libya, Egypt (Nubian Sandstone), Britain (the Permo-Triassic sand-stones), the north-central U.S. (St. Peter-Mount Simon Sandstone),and in the west central U.S. (Dakota Sandstone).

Limestone aquifers are the sources of some of the largest welland spring yields. Openings that existed at the time the rocks wereformed are commonly enlarged by solution (dissolved by water),providing highly permeable flow paths for groundwater. Limestoneis an important source of water in many parts of the world, forexample the southeast U.S. (Alabama, Texas-Edwards Aquifer, Mon-tana-Madison Aquifer, Illinois-Galena Aquifer, and Florida) andSouthern Europe.

Basalt and other volcanic rocks also constitute some of the mostproductive aquifers. Basalt aquifers contain water-bearing spaces inthe form of shrinkage cracks, joints, inter-flow zones, and lava caves.Lava tubes are formed when tunneling lava ceases to flow and thendrains, leaving a long, cavernous formation. Volcanic rocks are impor-tant aquifers in Hawaii, Nevada, and Idaho.

Fractured igneous and metamorphic rocks are the principal sourcesof groundwater for people living in many mountainous areas. Wherefractures are numerous and interconnected, these rocks can supplywater to wells and can be classified as aquifers. (Wells are commonlyless than 100 ft deep.) Igneous rocks are important source of groundwater in the Rocky Mountain states and New England.

FIGURE 1.3

Groundwater movement.

Discharge(Evapotranspiration)


WaterTable

FlowingWell

Fault

Confining Bed

Unconfined Aquifer

Confined Aquifer

Volcanic Rock

Crystalline Rocks

Riv

er Recharge



WaterTable

FlowingWell

Fault

Confining Bed

Unconfined Aquifer

Confined Aquifer

Volcanic Rock

Crystalline Rocks

Riv

er Recharge


Introduction 7

1.3 Groundwater Movement

The two principal functions of aquifers are to store and transmit water.Groundwater is transmitted through aquifers along the hydraulic gra-dient from areas of high head to areas of low head due to the drivingforce of gravity, generally (for unconfined aquifers) conforming to theslope of the land surface. It is very important that planners and allthose who own wells understand this concept.

Geologic conditions (type and sequence of rocks) in the subsurfacecan have major control on the direction and rate of groundwater flow.Groundwater movement is very slow compared with that of surfacewater. Surface-water flow is usually measured in feet per second (ft/s)and groundwater flow in feet per year (ft/yr).

Most of the water in an aquifer infiltrates the ground within aradius of a few tens of miles from where it is tapped by wells ordischarged to the land surface. Except for some very deep aquifers,groundwater does not travel for hundreds of miles. After entering theaquifer, the water moves downgradient, under gravity, to dischargeinto seeps, springs, streams, or wells.

As noted above, groundwater flows in response to an energygradient — it moves or flows from high energy or head to low energy.It is composed of two parts: the pressure head that produces thecolumn of water above the open interval in the well, and the elevationhead. The elevation of the top of the open interval is measuredrelative to a datum (usually mean sea level). Depth to water isnormally measured from a reference point (top of casing) that hasbeen surveyed to establish a precise elevation. These data are usedto compute water-level elevation. Although the depth to water isuseful data, without converting water depths from several wells tohydraulic head, the direction and rate of groundwater movementcannot be determined.

The first systematic study to define the movement of waterthrough porous materials was performed in 1856 by Henry Darcy,a French engineer. He observed that the volumetric rate of waterflow (Q) through a bed of sand is directly proportional to the amountof force on the water across an area (A) — i.e., the difference inpressure head (h) — and is inversely proportional to the length ofthe flow path (l). The quantity of flow is proportional to coefficientK (hydraulic conductivity). Darcy’s Law is sometimes written Q =KA h/l where A is the cross-sectional area through which thegroundwater flows.



Heads measured in wells tapping an unconfined aquifer are usedto construct a water-table contour map (Figure 1.3). This map helpshydrogeologists define groundwater recharge, movement, and dis-charge. Groundwater typically follows a path that is approximatelyperpendicular to water-table contours and is referred to as a flowline.

Head, measured in wells tapping a confined aquifer, is used toconstruct a water-table contour or potentiometric-surface map. It isanalogous to a topographic map, but represents the slopes of a pressurewater surface rather than of a land surface. Water flows from high headto low head (high elevation to lower elevation).

The rate at which groundwater moves through an aquifer rangesfrom only a fraction of an inch per day to several feet per day. In afractured permeable rock with small effective porosity, velocity canbe relatively fast. In contrast, it can take decades or centuries forgroundwater to pass through low-permeable aquifer beds, within thesame area.

1.4 Recharge and Discharge

Groundwater in unconfined aquifers moves from topographically highareas (recharge) to topographically low areas (discharge). In a rechargearea, the potential energy decreases with depth, which results in down-ward movement of water. Between the recharge and discharge areas,groundwater flow is primarily horizontal. In a discharge area, thepotential energy increases with depth, which results in upward move-ment of groundwater.

In humid areas with porous soils, 25% of annual rainfall mayrecharge the aquifer. In contrast, in desert regions recharge is verysmall — 1% of rainfall or less. Aquifers in these areas may containvery old water, which has accumulated over centuries or under differ-ent climatic conditions.

Although commonly displayed on a two-dimensional surface,hydraulic-head distribution is generally a three-dimensional phenom-enon (Figure 1.3); i.e., hydraulic head varies vertically as well aslaterally. The vertical distribution of hydraulic head can be determinedby drilling wells near each other (nested) but open to different depths.If hydraulic head increases with increasing depth, groundwater flowis upward and, in general, indicates an area of discharge. If hydraulichead decreases at a given location with increasing depth within the


Introduction 9

aquifer, then groundwater flow is downward, indicating an area ofgroundwater recharge.

For a local-scale flow system, the distance between recharge anddischarge points is relatively short and groundwater travel timesthrough the system may be on the order of days to years. Forregional-scale flow systems, the distance between recharge and dis-charge points is much greater and travel times for groundwater arealso much greater, on the order of decades to centuries. The deter-mination of groundwater flow rates and directions is frequentlydifficult because of local variations in hydraulic conductivity,changes in stream stage, well withdrawals, and rainfall, just to namea few factors.

Many surface-water bodies (lakes, rivers, springs, and seeps) are“outcrops” of the water table, similar to the outcrops of rocks. Espe-cially in humid regions, these surface-water bodies are useful forinferring water-table elevations where no wells exist. A stream intowhich groundwater naturally discharges is called a gaining stream. Inarid regions, streams commonly lie above the water table and, there-fore, recharge the groundwater systems; these streams are called losingstreams. A spring is a place of natural groundwater discharge from anatural opening at the land surface. Springs may be classified accord-ing to the geologic formation. They may also be classified accordingto the amount of water they discharge (large or small), their watertemperature (thermal, warm, or cold), or by the forces from whichthey are formed (gravity or artesian pressure). A spring is the resultof an aquifer’s being filled to the point that the water overflows ontothe land surface.

Springs may also flow from fractures (or other open-ings) connected to confined aquifers.

Withdrawing groundwater from shallow aquifers that are con-nected to streams can have a significant effect on streams. The with-drawal can diminish the surface-water supply by capturing some ofthe groundwater flow that otherwise would have discharged to thestream or by inducing from the stream to the aquifer. It should benoted that the change in direction of flow from the stream to the wellcan result in the movement of contaminants from the stream.

1.5 Source of Water to a Well

In a paper published in 1940, C.V. Theis described the response of anaquifer to withdrawal from wells as follows (see also Figure 1.4):



1. The groundwater system before development is in a state of dynamic equilib-rium: recharge to the aquifer is equal to groundwater discharge.

2. When the pump is first turned on, the source of water to the well is groundwaterstorage.

3. At a later time, water is obtained from groundwater that would have dischargedto a stream.

4. At a much later time, another source of water to the well is the result of anincrease in recharge due to lowering of water level in the recharge area(increase in unsaturated zone).

FIGURE 1.4

Source of water to a well. (a) System before development, (b) well pumping begins,and (c) well pumping continues (water from storage and stream).

(a)

(c)

(b)


Introduction 11

1.6 Locating Groundwater

Several techniques can be used to locate groundwater and to deter-mine depth to water, yield, and quality. The topography may offerclues to the hydrogeologist about the occurrence of shallow ground-water. Conditions for large quantities of shallow groundwater aremore favorable under valleys than under hills. In parts of the aridsouthwest, the presence of “water- loving plants,” such as salt cedarand cottonwood trees, indicates shallow groundwater. Areas wherethere are springs, wetlands, and also seeps reflect the presence ofgroundwater. Rocks are the most valuable clues. The hydrogeologistshould prepare maps and cross-sections showing the distribution ofrocks both on the surface and underground. The hydrogeologistshould also obtain information on the wells in the area: their loca-tions, depth to water, well yield and geology of rocks penetrated bywells.

Wells that fail are typically too shallow or constructed in porousmedia with small effective porosity. These wells are generally notdeep enough to provide adequate storage of water. If usable wateris available at a greater depth, then the well can be deepened. Often,wells in bedrock cannot be easily deepened. Well failure can also bebecause of well design or construction, or wrong sized and/orblocked screen.

The types and orientation of joints and other fractures might beclues to obtaining useful amounts of groundwater and indicate pref-erential paths of movement of contaminants in the water. A fracturethat has a thin coat of soil can be identified by a zone of differentcolored vegetation, or slight indentation on the surface.

Fractures arefound in many different rock types. Fracture trace analysis has gainedfavor from hydrogeologists is. Fracture traces are identified by astudy of linear features on aerial photographs (Fetter, 2001). Naturallinear features on aerial photographs appear as tonal variation insoils, vegetative patterns, straight stream segments or valleys, alignedsurface, or other linear features. Straight stream reaches or surfacesegments can be visible on the surface. Rows of trees might alignin a floodplain. Fracture traces are the surface expression of faultsor joints. Springs may indicate location of fracture trace. Cautionshould be observed because in some cases the traces may be theresult of deep seated structure.



1.7 Groundwater Key Facts

Groundwater is one of the nation’s most valuable natural resourcesthat is being increasingly developed for irrigation and drinking watersupplies. Groundwater use will increase in the future as surface watersupplies are diminished and reservoir space is used up. Some key factson groundwater are listed below.

1. Groundwater supplies more than half of the U.S. drinking water and 96% ofthe drinking water consumed in rural areas.

2. The Ogallala Aquifer, extending from Nebraska to Texas, supplies 30% of thegroundwater used in the U.S.

3. Groundwater withdrawal has caused the lowering (subsidence) of the groundsurface by 3 m in the Houston-Galveston area, Texas, giving rise to coastaland inland flooding.

4. Land in the San Joaquin Valley of California has sunk as much as 8 m sincethe 1920s as a result of groundwater withdrawal.

5. Mining of groundwater (withdrawing more groundwater than is beingrecharged) in the Northern Midwest has caused water levels to decline 300 m.

6. In the Chicago area, the switch from groundwater to surface water from

LakeMichigan for water supply has caused the groundwater level to rise 300 m.

7. Groundwater is a major contributor to the flow in many streams and riversand has a strong influence on river and wetland habitats for plants and animals.

8. As surface water becomes fully developed and appropriated, groundwateroffers the only available source for new development.

9. Groundwater occurs almost everywhere beneath the land surface.

10. Movement of groundwater is very slow. A groundwater velocity of 1 ft perday is considered to be high.

References

Fetter, C.W., 2001,

Applied Hydrogeology

, 4th Ed., Prentice Hall, Englewood Cliffs,NJ, 598 p.

Freeze, R.A. and Cherry, J.A., 1979,

Groundwater

, Prentice Hall, Englewood Cliffs,NJ, 604 p.

Heath, R.C., 1983,

Basic Ground-water Hydrology

. USGS Water Supply Paper 2220,235 p.

Moore, J.E. et al., 1995,

Groundwater — A Primer

, American Geological Institute,52 p.

Solley, W.B. et al., 1998,

Estimated Use of Water in the United States in 1995

, U.S.Geological Survey Circular 1200, 71 p.


Introduction 13

Theis, C.V., 1940, The source of water derived from wells, essential factors control-ling the response of an aquifer to development,

Civil Engineering

, Vol. 5,277–280 pp.

Wilson, W.E. and Moore, John E., 1998,

Glossary of Hydrology

, American Geolog-ical Institute, Alexandria, VA, 248 p.


15

2

Chapter

Responsibilities ofHydrogeologists

2.1 Rules for Professional Conduct

(American Institute of Hydrology, Registry, 2001)

According to the American Institute of Hydrology, hydrogeologistsshould

• Seek and engage in only professional work or assignments for which they arequalified by education, training or experience.

• Explain their work and merit modestly, and avoid any act tending to promotetheir own interests at the expense of the profession.

• Avoid any act that may diminish public confidence in the profession andconduct themselves to maintain their reputation for professional integrity.

• Be objective in professional reports and testimonies and not disseminateuntrue, sensational or exaggerated statements regarding their hydrogeologicwork.

• Avoid accepting a commission whereby duty to the client or to the publicwould conflict with personal interest or the interest of another client.

• Not accept compensation for services on the same project from more than oneparty unless the circumstances are fully disclosed and agreed to.

• Give proper credit for work done by others, not accept credit due to others,and not accept employment that would replace another professional exceptwith that person’s knowledge and concurrence.

• Associate only with reputable persons and organizations.



2.2 Field Notebook

A hydrogeologic investigation can be no better than the quality ofthe field data and the investigator’s application of the scientificmethod (Fetter, 2001). It is essential that the field hydrogeologistkeep a neat and complete field notebook. The field notebook shouldbe a bound book of numbered waterproof pages. The data should belisted at the time it is collected. It should be written clearly in inkso that someone else can read it. It should contain carefully drawnsketches and photographs.

Reference

Fetter, C.W., 2001,


, 3rd Ed., Prentice Hall, Upper SaddleRiver, NJ.


17

3

Chapter

Planning a FieldInvestigation

McGuinness (1969) describes the hydrogeologist’s work in the fol-lowing way: What does the hydrogeologist see as the deficiencies inknowledge that is his responsibility to remedy? At one time he had arather simple job. He mapped the geology of his area or refinedmapping done earlier by others. He gathered as much information ashe could on the depth and productivity of wells, the kinds of rocksthey penetrated, and the kinds of water they yielded. He interpretedthese data in terms of the subsurface stratigraphy and structure and ofthe water-bearing properties of the different geologic units. Ultimately,he prepared a report, maps, and charts showing where and at whatdepths water could be obtained, and in a general way, how much andof what quality. For rocks not penetrated by enough wells in his areato yield reliable information, he extrapolated information from otherareas where similar rocks were better known, according to his expe-rience and his familiarity with the literature. This procedure was finefor a start. As ground-water development progressed and demandsbecame larger, he found it necessary to think in quantitative termsabout the permeability and storage coefficients of the aquifers and theeffects on ground-water levels of pumping increasing amounts of waterfrom more closely spaced wells.

He tried to keep track of the effects of the withdrawals, not onlyon water levels but in diminishing natural discharge, perhaps increas-



ing natural recharge, inducing the inflow of salt water or other waterof undesirable quality, and so on. He discovered that it was not onlywater levels that were affected. In certain areas he found the with-drawal actually causing the land surface to subside.

Gradually, he began to realize that he was dealing with a system— a geologic-hydrologic-chemical-biologic system in which sub-stances and events of nature and the actions of man interacted socomplexly that only by understanding how the system operatedcould he predict its response to future events of nature and actionsof man and, thus, provide a basis for controlling the response indesired ways. This is where we are today. We are trying to definesubsurface hydrologic systems in terms of their internal character-istics and their external boundaries, and to devise models of themthat will simulate their response to various planned or otherwiseanticipated events. Repeated tests of the models will reveal thefidelity of their simulation of the prototype, and will reveal alsotheir sensitivity to data inputs of various types and thus serve as aguide to data-collection programs. In addition, the models will formthe physical basis of the planner’s overall model of the hydrologic-socioeconomic system.

What is this ground-water system whose operation the hydrogeol-ogist must understand? It is first of all a geologic system. It consistsof rocks, consolidated and unconsolidated, formed and placed wherethey are by geologic processes. It is a hydrologic system because therocks contain openings that can store and transmit water. It is a chem-ical system because the rock skeleton, far from being inert, reactschemically with the water and its dissolved and entrained constituents,and in this reaction changes are produced in both the rocks and thewater. It is a biologic system because living organisms play an impor-tant part in the chemical reactions that take place in it, or at least indetermining the chemistry of the water that enters it.

One of my assignments when I was staff hydrologist at the USGSregional office in Denver, Colorado was to do management and tech-nical reviews of water resources division district offices. After ten ofthese reviews, I noticed the same problems repeating themselves. Iprepared a paper with Hugh Hudson, a fellow hydrologist, that listedthese problems and indicated corrective action. The paper was wellreceived and formed the basis for courses in project planning andmanagement that were presented at the USGS training center in Denverand at the district office. More than 30 of the courses were presentedover 10 years. A copy of the paper titled “The Ideal Project — ItsPlanning and Supervision” is given in the Appendix.


Planning a Field Investigation 19

3.1 Project Planning

The key to successful project management is thorough planning (Fig-ures 3.1 and 3.2). An orderly plan is needed to direct the hydrogeologicproject and to prepare a report from conception through completion.A key to good planning is clearly defined project objectives. As anexample, the steps in a quality assurance system to guide projects,used in many USGS offices, is provided in this chapter.

This section describes the major aspects of planning. Project plan-ning begins with review of the cooperator or client’s needs, which aredescribed in terms of project objectives and deliverables. The projectmanager then develops a budget and work schedule to fit these needs.When the schedule and budget are defined, the project manager canplan for resources, including staff and materials. It may be necessaryto negotiate some of the details with management. The project manager

• The project proposal includes clear objectives, adequate planning, and a detailed work plan

• Reasonable goals

• Adequate budget

• Frequent reviews

• A technically correct and readable report

• A technically capable staff

• Timely completion of report

FIGURE 3.1

Elements of an ideal project.

• Unclear objectives

• Lack of a thorough planning

• Unreasonable goals

• Inadequate supervision

• No report outline

• No project reviews

• Over-optimistic scheduling

FIGURE 3.2

Elements of a nonideal project.



must be clearly granted authority that matches responsibility andshould be given the resources to get the job done.

A thorough technical understanding of the geology and hydrologyof the project (or study area) is a key factor for a successful project.If the project is planned in detail before it is undertaken, and if theplans are revised as necessary during the project, the project reportshould be relatively easy to produce and the schedule will be met. Infact, report planning is best carried out as an integral part of the initialplanning phase of the project. A senior USGS hydrologist told meseveral times that the report should be 90% finished before the hydro-geologist completes the field work.

A preliminary report outline should be developed to ensure thatall technical requirements are met, and to ensure a mutual understand-ing of the goal, management and client should review the outline.Questions on the objectives and scope of the project should be resolvedbefore the fieldwork starts. In some cases, this development and reviewof the report outline take place during the proposal negotiations. Thereport content should be described in a memorandum so that the clientdoes not forget the agreement. Such a memorandum puts a controlaround the project so the client cannot add work at the last minute.

Contingency planning is essential for success, and sometimes thesurvival of the project may require such planning. An experiencedproject manager can anticipate areas where problems may arise orwhere field or laboratory results may require changes in direction. Ifthese potential problem areas are identified before the project starts,the budget and schedule can provide for flexibility. These problemsshould be discussed with the client, who will not appreciate surprisesat a later date (Figure 3.1)

Project Definition

A project is a series of related activities with specific objectives, abeginning date, and an end date. The major elements of project plan-ning are the project proposal, which should include a detailed workplan, and a report outline (Figure 3.3). The steps that should be fol-lowed in planning the project are

1. Define the project objectives.

2. Select an approach to accomplish the objectives.

3. Decide on the major milestones for the project.

4. Select dates to begin and end milestones.



5. Determine budget for manpower, equipment, sampling, contractors (i.e., drill-ers and laboratory).

6. Select and assign manpower to accomplish work.

7. Carry out project.

8. Write and deliver a quality technical report on time.

Sound Planning

Solid planning can provide the project chief with the tools needed todesign and complete the project (and report) within the allotted timeand budget. A project can be successful only when the project chiefhas thoroughly planned all foreseeable aspects of the project beforethe project begins.

Project objectives must be specific, deadlines andbudgets must be realistic, and difficulties must be anticipated.

Project deliverables —

The most important part of project plan-ning is a thorough understanding of the scope of work, the nature ofthe deliverables, and the client’s expectations. The best time to clarifyobjectives is before the project starts. Once this understanding isreached, detailed plans can be prepared for executing the project. Thelist of deliverables is the natural starting point of the review, becausethey are what the client expects to receive.

Project budget —

Once the technical requirements have beendetermined, the budget can be developed. In some cases, the clientspecifies the total project budget. In others, it is developed to fit the

• Title

• Need for project

• Purpose and objectives

• Technical content and extent of study

• Approach

• Project benefits

• Planned reports

• Work plan

• Personnel

• Budget

FIGURE 3.3

Elements of a project proposal.



technical requirements, in which case the budget is presented to theclient as part of the proposal for review and approval. The detailedproject budget should include itemized costs for each activity, includ-ing project management and administration. This budget then specifiesthe level of staff effort and other resources that can be used to completethe required work and also costs for laboratory analyses, fieldwork,travel, report editorial and technical review, and equipment purchaseor rental.

Project schedule

— The project schedule is developed from thedeadlines imposed by the supervisor in consultation with the client.The project manager then examines the technical plan, available man-power, and budget, and then determines the amount of time that shouldbe devoted to each activity. This schedule should be detailed enoughto show all required activities and milestones, including separate peri-ods for report writing, review and revision. On complex projects,several tasks may be executed simultaneously and then interdependen-cies among the tasks must be taken into account on the schedule.

Project staffing

— The schedule and budget define the level ofeffort that can be expended to perform the project. Before any workbegins, the manager must determine the types of services needed toexecute the project. Any services needed, such as drilling, should bescheduled to ensure that they will be available when required. Labo-ratories, for example, should be alerted to expect samples for analysis.The most important resource is the manpower that will perform thework. In most offices, several projects are in progress at the same time,which means they may be competing for the same staff. Early planningof manpower needs allows the project manager to present managementwith a clear picture of the need for staff. Management can then eithertake the steps necessary to provide the resources or at least tell theproject manager of anticipated difficulties so contingency plans oralternative arrangements can be made.

This situation is ideal, but it can work only if all projects areplanned well, the organization is not overextended, and flexibilityexists for coping with unanticipated emergencies. A single projectmight use personnel from more than one office, and scheduling tomeet the needs of each office is essential.

Report outline —

The final report is the most important deliver-able for the project. The report is usually the only product of a projectthat is seen by the client, and in most cases it determines the successor failure of the project. It is often incorporated wholly or in part intoother documents, such as a license. An outline of the final report shouldbe prepared before the project starts. The scope of the work and other



client technical requirements are the basis for the final report, so thatpreparing an outline is straightforward. The report outline should bethematic; that is, it should contain a sentence describing each reportsection, but it should also be as detailed as possible — prepare a topicsentence for each report section. The outline is also useful in testingthe manager’s understanding of the project. The entire report can betreated this way, with the exception of details of the findings andrecommendations. If several similar projects are to be performed, itcan be efficient to use a standard report format that varies only inrecommendations, data and hydrologic description. The hydrogeologicreport section of this guide provides more detail on this subject.

Types of Projects

The scientist or engineer might be asked to plan many types of projects.In consulting, the most common projects are short term (fewer than 6months) and have a budget of less than $50,000. Clients includefederal, state, or local government agencies, insurance companies,industrial firms, financial or legal firms, and management districts. Thescientist or engineer is frequently involved in performing researchunder government contracts or grants. A government employee willoften work on long-term projects funded by the agency or may beasked to manage work contracted to other federal agencies, privatecontractors, or universities.

Short-term projects

— For many consultants in the earth sciencesand engineering, short-term single purpose projects make up the bulkof the work. Such projects are often done with a very low margin ofprofit and consequently must be run very efficiently. They might lastonly a day or two or several weeks. Usually there is a single,well-defined objective. A typical short-term project will require doc-ument review, a limited amount of field and laboratory work, datainterpretation and evaluation, and a final report.

Short-term projects are very useful for developing project man-agement skills in young staff members. These projects require carefulattention to planning and to monitoring progress and expenditures, andsuccessful completion is good training for managers and builds con-fidence. It is still important, however, for upper management to super-vise the young project manager and to provide guidance or support asneeded. In many firms, these projects are the bread and butter of theworkload, and they help to keep staff members productive betweentasks on larger projects.



Long-term projects —

Projects that have a single objective andthat last from several months to several years present more of a man-agement challenge. The best way to ensure successful project com-pletion is to specify short-term tasks or milestones that must be metduring the course of the project. The greatest danger of a long-term,single-objective project in a busy organization is that work on it willbe delayed to meet short-term needs of the organization, especiallycrises. Such delays commonly result in the need to operate at panicspeed for a short time near the completion date of the project.

Open-ended projects

— In many respects, the open-ended projectis the most difficult to manage effectively. These projects have no fixedcompletion date and often have one or more objectives without anyclear criteria for completion. Fiscally, such projects are often run aslevel-of-effort projects up to a ceiling amount. The only way to besuccessful is to define interim objectives or milestones with an asso-ciated schedule, budget, and report. This approach has the advantagethat progress can be clearly demonstrated during the course of theproject, which may make it easier to obtain additional funding as theneed arises. Many research projects performed at universities andgovernment laboratories are of this type.

Project Proposal

A project proposal is a plan to solve or address a specific problem orset of problems (Figure 3.3). It should outline the technical objectives,the period of time needed to achieve the objectives, and the fundingnecessary to complete the work. A proposal should be clear and con-cise and address the what, why, where, when, and how of the project.It should contain enough information to allow the client to evaluatethe proposal and report plan. It should also use a standard format asdescribed below.

Title

— The project title should relate to the purpose, scope, and location of theproposed study. Ideally, it should closely resemble the title of the proposedprincipal report resulting from the study, and it should be concise, yet informative.

Problem

— Explain why the project deserves the commitment of time and money.The project must produce results worthy of funding. The need for the studymust be more than just the satisfaction of intellectual curiosity.

Objectives —

Relate the proposed technical results to the expressed need forthose results. The objective should be specific. It is one of the most importantfactors in evaluating the project proposal.



Approach

— Describe how the objectives will be addressed. If standardapproaches and methods are to be used, a brief description will suffice. If theapproach is new and untested, a more detailed description will be needed.

Benefits

— Show how the results of the project will be of benefit to the clientor agency and/or to science.

Reports

— Describe the planned reports and state their probable titles, publica-tion outlets, and milestone dates. Important milestones include the preparationof report outlines, report writing, colleague review, submittal of the report forapproval, and anticipated approval and delivery dates. All report activitiesshould be planned for completion by the end of project funding.

Work plan

— Schedule the starting and ending dates for each work element.Remember that some elements might be performed/executed concurrently,whereas others must be completed in sequence.

Personnel

— List personnel needs by specialty and time needed. Note that allpersonnel must be available at the time needed in the work schedule. Indicate,too, the possible need for outside advisors and consultants.

Project costs

— With adequate reference to plans, schedule, and personnel,itemize costs for each fiscal year. Be certain that the budget is adequate forall planned project activities for the anticipated period of study, including allcosts associated with publishing the reports.

Summary of Project Planning

The inclusion of benefits, work plan, and summary in the projectproposal greatly enhances the client’s ability to focus on key issuesand to grasp quickly the importance of the work proposal (Figures 3.4and 3.5). The work plan is an essential part of project planning.

The major causes of project failure are

• Poorly prepared proposal

• Nonspecific objectives and approach

• Cost cutting

• Failure to reduce project scope when funding is reduced

• Not adhering to sound principles of cost estimation

The steps in project planning are

• Define objectives

• Prepare detailed project proposal

• Prepare detailed work plan

• Write report plan



3.2 Project Management

Project management is the organizational control used to achieve theproject objectives. It begins with a well-prepared proposal and followsthrough until completion of all project deliverables. Without suchmanagement, the project will probably exceed budget and produce alate report.

Management by objectives —

Management by objectives (MBO)is a major technique used by government agencies and the private sectorto define project objectives and monitor project progress. MBO wasfirst used by Peter Drucker (1964) and has been used successfully atGeneral Motors, Dupont, Ford Motor Company, and General Mills, justto name a few companies. It defines what must be done, how it mustbe done, how much it will cost, what constitutes satisfactory perfor-mance, how much progress is being made, and when action should betaken to revise the project objectives and schedule (Figure 3.6).

• Enthusiasm

• Disillusionment

• Panic

• Search for the guilty

• Punishment of the innocent

• Praise and honors for the nonparticipants

FIGURE 3.4

Six phases of any project.

• Define the project objectives

• Select an approach to accomplish the objectives

• Select milestones for project

• Define dates to begin and end milestones

• Assign manpower to do the work

• Carry out project

• Prepare a quality report on time

FIGURE 3.5

Project planning steps.



The major steps in MBO are

1. Supervisor and project manager meet to discuss the objectives and approachfor the project.

2. They agree on the objectives, approach, deliverables, work plan, and report.

3. The project manager strives to accomplish the agreed objectives.

4. Supervisor and project manager meet on a regular schedule to evaluate accom-plishments. They review milestones, revise the schedule, correct problems,evaluate report progress, funding, and plans for the next meeting.

5. The client is kept advised on project and report progress.

Project review —

The major element of project management is aperiodic review of progress. Written and oral reports on work progressare needed at least quarterly. Opportunities for review include staffmeetings, technical seminars, and briefings for cooperators and clients.An essential part of the review is to compare project progress with thework plan. Emphasis should be placed on project findings, changes inscope of work, report progress, accomplishments, needs for assistance,financial status, and future or anticipated activities. Some of the advan-tages of regular project review are listed below:

1. Project kept on time and focused on objectives.

2. Need for modifying project objectives is identified.

3. Personnel, technical, and financial problems are identified.

4. Guidance and assistance for project chief provided.

5. Technical quality control provided.

6. Morale improved.

7. Managers, supervisors, and clients educated.

8. Project and report kept on schedule.

• Define the project objectives

• Select an approach to accomplish the objectives

• Decide on the major milestones for project

• Select dates to begin and end milestones

• Assign manpower to accomplish work

• Carry out project

• Have frequent reviews of project progress

FIGURE 3.6

Management by objectives.



Project management file —

Early in the project, the projectchief should establish a

project-management file to maintain recordsand to document progress on project activity and planned reports(Figure 3.7). The file should be kept current and should include thefollowing items:

1. Project proposal

2. Work plans, including milestone dates

3. Budget

4. Topical and annotated outlines for reports

5. Lists of report illustrations and tables

6. List of references for bibliographic citations

7. News releases

8. Newspaper articles on project

9. Review summaries

10. Report drafts and review comments

11. Summary of meetings with cooperators or clients

12. All pertinent correspondence

13. Purchase orders

14. Cooperator or client authorization to proceed

15. Copy of contracts

16. Field notes and/or project notebook

17. Results of laboratory analysis

18. Project data

• Project proposal

• Project description

• Work plan

• Budget

• Report outline

• List of illustrations

• List of possible report reviewers

• Report drafts

• Newspaper articles

• Summaries of project reviews

FIGURE 3.7

Contents of the project file.



Project controls —

Project controls allow the project manager tomonitor progress. The controls can provide the manager with theinformation needed to anticipate problems and to take preventive orremedial actions. Quality assurance is a special type of control thatcan help to guarantee that all project work is performed to appropriatetechnical standards. It may also provide the documentation needed todemonstrate in courts, licensing hearings, or client reviews that thework was planned to be performed in accordance with professionalstandards, practices and procedures. As liability questions becomeincreasingly important, quality assurance takes on greater importance.

Projects performed for federal agencies require frequent progressreports. Many clients are beginning to require reports on complexprojects to ascertain that the project stays “on track.” In some compa-nies, internal management also requires this sort of reporting.

Project controls and management reports commonly required arelisted below. These project control techniques are very useful to theproject manager, particularly on complex or long-term projects inwhich parallel activities are involved. The computer graphics used toassist the control progress are described.

Work schedules —

Project schedules show progress as a functionof time. Every project, no matter how simple, has a schedule thatincludes the beginning and completion dates. From these two dates,the time schedule for the entire project can be developed. The projectmanager must calculate backward from the project end date, usingreasonable estimates of time for each task or activity, to determineintermediate schedule points. For government projects, milestonecharts (schedules) are commonly required in proposals and in monthlyor other regularly scheduled project management reports. The mile-stone chart shows actual progress against planned progress. It mightalso track the percentage of work completed relative to the allocatedresources on a task-specific basis.

A common problem in many projects is not allowing enough timefor report preparation, review, revision and production. Failure to planfor these activities is frequently the reason for late completion ofprojects. If client review and response are required before final reportdelivery, it is important to show them on the project schedule. Afterthe schedule is developed, project and support staff can be alerted toexpect various activities at specific times.

Manpower projections

— Manpower projections are routinelymade during the planning stage of projects. They project the rate atwhich manpower will be expended in performing the work requiredfor the project. More sophisticated versions show manpower divided



into labor grades to make cost calculations easier. Total man-hoursexpended are routinely compiled at least weekly in many firms; thesedata are readily compared to the projection. Cumulative manpowerexpenditure is one important piece of management information com-monly required in management reports.

Cost projections

— Budget can be handled in much the same wayas manpower data. Projected spending rates can be prepared from theinitial project budget, together with the projection of manpower expen-ditures, with cumulative expenditures calculated and plotted. Compar-ison of actual and cumulative costs with projected costs gives a goodidea of the financial progress of the project.

Technical Progress

Technical progress is much more difficult to quantify than are numericalmeasures such as cost or man-hours. Many management reports askfor an estimate such as “percent complete” or its equivalent. If thisestimate is to be meaningful, it must be independent from accumulatedcosts or accumulated man-hours. This somewhat necessarily qualitativemeasure of the amount of work required for a project should somehowbe qualified. It is always a highly subjective measure and is hardly areliable indicator for decision making, although it can be useful whenused with the more quantitative indicators discussed above.

One procedure that should be formally adopted in organizationsperforming technical work is the review of the reports of other deliv-erable documents. Internal review is absolutely essential to ensuretechnical quality and to protect against litigation and liability, and, infact, is an integral part of sound science and engineering. Several levelsof review exist and all have their place in project management.

The lowest level is editorial review, which is a check for errors inspelling, typing, and syntax. More important is the basic technical orpeer review, wherein a knowledgeable professional involved in the workor the report reviews it for technical content. Prior to colleague review,all data entry and calculations should be checked (and signed off by thereviewer) independently. This reviewer should also check the interpre-tations made by the author. The next review is management level, wheremanagement reviews the report to assure that contract requirements weresatisfied, that it is consistent with other work products or other infor-mation, and that it does not run counter to company or agency policies.Major technical reports, covering significant research or field or labo-ratory investigations, might need a peer review, especially if the findings



of the project are at, near, or beyond the recognized state of the art. Thepeer review requires that recognized independent experts in the field,often drawn from academic or government facilities, perform a thoroughreview of the data, analyses, and interpretations. This level of review isnot common in the consulting world but is similar to the refereeingprocess used for journal publications.

Progress Evaluation and Troubleshooting

The ability to evaluate progress and to recognize the need for remedialactions is extremely valuable to the project manager. Because veryfew projects run smoothly from start to finish with no problems orsurprises, the only way to avoid disaster is to be able to evaluateprogress and troubleshoot when necessary. Progress reporting tech-niques were discussed in the previous section; this section discussesrecognizing the need for corrective action and the types of correctiveactions usually possible. A supervisor often measures the success ofthe project by his or her ability to recognize problems and put correc-tive actions into play. A variation of corrective action infinitely morevaluable and difficult is preventive action.

Progress evaluation requires the comparison of project accomplish-ments and status with the project plans. Consequently, progress eval-uation can be only as good as the existing plans. As discussed inprevious chapters, before the start of work the project manager mustprepare plans as carefully and in as much detail as possible. Theseplans must include intermediate targets, or milestones, that will be metduring the course of the project. The final report, then, is only one ofthe milestones. The simplest form of progress evaluation is to comparethe accomplishment at each milestone with the schedule. This com-parison, however, will tell only part of the story. Equally important isan analysis of actual expenditures against projected budget or plannedmanpower. Meaningful analysis usually requires that the plans, includ-ing the schedule and budget, be updated whenever conditions change.

An early slip in milestone completion means that one of two thingsmust happen: (1) the final completion date for the project must slip,or (2) the lost time will need to be made up on later milestones in theproject, allowing the original completion date to be met. This situationmay require negotiating with the client or, more commonly, findingways to shorten future project activities. Decreasing the time requiredfor future activities can be accomplished by an accelerated expenditureof manpower, a reduction in scope, or a combination of both. Clearly



the earliest possible recognition of the need for action will provide thebroadest choice of possibilities for remediation.

The successful project chief manager needs to be directly involvedwith all aspects of the project in order to recognize problems.

Monitoring progress

— Reports are used to monitor projectprogress. Many computer programs are available to assist the projectchief in both planning and monitoring the project’s progress.

Progress reports have two advantages:

• They allow the project manager to visualize the relation, or interdepen-dency, of various project tasks, manpower requirements, needed services,and funding.

• They provide a concise mechanism for reporting progress to the project staff,managers and clients. These reports allow the project chief to define the project.

There are three ways of report progress: milestones, bar chart(Gantt), and quarterly progress review. The quarterly review of projectprogress (every 3 months) is a frequently used method frequently formonitoring progress. The summary is presented orally and in writtenform. Items discussed in the review are progress on milestones, diffi-culties, roadblocks, and plans for the next quarter. Milestone chartsand bar graphs can be used to describe planned and actual progress.A list of action items should be prepared after each review.

Milestone charts are very useful for analyzing and presentingproject information. Tables present milestones, starting dates and com-pletion dates. The report itself is a list of all milestones for the project,including the final report.

An example milestone chart is shown below.

Milestone Jan. March May July Sept. Nov.

Proposal # o @

Work plan # o

Report outline # o

Test drilling and sampling # o

Analysis of data # o @

Preparation of report # o

Review of report # o

Approval # o

Report delivery o

Postmortem o

#: Start task; o: Planned completion; @: Actual completion.



The milestone chart provides a means of comparing actual progressagainst planned completion. Departure from the planned completiondates is a fact of life in almost all projects. There are many reasonsfor departures such as reduction in funding, transfer of personnel, lackof management review, inadequate planning, and delay in obtainingequipment, to name a few.

PERT (Program Evaluation and Review Technique) is used exten-sively by government agencies and the private sector. It identifies tasksand specifies how they relate to and depend on each other. The objec-tive is to manage large and complex projects in the easiest and mostefficient manner. PERT is easily adapted to designing hydrologic andgeologic projects. The following steps are used to apply PERT to aproject:

1. List project tasks.

2. Determine duration for each task.

3. Determine available resources (manpower, equipment, and materials).

4. List costs.

5. Graph activities (network).

6. Compute latest allowable time.

7. Add slack time.

8. Determine critical path (the longest time path through the project network).Delays in a critical task will delay the completion of the project.

Bar, or Gantt, charts are used to display the project tasks over timein a graphical format. It is another way of viewing the same informa-tion displayed on the PERT chart.

Project Completion

When is a project complete? Is it when the final report has beensubmitted to the client? When the client has accepted it? Or when allpayment has been received? All of these may be correct in part.

The good project manager will conclude each project with ananalysis of the project, which should include an examination of thetechnical, financial and commercial success (or failure) of the project.Each project should be a learning experience for the manager and theorganization. In this way, the process should become more efficientover time, and specific areas in need of improvement can be identified.Such areas might include modifications in the accounting system,



tracking of time and material expenditures, or internal communicationprocedures. If the organization is unwilling or incapable of makingchanges, the project manager can at least take this problem area intoaccount when planning the next project.

A requirement for all projects is that it be completed on time andwithin the allocated budget. Sometimes when the project is relativelysimple and aimed at a clear and final objective, add-on work is notpossible. In such situations, success may not be apparent until afterfuture contracts are awarded by the client. One function of the projectmanager is to point out additional work that could be done by hisorganization for the client. This must be done carefully, in order notto alienate the client, by appearing to “make work” or by interpretingthe original scope of work too narrowly and requesting additionalmoney for work the client thinks is part of the existing contract.

Completing the task on time, however, is not the main criterionthat brings the client back for additional work. The project chief mustdeliver a quality report (product) that meets the project objectives, iswell organized, is comprehensive, and is technically sound.

Completion criteria

— Many projects have clearly defined end-points. The most common endpoint is the final report. However, oftenthe project does not end with the final report. On level-of-effortprojects, a discussion with the client is sometimes required to decideon the end of the project. For the project manager in a consulting firm,the project is not complete until the billing has been done and theclient has paid in full. In these cases, the project manager often hasto follow the project for months after all technical work has beencompleted. In many projects, the project is not final until commentshave been received and answered via a revised version of the report.

The clearest criterion of completion is finishing the assignmentsmade in the statement of work. Technical work is done when the clienthas accepted all reports and other deliverables and has certified thatthe contract has been fulfilled. At this point, no further costs can beincurred on that project. This limitation is precisely the reason that itis necessary to get written approval or direction from the client whenthe statement of work is modified during the course of the contract.

The project manager has the additional responsibility of ensuringthat all costs have been accumulated for the project, that all of themare justified expenditures on the contract, and that the billing reflectsall true costs. In some firms, this last step is left to the accountant,who prepares the actual bill and sends it to the client. The projectmanager’s responsibility might extend to collecting payment from theclient. If the client does not remit in a timely fashion, the manager



might be the one to remind the client of his responsibilities. Requiringpayment on delivery of the report avoids this embarrassment.

The project manager may need to decide which, if not all, costsare to be transmitted to the client. Any costs not passed on to the clientare charged against profit, so any such decision must be made verycarefully, and often requires approval by higher management.

Analysis after project completion —

The diligent project man-ager will evaluate the completed project as a way to improve skills,better analyze project results, and evaluate the management systemThis evaluation is a useful expenditure of staff resources only if theproject is analyzed for management weaknesses and strengths andwhat is learned is applied to future project management. Often, weak-nesses in the organization, such as priority setting, staff allocation,management support, inexperienced preliminary budgeting, andscheduling are recognized as systematic problems in the analysis. Atruly useful analysis or “post mortem” must go well beyond the stageof placing blame, as often happens.

Problems that surface during the analysis generally fall into twocategories: weakness in planning and weakness in execution. Weak-nesses in planning generally result from lack of sufficient planning orfrom the planner’s inexperience. Weaknesses in execution are usuallya result of communication problems, either with the client or with thesubcontractors, over-commitment of staff resources, or a lack of skillamong the technical staff.

Roles and responsibilities

— Client service can be improvedthrough better review and communication (both internal and external).The following policies can be taken to improve the communicationwith the client:

1. The division manager or equivalent is responsible for discussing new workwith clients.

2. The project manager is responsible for filling out the project assignment formsand project spreadsheets.

3. Designated client contact is responsible for communicating with the clientregarding all aspects (technical, schedule, budget) of the project.

4. Inform the client immediately if there is an increase in work effort.

5. The project chief must not undertake tasks beyond the project scope withoutmanagement and client authorization.

6. The client contact is responsible for daily client communications.

7. The client contact should notify the client regarding the scheduled arrival dateof deliverables.

8. Courtesy calls to monitor client satisfaction should be conducted.



9. The project manager is responsible for completing assignments consistent withclient goals. This includes being cognizant about the technical, scheduling,and budget aspects of the project.

10. The project chief should not exceed budgets and schedules. The project staffshould be aware of the overall schedule and project budget including allottedhours.

11. If the project chief cannot stay within the budget, the supervisor should beinformed immediately so that a response can be made in the budget or theclient can be alerted.

12. Contingencies should be anticipated and planned for at the inception of theproject. Clients do not like unpleasant surprises.

Checklist for Client Correspondence

The following checklist can be used before transmitting reports andcorrespondence.

1. Should the document be labeled “Privileged and Confidential — Prepared atthe Request of Counsel”?

2. Does the letter require courtesy copies to anyone?

3. Should the courtesy copies be blind or noted?

4. Are the copies going to the correct people?

5. Should the people receiving courtesy copies also receive enclosures?

6. Is the letter format correct?

7. Are the addressee’s name and title correct?

8. Is the addressee’s company name spelled correctly?

9. Does the name of the addressee match the salutation?

10. Is the date correct at the top of the letter?

11. Should any of the enclosures to a letter also be on letterhead to indicate whoauthored the enclosure?

12. If the document is a letter contract or a professional services agreement, aretwo originals being transmitted to the addressee? (The addressee retains onecopy and the other is signed and returned to the sender.)

13. If a signature stamp is used for a letter, does the imprint look authentic or isit crooked and off-center?

Total quality management (TQM)

— TQM is an integratedmanagement system for achieving client satisfaction. It involves allmanagers and employees and uses quantitative methods to improve anorganization’s progress. The TQM problem-solving process consistsof eight steps:



1. Identify problems.

2. Select problem.

3. Analyze root cause.

4. Identify possible solutions.

5. Select solutions.

6. Test the solution.

7. Implement solution.

8. Trace effectiveness.

Summary of Project Management

Groundwater investigations are designed to study the groundwaterresources of a specified area and to determine cause and effect rela-tionships for phenomena such as reduction in aquifer storage, reducedwell yield, contamination or deterioration in quality. The boundariesof the areas may be determined arbitrarily to coincide with county orstate boundaries, or they may be based on hydrologic criteria andenclose entire drainage basins or hydrologic units.

A groundwater investigation can be separated into three steps:planning, execution, and reporting.

1. Project management begins with proper project planning and succeeds withimplementation of the work plan. Well-managed projects achieve objectivesand produce quality reports on time.

2. Poorly managed projects exceed the project budget and result in late or weaktechnical reports.

3. The project manager is responsible for

• Identifying milestones and completion dates.

• Defining equipment and manpower needs.

• Providing detailed progress reports.

4. Management by objectives keeps the project on schedule and focused onobjectives.

5. A project file should be started at the beginning of the project and maintainedthroughout the life of the project. The file should contain the up-to-dateproposal, quarterly reviews, work plan and milestones, budget, expenditures,report topic and annotated outline, and press statements.

6. Three useful management charts are milestone, PERT, and bar (Gantt).

7. Project reviews are important to project success and should emphasize find-ings, progress of field studies, reports, needs for assistance, plans for nextquarter, and report review.



8. Each project should conclude with an evaluation of the success and failure ofthe project.

9. The main criterion that brings repeat business is good customer relations,including a quality report that is delivered on time, meets objectives, is wellorganized, and is readable by the intended audience.

Every investigation should have a plan to guide the project fromconception, to development, to the conclusion. The plan can be simpleor complex depending on the objective, the scope of the investigation,the funds and time available, and the people involved. Any plan shouldbe kept as simple as possible to guide the investigation

The project plan should also be flexible to allow for unforeseenevents, windfalls of data, and other information. In some instances,the objectives may need to be revised during the investigation. Thewhole project should be examined periodically to avoid errors inplanning and execution of the investigation.

3.3 Types of Investigations

The scope of an investigation may be classified, on the basis of inten-sity of effort, as

reconnaissance

or

comprehensive

. These terms areused merely to indicate, in a general way, the variation in the scopeof investigations. For example, a contamination investigation is a spe-cial type of comprehensive investigation.

A reconnaissance investigation is made of an area where little ornothing is known of the groundwater resources. Commonly, the objec-tives are to determine the general occurrence and quality of water, theimportance and types of use of groundwater in the area, and the kindsand locations of existing and potential problems, including contami-nation. A rapid reconnaissance may be necessary to determine the needfor a more thorough or particular type of investigation. The areacovered by a reconnaissance investigation might be only a few squaremiles or might include several hundred square miles.

A comprehensive investigation commonly covers an area nolarger than a few hundred square miles, and it can be as small as acontamination site of a few acres or less. The objective of a com-prehensive investigation is to describe the groundwater resources ofthe area both quantitatively and qualitatively. Such an investigationincludes sufficient analysis of recognizable problems so the neces-sary data can be collected and presented in usable form to those whoare responsible for the actual solution of the problems. Ideally, the



relation of groundwater to surface water and the quality of ground-water, including changes owing to development, are determined anddescribed so all of the water resources of the area can be developedfully and efficiently. Rarely is it practical to meet all the objectives.The investigation, therefore, generally is tailored to meet the objec-tives within the limits prescribed by time and funds. If the projectinvolves tracer isotope analysis and hydrochemical modeling, it willtake one to two years to evaluate the hydrogeology.

The length of time and amount of effort required for an investiga-tion depend upon the size of the area, the complexity of the geologicand hydrologic environment, the amount of data readily available, andthe scope of the investigation. Typical studies might last only a fewweeks or months or as long as one year, and the effort required canrange from a few man-months to tens of man-years.

Groundwater problems can be classified as problems of quantity,quality, distribution, and development. Rarely can the problems in anarea be relegated to a single classification, but the terms are useful,nonetheless, for indicating the type of information and investigationthat will be needed for full utilization of the resource.

A

contamination investigation

provides a comprehensive overviewof the hydrogeology and contamination at a site and guidance forfuture investigations. Such investigations commonly are designated asphases 1 and 2.

A

phase 1

investigation might consist of the following elementsor activities:

1. Summarize the available literature.

2. Provide as complete a picture as possible of the basic geologic and hydrogeo-logic environment

• Literature review

• Well inventory

• Site reconnaissance visits and interviews

• Conceptual hydrogeologic model

3. Phase 1 report preparation

The literature review may identify concerns such as presence offaults, pre-existing land uses, potential for reverse groundwater gradi-ent, and the variability of background water quality. It would be helpfulto take pictures at the site, emphasizing plant operations and thestorage of waste. The phase 1 report should make recommendationsfor the placement of phase 2 monitor wells and information about thesampling plan.



A

phase 2

investigation

should provide a detailed description ofthe site to test the conceptual hydrologic model. Monitor wells areinstalled and water levels measured. Water-table contour maps areprepared. Aquifer tests are run to determine hydraulic conductivityand specific yield.

The following table lists actions typically taken at hazardous wastesites in the early 1980s and those recommended in 2002. Two datagaps are the vertical distribution of hydraulic head and hydraulicconductivity values.

Actions taken in the 1980s

• Install a few dozen shallow monitor wells. Sample groundwater numeroustimes for 120 pollutants.

• Define geology primarily by driller’s logs and cuttings.

• Possibly obtain soil and core samples for chemical analysis.

Actions recommended in 2002

• Conduct surface and borehole geophysical surveys (resistively, electromag-netic and ground-penetrating radar), as needed.

• Install depth-specific clusters of monitor wells.

• Initially sample for 120 selected pollutants.

• Sample for aquifer hydrogeochemistry (redox conditions) to evaluate chlori-nated solvent contaminants or some metals.

• Define geology by extensive coring and sediment sampling.

• Evaluate local hydrology with well clusters. Perform limited tests on sedimentsamples.

• The results of laboratory analyses are only as reliable as the samples, fieldstandards, and blanks received. Maintaining representative samples requiresconsideration of well purging, sample collection and sample preservation. Fordetailed information on groundwater data collection see Lapham et al. (1997).

3.4 Objectives of Investigations

The objectives of a comprehensive investigation include a quantita-tive description of the groundwater resources, their quality, and their



relationship to surface water. The following list states the objectivesmore specifically:

1. To determine the hydraulic properties and the dimensions of each unit in thegeologic section, at least down to the deepest source of water usable for anypractical purpose.

2. To determine the source and amount of recharge to each aquifer.

3. To determine the amount and location of discharge from each aquifer.

4. To determine the quality of the water from each aquifer.

5. To determine the effects of withdrawal of water from each aquifer.

6. To determine the effects on surface water of changes in recharge and dischargeof groundwater.

7. To determine the direction of water movement.

8. To determine the effects on groundwater of the changes in surface water.

9. To determine the source(s) and fate of contaminants.

3.5 Sources of Hydrologic Data

The first step in a project is the collection of data and a thoroughsearch of the literature and other sources of information. For example,much information might be stored in the files of public agencies. Aliterature search commonly will yield considerable geologic informa-tion and might give information on well drilling and water develop-ment in the area. In addition to scientific reports, newspaper files andhistorical articles or books might yield significant information. Anexamination of surface water records might reveal areas and magni-tudes of recharge or discharge of groundwater.

A primary consideration in collecting data for a hydrologic inves-tigation is to gather all easily obtainable published materials. Thefirst step is to obtain information on the project area from federal,state, and university sources. The search could start with the USGSand state literature. Useful publications include hydrologic atlases,geologic maps, water supply papers, basic data reports, state (USGS)circulars, open file reports, and water resources investigation reports.Contact the USGS District Office to learn if current investigationsare or have been carried out in the area. Literature searches, bysubject and area, can now be made easily via computer. The librarystaff of the USGS, EPA, or Bureau of Land Management (BLM) canassist with such searches. The following list provides potential datasources for hydrogeologic studies:



Federal agencies — USGS (U.S. Geological Survey), Environ-mental Protection Agency, Bureau of Reclamation, National Park Ser-vice, Bureau of Land Management, U.S. Army Corps of Engineers,Soil Conservation Service (National Resources Conservation Service),Fish and Wildlife Service, Forest Service.

State and local agencies — City and county planning boards,state environmental protection agencies, state geological surveys,state engineer.

Knowledgeable individuals — Past and current land owners, fed-eral agency personnel, local well drillers, consulting engineers, plantmanagers, neighbors.

State and federal projects — Site-specific assessment data fordams, harbors, river basin impoundments and highways.

American Geological Institute — Directory of Geoscience Depart-ments, GEOREF (bibliographic database).

Government and university libraries — USGS libraries in Reston(VA), Menlo Park (CA), and Denver (CO), USGS web site(www.usgs.gov), EPA libraries in Washington, D.C. and regional andresearch offices in Cincinnati(OH), Athens (GA), Las Vegas (NV), andAda (OK).

Computerized online databases — DIALOG (800-dialog) pro-vides access to over 420 databases from many disciplines, includingGEOREF, book reviews, biographies, and access to newspapers,journals and other sources; Earth Science Data Directory (ESDD)at USGS (703–648–7112) contains geologic, hydrologic, carto-graphic and biological information. Real-time hydrologic data areavailable for each state and web sites are available for each USGSDistrict offices.

Topographic data sources — USGS Branch of Distribution andEarth Science Distribution Center (800-USA-MAPS) have map datain both graphical and digital form. Many topographic maps are avail-able online.

Aerial photographs — Earth Resources Observation System(EROS) data center USGS Sioux Falls, SD (605–594–6151), aerialphotography obtained by the USGS and other federal agencies andLandsat satellite imagery. Mosaic and aerial photographs can also beobtained from the USGS map sales office in Denver.

Soils — USDA Soil Conservation Service county-level soil sur-veys, available for about 75% of the country.

Geophysical maps — USGS Denver CO has aeromagneticmaps, magnetic delineation, landslide information, and earthquakedata.



Hydrologic information reports — Water Data Information Coor-dination Program (703–648–6810) of the USGS in Reston, VA, haspublications on recommended methods for water data acquisition andguidelines for determining flood frequency.

USGS also has the National Water Data Storage and RetrievalSystem (WATSTORE) for surface-water and water-quality files andthe Office of Water Resources which publishes water-resourceabstracts from throughout the world.

Water Resource Discipline offices in all 50 states have statelevel water resources investigation reports and data on groundwater,surface water and water quality and USGS publications — watersupply papers, hydrologic atlas reports, ground water atlases, pro-fessional papers and fact sheets, state geological surveys. Statewater resource agencies have well logs, well permits, stream flowrecords, drilling permits. National Groundwater Information of theNational Water Resources Association, Dublin, Ohio, has an onlinebibliographic database.

Climatic data: National Climatic Data Center in Battery Park,Asheville, NC, collects and catalogs nearly all U.S. weather records.

3.6 Hydrologic Web Sites

The following is a partial listing of key hydrogeologic informationWeb sites.

Aerial photographs and maps: www.aerotoplia.org

American Geological Institute: www.agi.org

American Geophysical Union: www.agu.org

American Institute of Hydrology: www.aih.org

American Society for Testing and Materials: www.astm.org

American Water Resources Association: www.awra.org

U.S. Army Corps of Engineers: www.usaec.army.mil

Elements of Style: www.bartleby.com

Environmental Protection Agency: www.epa.gov

Geoscience Information Society: www.geoinfo.org

Government printing office: www.access.gpo.gov

Ground water information: www.groundwater.com

International Association of Hydrogeologists: www.iah.org

Merriam Webster Dictionary: www.m-w.com



National Climatic Data Center: www.ncdc.noaa.gov

Office of Surface Mining: www.osmrc.gov

U.S. Geological Survey (USGS): www.usgs.gov

3.7 Geographic Information Systems

A computer program called a geographic information system (GIS)can be used to store large amounts of data from a project and tostore, analyze, and display geographic information in multiple layers.The program is based on maps of different features: topography,water table, well locations, location of buildings, and hydrologicfeatures.

ReferencesASTM, 1995, D 5753 Guide for planning and conducting borehole geophysical

logging.ASTM, 1996b, D 5979 Guide for conceptualization and characterization of

ground-water flow systems.ASTM, 1999, D 6063 Guide to selection and methods for assessing ground water

or aquifer sensitivity and vulnerability.ASTM, 1996c, D 5980 Guide for selection and documentation of existing wells for

use in environmental site characterization and monitoring.ASTM, 1996d, D 6000 Guide for the presentation of water-level information from

ground water sites.ASTM, 1994, D 5612 Guide for quality planning and field implementation of a

water quality measurement program.Drucker, Peter, 1964, Managing for Results, Harper & Row, New York, 240 p.Koterba, M.T. et al., 1995, Ground-water data-collection protocols and procedures

for the national water-quality assessment program: collection and documen-tation of water-quality samples and related data. U.S. Geological SurveyOpen-File Report 95–399.

Lapham, W.W., Wilde, F.D., and Koterba, M.T., 1997, Guidelines and standardprocedures for studies of ground-water quality: selection and installation ofwells, and supporting documentation. U.S. Geological Survey WRI Report96–4233.

Moore, John E., 1991, A Guide for Preparing Hydrologic and Geologic Projectsand Reports, Kendall/Hunt Publishing Co., Dubuque, IA.



McGuinness, E.L., 1969, Scientific or rule-of-thumb techniques of ground-watermanagement-which will prevail? U.S. Geological Survey Circular 608, 8 p.

USGS, 1991, WRD project and report management guide, U.S. Geological SurveyOpen-File Report, 91–224, 152 p.


47

4

Chapter

Field Investigations

4.1 Conceptual Model

A conceptual model of a hydrologic system should be a clear, quali-tative, physical description of the operation of the system. A hydrol-ogist’s conceptual model determines the direction, focus, and specificcontent of the investigation. The model consists of maps and cross-sec-tions showing the subsurface geology, distribution of recharge, flowpaths, and discharge. If the conceptual model does not accuratelyrepresent the operation of the real hydrologic system, then the resultsof the investigation will at best be misleading and at worst grossly inerror. The steps for developing a conceptual model are

1. Determine the type and distribution of recharge areas: infiltration from pre-cipitation and surface water bodies, irrigation, and leakage from other aquifersor adjacent areas.

2. Determine the type and distribution of discharge: to springs, seeps, streams,and lakes, by evapotranspiration and by leakage to other aquifers and wells.

3. Describe the head distribution (both vertically and areally) and flow anddirection in three directions.

4. Show the distribution and extent of the principal aquifers and confining bedswith maps and sections.



5. Estimate hydraulic properties of the aquifers (specific yield and hydraulicconductivity).

6. Evaluate the response of the system to withdrawal or other stresses.

Examples of conceptual models in different hydrogeologic settingsare shown in Figures 4.1, 4.2, and 4.3.

FIGURE 4.1

Unconfined aquifer hydrogeologic section (Colorado).

FIGURE 4.2

Confined aquifer hydrogeologic section (Florida).

FIGURE 4.3

Groundwater mining hydrogeologic section (Colorado).

SIDEINFLOW

WATERTABLE R

IVE

R

CA

NA

L

CA

NA

L

BEDROCK

SALTWATER

WATERTABLE

GULF OF MEXICO

SINKHOLE LAKE

CLAY CONFINING BED

UNCONFINED AQUIFER

CONFINED AQUIFER

FRESH WATER

BEDROCK

OGALLALA

RIV

ER


Field Investigations 49

4.2 Preliminary Site Reconnaissance

A field site reconnaissance is the first step in a hydrogeologic field inves-tigation. It provides a preliminary evaluation of the hydrogeologic condi-tions at the site. These site visits are interesting, exciting, and challengingbecause they are like a detective investigation. At the beginning there aremany unknowns that have to be determined by scientific investigation.This aspect is especially true for evaluations at contaminated sites.

Site investigations are conducted for almost all hydrogeologicprojects, such as investigation for water supply, geological engineeringconstruction, real estate transfer, groundwater contamination, or ground-water remediation. The planning of the field investigation is determinedby the project objectives, but many elements are common to all studies.Field data collection is the most expensive part of the project. Geophys-ical surveys, well inventory, aquifer tests, laboratory tests, monitor wells,borehole logging, and test drilling are expensive and time consuming.It is the responsibility of the project chief to keep these costs to aminimum and still accomplish the objectives of the project.

ASTM standards are available for investigation of soil, rock andgroundwater projects. They are intended to improve consistency ofhydrologic data and to encourage organized planning of site charac-terization. An adequate and organized exploration program is neededbecause the hydrogeologic conditions at a specific site are the resultof a combination of natural, geologic, topographic, and climatic fac-tors, complicated by man-made modifications.

Suggestions for Planning a Field Investigation

Develop a preliminary site investigation that includes geophysicalsurveys and field sampling and collection of hydrologic and otherinformation to define and refine the conceptual model of the site. Afterthe preliminary site investigation is completed, a detailed site investi-gation can be planned, if necessary.

1. Include in the site history information on where commercial and industrialactivity has taken place. The site history should include location of buildings,storage tanks, and transportation facilities (pipes, trucks, trains etc.), andchemicals manufactured or used in manufacturing.

2. Study the soil and rock outcrops in the project area. Take pictures, makesketches, and take notes about relevant features and conditions (rocks, vege-tation, drainage, man-made structures, facilities, etc.).



3. Compile a preliminary map of the area using topographic maps and aerialphotography. Plot the location of wells, springs, streams, vegetation and wet-lands. The field site reconnaissance gives an opportunity to check the accuracyof the map that was compiled in the planning phase. It is also an opportunityto refine the conceptual model of the area. Site features that require furtherinvestigation should be identified (ASTM 1996 Guide D 5979).

4. Select methods and dates and frequency of field data collection periods. Accu-rate elevation data and x-y coordinates are critical in the data compilationsand accuracy of interpretations. Develop a detailed site-sampling plan thatincludes a description of the methods to be used to collect and analyze fielddata, establishes protocols for sampling and field measurements and chain ofcustody procedures to ensure quality assurance and quality control.

5. Make preliminary geophysical surveys to select sites for additional test drilling,if necessary.

6. Identify the type and extent of contaminants present.

7. Visit municipal or county government offices to obtain valuable informationon the area. Visit the local university or public library to find publications onprevious studies. A trip to the local USGS district or subdistrict office canhave a large technical payoff. Inquire about current projects in the area andmeet with the project chief. This information can also be obtained on theUSGS web site. Visit the USDA office to obtain soil maps of the study area.

8. Take water-level measurements and water-quality samples.

9. Prepare preliminary water table contour maps and determine flow directions.

Site Visit

After the office review of historical records and documents and thetitle search to identify previous owners of the property are complete,the hydrogeologist returns to the site and interviews employees andneighbors to learn about the present and past history. A walk-throughis made to confirm the document records — the hydrologist walks theentire site, noting natural as well as constructed features, includingdepressions, canals, mounds, waste pits, and lagoons. Close attentionshould be given to discolored soil and oil stains.

Springs Investigation*

Springs are an important source of hydrogeologic information. Aspring is a natural groundwater discharge at the land surface. Springs

* The information in this section is taken from Moore, J.E. et al.,

Field Guide to Evaluate Springs

,USEPA, 2002, in preparation.



may be classified according to their geologic formation, the quantityof discharge, water temperature and gravity and/or artesian.

Springs have been important in the social, cultural, and economichistory of mankind. They have been an important source of water forpeople. Our ancestors did not have drilling equipment, so in theabsence of surface water they had to rely on springs. Many early townsin Greece, Egypt, Mesopotamia, India and China developed aroundsprings. Many towns in the United States have taken their name fromsprings, such as Steamboat Springs, Colorado; Glenwood Springs,Colorado; Springfield, Missouri; and Rock Springs, Wyoming.

For centuries, hot springs and mineral springs were thought to beof medicinal or therapeutic value. Many people still consider bottled“spring water” of higher quality than ordinary tap water. This beliefis at least partially responsible for the current high volume sales ofbottled water. This association of spring water with purity is not basedon fact. Spring water can contain higher concentrations of dissolvedsolids than local public water supplies, and many types of springs areeasily contaminated. Spring water is generally more easily contami-nated than wells because many springs are open, unprotected andaccessible to human beings and animals. Contamination may alsooccur from surface–water runoff into spring collection systems.

In 1992, more than 3400 public water supply systems in the UnitedStates obtained part or all of their drinking water from springs. Thesesystems provide drinking water for more than 7 million people. How-ever, the average number of people served by a single public supplysystem utilizing springs as a water source is small. Springs are animportant component of the drinking water supply in many states.Public water supplies that utilize springs are more numerous in thewestern United States. More than 200 public systems use springs ineach of the states of Colorado, Idaho, Oregon, Utah, and Washington.There are several states in which more than 100,000 people are servedby public systems that include springs. In the state of California, morethan 4 million people (14.2% of the population in 1990) received theirdrinking water from systems with springs. In Hawaii, Tennessee, andVermont more than 10% of the population is served by public waterusing springs. In Tennessee and Pennsylvania, more than 500,000people receive their domestic water supply from springs. Wyominghas 80 springs that are used for public water supply.

A spring is where water flows naturally from an aquifer or soil onthe land or into a body of surface water. Springs occur in many formsincluding (1) those resulting from gravitational forces and (2) thoseresulting from nongravitational forces (artesian). Springs are replen-



ished by precipitation that recharges aquifers. The precipitation seepsinto the soil and enters fractures, joints, bedding planes or pore spacesin sand aquifers and sedimentary rocks. Springs occur where waterflowing through aquifers discharges at the land surface through faults,fractures, or by flow along an impermeable layer. They may also occurwhere water flows from large orifices that result when the water dis-solves carbonate rock, enlarging fractures or joints to create a passage.

Springs are generally listed as gravity springs and artesian springs.Thermal springs typically are considered as a type of artesian spring. Thevast majority of springs are gravity springs. Gravity springs are createdby water that moves down gradient (downhill) emerging at the surface.Artesian (nongravitational) occur where the potentiometric level of thegroundwater system is above the land surface and water flows at the landsurface under pressure either at the aquifer outcrop or from fractures orfaults. Water is sometimes forced to the surface along a fault from deepsources by thermal pressure gradients. Springs associated with volcanismand fractures that extend to great depths in the earth’s crust.

Springs are a common feature in some hydrogeologic settings.They are common in mountains in watersheds that are underlain byfractured rock aquifers. They are also a common feature in karst areas(limestone).

Springs can be regional (long flow paths) or local (short flowpaths). Local springs are comparatively small, can have low flow, andare typically from shallow aquifers. The discharge from these springsoften fluctuates either seasonally or in greater cycles, sometimes inresponse to local precipitation. Local aquifers are quickly rechargedand water movement through them is comparatively rapid, resultingin low water mineralization. Springs supported by local aquifers aremore likely than regional flow springs to periodically stop flowing.Regional springs are more typically large discharges of nearly constantdischarge and are more mineralized than local springs. Spring tem-peratures can be cold or warm depending on the depth of circulation.Regional springs rarely stop flowing even during long droughts.

The discharge rate of a spring is a function of three main variables:(1) hydraulic conductivity of the aquifer, (2) area contributing rechargeto the aquifer, and (3) quantity of recharge. The recharge area for aspring ranges from a few thousands of square feet to as much as 4000square miles.

Springs are also classified based on hydrogeologic characteris-tics. The Water Resources Division of the United States GeologicalSurvey recognizes eight principal types of springs based on hydro-geologic characteristics:



1.

Artesian spring —

release of pressurized water from a confined aquifer atthe aquifer outcrop or through an opening in the confining unit.

2.

Depression spring —

is formed when the water table intersects a steeplysloping land surface. This type of spring is sensitive to seasonal fluctuationsin groundwater storage, and frequently disappears during dry periods.

3.

Fracture spring

(fault spring)

—

is formed in fractured or jointed rocks. Watermovement through fractures and springs form where the fractures intersectthe land surface. This type of spring is particularly sensitive to seasonalfluctuations in groundwater storage, and frequently disappears due to reducedflow during dry periods. Daily fluctuations of discharge of small springs arecommonly the result of use of water by vegetation.

4.

Contact spring —

occurs where a permeable water-bearing unit overlies aless permeable unit that intersects the ground surface.

5.

Geyser spring —

periodic thermal spring resulting from an expansive forceof superheated steam within constricted subsurface channels.

6.

Perched spring —

occurs where infiltrating water discharges above theregional water table from a permeable geologic unit.

7.

Seep spring —

discharges from numerous small openings in permeable mate-rial. Seep springs typically have a very low discharge rate.

8.

Tubular spring —

discharges from rounded channels (karst solution openings,lava tubes).

Springs occur in many sizes, types of discharge points, and loca-tions with respect to topography. They occur in the highest elevationsof mountainous areas to valley floors. Many of the public water supplysprings in the western United States are small with discharges of lessthan 5 gallons per minute. Springs vary in their physical and chemicalcomposition. They can be cold (50°F) or hot (more than 90°F). Shallowsprings usually have a temperature within a few degrees of ambientair temperature. Higher temperatures usually indicate deeper regionalcirculation. Thermal springs gain their temperature increases when thewater comes in contact with recently emplaced igneous masses. Ther-mal and hot springs result from deep-seated thermal sources and areclassified as: volcanic springs or fissure springs. Springs may occursingly or in groups that may include dozens of habitats in various sizes.

Springs may be highly mineralized especially thermal springs andsometimes regional springs that have a very long flow path. Thermalsprings have pH values ranging from 7.2 to 7.6. Electrical conductanceof spring water ranges from 2 milligrams per million to 10,000.

When a spring is developed as a public drinking water supply,measures must be taken to protect the purity of the water. Contam-ination of groundwater discharging at a public water supply springcan result from infiltration from outhouses, sewers, septic tanks,



concentrated livestock areas, underground storage tanks, or nearbycommercial facilities (dry cleaners, auto repair, etc.). This puts asignificant importance on delineating the recharge area over thespring. Springs that are not adequately protected can be impactedby surface water runoff that has been contaminated by nonpointsource contamination (agricultural contaminants, urban runoff, etc.).

A spring box or tank is a common way to protect the spring fromcontamination. The box is constructed in place with reinforced con-crete to intercept as much of the spring flow as possible. When a springis on a hillside, the downhill wall and sides are extended downwardto bedrock or another lower permeability unit to ensure that the struc-ture will hold back water to maintain the desired level in the chamber.

Supplementary cutoff walls of concrete may be used to assist incontrolling the water level in the vicinity of the spring box. The lowerportion of the uphill wall of the tank must have an open constructionto allow water to move in freely, while the aquifer material is heldback. Back filling with graded gravel will aid in restricting movementof aquifer material. The box covers should be placed to ensure a goodfit. The cover should extend down over the top edge of the tank (shoebox lid) at least 2 inches, and should be heavy enough to preventdislodging and should be lockable. A drainpipe with an exterior valveshould be placed close to a wall of the tank at the floor level to permitdraining. The end of the pipe should extend far enough to allow freedischarge to the ground surface away from the tank.

The discharge end of the pipe should be screened to prevent nestingby insects and animals. The overflow should be placed slightly belowthe maximum water-level elevation in the collection system. The over-flow should have a free discharge to a drain apron of rock to preventsoil erosion and should be screened.

People often modify springs in order to flow or create collectionsystems. A number of different types of collection systems are utilizedto collect and distribute. Spring flow is collected by a variety ofmethods: collection pipe, collection by controlling discharge, extrac-tion by shaft or collection gallery, and extraction by a well as follows:

Collection pipe —

The spring flow is intercepted by a perforatedpipe(s) driven into the aquifer. The flow can be directed into a storagetank or a watertight concrete collection chamber. The watertight wallsof the collection chamber should extend at least 8 inches above theland surface to prevent entrance of surface water.

Collection by controlling discharge —

For some large karst orfracture springs where it is difficult to collect the spring water at thedischarge point, a grout curtain can be installed to collect the spring



water through a device such as a vertical well. The construction canresult in increased storage of water

Vertical shafts to intercept spring water —

One or more hori-zontal conduits are bored onto the base of the aquifer shafts and areused to drain the spring into these horizontal conduits.

Extraction by well —

A well can be drilled up gradient from thespring and pumped to intercept the spring flow. Properly constructedwells can provide total isolation of the water from surface water andprevent the introduction of contaminants from surface sources. Thestate of Tennessee requires that if a spring is directly influenced bycontaminated surface water, modifications must be made to the systemor a properly constructed well must be installed that is either deeperor at a different location.

It is very important to determine the hydrogeologic setting fora public water supply spring. This is essential to conduct an ade-quate sanitary survey, to develop and to design and implementprotection strategies.

When possible the following information should be collected whena field evaluation of a spring is made (Sanders, 1998):

• Topographic setting (hilly, mountain, desert playa)

• Collection device (vertical shaft, horizontal well)

• Extent of wetted area

• Hydrogeology of springs

• Rock types

• Nature of aquifer from which spring discharges

• Presence/absence of confining units

• Type of spring

• Size and location of recharge area

• Type and magnitude of discharge (seep or tubular)

• Vegetation type and condition

• Photograph of spring (to help evaluate seasonal changes)

• Collect water quality sample to be analyzed for coliform (Field measurementsof conductance, temperature, pH)

• Tracer studies to identify groundwater flow paths

The following is a list of questions about springs:

1. What is the location and size of the recharge area (trees, crops, crass)?

2. Is the recharge area protected with fencing?



3. Is the site subject to flooding? If so, is there a diversion ditch? Is the diversionditch around the upper end of the spring area to divert surface water runofffrom flooding downhill to the spring? Is the supply intake properly locatedand screened?

4. Has a dye test been conducted to determine potential breakthrough?

5. Has a Microscopic Particulate Analysis (MPA) been made to determine if thespring is under the direct influence of surface water?

6. Is the collection area adequately protected?

7. Is the supply intake adequate? The supply intake should be 6 inches abovethe floor of the chamber and should be screened. This reduces the introductionof sludge that may build up in the chamber.

8. Is the collection chamber properly constructed? The collection chambershould be watertight to prevent inflow of unwanted water. The cover shouldbe impervious and lockable. The drain outflow should have a screenedexterior valve.

9. Are there conditions that may cause changes to the quality of the water?Identify possible sources of contamination. An increase in turbidity or flowafter rain is an indication that surface runoff is reaching the spring, andshort-circuiting the natural filtration by the aquifer.

10. Is the spring area protected from animals?

11. Is there an impervious barrier over the spring area to keep out rainwater andcontamination?

12. Is the spring box watertight with a lockable, watertight lid or cover?

13. Does the spring meet state requirements for setbacks from sanitary hazards(50 feet for septic systems, 100 feet for cisterns)?

14. Has the spring source been tested by a certified laboratory for bacteria, nitrates,and other constituents of concern?

15. Does the area around the spring slope to drain surface runoff away from thespring?

16. Is there deep-rooted vegetation around the collection chamber, which couldserve as conduits for surface-water flow down to the collection chamber?

17. Has a protection area been delineated for the spring? Is it available?

Hazardous Waste Site Investigation

Many factors influence the selection of a site for a landfill, such aspublic concerns, rainfall, runoff, and air quality. However, two of themost critical concerns are geology and hydrology. Consequently, themost important element in this type of site investigation is the devel-opment of a conceptual hydrogeologic model.



Hazardous waste site investigations can be divided into threephases: Phase I — desk studies; phase II — field investigations,data analysis, and monitoring design and installation; phase III —remediation.

Phase I investigations (Figure 4.4) are designed to provide acomprehensive overview of available information on the site. It canbe conducted as the first step in a Superfund Remedial Investiga-tion/Feasibility Study (RI/FS). Phase I provides a summary ofknown site features for planning. The elements of a phase I inves-tigation are

• Literature review and conceptual hydrogeologic model

• Well inventory

• Site visit

• Phase I report

Information from the phase I investigation is used to developthe conceptual model of the hydrogeologic conditions. This modelis the essential element for planning field investigations in phase II.The final conceptual model will make apparent the need for addi-tional verification data and the desired locations of phase II moni-toring wells.

Phase II field investigations (Figure 4.5) consist of detailed fielddata collection and measurements, data analysis, and monitoring wellinstallation. The following specific activities are included:

Map and describe site lithology and geologic structure

Install piezometers

Measure water levels

• Literature review

• Well inventory

• Site visit

• Flow analysis

• Conceptual model

• Phase I report

FIGURE 4.4

Phase I investigation.



The data analysis phase has the following elements:

Refine conceptual model

Prepare water table contour map

Analyze and refine description of flow system

The monitoring system design phase consists of

Selecting target monitoring zones

Selecting monitor well depth

Establishing well locations

Installing monitor wells

Testing and operating system

Phase III investigations consist of developing and carrying out aremediation plan that is pump-and-treat and/or bioremediation.

4.3 Geophysical Survey Methods

Geophysical surveys assist in the placement of test holes, pumpingwells, and monitor wells. Geophysical methods are essential at mostcontaminated sites to avoid hazardous drilling locations. For more

• Field investigations

– Install piezometers

– Measure water levels

• Data Analysis

– Prepare water table contour map

– Define flow system

• Monitoring Well Design

– Target zones

– Monitor well depth

– Well locations

– Install monitor wells

– Test and operate system

• Phase II report

Figure 4.5

Phase II investigation.



detailed information, refer to Zody et al., 1974; USEPA, 1978; Benson,1983; National Water Well Association, 1985; USGS Branch of Geo-physics web site: water.usgs.gov/ogw/bgas. The various types of geo-physical surveys and their application to hydrogeologic investigationsinclude surface geophysics and electrical resistivity.

Electrical resistivity measurements can be useful for determiningsubsurface characteristics for highway construction and dam site loca-tion. Earth resistivity methods assist in distinguishing subsurface mate-rials without requiring physical excavation. Resistivity can helpcharacterize material as clay, silt, sand, gravel or consolidated rock.The moisture content of the rock and the specific conductance of thegroundwater cause variations in the electrical resistivity of the rock.

Electrical resistivity method is useful for

Subsurface stratigraphy

Mapping contaminant plumes

Locating abandoned wells

Mapping freshwater and saltwater

Indicating fracture orientation

Electromagnetic induction method is used in the following tasks:

Mapping conductive organic contaminant

Locating buried utilities, tanks and drums

Locating abandoned wells

Subsurface stratigraphic profiling

Locating freshwater/saltwater interface

Seismic refraction and reflection methods are useful for

Mapping top of bedrock and buried channels

Measuring depth to groundwater

Indicating fracture orientation

Subsurface stratigraphy

Ground penetrating radar method is used for the following tasks:

Locating buried objects

Measuring depth to shallow water table

Detecting buried containers and leaks

Delineating solution channels and cavities (karst)



Magnetometry method is used to locate the following items:

Buried steel containers (55-gal drums)

Abandoned wells

Pipes and tanks

Metal detectors method is used to locate the following items:

Metallic containers

Buried metallic tanks and pipes

Abandoned wells

Gravity method can be used for the following tasks:

Locating buried alluvial sediments in bedrock

Delineating subsurface cavities

Estimating recharge and specific yield

Borehole geophysical method is used to identify the following:

High permeability zones

Salinity zones

Water quality

Lithologic correlation

References

ASTM, 1993, D 5474, Standard guide for selection of data elements for ground-waterinvestigations.

ASTM, 1995, D 5777, Standard guide for using the seismic refraction method forsubsurface investigation.

ASTM, 1996, D 5979, Guide to conceptualization and characterization ofground-water flow systems.

Fetter, C.W., 2001,


, 3rd Ed., Prentice Hall, Upper SaddleRiver, NJ.

Duttro, J.T. et al., 1989,

AGI Data Sheets for Geology in the Field, Laboratory andOffice

, American Geological Institute.Driscoll, Fletcher G., 1986,

Groundwater and Wells

, Johnson Division, St. Paul,MN, 1108 p.



Keys, W.S. and MacCary, L.M., 1971, Application of borehole geophysics to waterresources investigations.

In USGS Techniques of Water Resources Investiga-tions

, 126 p.McGuinness, E.L., 1969, Scientific or rule-of-thumb techniques of ground-water

management: which will prevail? USGS Circular 608, 8 p.Moore, J.E. et al., 2002,

Field Guide to Evaluate Springs

, USEPA, in preparation.Sanders, Laura L., 1998,

Field Hydrogeology

, Prentice Hall, Englewood Cliffs, NJ,381 p.

Sara, Martin, 1989,

Site Assessment Manual

, Waste Management of North AmericaInc.

Summers, Paul, 1985,

Guidelines for Conducting Ground-Water Studies in Supportof Resource Program Activities

, U.S. Department of Interior, Bureau of LandManagement.

USEPA, 1978,

Electrical Resistivity Evaluations at Solid Water Disposal Facilities

:USEPA Report SW-729.

USEPA, 1991,

Site Characterization for Subsurface Remediation

, Office of Researchand Development, EPA/625/4–91/026.

USEPA, 1993,

Subsurface Characterization and Monitoring Techniques, Vol. I:Solids and Ground Water Appendices A and B

. Center for EnvironmentalResearch Information Cincinnati, OH, EPA/625/R-93/003a.

USEPA, 1993,

Subsurface Characterization and Monitoring Techniques, Vol. II: TheVadose Zone, Field Screening and Analytical Methods Appendices C and D.

Weight, W.D. and Sonderegger, J.L., 2001,

Manual of Applied Field Hydrogeology

,McGraw-Hill, New York, 608 p.

Zody, A., Eaton, G. and Mabey, D.R., 1974,

Application of Surface Geophysics toGround Water Investigations

, U.S. Geological Techniques of Water-ResourcesInvestigations.


63

5

Chapter

SubsurfaceInvestigations

Fieldwork for a hydrogeologic investigation can be divided into severalphases: geologic mapping, well inventory, well logging, observation ofwater levels, water sample collection for chemical analysis, data collec-tion on pumpage amount and water use, test drilling, and aquifer tests.Some of these activities can be undertaken simultaneously, for example,inventorying of wells, measurement of water levels, and collection ofwater samples. Some phases, however, may be interdependent. Theamount of test drilling needed will depend on number and location ofexisting wells and the adequacy of information on them.

5.1 Geologic Mapping

Geology is the key to any groundwater investigation. It follows, therefore,that geologic mapping, of both the surface and subsurface, would be oneof the first field phases of an investigation. In most areas, some geologicmapping has been completed and serves as a basis for that required in agroundwater study. Particular attention is paid to the geologic units thatwill most affect the occurrence, movement, and quality of groundwater.

At the start of many investigations, subsurface mapping of aquiferthickness and configuration is often lacking. The subsurface is mappedfrom logs of wells and, in some places, with the aid of geophysicalsurvey techniques. The logs collected from well drillers, well owners,public-agency files, and oil and gas exploration companies are useful.If possible, wells for which no logs are available should be logged by



geophysical equipment and correlated with known geology in thevicinity of the well.

5.2 Well Inventory

A well inventory is a detailed listing of all known wells, test holesand springs in the project area (Figure 5.1). The list is made bycontacting well owners, well drillers, state engineer, U.S. GeologicalSurvey (USGS) and other federal agencies. The well inventoryincludes those abandoned as well as those in use. Each entry shouldbe assigned a unique number. In some cases the number will be thelatitude and longitude. The inventory for each well should includename and address of site, map reference, well construction informa-tion, water level, drilling method, diameter, depth, screen, aquiferdescription, geology, water quality, yield, and annual withdrawal.

While the geology is being mapped, the existing wells and springsin the area are examined — i.e., the area is visited and all informationis recorded relative to elevation, depth, diameter, location, age, waterlevel, pumping rate and drawdown, use, and formations penetrated.Water samples are collected from wells and springs that are represen-tative of aquifers and are then sent to a laboratory for analysis. If awater quality problem is known or suspected, partial analyses may bemade in the field to determine the best locations for more extensiveand detailed sampling (Figure 5.2).

In addition to the water level measurements made at the time wellsare inventoried, water levels in selected wells are measured periodi-cally, and automatic recorders are installed on some to determinemagnitudes of fluctuations. Also, owners of irrigation wells are can-vassed to determine the amount and rate of withdrawal of water fromthe area. Well owners can be a good source of information to locateexisting and abandoned wells in the area. Geographic positioningsystems (GPS) can be very helpful in determining location and altitude.

5.3 Monitor Wells

Monitor wells are designed to obtain representative groundwater infor-mation and water quality samples from specific aquifers at selecteddepth intervals. Monitoring wells constructed and developed followingstandard practice should produce relatively turbidity-free samples


Subsurface Investigations 65

Date _________________________Field Number ___________________Recorded by ___________________ Source of data__________________ USGS quad sheet location: State ___________ County _____________________ 1/4 _________ 1/4 SEC ________ T _________ R ___________

Owner _______________________Address ________________________Tenant _______________________Address ________________________Driller ________________________ Topography ____________________Elevation _______________________Drilling method ________________Depth __________________________Casing: Diameter _______________Inch type _______________________

Depth to _______________Finish__________________________Aquifer _______________________Water level _________ Date ___________ _______ Below/above surfacePump _____________ Power __________Yield ____________________Use of water ___________________Adequacy _______________________Quality _______________________Temp __________________________Remarks ____________________________________________________

FIGURE 5.1

Well inventory form (U.S. Geological Survey).

• Team members

• Purpose of sampling

• Location (topographic map)

• Type of site

• Name and address of field contact

• Date and time of sample collection

• Weather conditions

• Purging information

• Sampling device

• Sample containers

• Sample treatment

• Photograph

FIGURE 5.2

Items listed in a field notebook.



(Figure 5.3). A suggested monitor well design is given in ASTM, 1990D 5092, page 952, and a detailed discussion of monitor well construc-tion is given in Nielsen (1991).

The objective is to construct a well in which you can have confi-dence in the water level and water quality samples. The purpose forthe monitor well (or monitor well program) must be well defined toachieve the given objectives. The following list provides some of theinformation that is needed for a monitoring project:

How many aquifers?

Where is the contamination?

Are there perched zones?

What is the nature of the contaminant?

Where are the recharge and discharge areas?

FIGURE 5.3

Monitor well (from Driscoll, F.G., 1986.


, 2nd Edition. Withpermission).

Concretesurfaceseal

Cementgrout

Wellscreen

Bentonitepellets

Filterpack

Ventedlockingprotectivecover

Aquifer



5.4 Test Drilling and Examination of Drill Cuttings

If the data from existing wells are so incomplete that interpolationand interpretation cannot fill the gaps, it might be necessary todetermine the lateral extent of formations, to obtain samples of rocksand water, or to provide wells for conducting pumping tests. Inalluvial-filled valleys, it is generally desirable to drill rows of testwells perpendicular to the axis of the valley. Preliminary surface-geo-physical surveys should be used to help determine the location oftest wells.

Detailed information on the hydrogeology for an area usually canbe obtained only by drilling test holes and wells. The value of theinformation depends on the care exercised in collection of the cuttings,sample collection, and examination, and on the accuracy and com-pleteness of the description of the sample. The more subsurface infor-mation gathered for the area, the better the understanding of thegeology and the greater the success in locating groundwater supplies(Bentall, 1963). It is helpful to be familiar with different drillingmethods before attempting to log your first test hole. You will need toknow how the cuttings are moved to the surface. For example, asdrilling proceeds, the cuttings near the drill bit are mixed with cuttingsfrom earlier drilling. This yields a mixture of cuttings that you mustinterpret. A hand lens, and in some cases a microscope, should be usedto examine the cuttings. A field geotechnical gage (W.F. McCollough,Beltsville, MD) should be used to describe the color and grain size(sieve size) for consistency. When preparing the lithologic log, therock type is recorded first (sandstone, shale, limestone, etc.), followedby the color of the rock. The Wentworth grade scale is used to deter-mine the size of particles.

The following information should be shown on the log:

• Driller, agency or consultant

• Location and number of the well

• Start and end date of well drilling and completion

• Depth of well

• Depth to water

• Results of pumping or bailing tests

• Temperature and water-quality field data

• Depth to “first water”



Another objective of the test drilling is to identify when water isfirst observed and where it might be coming from. The hydrogeologistshould measure water level in the test hole at the start of each day.

5.5 Water-Quality Sampling and Field Measurements

The chemical character of groundwater is studied for various reasons:to determine the suitability of the water for drinking water supply,irrigation, and commercial use; to establish background conditions(pristine or altered by man), to detect the presence of contaminants,and to monitor the effectiveness of remediation. When samplingstreams and springs it is important to collect the sample from a freelyflowing area as close to the source as possible. In sampling wellwater must be purged from the well to get rid of “old” water thathas been standing in the well. Ideally one should flush three timesthe volume of the bore hole. This means pumping the well at least30 minutes depending on the diameter of the well and depth to thewater table. The number of well volumes that should be removed toremove stagnant water is controversial. If the sample contains visibleundissolved solids it should be passed through a pump filter. Allsamples should marked immediately with the date and location.Sample bottles should be completely filled with water and containno water bubbles. In some cases acid is added to some of the samplebottles to preserve the sample.

Groundwater sampling is more complicated than just removinga volume of water from a monitor well, pouring it into a samplecontainer, and shipping it to a laboratory for analysis. Samples mustbe representative of

in situ

conditions. Errors may result or contam-ination introduced by the material and methods employed in sam-pling or in sample analysis. The spatial and temporal heterogeneityin the hydrology and geochemistry of the groundwater environmentcan also affect the chemical character of the water. Materials forwell construction and sampling equipment should be selected so asnot interact or interfere with the constituents being analyzed. Therecommended materials for sampling applications are Teflon (flushthreaded), Stainless Steel (flush threaded), and PVC (flushthreaded).

Tests for groundwater quality made in the field are temperature,dissolved oxygen (DO), pH, and specific conductance.



Temperature —

Changes in temperature may indicate an inflowof surface water into the well.

Dissolved oxygen (DO)

— DO is an important hydrochemicalparameter for surface water and groundwater. Aquatic fauna need DOto survive, and generally the higher the reading, the better the quality.Measurements should be made with a field kit immediately after thesample is taken.

pH

— For measuring pH, the meter must be carefully calibratedwith standard buffers of pH 4, 7, and 10 before a measurement istaken. Failure to calibrate will result in meaningless data.

Specific conductance

— Specific conductance is the numericalexpression of the ability of the water to conduct an electrical current.Conductance measures the total dissolved ion concentration in water.Field determinations of specific conductance can aid in choosingadditional sampling sites and frequency of sampling. Conductancemeters should be battery operated, equipped with a temperaturecompensation, and read in micro-omhs at 25 centigrade. The con-version factor from conductivity to total dissolved solids is TDS =Asc A = 0.5 and 0.75.

When sampling stream and springs, it is important to collect thesample from a freely flowing water and as close to the source aspossible. When sampling a stream hold the open end of the bottledownstream and cap it underwater to help eliminate air bubbles. Whensampling in a lake, invert the bottle and push it down under watersurface. When the whole bottle is submerged, turn it upright and allowto fill. Take the temperature at the same time you take the sample.

5.6 Water Level Measurements

Water level measurements in observation wells are the principalsource of information about the hydrologic stresses acting on aqui-fers and how these stresses affect groundwater recharge, storage, anddischarge (Taylor and Alley, 2001). Long-term systematic measure-ments provide essential data needed to evaluate changes in theresource over time, to develop groundwater models and forecasttrends, and to design and monitor the effectiveness of groundwatermanagement and protection programs.

The number and location of observation wells are critical to anywater level data program. Selection of the location and depth of obser-vation wells should consider the physical boundaries and geologic



complexity of aquifers in the area. Multilayer aquifer systems mightrequire measurements in wells completed at multiple depths in differ-ent hydrogeologic units. Commonly overlooked is the need to collectother types of hydrologic information (such as rainfall and streamflow) as part of a monitoring program. Observation wells should beselected with

an emphasis on wells for which measurements can bemade for an indefinite time.

Good quality assurance practices help to maintain the accuracyand precision of water level measurements, ensure wells reflect con-ditions in the aquifer that is monitored, and provide data that can berelied on for many intended uses. Field practices that will ensurequality data include the establishment of permanent reference points,periodic inspection of the well structure, and periodic hydraulic testingof the well to ensure connection with the aquifer.

Measurements in observation wells can be obtained by one of thefollowing methods:

Wetted steel tape

Air-line submergence method

Electrical tape

Pressure transducer

Float method

Audible methods

Wetted Steel Tape

Before the 1960s, most water level measurements were made witha steel tape (most likely a 100- or 200-ft Lufkin tape). Tapes havebeen replaced by electrical methods and pressure transducers. How-ever, the steel tape still has applications today, for example, tocalibrate pressure transducers. Before the tape is lowered down thewell, the bottom 1 to 2 ft of it is coated with carpenter’s chalk. Thetape is then lowered into the well until the lower part is submerged.The tape is held on an even foot read at the measuring point (MP)and this value is noted (e.g., 40 ft). The tape is then pulled back tothe surface, and the wet mark on the tape (e.g., 1 ft) is recorded. Inthis example, a reading of 40 ft minus the reading of 1 ft would givea reading of 39 ft to water below the measuring point. The MP isusually the top of the casing and the distance of the MP from theland surface is noted on the well measurement form. If the MP is



changed, it should be noted on the measurement form. The watermeasurement should be repeated at least three times to ensure aprecise depth-to-water value. Measurements are made to 1/100 of afoot. Problems that might be encountered with this method includemoisture on the well casing, cascading water, and oil (leaking frompump lubrication). For water level measurements made at depthsgreater than 200 ft, refer to Garber and Koopman (1968).

Electrical Tape

Most electrical tapes are marked every 1/10 ft. With the electrical tapemethod, an electrical probe is lowered into the water, completing anelectrical circuit so a buzzer or light is activated (Figure 5.4).

FIGURE 5.4

Electrical water level indicator (from Driscoll, F.G., 1986.


,2nd Edition. With permission).

Lightindicator

Casing

Water

Electrode

Electiccable

Reel



Pressure Transducer

The transducer probe measures the column of water above the probe.It is very useful for testing aquifers where the water level changesrapidly. Data are transferred to data loggers such as the In-Situ logger(Figure 5.5).

5.7

Tracing Techniques

*

In recent years, groundwater tracing techniques have been used in avariety of hydrogeologic settings as a tool for aiding in characterizationof groundwater flow systems. Tracing techniques have been demon-strated to be especially useful in fractured rock and karst hydrogeo-logic settings and for identifying and characterizing contaminanttransport pathways and transport velocities. Groundwater tracing tech-niques make fewer assumptions about flow paths than do hypothetical(e.g., Darcy) or numeric simulations, and therefore they are often morereliable. Tracer tests can be used to obtain empirical data related togroundwater recharge, groundwater flow direction, flow rates, flowdestinations and flow system boundaries. Dye recovery data, whencombined with groundwater flow data, can also provide quantitative

FIGURE 5.5

Pressure transducer water level instrument (courtesy of In-Situ, Inc.).

* This section is contributed by Mike Wireman, hydrogeologist, USEPA Region 8, Denver, Colorado.



data that can be useful for assessing contaminant behavior and fate inthe subsurface. Several tracers can be used together allowing severalpotential pathways to be evaluated simultaneously.

Tracing can generally be divided into two categories: label tracingand pulse tracing. Using tracers as labels allows for identification ofspecific waters or plumes. Pulse tracing involves sending an identifi-able signal through part of a groundwater flow system at concentrationssignificantly above background. Groundwater tracers can also bedivided into two types: natural and artificial. Natural tracers are moreapplicable for labeling waters whereas artificial tracers are more suit-able for pulse tracing. Important natural tracers include stable andradioactive isotopes, selected ions in solution, selected field parameters(specific conductance and temperature) and selected microorganisms.Commonly used artificial tracers include organic dyes and dye inter-mediates, fluorocarbons, gases and salts (chloride, bromide, etc.).

Natural Tracers

Stable Isotopes

Stable isotopes have proven to be the most versatile natural tracers.For a given element, isotopic composition can vary due to partitioningor fractionation related to differences in reaction rates. Fractionationis proportional to differences in isotopic mass. This feature allows theratios of isotopes to become fingerprints of climatic and hydrologicalconditions. For example, variations in annual rainfall and snow meltstrongly affect the isotopic composition of melt waters, and isotopicfractionation can be more pronounced in low temperature settings thanin warmer ones.

Data for ratios of stable isotopes of oxygen, hydrogen, sulfur,nitrogen and carbon can be especially useful for characterizing ground-water flow paths from areas of recharge to areas of discharge, identi-fying mechanisms responsible

for stream flow generation, testing flowpath, and modeling water budget using hydrometric data.

Stable isotopes of oxygen and hydrogen are ideal tracers of watersources and movement because they are integral constituents of thewater molecule. Oxygen isotopes include oxygen 16, oxygen 17 andoxygen 18, and hydrogen isotopes include protium (

1

H), deuterium(

2

H), and tritium (

3

H). Stable isotopes of oxygen and hydrogen behaveconservatively because interactions with organic and geologic materialalong the flow path will have a negligible effect on the ratios of isotopesin the water molecule. The ratios of stable isotopes of dissolved sulfur,



nitrogen and carbon can be significantly altered by reactions withorganic and geologic material. Thus, these solute isotopes have limiteduse for tracing water sources and flow paths. However, data for soluteisotopes can provide information on the reactions that are responsiblefor their presence in the water and the flow paths implied by theirpresence (Kendall, 1998).

For detailed information on isotope geochemistry, processes affect-ing isotopic compositions, and isotopes in groundwater hydrology, seeKendall and McDonnell (1998) and Clark and Fritz (1997).

Radioactive Isotopes

Tritium, a radioactive isotope of hydrogen (half-life = 12.43 years), isnaturally produced in the upper atmosphere by bombardment of nitro-gen by neutrons. It was also released to the atmosphere during theperiod of above-ground thermonuclear bomb testing, which was at itsheight during the 1950s and discontinued in 1963. Pre-bomb concen-trations of tritium in water have been determined to be about 1 tritiumunit (TU). The presence of tritium above background levels in ground-water is an indication that recharge occurred during or after the bombtesting period. In addition to radioactive decay, tritium in groundwateris subject to significant attenuation by diffusion and dilution by mixingwith younger water with less tritium. Consequently, tritium concen-trations cannot be used to obtain an absolute age of groundwater.

Artificial Tracers

Artificial tracers are those introduced into the groundwater flow systemeither purposely, as part of a designed tracer test, or inadvertently, asa spill or other human related activities that result in the introductionof a tracer into the groundwater. To serve as a suitable tracer, a sub-stance must be (1) nontoxic to people and the ecosystem, (2) eithernot present naturally in the groundwater system or present at very low,near-constant levels, (3) for chemical substances, soluble in water withthe resultant solution having nearly the same density as water, (4)conservative, (5) easy to introduce into the flow system, and (6) unam-biguously detectable in very low concentrations.

Salts

Chloride and bromide solutions are commonly used for both ground-water and surface water tracing. These salts are very soluble, relatively



inexpensive, conservative and non-toxic at concentrations typically usedfor tracing. They are also easily detectable at low concentrations. Chlo-ride occurs naturally in some groundwater, often in tens to hundreds ofparts per million, but natural concentrations of bromide are much lower.Chloride has commonly been used to trace contaminant plumes thatoriginate at landfills or other industrial facilities. Stream tracing tech-niques that include the continuous injection of a constant concentrationof a tracer (bromide) provide very accurate stream discharge measure-ments based on dilution of the tracer. The application of surface watertracing techniques in combination with groundwater tracing providesdetailed information on groundwater inflow zones to streams.

Organic Dyes

Fluorescent dyes constitute some of the most analytically sensitive,versatile, non-toxic and inexpensive artificial water tracers available.Commonly used fluorescent dyes include uranine, rhodamine, eosin,phloxine, sulpho-rhodamine B. Most fluorescent dyes will work wellin waters where pH is near neutral. In acidic conditions the fluores-cence of some dyes is minimized. However, these dyes will usuallyfluoresce again if the sample is adjusted to more alkaline conditions(Davies, personal communication). Commercial grade, organic fluo-rescent dyes can be purchased as a liquid compound or as a powder.Uranine, eosin and phloxine are FDA approved. Many organic dyesand salt tracers have been approved for use in aquifers and streamswhich are used to obtain drinking water supplies. However, some states(such as Wisconsin) have restricted the use of some dyes for use asartificial tracers.

Field Methods

The usefulness and appropriateness of a groundwater tracer test dependon the questions to be answered by the hydrogeologic investigation.Tracer tests are appropriate when groundwater flow velocities are suchthat results will be obtained within a reasonable period of time —usually less than a year. The usefulness of tracer test results are highlydependent on proper test design (particularly determination of sam-pling locations) and execution, the nature of the tracer, the ability todetect the tracer at low concentrations, and correct interpretation recov-ery data. Prior to conducting a tracer test, it is very important to useother geologic and hydrologic data and information to develop a fun-



damental understanding of the hydrogeologic setting and the ground-water flow system to be traced. This understanding can then be usedto determine the appropriate type of tracer, the tracer injection locationand method, the appropriate sample collection locations, and/or whichstable or radioactive isotopes should be included in the sampling plan.It is always advisable to sample more locations rather than fewerlocations. It is also important to know precisely how much tracer massis injected. This will allow for a determination of the percent of tracermass recovered at a given sampling location if the flow can be mea-sured at the sampling location. This quantitative aspect of tracing canbe important in helping to evaluate the significance of any givengroundwater flow path.

Isotopes

Chapter 10 of Clark and Fritz (1997) includes an excellent discussionand comparison of sampling and analytical protocols and proceduresfor collection of water samples for isotopic analysis. Sample size,filtering, preservation, container type, holding times, and analysismethod vary quite a bit with different stable and radioactive isotopes.Generally, isotopes of water (oxygen 18, deuterium, tritium) havesimpler sampling protocols than do isotopes of dissolved inorganicand organic carbon (carbon 13 and carbon 14), dissolved sulphate andsulphide (sulfur 34), dissolved gases (helium, argon 39, krypton 85)and dissolved uranium (uranium 234 and uranium 238). Water samplesfor isotopic analyses must be collected and stored in well-sealed bottlesto prevent any additional fractionation.

Organic Dyes

The use of organic dyes as hydrogeologic tracers also requires specificfield sampling and analysis procedures. Careful thought should begiven to the selection of the proper dye and the method used tointroduce the dye into the groundwater. Dye selection is based on thechemical and toxicity characteristics of the dye. For example, researchfrom Germany indicates that rhodamine is somewhat toxic. Also,fluorescence is reduced in some dyes when dissolved in low pH waters,and some dyes will fluoresce better in cooler waters. All of thesefactors should be considered when choosing an organic fluorescentdye for use as a tracer.

It is also very important to consider carefully the best way tointroduce the dye tracer into the groundwater system. There are fourcommon methods:



• Inject into a previously constructed or a new well, making sure the well willtake water prior to introducing a dye tracer, which can be ascertained byconducting simple aquifer tests using the proposed injection well.

• Inject into a stream, making sure the stream gradient is low and the reach ofstream below the injection point is a losing reach.

• Inject into a constructed trench, making sure trench takes water.

• Inject into a sinkhole (Karst terrain).

Sample collection protocol for water samples that might containthe dye tracer is relatively simple. Sample containers and storageshould minimize all exposure to light to prevent degradation of thedye. Samples do not require filtering or preservation, but water samplesthat might contain dye should be kept cool until analysis is complete.They should be analyzed within two weeks to minimize bacterialdegradation of the dye.

Collection of water samples can be done using an autosampler(useful for collecting many samples in a short time and from locationswith difficult access) or by grab sampling. Once the water samples arecollected, they should be analyzed on a spectrofluorometer to confirmthe nature of the fluorescence and then analyzed with wet chemistrymethods for dye concentration. It is important to conduct both typesof analysis to better confirm the presence of the dye that was injected.Sophisticated sampling techniques can be achieved by usingflow-through fluorometers which measure the fluorescence of the dyein water on a real-time basis. This type of sampling requires a powersource and data loggers.

Small bags of activated charcoal can also be used to detect dyes.Organic dyes will sorb onto charcoal if water containing dye comesinto contact with the charcoal. Charcoal bags are placed in water atsampling locations and then retrieved for analysis at selected timeintervals. It is important to note that determining the travel time froman injection location to a given charcoal bag is constrained by the timeinterval between retrieval of the bags.

The most important rule of thumb for sampling is to collectsamples often at many places. Collecting samples for organic dyeanalysis is relatively easy and inexpensive. Since it is not alwayspossible to predict all locations where dye might be recovered, it isbest to have more rather than fewer sampling locations. By collectingsamples frequently, at important locations, the data can be used toconstruct breakthrough curves of recovery versus time. Detailedbreakthrough curves can be used to do rigorous analyses of therecovery data.



References

ASTM, 1990, D 5092, Standard practice for design and installation of ground watermonitoring wells in aquifers.

Bentall, Ray, 1963, Methods of collecting and interpreting ground-water data, exam-ination of drill cuttings: U.S. Geological Survey Water Supply Paper 1544-H,Washington, D.C.

Clark, Ian D. and Fritz, Peter, 1997,

Environmental Isotopes in Hydrogeology

, CRCPress LLC, Boca Raton, FL, 328 p.

Garber, M.S. and Koopman, F.C., 1968, Methods for measuring water levels in deepwells: U.S. Geological Survey Techniques for Water Resources Investigations,Book 8, Chapter A1, 32 p.

Kendall, Carol and McDonnel, J.J., 1998,

Isotope Tracers in Catchment Hydrology

,Elsevier, Amsterdam, the Netherlands, 839 p.

Nielsen, David M., 1991,

Practical Handbook of Ground-water Monitoring

, LewisPublishers, 717 p.

Taylor, C.J. and Alley, W.H., 2001, Ground-water level monitoring and the impor-tance of long-term water-level data: U.S. Geological Survey Circular 1217,68 p., Reston, VA.


79

6

Chapter

Aquifer Evaluation

6.1 Determination of Hydraulic Conductivity (K)

Hydraulic conductivity (K) represents the ability of water to move throughaquifers of a given permeability. It can be estimated from lithologic logs(grain size), laboratory measurements and aquifer tests. Laboratory andfield methods are useful for determining hydraulic conductivity. However,values obtained in the laboratory are applicable to small scale situationsand may not be representative of the bulk properties of the aquifer. Thevalue of aquifer tests is that they measure less disturbed materials.

Grain Size

Hydraulic conductivity (K) for unconsolidated deposits can be estimatedfrom logs of test holes and drill cuttings. Values of K are assigned tothe grain size for the material as shown in the following table and thenmultiplied by the thickness of the lithologic unit (Lohman, 1972).

Size K

(ft/day)

Gravel 900

Course sand 200

Medium sand 100

Fine sand 15



Laboratory Measurements

Laboratory determinations from cores of consolidated rocks such ascemented sandstone can be used to estimate hydraulic conductivity.Reconstituted disturbed samples of unconsolidated cuttings are notrepresentative of field conditions and should not be used for labora-tory measurements. It is essential that formation water be used forthe laboratory tests. Laboratory tests represent only a small area ofthe aquifer. An aquifer test, on the other hand, integrates a muchlarger area.

6.2 Design of Aquifer Tests*

The objectives of an aquifer test are to identify the performance of thewell, to estimate the yield capability and the drawdown, and to estimateaquifer properties. Accurate estimation of the hydraulic characteristicsof aquifers is dependent on reliable data from an aquifer test. Aquifertests are made with existing wells or wells drilled for that purpose(Figure 6.1). An aquifer test is a controlled,

in situ

experiment. Thetest is made by measuring groundwater flow and observing water level

* This section is contributed in part by J. Joel Carrillo-Rivera, professor at the Instituto Geograffa de laUniversidad Autonama de Mexico and president of the Mexican chapter of the International Associationof Hydrogeologists.

FIGURE 6.1

Diagram of aquifer test.

Map of Aquifer Test SiteChange in Water Level in Well B

0 50 100

Meters

Pumped Well

ObservationWell A

ObservationWell B

ObservationWell C

Dep

th t

o W

ater

in M

eter

s

Pump On

Pump Off

Dra

wd

ow

n

Rec

over

y

RecoveryPeriod

PumpingPeriod

PrepumpingPeriod

Regional Trend

3

5

7

4

8

10

9

11

12

6

Days6 7 8 9 10 11 12 13 14 15 16


Aquifer Evaluation 81

changes in observation wells. The ASTM standards and guides foraquifer tests are as follows:

• Standard guide for the selection of aquifer test methods (ASTM 1991, D 4043).

• Standard practice for design and installation of monitoring wells in aquifers(ASTM 1990, D 5092).

• Standard guide for sampling groundwater monitoring wells (ASTM 1985,D 4448).

An understanding of the subsurface hydrogeology is essential inplanning the aquifer test. The following is a list of hydrological andgeological conditions needed for a successful aquifer test:

• Hydrogeological conditions should not change over short distances.

• No discharging well or stream should be nearby.

• Discharge water should not return to aquifer.

• Pumped well should be completed to the bottom of the aquifer and should bescreened or perforated through the entire thickness of the aquifer.

• Observation wells (at least three) should be screened at the middle of theaquifer, and one should be located outside the area of influence of the coneof depression.

• Location of observation wells should be based on aquifer character.

• Pre-pumping water-level trend should be determined.

The following well conditions and field measurements are neededfor the aquifer test:

• Accurate water-level measurements should be made during pumping and recovery.

• Pumped well should be developed adequately prior to test (several hours ofpumping and surging).

• Dependable power source should be available to provide a constant pumping rate.

• A flow meter capable of reading instantaneous and cumulative dischargeshould be available.

• Electrical conductance, Eh, pH, DO, and temperature measurements shouldbe done.

• Water levels should be measured several hours before test begins.

• Pumping rate should be maintained at 5% tolerance. An optimal pumping rateis 50% of maximum yield.

• Water-level measurements should be made with a electric sounder orpressure transducer.

• The discharge water should be removed from the site.



• Observation wells should be tested by injecting a known volume of water andmeasuring the recovery response.

• Baseline trends of regional water level changes, barometric pressure changes,and local activities should be established.

• Pumping well lithology and construction data should be done.

6.3 Types of Tests

Specific Capacity Test

An expression of the productivity of a well can be determined by aspecific capacity test. In this test, the pumping rate and water levelchanges are monitored for a set period of time (Figure 6.1). The firststep in the test is to measure the initial water level in the well. Typicallya well is pumped at several successively increasing rates for uniformperiods (usually one hour) to establish a rate that can be maintainedfor long- term pumping. The well is then pumped at a steady rate, andthe water level changes are monitored at the pumped well. Water levelsshould also be monitored in at least one observation well 6 to 65 ftfrom the pumped well. The water level will at first decline quickly aswater is removed from the well, then more slowly as the rate of flowinto the well approaches the pumping rate. The ratio of the dischargerate (Q) to water level change (drawdown, dd) gives the well’s specificcapacity, or Sc = Q/dd (Figure 6.2). For example, if the discharge rateis 100 gal/min (6 L/s) and drawdown is 10 ft (3 m), the specific capacityof the well is 10 gal/min per ft (2 L/s per meter) of drawdown. Oncespecific capacity and the available amount of drawdown are known,the yield of the well can be determined from the formula Q = Sc

×

dd.The pump should be set deep enough so the water level does not

go below the pump intake. The pump depth should also be sufficientto allow for drawdown caused by pumping and for natural declines inwater level during periods of drought.

Step-Drawdown Test

The step-drawdown test evaluates the performance of the well. Wellperformance can be affected by resistance to flow in the aquifer itself,partial penetration of the well screen, incomplete removal of drilling mudor invasion of fines, and blockage of part of the screen area. The well



should be developed prior to the test using a surge block and/or pumpinguntil the well discharge is clear. In this test the well is pumped at several(three or more) successively higher pumping rates and the drawdown foreach rate is recorded. The test is usually conducted during one day. Thedischarge is kept constant through each step. The test measures thechange in specific capacity. The data provides a basis for choosing thepump size and rate for the aquifer test and for long-term production.

Slug Test

In a slug test, a small volume of water is removed from a well (or asmall volume is added) and measurements are made of the recovery ofthe water level. From the time-drawdown or recovery data, the aquifertransmissivity can be determined. The disadvantages of the test are thata data logger is required for measuring changes and it represents onlya small volume of the aquifer. The Bower and Rice (1976) methodapplies to unconfined aquifers, while the Cooper, Bredehoeft, and Pap-adopulos (1967) method is for confined conditions. The advantage ofthese tests, compared to those of aquifer tests with observation wells, is

FIGURE 6.2

Instrument for multiple well aquifer test Hermit 3000 (courtesy of In-Situ, Inc.).



reduction in cost and time. The disadvantage is that a storage coefficientis not determined and only a small volume of the aquifer is sampled.Many factors contribute to error in slug tests, such as entrapped air,partial penetration, leaky joints, and the radius of influence of the test.

6.4 Analysis of Aquifer Test Data

Theis Equation

The Theis equation (Theis, 1935) is used to determine hydraulic charac-teristics of the aquifer. In this test, a well is pumped, and the rate of waterlevel decline in nearby observation wells (2 or more) is noted. The timedrawdown is then interpreted to yield the aquifer parameters. In 1935,C.V. Theis developed the first equation to include time of pumping as afactor (Heath, 1983), which makes the following assumptions:

• The pumping well is screened only in the aquifer being tested.

• The transmissivity of the aquifer is constant during the test to the limits of thecone of depression.

• The discharging well penetrates the entire thickness of the aquifer, and itsdiameter is small in comparison with the pumping rate.

These assumptions are most nearly met by confined aquifers atsites far from the aquifer boundaries. However, if certain precautionsare observed, this equation can also be used to analyze tests of uncon-fined aquifers. Use of the Theis equation for unconfined aquifersinvolves two considerations.

• If the aquifer is fine grained, water is released slowly over a period of hoursor days, not instantaneously with the decline in head. Therefore, the value ofspecific yield determined from a short-period test might be too small.

• If the pumping rate is large and the observation well is near the pumping well,dewatering of the aquifer might be significant and the assumption that thetransmissivity of the aquifer is constant is not satisfied.

Cooper-Jacob Straight Line Method

The Theis equation is only one of several methods that have beendeveloped for the analysis of aquifer test data. Cooper and Jacob



(1946) developed a method that is more convenient than the Theisequation. The greater convenience derives partly from its use ofsimilogarithmic graph paper, instead of the logarithmic paper, and thefact that under ideal conditions the data plot is along a straight linerather than along a curve.

6.5 A Computer Program to Design an Aquifer Test

A computer model program, written by Daniel K. Sunada (ColoradoState University, Fort Collins, Colorado, U.S.A.) can be used to cal-culate the water-level response to withdrawal of groundwater (Molden,Sunada, and Warner, 1984). The model can be used to determine thebest placement of observation wells for an aquifer test and to estimatetest duration. The model can also calculate discharge or recharge tothe stream in a stream-aquifer system. It can be run with or withouta stream in the system. The program is menu driven and self explan-atory (Figures 6.3 and 6.4).

1. Recharge Rate (ft/day) . . . . . . . . . . . . . . . . . 22. Transmissivity (ft

2

/day) . . . . . . . . . . . . . 25003. Specific Yield . . . . . . . . . . . . . . . . . . . . . . . . 24. Beginning Time (days) . . . . . . . . . . . . . . . 305. End of Recharge Period . . . . . . . . . . . . . . . 06. Beginning Distance (ft) . . . . . . . . . . . . . . . . 0 Final Distance (ft) . . . . . . . . . . . . . . . . . . 500 Distance Increment (ft) . . . . . . . . . . . . . . . 507. Depth to Water (ft) . . . . . . . . . . . . . . . . . . 308. Basin Width (ft) . . . . . . . . . . . . . . . . . . . . 2009. Basin Length (ft) . . . . . . . . . . . . . . . . . . . 20010. Angle from Length Axis (deg) . . . . . . . . . . 011. Distance to Stream . . . . . . . . . . . . . . . . . 25012. Calculate Mound Profile . . . . . . . . . . . . . yes13. Calculate Discharge to Stream . . . . . . . . yes

Type the number of the variable you wish to change. Type 0 if you wish to continue without changing.

FIGURE 6.3

Computer screen display (parameters).



The following is a list of steps to follow to run the model:

1. Download the model from the CRC Press Web site (www.crcpress.com).

2. Click on CSUPAWE.

3. The first menu gives options for selecting flow to a well or flow to a rechargearea.

4. Select flow to a well.

5. Select stream in vicinity or no stream.

6. Data input:

RECHARGE RATE: (ft/day) A constant discharge is used.

AQUIFER PARAMETERS: Transmissivity (ft

2

/day); Specific Yield (dimensionless).

TIME PERIOD: Calculations are performed at discrete times. Beginning Time (days)must be greater than 0 and is the first time that the calculations are made. TimeIncrement (days) gives the time interval between calculations. Final Time gives thelast time that calculations are to be made. For example, if the beginning time is 10days, the time increment is 5 days, and the final time is 20 days, the calculationsare to be made at 10, 15, and 20 days. The final and initial times must be integermultiples of the time increment.

END OF RECHARGE PERIOD: The time (days) when artificial recharge or welldischarge is terminated. The program will continue to calculate mound profiles untilthe specified final times.

DISTANCE: Specify the points at which the recharge mound height or water leveldecline is to be calculated. The Beginning Distance (ft) is always set at 0, whichis directly under the center of the basin or at the well. Distance Increments (ft) givethe distance between points of mound height calculations.

FINAL DISTANCE (ft): Final disctance is the last point at which the mound heightis to be calculated.

DEPTH TO WATER (ft): Depth to water is the distance from the ground surface tothe water table in feet. A different depth to water may be selected to change thescale of mound heights.

SATURATED THICKNESS (ft): This parameter is the distance from the bottom ofthe aquifer to the initial water table.

BASIN GEOMETRY: A rectangular basin is used, so enter Length and Width in feet.

1. Data display2. Results display3. Graphics display4. Results printout5. Create file6. Another run7. Exit

FIGURE 6.4

Computer screen display (options).



ANGLE: This parameter specifies, in degrees, the angle that a vertical plane makeswith a line drawn from the center of the well or recharge basin.

DISTANCE TO STREAM OR DISTANCE TO IMPERMEABLE BOUNDARY (ft):The distance to the boundary is measured from the center of the recharge basin orwell to the stream.

CALCULATE MOUND PROFILE AND CALCULATE DISCHARGE TO STREAM:You can have the program calculate the mound profile, the discharge to the stream,or both.

CHANGE IN VARIABLES: Variables are changed by typing the number correspond-ing to the variable. The current value of the variable will appear on the screen, andyou will be prompted to enter the updated value. After the updating is completed,you will be returned to the main data display. When you press the Enter key, theprogram begins calculating with the current parameters.

7. CALCULATIONS: As points are calculated, they are plotted on the screen.When the calculations are complete, you will be prompted to press “ENTERTO CONTINUE”. All results are kept in memory, and the output options menuappears.

6.6 Construction of Hydrogeologic Maps

The key maps constructed by hydrogeologists are water table contour,saturated thickness, bedrock contour, water level change, and trans-missivity. The water table contour map shows the elevation of thewater table for a specific hydrogeologic unit. Depth to water data isfirst converted to water level elevations. The water level measurementsshould be measured within a few days of each other because the maprepresents a specific point in time. Elevations of streams, lakes, andponds should be used in the map if they are in hydrologic connection.After the map is constructed, the contour lines should be smoothed.Avoid

bull’s eye

contours that have only a single point for control.Water table contour maps are valuable tools for understanding the flowsystem by providing information on gaining and losing reaches of thestream, no flow and flow boundaries, and areas of groundwater

with-drawal.

References

ASTM, 1985, D 4448 Standard Guide for Sampling Ground Water Monitoring Wells.ASTM, 1990, D 5092 Design and Installation of Ground-Water Monitoring Wells

in Aquifers.



ASTM, 1990, D 5092 Standard Practice for Design and Installation of Ground WaterMonitoring Wells in Aquifers.

ASTM, 1991, D 4043 Standard Guide for Selection of Aquifer Test Method inDetermining of Hydraulic Properties by Well Techniques.

ASTM, 1993, D 4750 Standard Test Method for Determining Subsurface LiquidLevels in a Borehole or Monitoring Well (Observation Well).

ASTM, 1995, D 5717, Guide for the Design of Ground-Water Monitoring Systemsin Karst and Fractured Rock Aquifers.

ASTM, 1996, D 5730 Standard Guide for Site Characteristics for EnvironmentalPurposes with Emphasis on Soil, Rock, the Vadose Zone and Ground Water.

ASTM, 1996, D 6000 Standard Guide for Presentation of Water-Level Informationfrom Ground-Water Sites.

Bentall, Ray, 1963, Methods of Collecting and Interpreting Ground-Water Data,Examination of Drill Cuttings, U.S. Geological Survey, WSP 1544-H.

Bower, H. and Rice, R.C., 1976, A slug test for determining hydraulic conductivityof unconfined aquifers with completely or partially penetrating wells,

WaterResources Res.

12: 423–428.Clark, Ian D. and Fritz, Peter, 1997,

Environmental Isotopes in Hydrogeology,

CRCPress LLC, Boca Raton, FL, 328 p.

Cooper, H.H., Bredehoeft, J.D., and Papadopulos, I.S. 1966, Response of afinite-diameter well to an instantaneous charge of water,

Water Resources Res.

3: 263–269.Dawson, K.J. and Istok, J.D., 1991,

Aquifer Testing, Design and Analysis of Pumpingand Slug Tests

, Lewis Publishers.Garber, M.S. and Koopman, F.C., 1968, Methods for measuring water levels in deep

wells

, U.S. Geological Survey Techniques for Water Resourses Investigations

,Book 8, Chapter A1, 32 p.

Heath, Ralph, 1983,


, U.S. Geological Water SupplyPaper 2220, 84 p.

Kendall, Carol, and McDonnell, J.J., 1998,

Isotope Tracers in Catchment Hydrology

,Elsevier, Amsterdam, the Netherlands, 839 p.

Lohman, Stan W., 1972, Ground-water hydraulics, USGS Professional paper 708,70 p.

Mercer, J.W., 1991,

Methods for Subsurface Characterization

: USEPA.Molden, D., Sunada, D.K., and Warner, J.W., 1984, Microcomputer model of arti-

ficial recharge:

Groundwater

, 73–79.Moore, John E., 1991,

A Guide for Preparing Hydrologic and Geologic Projectsand Reports,

Kendall/Hunt Publishing Corp., Dubuque, IA, 96 p.Nielsen, David M., 1991,

Practical Handbook of Ground-Water Monitoring,

, LewisPublishers, CRC Press, Boca Raton, FL, 717 p.

L1587_Frame_C06 Page 88 Thursday, June 6, 2002 10:55 AM


Taylor, C.J. and Alley, W.H., 2001,

Ground-Water-Level Monitoring and the Impor-tance of Long-Term Water-Level Data

, U.S. Geological Survey Circular 1217,68 p.


91

7

Chapter

Stream FlowMeasurements

Stream gaging is the measurement of discharge in an open-waterchannel. Gaging streamflow has practical application to the design ofdams, flood control structures, surface water allocation, and relationsto groundwater. Stream rating curves are constructed by plotting valuesof gaged streamflow against the stage of the stream for a given flow.The rating curve is used to predict base flow recession.

7.1 Basic Equipment

The basic equipment for performing discharge measurementsincludes a current meter, timer, sounding equipment, and tag line. Acurrent meter consists of an impeller which, when placed in thestream, rotates relative to the speed of water passing the instrument.The impeller rotation rate is recorded by an electronic counter thatis heard on earphones.

7.2 Measurement Procedure

The stream discharge is measured according to the following steps:

1. Select a straight reach of stream with a smooth shoreline.

2. Extend a tape (tag line) across the stream.



3. Develop a water depth profile.

4. Divide the stream into segments at regular intervals.

5. Take measurements at 10–20 stations along a profile.

6. Clamp the current meter at 0.2 and 0.8 of the total depth.

7. Make a velocity reading at each station.

8. Compute discharge: cross-section area

×

velocity = discharge.

The area is computed from observations of width and depth. Forwading measurements, the width is generally marked by a tagline. Thedepth of the stream is measured at enough intervals across the streamsection to determine adequately the total area. For wading measure-ments, depths should be read to hundredths where practical.

Difficulties in obtaining accurate velocity observations will oftentax the ingenuity of the hydrologist. These difficulties arise from fieldconditions such as soft streambeds, scour under the wading rod, sanddunes, boulders, and swift or shallow water. Shallow depth and lowvelocity in streams render current-meter measurements inaccurate, ifnot impossible to obtain. Under these conditions, a weir or flume maybe useful for obtaining the discharge measurements.

Stream gaging poses hazards to the safety of the hydrologist.Personal safety depends upon a healthy respect for rivers and streams— “Discretion is the better part of valor.”

7.3 Methods To Determine Stream–Aquifer Relations

Several field techniques can be used to determine the relation of theaquifer and a stream. The most commonly used ones are

Stream seepage run measurements

Stream gaging

Tracer studies

Water table contour maps

Stream-channel gain and loss studies can be made to evaluate theeffect of groundwater withdrawal on the stream flow. Groundwaterand surface water seepage run measurements were used to evaluatethe effect of municipal wells on the flow of the Arkansas River atLamar Colorado (Moore and Jenkins, 1966). The study showed thatmunicipal pumping had lowered the water table below the streambed,


Stream Flow Measurements 93

the hydraulic connection between the stream and the water table wasbroken, and an unsaturated zone had developed below the streambednear the area of greatest pumping. The channel loss data was used tocompute the vertical hydraulic conductivity of the streambed.

Streamflow hydrographs can be analyzed to estimate the ground-water component, termed base flow, of streamflow. Environmentaltracers can be used to determine the source areas of water, water ageand chemical reactions that take place during transport. Useful trac-ers include dissolved constituent (cations and anions), isotopes ofoxygen, tritium, radon, and water temperature. Water table contourmaps can be analyzed to determine if the stream is gaining or losingwater from the aquifer. Contours of water-table elevation indicategaining streams by pointing in an upstream direction in the imme-diate vicinity of the stream, and they indicate losing streams bypointing in a downstream direction (Hurr and Moore, 1972).

References

Buchanan, T.J. and Somers, W.P., 1969, Discharge measurements at gaging stations,

Techniques of Water-Resources Investigations of the U.S. Geological Survey

,TWI 3-A8, 65 p.

Hurr, R.T. and Moore, J.E., 1972, Hydrologic characteristics of the valley-fill aquiferin the Arkansas River Valley, Bent County, Colorado,

U.S. Geological SurveyHydrologic Atlas

, 461.Moore, J.E. and Jenkins, C.T., 1966, An evaluation of the effect of groundwater

pumpage on the infiltration rate of a semipervious streambed,

Water ResourcesResearch,

2(4): 5 p.Winter, T.C., Harvey, J.W., Frankes, O.L., and Alley, W.M., 1998, Ground water and

surface water: a single resource, U.S. Geological Survey Circular 1139, 79 p.


95

8

Chapter

Hydrogeologic Reports

The report is the most important aspect of many geologic and hydro-logic projects because it usually is the only product of the project thatthe client will see. A properly planned, well-written, and carefullyreviewed report enhances the credibility of the project investigator andthe parent organization (Figure 8.1). The report is written for otherspecialists and/or educated laymen. The technical report might haveto be reorganized to make it more useful to the educated layman.

This chapter describes the logical steps for planning, writing, andreviewing hydrologic, geologic, and related reports. It includes guide-lines, checklists, and source references to assist authors in the variousstages of report preparation. The information this chapter presents isa suggestion and is not intended as a replacement for report formatsestablished by organizations or supervisors (Figure 8.2).

This guide consists of three basic sections:

Report planning — use of report work plans and outlines

Report writing — writing the report title, executive summary or abstract, intro-duction, body, and summary

Report review — procedures followed during editorial and technical review ofa report

8.1 Report Planning

Report planning should precede report preparation (Figure 8.3). Somesuggestions for report planning are



Prepare a topical outline during the first week of the project.

Prepare an annotated report outline during the first one-third of the project (forexample, first month of a 3-month project).

Write interim reports to reduce the size and complexity of the final report. Interimreports can be useful for describing the preliminary results of analyses andpreliminary interpretations during the duration of the project.

Report Work Plan

The report work plan should include projected dates for completionof outlines, report writing, first draft, review, approval, and release.One third of the life of the project is typically devoted to report writing,review, and approval.

• Think about the report topic and list ideas that come to mind(brainstorm)

• Write a rough draft on a word processor

• Print a copy of the draft and mark it up

• Revise the draft

• Print a copy of the draft and mark it up

• Have a colleague review the draft

• Write a final draft

• Proofread and correct

FIGURE 8.1

Report writing process.

• Logical organization where more important items stand out

• Writing style fits the intended audience

• Minimal jargon

• Effective illustrations

• Clear simple tables

• Pleasing design (cover page)

• Pleasing and appropriate layout

FIGURE 8.2

Attributes of a high quality report.


Hydrogeologic Reports 97

Report Writing Guides

Writing is an ongoing effort throughout the duration of the project andshould never be treated as a chore to be left until the end of the project.The writing of a report is more likely to be successful if carefulplanning precedes the effort. Follow these steps to write the report:

1. Define the audience of the report.

2. Find published reports that could serve as models.

3. Prepare a topical outline and have it reviewed.

4. Prepare an annotated outline and have it reviewed.

A thorough and competent review is essential to maintain the tech-nical quality of reports. The purpose of the review is to give atechnical evaluation that will improve the report and eliminate errorsthat would embarrass the author and his agency. The following areguidelines and procedures for technical reviews.

Items to consider during review:

•

Technical corrrectness

— Is the report technically valid? Are conclusionsproperly supported by correctly interpreted data? Are assumptions reasonableand clearly stated?

•

Readability

— Is it written for the intended audience, with correct grammar,syntax and a minimum of scientific jargon? Are illustrations and tables legibleand understandable?

•

Title

— Is it explicit and does it reflect the objectives of the report?

•

Abstract

— Does it state the purpose of the report? Does it describe the studyand summarize the results and conclusions?

•

Introduction

— Does it clearly describe the problems addressed in the report,state objectives, and scope of the report.

•

Methods

— Were appropriate techniques used in the study?

•

Conclusions or results

— Do they summarize the principal findings of thestudy and answer each of the objectives described in the introduction? Arethey sound and properly documented?

•

References

— Are all references cited in text included in this section? Arethey complete and cited correctly?

FIGURE 8.3

Instructions for technical reviewers (from the U.S. Geological Survey).



5. Send a copy of the annotated outline to the client for review.

6. Write the report background, purpose and scope, description of study area,methods of study, and review of previous studies.

7. For the first draft, put each paragraph on a separate page to make revisioneasier.

8. Revise the first draft. It usually takes several drafts (4–5) to prepare a report.

9. Have the report edited prior to submitting it for peer (technical) review.

10. Arrange for concurrent peer reviewers.

11. Respond in writing to peer review comments.

12. Have the report edited again, if many revisions were made after the peer review.

13. Complete work on the report, print it, and then deliver it to the client as quicklyas possible.

General Report Outline

The following general outline can be used for technical reports.

1. Title

2. Executive summary or abstract

3. Introduction

4. Purpose and scope

5. Body of report

6. Summary and/or conclusions

7. References

Report Organization

The organization of a report requires the author to make decisions onthe content and order of presentation. Each report presents a differentproblem in organization, and no cookbook method of report organi-zation can be given. The first step in report organization is the prep-aration of an outline. An outline helps authors organize their thoughtsand plans early in the project and to focus project activities throughoutthe life of the project.

After selection of the title (see the following section), authorsshould prepare a topical outline with major and minor headings thatreflect the title and organization of the report. It is far easier to reor-ganize an outline than a completed report. A topic (lead) sentence orparagraph is then prepared for each heading in the topical outline.



The next step is to prepare an annotated outline, an expandedversion of the topical outline, which should be as detailed as possible.The annotated outline is then sent to the client for review. This earlyreview helps ensure that the final report will meet the needs of the client.

8.2 Report Writing

Overcoming Writer’s Block

Putting down the first word is hard for some writers, including manywho have written best sellers. Writer’s block and procrastination areclosely related. Authors who have writer’s block must put down thatfirst word or sentence, good or bad, and use self-imposed control tofinish the report. Some authors begin by writing the description of thestudy area or previous investigations (Figure 8.1).

One way to develop a report outline is to randomly write yourmain thoughts (bullet format) of what you want to say. Then reviewwhat you wrote, group the related ideas, and arrange them in anoutline format.

Title

The title of the report should be brief (preferably no more than 15words) but informative. It is a concise description, perhaps even theultimate abstract, of the report subject. The title will be read by manymore readers than will the report itself. Moreover, one of the bestmethods to ensure that the report will reach the intended audience isto provide a complete title that can be properly indexed. Ideally, thetitle should be as short as possible while containing

Report subjects

Location of study area (if appropriate)

Time or period of study (if appropriate)

For example, the report title “Potentiometric surface of the Flori-dan aquifer in southwestern Florida, October 1988” includes all theabove elements.

The title should not contain abbreviations or jargon. Acronyms arepermitted only if the source words are first spelled out in the title and



the acronym is needed to describe the subject of the report. Computerprogram names also are permitted if the report title clearly definestheir meaning.

The following examples show weak titles and suggested revisions:

Weak: HYDRAUX: a one-dimensional, unsteady, open-channel flow model

Revised: The computer program HYDRAUX, a model for simulating one-dimen-sional, unsteady, open-channel flow

Weak: Integration of Computer Associates Telegraph and Text Editors

Revised: Integration of computer graphics and text-editing software for produc-tion of reports

Weak: Colorado uranium

Revised: A history of the development of uranium mining in Colorado

Executive Summary or Abstract

A well-prepared executive summary (expanded abstract) or abstractcaptures the basic content of the report. The summary/abstract sectionshould contain the following parts:

An opening statement that includes the reason for the study, its scope, and astatement of cooperation, if any. For example: “This report describes the resultsof a study by Dames and Miller done in cooperation with [

insert name

] toevaluate [

insert subject

].”

Type of study if not evident from report title. For example, water-quality study,case history, hydrologic reconnaissance, progress report, original research,areal investigation.

Results of study, in order of decreasing importance, and conclusions, if any.

The executive summary or abstract is prepared after the report iswritten and should not contain information that is not included in thereport. Although there is no general word limit, a 250-word limit isimposed by many journals for abstracts. An executive summary iscommonly 750–1000 words. Avoid the inclusion of reference citations,abbreviations, and acronyms in summaries. Some journals do notrequire that abbreviations be spelled out when first used. Authorsshould be aware of publishers’ guidelines when preparing executivesummaries or abstracts for journals and symposia.



The following examples show weak executive summaries orabstracts (a.) and their revisions (b.):

a. This report describes a computer-modeling program that simulates conditionsin the water-table aquifer of the Pine Barrens in southern New Jersey. Themodel simulates seepage from the aquifer to streams and swamps. Ground-water flow is approximated in two dimensions. Theoretical development ofequations is presented as well as documentation of input data and instructionsfor use of the model.

b. A preliminary, two-dimensional, steady-state model of the water-table aquiferunderlying the Mullica River basin, New Jersey Pine Barrens, was constructedas an initial step in developing a predictive model. The purpose of the model isto evaluate concepts of the flow system and data required to simulate it. Thecomputer model is based on the finite-difference method for solving stream-seep-age equations coupled to the groundwater-flow equation. Model-simulated waterlevels and stream flow compare closely with measured values. Initial estimatesof streambed hydraulic conductance and aquifer hydraulic conductivity wereadjusted to those used in the model. Simulated water levels were within 5 ft ofmeasured water levels at 41 of 42 wells. Simulated stream flow was within 20%of measured stream flow at 12 of 15 sites.

a. This report contains information about the occurrence, quality, quantity, anddirection of movement of ground water in Hampton County.

b. During an investigation of groundwater hydrology in Hampton County,Nebraska, water levels were measured in 196 wells and water samples forchemical analysis were collected from 188 wells and springs, mainly duringSeptember 16–27, 1974. Fifteen wells and 3 springs were resampled in Marchand May 1975. The dissolved solids in the samples ranged from 150 to 300mg/l. The groundwater movement is toward the stream, which is the dischargepoint for the sand and gravel aquifer.

Introduction

The introduction begins with a brief discussion of the need for the study:why was the study done? The introduction also includes a brief descrip-tion of the study area and a statement of cooperation, if applicable.

Purpose and Scope

The purpose, or objective, of a report needs to be related to thatof the study. For example, the purpose of a report might be to



describe long-term trends in concentration of chloride within astudy area, whereas the purpose of the study might be to describethe overall hydrogeology of the study area. The scope of a reportmight include, for example, the time period analyzed, the numberof samples collected and analyzed, the database used, and theanalytical techniques.

Study Area Description

The description of the study area contains a brief discussion of thelocation and size of the study area, its climate, and physiographic,geologic, and hydrologic (or hydrogeologic) setting. Other descriptiveinformation on the study should be given only if it is pertinent to theobjectives of the report.

Methods of Study

An example of the methods of study section might be as follows:Observation wells for water-level measurements were installed at 14sites to obtain geologic and hydrologic information. Five of these wellswere installed in the bed of the river. Three channel gain and lossstudies were made between the diversion dam and the sewage lagoons.

Approach

The approach section differs from the methods of study section bypresenting the rationale behind the study and the manner in whichthe study was performed. For example, a statement of an approachmight be:

The study involved three phases of activity: (1) Organizing and evalu-ating the geohydrologic data in order to develop a conceptual model ofthe groundwater basin of the San Bernardino Valley; (2) developing asteady-state and transient-state digital-computer model of the basin; and(3) using the computer model to predict groundwater levels underselected pumping alternatives, primarily in the artesian areas of thebasin.



Previous Studies

The previous studies section presents work encountered in the projectliterature review. Be sure that this information is accurate and ascomplete as possible. Be sure to compile all bibliographic informationfor all citations (here and in the rest of the report) at the time thesource publication is examined to avoid time-consuming bibliographicsearches after the report is written. The author should obtain permsis-sion for copyrighted material.

Body of Report

The body of the report contains the data and interpretations that answerthe problems stated in the introduction. In addition to text, it usesillustrations and tables to present the information. The author needsto develop all discussions along the main theme of the report as notedin the title, contents, introduction, purpose and scope.

Summary, Conclusions, and/or Recommendations

These sections provide a solution to the problems stated in the intro-duction, focus on the significant findings, and recommend a course ofaction. The most widely read parts of a report are the executive sum-mary or abstract and the summary, conclusions, and recommendationsbecause they state in condensed form the most important ideas andfindings and their significance. The executive summary or abstract andthe concluding material must be in complete agreement and presentthe essential information in the report. They should not, however, bemere repetitions of one another, although the same statements and datacan be included in both. Guidelines for preparing these sections aregiven below.

A summary is a restatement of all the main ideas presented in thereport and generally is required for all interpretive reports. The purposeof a summary is to review the most important facts so the reader cancorrectly recall the results and their significance. It should describe orlist these items in the order in which they were presented in the text;the author should review the table of contents and the main discussionswhen writing the summary.



The conclusions or recommendations state the final results, studyinterpretations, and recommendations for further action. All conclu-sions must either be stated in the report or be able to be readily derivedfrom the material presented. In preparing the conclusions, the authorshould refer to the “Purpose and Scope” section to verify that thesections support each other, i.e., check that the stated purpose of thestudy has been fulfilled, the scope adhered to, and purpose and scopeare reflected in the body of the report and in the conclusions. In general,conclusions are listed in the same order as the corresponding objectivesin the “Purpose and Scope” section. The main conclusions should alsobe incorporated in the executive summary or abstract. The recommen-dations state what actions, if any, should be taken to address or resolvethe problems stated in the introduction and the potential consequencesor benefits of such actions.

8.3 Report Review

The objective of a competent and thorough review is to

Ensure the report achieves the goals stated in the proposal.

Ensure the readability of the report.

Ensure the technical quality of the report.

Evaluate the suitability of the proposed publication media.

Evaluate the effectiveness of the presentation.

Correct errors and deficiencies that could embarrass the author and/or the parentorganization.

The peer/technical reviewer (Figure 8.3) should evaluate the organizationof the report. Are the major headings in the table of contents reflected inthe title, purpose, and scope, and do the summary or conclusions addressthe objectives stated in the purpose and scope? The peer reviewer shouldalso determine if the report is free of technical errors.

The reviewer should be objective, direct, careful, reasonable, andconsiderate. The following guidelines are provided to reviewers toimprove the quality of their review:

Be objective — Examine your attitude carefully before you begin a review andexamine your attitude frequently during the review. Are you trying to showhow smart you are? There is no place for sarcasm in review comments.Remember a reviewer is in a position of trust.



Be direct — You should avoid vagueness and ask clear questions. If there isn’troom to make intelligent questions or comments, use a separate sheet of paper.Isolated question marks are not acceptable forms of inquiry.

Be careful — The author and supervisor have a responsibility to ensure that thereport is as free from errors as they can possibly make it. Most editorial andtechnical errors should have been eliminated before the report is submittedfor technical review. Very little time should be spent by the reviewer in editing.

Be reasonable — Constructive suggestions are appreciated. Remember, however,that when the report is sent for a colleague to review, most of the allotted timeand money have already been spent. Unless necessary, avoid suggesting thingsthat will require additional time and money.

Be considerate — Place yourself in the shoes of the author. Refrain from the use ofhumor, wit, and sarcasm in your comments. No matter how funny it seems to youat the moment, assume the author will misunderstand and resent even the mostwell-meant barbs. Be brief and courteous in your remarks. Remember that yourreport will be reviewed; treat your peer’s report as you would like yours treated.

Peer Reviewers

The peer reviewer is, next to the author, the most important memberof the report team. The ability to do a good technical review is learnedby practice. The objective of the peer review of the report is to ensureits technical soundness and to help the author improve the report. Thepeer reviewers’ responsibilities include

Identifying technical aspects of a report for which they do not have the necessaryexpertise and conveying this information to the author so additional reviewerscan be selected.

Showing willingness to review the report in a timely manner.

Ensuring technical soundness and clarity, and suggesting alternative methods ofanalysis or interpretation, if appropriate.

Devoting adequate time and effort to check the mathematics, approach, organi-zation, editing, adequacy of data used to support conclusions, applicabilityand soundness of illustrations and tables, and readability.

Clearly indicating and describing problems in the report and preparing a summaryof the review.

Making constructive suggestions for improvements. Reviewers should point outboth positive and negative aspects of the report.

Communicating with the author during the review process.

It is helpful to put all calculations on a separate sheet.



Review Methods

There are four basic methods of peer review: concurrent, consecutive,group, and storyboard. Concurrent review is most commonly used becauseit consumes the shortest period of time. Group and storyboard reviews aresimilar and are useful when the author needs special assistance.

Concurrent review — Copies of the report are sent simultaneously to eachreviewer, and all comments are incorporated at one time. If reviewers disagreeon a particular point, the author should send each a set of the other’s comments,ask them to resolve the conflict, and notify the author of the resolution. If theconflicts are minor, they might be resolved by a telephone conference call.Authors are required to document all correspondence with reviewers, whetherwritten or oral.

Consecutive review — Copies of the report are sent to a reviewer and, after his/hercomments are received and corrections have been made, the report is subse-quently sent to a second reviewer. An advantage of this type of review is thatthe report, in theory, is improved after each review, assuming each reviewerdetects errors missed by the previous reviewer.

Group review — Two or more colleague reviewers are sent copies of the manu-script. After they have completed their review, they meet with the author todiscuss and revise the report. Commonly, these meetings result in interactionand discussion that greatly improve the report. A facilitator might be neededto control the pace of the meeting and to mediate any conflicts that arise.

Storyboard review — Mockups of the text and illustrations are displayed insequence on a table or wall. A blank sheet of paper can be attached to thepages for reviewers’ comments. After the review, the author compiles thecomments and discusses them with the reviewers. This type of review isespecially well suited for map and stop-format reports.

Editorial Review

The editorial review of text, illustrations, tables, and the manuscriptpackage should consider consistency in the use of terminology, clarityof expression, proper grammar, agreement of content with headingsand figure titles, adherence to publisher’s style, consistent use of topicsentences for paragraphs, completeness of all components and supportdocuments, suitability of illustrations, and readability. The reviewershould have a basic knowledge of hydrology. The key questions areviewer considers during the editorial review of text, illustrations,tables, and manuscript are listed below.



Text

Is the format of the report appropriate for the intended outlet?

Is the title of the report concise and accurate, and does it follow policy?

Are the title and authorship the same on the cover title page, abstract or executivesummary page, and transmittal memorandum?

Has assistance given by outside sources been acknowledged?

In the illustration list, is the type of illustration indicated? Is the caption correctlyabridged? Does it avoid abbreviations and acronyms?

In the list of tables, does the title of each table match the table title or a correctlyabridged version thereof? Does it avoid abbreviations and acronyms? Are headnotes and footnotes used correctly?

Does the list of conversion factors and abbreviations include all units of measurein the text, illustrations, and tables, and no others? Is the format correct?

Is the wording clear and free of jargon?

Do text headings agree with the table of contents in wording, rank, and pagenumber? Do discussions under a heading pertain to the heading?

Are International System (metric) or inch-pound units, among others, used con-sistently? (Note that it is acceptable to mix inch-pound units with metric unitsof chemical concentration and specific conductance.)

Do numbers and descriptive material in the text agree with the data in tables andwith information shown in illustrations?

Are all bibliographic citations in the text, tables, and illustrations in the list ofreferences? Are they in the correct format, and do authorship and year ofpublication agree with information in the list of references?

Are figure and table cut-ins placed in the text or in the margins where they arefirst mentioned in the text?

Are figure and table caption pages immediately following the page containingthe initial reference?

Do the summary and conclusions contain only information given in the report,and do they fulfill the purposes of the report?

Are the recommendations reasonable for information given in the report?

Illustrations

Is the format of the illustration correct?

Does the format meet the standards of the publisher?

Is the format of similar illustrations the same?

Is the explanation, if needed, complete and in the proper format?

Is the illustration caption correct?

Does the caption reflect the figure’s content?



Is the source of the illustration cited at the end of the caption, and is the numberof the figure in the cited source included in the citation?

Are the illustrations properly cross-referenced in the text?

If the illustration is a graph, are axis labels, grid, scale, and units of measurementappropriate? Are the axes properly labeled?

Are necessary geographic names given in the figure captions?

Does the title of the graph reflect information depicted by the graph?

Maps

If the illustration is a map, does the map contain all geographic names and sitesin the study area that were mentioned in the text?

Are the coordinate systems properly presented?

Is the explanation correct?

Are all symbols, physical features, and abbreviations labeled and explained?

If the map is a plate, is the plate caption complete, including the type of illustrationand complete geographic location?

Is a base-map and/or a data-credit note needed?

If colors are used, are they the same on the map and sections?

Are data contours explained and are datum notes needed?

Is information in the map in agreement with data mentioned in the text, presentedin a table, or shown in another illustration?

Are the scale and a north arrow included?

Cross-sections

Are the same vertical and horizontal scales used and, if not, is the amount ofexaggeration shown?

Is the view from the east or south?

Are the end points labeled and do they correspond to those shown on the map trace?

Are the maps that show the section traces referred to?

Is it possible to use the same horizontal scale as that on the map showing thesection traces?

Are the intersections with other sections identified?

Are all symbols, physical features, and abbreviations explained?

Tables

Are the data accurate?

Are the data presented logically?

Were the data in the table checked against the data mentioned in the text, presentedin an illustration, or presented in another table?



Are the tables properly cross-referenced in the text?

Is the position of the table in the report appropriate?

Does the table follow the first principal reference to the table?

If a table is long, should it be moved to the back of the report, perhaps as anappendix?

Is the format of the table correct?

Does the format meet the standards of the publisher?

Is the format of similar tables the same?

Are head notes and footnotes used properly?

Is the presentation of data in the table parallel to the table title and the discussionof the table in the text?

Are the location of the data and period of record needed in the table title tounderstand the table?

Is the source of the table or data cited?

Is the number of significant figures presented correctly and in a consistentmanner?

Is an unnumbered table properly introduced?

Are all geographic names and sites in a table located on a map?

Peer/Technical Review

The importance of technical review in the preparation of quality reportscannot be overemphasized. It is suggested that at least two reviews beused for all reports. The reviewers should be selected on the basis ofspecial knowledge or interest in the report’s subject. In the case ofinterpretive reports, it is desirable that at least one technical reviewerbe selected from outside the originating office.

Technical review of a report might reveal shortcomings or omis-sions that cannot be corrected in the final stages of the report. Toavoid this occurrence, it is advisable that some of the reviewers beselected at the beginning of the project and be informed and con-sulted during performance of the project in order to allow incorpo-ration of methods, actions, etc. at the appropriate time and asnecessary for the completion of a satisfactory report review. Com-promise in report quality or substantial delays and extra costs mayresult if this course of action is not followed.

A technical reviewer should concentrate on the technical adequacyof the report, but any major editorial errors, particularly in organiza-tion, should also be pointed out. Reviewers should summarize their



comments and make recommendations for improvement of the reportin a memorandum to the author. Brief, clear, and legible review com-ments should be entered directly on the manuscript. The author shouldrespond in writing to all reviewers’ comments, whether they areaccepted or rejected.

Reviewers should adopt a systematic approach when evaluatingreports. The 14-step process below provides a system for performingtechnical reviews. If followed, these steps can greatly improve thequality of peer review. Although not included in the steps, peer review-ers should attempt, as part of their review, to evaluate the editorialquality of text, tables, and illustrations, as described previously.

1. Transmittal memorandum — Carefully read the transmittal memorandumfrom the originating office and other background information on the projectthat generated the report. Such information can be extremely helpful byindicating how much emphasis needs to be placed on various parts of thereport.

2. Title — Carefully read and study the report title. The title should conveythe report subject yet be as short as possible. More than 15 words might betoo many.

• Does the title accurately reflect the main theme of the report and first-orderheadings in the contents?

• Is the location of the study area included?

• Is it necessary to include the time period of the study or of the data set?

• Does the title avoid abbreviations, acronyms, brand names, and extraneouswords?

3. Table of contents — Carefully examine the table of contents. It tells the readerthe order in which the topics are discussed and indicates the relative importanceof these topics. A well-organized table of contents shows that the author haswritten a report with a logical and orderly presentation of information. Thingsto consider include

• Do the first-order headings in the main body of the report accurately relateto the key words in the report title, both in wording and in order ofpresentation?

• Are the contents logically organized in a manner that contributes to conti-nuity of thought?

• Are all headings appropriately subdivided so that the subheadings furtherdevelop the subject of the heading?

• If subheadings are listed under a heading, are at least two subheadings used?

4. Conversion table — If the report contains a unit-of-measurement conversiontable, compare it with units of measurement in the text, illustrations, and tablesof the report.



• Does the table include all units of measurement used in the text, illustra-tions, and tables, and no others?

• Are the units of measurement worded correctly, and are the abbreviationsin the form required by the publisher?

5. Abstract or executive summary — Read the abstract or executive summaryseveral times. This section is a digest of the information in the report.

• If the report is interpretive, is this section informative rather than indicative?

• Does it reflect the summary or conclusions and stress the most importantresults in order of decreasing importance?

• Does it contain information that the reader can readily find in the body ofthe report?

6. Introduction — The introduction sets the theme of the report and establishesthe logic of the presentation that follows. It also is a place for miscellaneousinformation that does not belong in the body of the report.

• Does the introduction clearly define the need for and purpose of the inves-tigation — the what, why, where, and when of the investigation? Does itrelate to the main theme of the report as indicated in the title and table ofcontents?

• Do the purpose and scope of the report define the objectives of the reportand reflect the title and table of contents? Do they pertain only to the report(not to the project itself)? Does the scope of the report describe the depthof discussion in developing the subject of the report?

• Are the methods, approach, or both stated briefly, and are they appropriateto the problem and purpose of study? Does the methods section pertainonly to methods? New methods and approaches require more detailedexplanations than will standard methods and approaches, so methods sec-tions describing new methods will be longer.

• Does the introduction describe the physical setting of the project area, givingonly that information necessary to understand the data and interpretations?

• Is previous work in the subject area discussed and properly referenced?

• Are information and assistance from outside sources acknowledged?

7. Body — Read the body of the report, keeping the following questions in mind:

• Does the body present information to address the purpose of the report,and does it stay within the intended technical and geographic scope?

• Are equations and formulas accurate, clear, numbered, referenced, andappropriate to the problem and methods used?

• Does the text discuss the significance of the data in tables and illustrationsand not just repeat the data?

• Has written permission to use copyrighted material in the report beensecured from the copyright holder? A letter of authorization should beincluded.



• Are the data shown in text, tables, and illustrations in agreement?

• Has the discussion been developed along the main theme of the report asindicated in the title, table of contents, and purpose and scope?

• Are all methods discussed relevant to the theme of the report? Do discus-sions further the purpose of the report?

• Is the report free of agency/company policy violations?

8. Summary, conclusions, and recommendations — The summary, conclusions,or summary and conclusions section is the terminal section of the report. Asummary is a brief review of the informative parts of the report. The conclusionsare answers to questions addressed by the purposes of the report. The summaryand conclusions are second in importance to the abstract or executive summaryand usually serve as the principal source of information for those sections. Therecommendations, if included, state what action, if any, should be taken, andthe potential consequences of such actions. The reviewer should consider thefollowing questions about the summary and conclusions:

• Are the summary, conclusions, or recommendations a logical outgrowth ofinformation in the report?

• Does it contain or is it based on only information that is in the body of thereport?

• Does it reiterate the theme expressed in the title, purpose and scope?

• Does it draw together and briefly reiterate the principal findings of theinvestigation?

• Does it provide solutions or answers to problems addressed in the intro-duction?

• Is it as quantitative as possible, and does it include numerical findingspresented in body of the report?

9. References —The list of references gives credit to the sources of all publica-tions cited in the report. If the list contains only references that are cited inthe report, it is called “References” or “References Cited.” If the list is anextensive or exhaustive compilation of pertinent references, it is called a“Bibliography.”

• Are all literature citations in the text, tables, and illustrations listed? Hasthe author included the page, figure, or table number of the source materialin the citation?

• Are the references listed in the proper style and format for the intendedpublication?

10. Tables — Tables should be self-explanatory and in a format appropriate to thepublication. Is the table needed? If so, are the data presented in a table repeatedunnecessarily in the text? Are all data presented in the table needed? See thesection on editorial review, above, for additional guidelines in reviewing tables.

11. Illustrations — Maps, hydrologic and geologic sections, graphs, diagrams, linedrawings, and photographs should be self-explanatory. They should comple-



ment and support the text. They must be technically correct. Most problemswith illustrations can be identified during a thorough editorial review.

12. Verification — Verification is the process that is intended to make the reportinternally consistent. Internal consistency can be improved by use of thefollowing checklist:

• Is the report title the same wherever it appears — cover, title page, abstractor executive summary page, routing sheet, and transmittal memorandum?

• Do values in the text, tables and illustrations agree with one other?

• Is the wording and rank of headings in the table of contents the same asthose in the body of the report?

• Do figure and table titles agree with the lists in the table of contents?

• Is the pagination correct?

• Is the arithmetic in calculations correct?

• Are units of measurements in a consistent form and applicable, and are allof them included in the conversion table? Depending on the publicationoutlet, are all abbreviations that are used more than once spelled out inparentheses the first place they appear?

• Are chemical, geologic, hydrologic, and other symbols in a standard format,and are they consistent throughout the report?

• Are all geographic names in the text, tables, and illustrations shown on amap, or noted as being outside of map boundaries?

• Are contours shown on maps supported by values placed at data-controlpoints on a review copy?

• Have changes made to the body of the report during review been incorpo-rated in the abstract?

13. Re-examination — After all parts of the report have been reviewed, go backand check it all again. The reviewer has a good idea what the author hasattempted to say, what the author really has said, and how the author has saidit. A re-examination might disclose parts of the report where additionalimprovement is needed.

14. Review memorandum — After the review has been completed, the reviewershould prepare a memorandum that summarizes the results of the review. Majorproblems should be described. Comments written in the manuscript need notbe reiterated in the memorandum unless they have special significance. Com-ments of a complimentary nature also should be included in the memorandum.

References

Association of Engineering Firms Practicing in the Geosciences (ASFE), 1994,

TheASFE Guide to the In-House Review of Reports

, 3rd ed., ASFE, Silver Springs,MD, 19 p.



Association of Engineering Firms Practicing in the Geosciences (ASFE), 1992,

Important Information about Your Geotechnical Engineering Report

, ASFE,Silver Springs, MD, 2 p.

Bates, R.L. and Jackson, J. A., 1987,

Glossary of Geology

, 3rd ed., American Geo-logical Institute, Alexandria, VA, 787 p.

Cash, P., 1988,

How to Develop and Write a Research Paper

, 2nd ed., Prentice Hall,New York, NY, 96 p.

CBE Style Manual Committee, 1983,

CBE Style Manual — A Guide for Authors,Editors, and Publishers in Biological Sciences

, Council of Biology Editors,Inc., Bethesda, MD, 324 p.

Day, R.A., 1988,

How to Write and Publish a Scientific Paper

, 3rd ed., Oryx Press,Phoenix, AZ, 211 p.

Heath, R.C., 1983,


, U.S. Geological SurveyWater-Supply Paper 2220, 84 p.

Hem, J.D., 1985,

Study and Interpretation of the Chemical Characteristics of NaturalWater

, 3rd ed., U.S. Geological Survey Water-Supply Paper 2254, 263 p.Lamott, Anne, 1994,

Bird by Bird, Some Instructions on Writing and Life

, AnchorBooks, New York, NY, 239 p.

Lohman, S.W., 1972,

Ground-Water Hydraulics

, U.S. Geological Survey Profes-sional Paper 708, 70 p.

Lohman, S.W. et al., 1972,

Definition of Selected Ground-water Terms — Revisionsand Conceptual Refinements

, U.S. Geological Survey Water Supply Paper1988, 21 p.

Malde, H.E., 1986,

Guidelines for Reviewers of Geological Manuscripts

, AmericanGeological Institute, Alexandria, VA, 28 p.

Moore, J.E., 1991,

A Guide for Preparing Hydrologic and Geologic Projects andReport

, Kendall/Hunt, Dubuque, 96 p.Moore, J.E., Aronson, D.A., Green, J.H., and Puente, C., 1988,

Report Planningand Review Guide

, U.S. Geological Survey Open-File Report 88–320, 75 p.Moore, J.E. and Chase, E.B., 1982,

WRD Project and Report Management Guide

,U.S. Geological Survey Open-File Report 85–634, 243 p.

Strunk, W., Jr. and White, E.B., 1979,

The Elements of Style

, Macmillan, New York,85 p.

U.S. Geological Survey, 1991,

Suggestions to Authors of the Reports of the UnitedStates Geological Survey

, 7th ed., U.S. Government Printing Office, Washing-ton, D.C., 289 p.


Water Resources Division Publications Guide —Volume 1. Publications Policy and Text Preparation

, U.S. Geological SurveyOpen-File Report 87–205, 429 p.

U.S. Government Printing Office, 1984,

United States Government Printing OfficeStyle Manual

, Washington, D.C., 479 p.



Wilson, W.E. and Moore, J.E., 1998,

Glossary of Hydrology

, American GeologicalInstitute, Alexandria, VA, 248 p.


117

9

Chapter

Case Studies

Hydrogeologic systems are dynamic and adjust continually to changesin climate, groundwater withdrawal, and land use. Water level mea-surements from observation wells are the major source of informationabout hydrologic stresses affecting aquifers, groundwater recharge,storage, and discharge. Long-term measurements of water levels pro-vide essential data needed to evaluate changes over time, to developcomputer models, forecast trends monitor effectiveness of protectionand management programs.

9.1 Central Valley, California

Mining groundwater for irrigation has enabled the Central Valley ofCalifornia to become one of the world’s most productive agriculturalregions, while also contributing to one of the single largest alterationsof the land surface attributed to mankind. The central valley produces25% of the nation’s food on only 1% of the country’s farmland(Figure 9.1). The valley is 500 mi long by 50 mi wide, with a totalarea of about 16,000 mi

2

. It is arid to semiarid, receiving an averageof 5 to 16 in. of rainfall annually. The valley is underlain by a largeunconfined and partially confined alluvial aquifer throughout to adepth of 25,000 ft. Fresh groundwater is present to depths of as muchas 4000 ft, but most well are less than 1000 ft deep. A laterallyextensive lake clay known as the “Corcoran Clay” is distributedthroughout the central and western valley. The clay varies in thick-ness from a feather edge to 160 ft. Significant development ofgroundwater for irrigation began in the early 1900s. As groundwater



withdrawal increased to the point that its withdrawal exceededrecharge, the potentiometric surface started to decline. In some areas,potentiometric surface declined 260 ft (between 1940 and 1963). Thegroundwater withdrawal caused the compaction of fine-grained con-fining beds, which resulted in subsidence of the land surface. Waterlevel declines of 160 ft or more have resulted in land subsidence ofabout 30 ft in the Los Banos-Kettleman city area. Until 1968, irri-gation water was almost entirely supplied by groundwater. As of1960, water levels in the deep aquifer system were declining at arate of about 10 ft per year. In the late 1960s, surface water irrigationbegan to replace groundwater. This resulted in a dramatic period ofrecovery and subsidence slowed over a large part of the valley. Theannual cost of subsidence was $180 million due to the loss of prop-erty values, replacement of irrigation pipelines and wells.

9.2 Chicago, Illinois

Since 1864, large quantities of groundwater have been withdrawn fromglacial drift and bedrock aquifers for municipal and industrial use(Figure 9.2). In the Chicago area, two Cambrian-Ordovician bedrockaquifers (sandstone and dolomite) supply water. One of the first wellswas drilled to a depth of 711 ft and flowed at the land surface at 400gal/min (Alley et al., 1999). Groundwater withdrawal from the Cam-brian-Ordovician bedrock aquifers (sandstone and dolomite) hascaused water level (artesian head) declines of more than 800 ft. Water

FIGURE 9.1

Central Valley, California.

17 Alluvial aquifer ConfinedD

EP

TH

TO

WA

TE

R, F

EE

T B

EL

OW

LA

ND

SU

RFA

CE

120

140

160

1925 1935 1945 1955 1965 1975 1985

60

20

40

0

80

180

100


Case Studies 119

use has increased from 9.2 to 340 million gallons per day from 1864to 1980. No major land subsidence has been reported as a result ofthese large withdrawals because the rocks in the area are consolidatedand resist compaction. A principal concern has been the potential toconvert the confined aquifer to an unconfined aquifer and thus allowmining to take place. Since 1980, many public water supplies wereshifted to water from Lake Michigan, which has resulted in a signif-icant decrease in withdrawal and general recovery of potentiometricheads. Pumping continues in all parts of the area, however, and maybe increasing in some areas.

9.3 Las Vegas Valley, Nevada

The Las Vegas Valley is presently the fastest growing metropolitanarea in the United States (Figure 9.3). Water to support this rapidgrowth is supplied by imported Colorado River water and localgroundwater. Groundwater is pumped from the upper 2000 ft of uncon-solidated alluvial sediments. The deeper aquifers, called “principalartesian aquifers” (below 300 ft) can yield large quantities of ground-water. Overlying the principal aquifers are 100- to 300-ft thick depositsof clay. Since the 1970s, the annual groundwater withdrawal hasremained between 60,000 and 90,000 acre ft. Most of the withdrawalis from the northwest area, which has seen declines of more than300 ft. Areas in central Las Vegas (The Strip) have declined as much

FIGURE 9.2

Chicago, Illinois.

250

1940 1950 1960 1970 1980 1990 2000–50

0

50

150

200

100

YEAR

WAT

ER

LE

VE

L, IN

FE

ET

AB

OV

E S

EA

LE

VE

L



as 200 ft. Since 1935, compaction of the aquifer has caused nearly 6ft of subsidence and has led to the formation of numerous earth fissuresand surface faults. Before groundwater development, the aquifer sus-tained the flow of many springs that discharged into Las Vegas Wash;groundwater withdrawal has caused the springs to dry up. Urban runoffhas created a reservoir of poorer quality, and this contaminated waternow recharges the principal artesian aquifer.

9.4 Tucson and Phoenix, Arizona

Large water level declines in the unconfined aquifers have caused landsubsidence and earth fissures to develop in a 3000 mi

2

area thatincludes Tucson and Phoenix (Figure 9.4); water levels in the Tucsonarea have declined 160 ft from 1945 to 1984. The subsidence is causedby compaction of fine-grained sediments in the basin fill. The sedi-ments deform and compact when decreased water-levels subject thesediments to additional compression from the weight of the overlyingdeposits. Compaction increases slowly as the water levels decline.Land subsidence has exceeded 15 ft since the start of groundwaterdevelopment in 1915. Compaction and land subsidence have causedcracks to develop in the land surface, which can extend for hundreds

FIGURE 9.3

Las Vegas, Nevada.

W

E

Springs

Water tableWater flow

Spring Mts.

Faults (arrow indicatesdirection of relative movement)

Bedrock Silt and Clay

Las Vegas Wash

Sand and gravel


Case Studies 121

to thousands of feet along the surface and can be hundreds of feetdeep (USGS, 1995).

References

Alley, W.M. et al., 1999,

Sustainability of Ground-Water Resources

, U.S. GeologicalSurvey Circular 1186, Denver, CO, 79 p.


Colorado, New Mexico, Nevada, and Arizona: Hydro-logic Atlas

, 730-C.

FIGURE 9.4

Tucson, Arizona.

2 Alluvial aquifer Unconfined

Missing record

DE

PT

H T

O W

AT

ER

, FE

ET

BE

LO

W L

AN

D S

UR

FAC

E

240

260

280

1945 1955 1965 1975 1985

180

140

160

120

200

300

220


123

Further Reading

Alley, W.M. et al., 1999,

Sustainability of Ground-Water Resources

, U.S. GeologicalSurvey Circular 1186, Denver, CO, 79 p.

Brassington, R., 1988,

Field Hydrogeology,

John Wiley, New York.Clark, L., 1988,

The Field Guide To Water Wells And Boreholes

, John Wiley, NewYork.

Fetter, C.W., 2001,


, Prentice Hall, Upper Saddle River, NJ.Galloway, D. et al., 1999,

Land Subsidence in the United States

, U.S. GeologicalSurvey Circular 1182, 177 p.

Moore, J.E. et al., 1985,

Groundwater — A Primer

, American Geological Institute,Alexandria, VA.

Sanders, Laura L., 1998,

A Manual Of Field Hydrogeology

, Prentice Hall, EnglewoodCliffs, NJ.

U.S. Bureau of Reclamation, 1977,

Ground Water Manual

, U.S. Department ofInterior.

Wilson, W.E. and Moore, John E., 1998,

Hydrologic Glossary

, American GeologicalInstitute, Alexandria, VA.

Winter, T.C. et al., 1999,

Ground Water and Surface Water — A Single Resource

, U.S. Geological Survey Circular 1139.

Wright, W.D. and Sonderegger, J.L., 2001,

Manual of Applied Field Hydrogeology

,McGraw-Hill, New York.


125

Glossary

A

Abandoned well

A well whose use has been permanently discon-tinued or which is in a state of such disrepair that it cannot beused for its intended purpose (U.S. Environmental ProtectionAgency, 1994).

Acre foot (AF)

The quantity of water required to cover 1 acre to adepth of 1 foot, and is equal to 43,560 cubic feet or about 326,000gallons or 1,233 cubic meters (Novak, 1985).

Affluent stream

Stream flowing toward or into a larger stream orlake (AGE, 1987).

Alluvium

(1) A general term for all detrital deposits resultingdirectly or indirectly from the sediment transport of streams,thus including the sediments laid down in riverbeds, floodplains, lakes, fans, and estuaries (Interagency Committee onWater Data, 1977). (2) A general term for clay, silt, sand gravel,or similar unconsolidated detrital material deposited duringcomparatively recent geologic time by a stream or other bodyof running water, as sorted or semisorted sediment in the bedof the stream or on its flood plain or delta, as a cone or fan atthe base of a mountain slope (AGE, 1987).

Aquiclude

A saturated geologic unit that is incapable of transmittingsignificant quantities of water under ordinary hydraulic gradients(Freeze and Cherry, 1979). Replaced by

confining bed

(Lohman,1972, p. 2).



Aquifer

A formation, group of formations, or part of a formationthat contains sufficient saturated permeable material to yield sig-nificant quantities of water to wells and springs (Lohman, 1972,p. 2). Also called water-bearing formation.

Aquifer system

A heterogeneous body of permeable material thatacts as a water-yielding hydraulic unit of regional extent (Batesand Jackson, 1987).

Aquifer test

A test involving the withdrawal of measured quantitiesof water from, or addition of water to, a well and the measurementof resulting changes in hydraulic head in the aquifer both duringand after the period of discharge or addition (AGE, 1980, p. 31).

Area of influence

The area surrounding a pumping or rechargingwell within which the potentiometric surface has been changed.

Artesian aquifer

See also

confined aquifer.

Artesian head

The hydrostatic head of an artesian aquifer or of thewater in the aquifer (AGE, 1980, p. 36).

Artesian pressure

Hydrostatic pressure of artesian water, oftenexpressed in terms of pounds per square inch at the land surfaceor as height, in feet above the land surface, of a column of waterthat would be supported by the pressure (AGE, 1980, p. 36).

Artesian spring

A spring from which the water flows under artesianpressure, usually through a fissure or other opening in the con-fining bed above the aquifer (AGE, 1980, p. 36).

Artesian well

A well tapping confined groundwater. Water in thewell rises above the level of the water table under artesianpressure, but it does not necessarily reach the land surface.Sometimes restricted to mean only a flowing artesian well.(AGE, 1980, p. 36).


Glossary 127

B

Baseflow

(1) That part of stream discharge that is groundwater seep-ing into the stream (Fetter, 2001, p. 636). (2) That part of thestream discharge that is not attributable to direct runoff fromprecipitation or melting snow. It is sustained by groundwaterdischarge (Groundwater subcommittee, 1989).

Baseflow recession hydrograph

A hydrograph that shows a base-flow-recession curve (Fetter, 2001).

Bladder pump

A positive-displacement pumping device that usespulses of gas to push a water-quality sample toward the surface(Fetter, 2001).

Basic hydrologic data

Includes inventories of features of land andwater that vary only from place to place (topographic and geo-logic maps are examples), and records of processes that vary withboth place and time (Langbein and Iseri, 1960).

Bedrock

(1) A general term for the rock, usually solid, that underliessoil or other unconsolidated, superficial material (AGE, 1980, p.60). (2) The solid rock underlying soils and regolith or exposedat surface (ASTM, 1994).

Biologic oxygen demand (BOD)

An index of the amount of oxygenconsumed by living organisms (mainly bacteria) while utilizingthe organic matter in waste (Dunne and Leopold, 1978).

Bioremediation

Use of microorganisms to control and destroy con-taminants (NAS-NRC, 1994).

Borehole

A circular hole in the ground made by boring. Commonlya deep hole of small diameter, such as an oil well or a water well(AGE, 1980, p. 76).

Borehole geophysics

The application of certain physical principles,such as magnetic attraction, gravitational pull, speed of soundwaves, and the behavior of electric currents to determine thenature of rock and water penetrated by a bore hole. A generalfield of geophysics developed around the lowering of variousprobes into a well (Fetter, 2001).

Boring

A hole advanced into the ground by means of a drilling rig(Fetter, 2001).



Brackish water

(1) An indefinite term for water with a salinity inter-mediate between that of normal seawater and that of normal freshwater (AGE, 1980, p. 79). (2) Water that contains more than 1500mg/L but not more than 15,000 mg/L total dissolved solids(USDOI, 1986, p. 24).


Glossary 129

C

Cable tool drilling

A method of drilling. Rock at the bottom of thehole is broken up by a steel bit with a blunt, chisel-shaped cuttingedge. The bit is at the bottom of a heavy string of steel toolssuspended on a cable that is activated by a walking beam, the bitchipping the rock by regularly repeated blows. The method isadapted to drilling water wells and relatively shallow oil wells(AGE, 1980, p. 87).

Calibration

The process of fitting a model to a set of observed databy changing unknown or uncertain model parameters systemati-cally within their allowable ranges until a “best” fit of model tothe observed data is achieved (Fetter, 2001). See also

modelcalibration.

Cone of depression

A depression of the potentiometric surface inthe shape of an inverted cone that develops around a well that isbeing pumped. See also

pumping cone.

Confined aquifer

An aquifer that is overlain by a confining bed(Fetter, 2001, p. 635). See also

artesian aquifer.

Confined groundwater

Groundwater under pressure significantlygreater than that of the atmosphere. Its upper surface is the bottomof an impermeable bed or a bed of distinctly lower permeabilitythan the material in which the water occurs (AGE, 1980, p. 132).See also

artesian water.

Confined-water well

A well for which the sole source of supply isconfined groundwater (Rogers et al., 1981, p. 75). See also

artesianwell.

Confining bed

(1) A layer (bed) of “impermeable” material strati-graphically adjacent to one or more aquifers. In nature, its hydrau-lic conductivity may range from nearly zero to some valuedistinctly lower than that of the aquifer. It supplants aquifuge,aquitard, and aquiclude (Lohman et al., 1972, p. 5). (2) A bodyof material of low hydraulic conductivity that is stratigraphicallyadjacent to one or more aquifers. It may be above or below theaquifer (Fetter, 2001).

Conjunctive use of water

The joining together of two sources ofwater, such as groundwater and surface water, to serve a particularuse (NAS-NRC, 1994).



Connate water

(1) Water entrapped in the interstices of a sedimentat the time of its deposition; recommended definition is “waterthat has been out of contact with the atmosphere for at least anappreciable part of a geologic period” (White, 1957, p. 1661).(2) Commonly misused by reservoir engineers and well-log ana-lysts to mean interstitial water or formation water (Bates andJackson, 1987). See also

fossil water.

Constant head boundary

The conceptual representation of a natu-ral feature such as a lake or river that effectively fully penetratesthe aquifer at that location (ASTM, 1994).

Consumptive use

A term used mainly by irrigation engineers tomean the amount of water used in crop growth plus evaporationfrom the soil. Water absorbed by the crop and transpired or useddirectly in the building of plant tissue together with that evap-orated from the cropped area (U.S. Army Corps of Engineers,1991).

Contact spring

A type of gravity spring whose water flows to theland surface from permeable strata over less permeable or imper-meable strata that prevent or retard the downward percolation ofthe water (Meinzer, 1923, p. 51).

Contaminant

Any physical, chemical, biological, or radiologicalsubstance or matter that has an adverse effect on air, water, orsoil (USEPA, 1994). See also

pollutant

.

Contamination

As applied to water, the addition of any substanceor property preventing the use or reducing the usability of thewater for ordinary purposes, such as drinking, preparing food,bathing, washing, recreation, and cooling. Sometimes arbitrarilydefined differently from pollution, but generally considered syn-onymous (AGE, p. 135).

Core

In drilling, a cylindrical column of rock taken as a sample ofthe interval penetrated by a core bit, and brought to the surfacefor geologic examination and/or laboratory analysis (AGE, 1980,p. 140).

Core log

A record showing, for example, the depth, character, lithol-ogy, porosity, permeability, and fluid content of a core (AGE,1980, p. 141).


Glossary 131

Crest gage

A device for obtaining the elevation of the flood crestof streams or lakes (Rantz et al., 1982, p. 77). See also

crest-state gage.

Crystalline rock

An inexact but convenient term designating anigneous or metamorphic rock as opposed to a sedimentary rock(AGE, 1987). An igneous or metamorphic rock consisting whollyof relatively large mineral grains.

Cubic feet per second (CFS)

A unit expressing rates of discharge(Langbein and Iseri, 1960).

Current

(1) The flowing of water or other liquid. (2) That portionof a stream of water that is moving with a velocity much greaterthan the average or in which the progress of the water is princi-pally concentrated (Rogers et al., 198l, p. 87).

Current meter

Instrument for measuring the speed of flowing water(Lohman et al., 1972, p. 7). The U.S. Geological Survey uses arotating cup meter.



D

Daily hydrograph

A hydrograph showing days as the units of time.

Data

Records of observations or measurements of facts, occurrencesand conditions in written, graphical or tabular form. (U.S. Corpsof Engineers, 1991).

Darcy’s law

An empirical law stating that the velocity of flow in apermeable media is directly proportional to the hydraulic gradientassuming that the flow is laminar and inertia can be neglected(USDOI, 1986).

Deep well

Water wells, generally drilled, extending to a depth greaterthan that typical of shallow wells in the vicinity. The term maybe applied to a well 20 m deep in an area where shallow wellsaverage 7 or 8 m deep, or to a much deeper well in an area wherethe shallowest aquifer supplies wells 100 m deep or more (AGE,1980, p. 163).

Discharge area

An area in which there are vertical components ofhydraulic head in which head increases downward the aquifer.Groundwater is flowing toward the surface in a discharge areaand may exit as a spring, seep, or stream baseflow or by evapo-ration and transpiration (Fetter, 2001, p. 637).

Dispersion

The phenomenon by which solute in flowing groundwa-ter is mixed with uncontaminated water and becomes reduced inconcentration. Dispersion is caused by both differences in thevelocity that the water travels at the pore level and differences inthe rate at which water travels through different strata in the flowpath (Fetter, 2001, p. 639).

Distribution coefficient

Refers to the quantity of the solute sorbed bythe solid per unit weight of solid divided by the quantity dissolvedin the water per unit volume of water (Cohen and Mercer, 1993).

Distilled water

Water formed by the condensation of steam or watervapor (Rogers et al., 1981, p. 107).

DNAPL

(1) Dense nonaqueous phase liquid. A polluting liquid witha density greater than water that sinks to the base of the aquifer,e.g., creosote and trichloro-ethylene (Stanger, 1994). (2) It issynonymous with denser-than-water immiscible phase liquid(Cohen and Mercer, 1993).


Glossary 133

Domestic water

Water used in homes and on lawns, including usefor laundry, washing cars, cooling, and swimming pools (Wang,1974, p. 123).

Double porosity

Water can be withdrawn from both the fracturesand matrix of a fractured porous medium and discrete flow inindividual fractures (Dominico and Schwartz, 1990).

Drawdown

(1) The lowering of the surface elevation of a body ofwater, the water surface of a well, the water table, or the poten-tiometric surface adjacent to the well, resulting from the with-drawal of water. The difference between the nonpumping waterlevel at some time and pumping level at that time. (U.S. ArmyCorps. of Engineers, 1991). (2) The lowering of the water tableof an unconfined aquifer or the potentiometric surface of aconfined aquifer caused by pumping of groundwater from wells(Fetter, 2001, p. 238).

Dug well

Well excavated by means of picks, shovels, or other handtools, or by means of a power shovel or other dredging ortrenching machinery, as distinguished from one excavated by adrill or auger.



E

Effective porosity

The amount of interconnected pore space avail-able for fluid transmission. It is expressed as a percentage of thetotal rock volume that is occupied by the interconnecting inter-stices. Although effective porosity has been used synonymouslywith specific yield, such use is discouraged (Lohman et al., 1972).This definition of effective porosity differs from that of Meinzer(1923, p. 28).

EIS

Environmental Impact Statement. A legally required documentto describe the environmental impact of a project (Stanger, 1994).

Electrical well log

A record obtained in a well investigation in rockfrom a traveling electrode; it is in the form of curves that representthe apparent values of the electric potential and electric resistivityor impedance of the rocks and their contained fluids throughoutthe uncased portions of a well (Rogers et al., 1981, p. 1260).

Ephemeral stream

A stream or reach of a stream that flows brieflyonly in direct response to precipitation in the immediate locality andwhose channel is at all times above the water table. The term maybe arbitrarily restricted to a stream that does not flow continuouslyduring periods of as much as one month (Meinzer, 1923, p. 58).

Equipotential line

A line, in a field of flow, such that the total headis the same for all points on the line; therefore, the direction offlow is perpendicular to the line at all points (U.S. Army Corpsof Engineers, 1991).

Equipotential surface

A surface in a three-dimensional groundwa-ter flow field such that the total hydraulic head is the same forall points along the line (Fetter, 2001).

Evaporation

The process by which water passes from the liquid tothe vapor state (Fetter, 2001) The quantity of water that is evap-orated; the rate is expressed as depth of liquid water removedfrom a specified surface per unit of time, generally in inches orcentimeters per day, month, or year. The concentration of dis-solved solids by driving off water through the application of heat(Rogers et al., 1981, p. 132).

Evapotranspiration

Water withdrawn from the land area by evapo-ration from the water surfaces, moist soil and plant transpiration(Langbein and Iseri, 1960).


Glossary 135

F

Fault spring

Spring flowing onto the land surface from a fault whosemovement resulted in a permeable bed coming in contact withan impermeable bed (AGE, 1980, p. 224).

Field capacity

The quantity of water that can be permanentlyretained in the soil in opposition to the downward pull of gravity(Langbein and Iseri, 1960, p. 9)

.

Finite-difference model

A digital groundwater flow model basedupon a rectangular grid that sets the boundaries of the model andnodes where the model will be solved (Fetter, 2001).

Finite-element model

A digital groundwater flow model where theaquifer is divided into a mesh formed by multiple polygonal cells(Fetter, 2001).

Flowing well

Well that discharges water at the surface without theaid of a pump or other lifting device; a type of artesian well(Rogers et al., 1981, p. 153).

Fracture

Joint, or fault in rock or rock material.

Fracture permeability

The property of a rock or rock material thatpermits movement of water along interconnecting joints andfaults.

French drain

An underground passageway for water through theinterstices among stones placed loosely in a trench (U.S. ArmyCorps of Engineers, 1991).

Fresh water

Water that contains less than 1000 mg/L of dissolvedsolids; generally more than 500mg/L is undesirable for drinkingand many industrial uses (Bates and Jackson, 1987).

Fringe water

Water of the capillary fringe (Bates and Jackson,1987).

Fully penetrating well

Well that penetrates and is open to entiresaturated thickness of the aquifer.



G

Gage

A device for indicating the magnitude or position of an elementin specific units when such magnitude or position is subject tochange; examples of such elements are the elevation of a watersurface, the velocity of flowing water, the pressure of water, theamount or intensity of precipitation, and the depth of snowfall(Rogers et al., 1981, p. 162).

Gage height

The water-surface elevation referred to some arbitrarygage datum. Gage height is often used interchangeably with themore general term

stage

, although gage height is more appropri-ate when used with a reading on a gage (Langbein and Iseri,1960, p. 11).

Gaging station A site on a stream, canal, lake, or reservoir wheresystematic observations of gage height or discharge are obtained(Langbein and Iseri, 1960, p. 11).

Gaining stream A stream or stretch of stream that receives waterfrom groundwater in the saturation zone. The water surface ofsuch a stream stands at a lower level that the water table orpiezometric surface of the groundwater body from which itsreceives water (Rogers et al., 1981, p. 163).

Geographic information system (GIS) An organized collection ofcomputer hardware, software, geographic data, and personneldesigned to efficiently collect, store, update, manipulate, analyze,and display all forms of geographically referenced information.

Geohydrologic unit An aquifer, a confining unit or a combinationof aquifers and confining units, comprising “a framework reason-ably distinct hydraulic system” (Maxey, 1964, p. 126).

Geohydrology The study of earth science aspects of groundwater.Emphasis is usually on the hydraulic groundwater flow in aqui-fers. Also used in reference to all hydrology on the Earth withoutrestriction to geologic aspects (Stringfield, 1966, p. 3).

Geologic map A graphic representation of geologic information,such as the distribution, nature, and age relationships of rock units(surficial deposits may or may not be mapped separately) and theoccurrence of structural features (folds, faults, joints), mineraldeposits, and fossil localities. It may indicate geologic structureby means of formational outcrop patterns, by conventional sym-


Glossary 137

bols giving the direction and amount of dip at certain points, orby structure-contour lines (Bates and Jackson, 1987).

Gyben-Herzberg principle An equation that relates the depth of asaltwater interface in a coastal aquifer to the height of the fresh-water table above sea level (Fetter, 2001).

Ganat Long gently sloping tunnels used to collect groundwater inNorth Africa, Egypt, and Iran. Because the water flows undergravity, the tunnels do not have to be pumped.

Glacial aquifer Material deposited by a glacier or in connection withglacial processes that is capable of yielding water to wells.

Gravel Unconsolidated coarse, granular material, larger than sandgrains, resulting from reduction of rock by natural or artificialmeans. Sizes range from 0.16 cm (No. 4 sieve) to 2.6 cm in diameter.Coarse gravel ranges from 7.6 cm to 1.9 cm, whereas fine gravelranges from 1.9 cm to 0.16 cm (Bates and Jackson, 1987).

Gravity drainage Movement of DNAPL in an aquifer that resultsfrom the force of gravity (Cohen and Mercer, 1993).

Gravity flow Movement of glacier ice as a result of the inclinationof the slope on which the glacier rests (Bates and Jackson, 1987).

Gravity water A supply of water that is transported from its sourcesto its place of use by means of gravity, as distinguished from asupply that is pumped (Rogers et al., 1981, p. 169) and compactedhard by traffic (Rogers et al., 1981, p. 171).

Groundwater (1) Water in the ground that is in the zone of satura-tion, from which wells, springs, and groundwater runoff are sup-plied (Langbein and Iseri, 1960). (2) The part of the subsurfacewater that is in the saturated zone. Loosely, all subsurface water(excluding internal water) as distinct from surface water (Batesand Jackson, 1987). All subsurface water distinct from surfacewater. Water in the saturated zone beneath the water table.

Groundwater barrier A natural or artificial obstacle, such as a dikeor fault gouge, to the lateral movement of groundwater, not inthe sense of a confining bed. It is characterized by a markeddifference in the level of the groundwater on opposite sides (AGE,1980, p. 278).

Groundwater basin (1) A subsurface geologic structure having thecharacter of a basin with respect to the collection, retention, andoutflow of water. (2) An aquifer or system of aquifers, whether



basin-shaped or not, that has reasonably well defined boundariesand more or less definite areas of recharge and discharge.

Groundwater budget A numerical account, the groundwater equa-tion, relating recharge, discharge, and changes in storage of anaquifer, part of an aquifer, or system of aquifers (AGE, 1980, p. 278).

Groundwater depletion The lowering of the ground-water level ofan area (Rogers et al., 1981, p. 174). The decrease in availablegroundwater supplies.

Groundwater flow Groundwater runoff and groundwater movement.Groundwater irrigation Irrigation by water derived from wells,

springs, or shallow ponds not supplied by surface runoff (Rogerset al., 1981, p. 173).

Groundwater level The elevation of the water table or other poten-tiometric surface at a particular place or in a particular area, asrepresented by the level of water in wells or other natural orartificial openings or depressions communicating with the zoneof saturation (Bates and Jackson, 1987).

Groundwater outflow That part of the discharge from a drainagebasin that occurs through the aquifer. The term underflow is oftenused to describe the groundwater outflow that takes place inalluvium and thus is not measured at a gauging station (U.S.Army Corps of Engineers, 1991).

Groundwater movement The flow of groundwater in response to ahydraulic gradient.

Groundwater pollution Impairment of groundwater quality canresult from land disposal of waste materials that are dissolved bypercolating water and then leach downward through the unsatur-ated zone to the groundwater, or from improperly constructed oroperated wells (Flick, 1980, p. 83).

Groundwater recharge Replenishment of groundwater naturally byprecipitation or runoff or artificially by spreading or injection.

Groundwater reservoir (1) An aquifer. (2) A term used to refer toall the rocks in the zone of saturation, including those containingpermanent or temporary bodies of perched groundwater (AGE1980, p. 278).

Groundwater runoff That portion of the runoff that has infiltratedthe groundwater system and has later been discharged into astream channel or other surface water body as spring or lake.


Glossary 139

Groundwater runoff is the principal source of base or dry weatherflow of streams unregulated by surface storage, and such flow issometimes called groundwater flow (Rogers et al., 1981, p. 174).



H

Hantush-Jacob formula An equation to describe the change inhydraulic head with time during pumping of a leaky confinedaquifer (Fetter, 2001).

Hardpan A shallow layer of earth material which is relatively hardand impermeable, usually through the deposition of minerals(U.S. Army Corps of Engineers, 1991).

Head, elevation The elevation of a given point in a column of liquidabove a datum (U.S. Army Corps of Engineers, 1991).

Heterogeneity (1) A characteristic of a medium in which materialproperties vary from point to point (U.S. Geological Survey, 1989).(2) A lack of uniformity in porous media properties and conditions(Cohen and Mercer, 1993). (3) Pertaining to a substance havingdifferent characteristics in different locations (Fetter, 2001).

Hollow-stem auger A particular kind of a drilling device wherebya hole can be rapidly advanced into sediment. Sampling andinstallation of the equipment can take place through the hollowcenter of the auger (Fetter, 2001).

Homogeneous Of uniform composition throughout (U.S. ArmyCorps of Engineers, 1991).

Horizontal well A tubular well pushed approximately horizontallyinto a water-bearing stratum or under the bed of a lake or stream.Also called push well (Rogers et al., 1981, p. 181).

Hot spring Thermal spring, the water of which has a temperaturehigher than that of the human body (higher than 98°F/36°C).

Hvorslev method A procedure for performing a slug test in a piezom-eter that partially penetrates a water-table aquifer (Fetter, 2001).

Hydraulic conductivity Property of an aquite rock that indicates itscapability to transmit water, expressed as the volume of water atthe existing kinematic viscosity that will move in unit time undera unit hydraulic gradient through a unit area of aquifer measuredat right angles to the direction of flow (Lohman et al., 1972). Seealso permeability coefficient.

Hydraulic diffusivity Property of an aquifer or confining bed thatis defined as the ratio of the transmissivity to the storativity(Fetter, 2001).


Glossary 141

Hydraulic gradient (1) The change in head per unit distance in agiven direction, typically in the principal flow direction (Cohenand Mercer, 1993). (2) In a stream, the slope of the hydraulicgrade line (Bates and Jackson, 1987). The change in total headwith a change in distance in a given direction. (3) The directionis that which yields a maximum rate of decrease in head (Fetter,2001).

Hydraulic head The height above a datum plane (such as sea level)of the column of water that can be supported by the hydraulicpressure at a given point in a groundwater system. (U.S. Depart-ment of Interior, 1986).

Hydrochemical facies Bodies of water with separate but distinctchemical compositions contained in an aquifer (Fetter, 2001).

Hydrogen-ion concentration The negative log of the hydrogen-ionactivity in solution; a measure of the acidity of a solution; com-monly designated as pH (Bates and Jackson, 1987).

hydrogeology The study of the interrelationships of geologic mate-rials and processes with water, especially groundwater (Fetter,2001). Emphasis is on the geologic aspects of groundwater flowand occurrence.

Hydrograph Graph showing stage, flow, velocity, or other propertyof water with respect to time (Langbein and Iseri, 1960, p. 12).

Hydrologic cycle A convenient term to denote the circulation ofwater from the sea, through the atmosphere, to the land and then,with many delays, back to the sea by overland and subterraneanroutes and in part by way of the atmosphere; also the many shortcircuits of water that is returned to the atmosphere without reach-ing the sea (Langbein and Iseri, 1960; Meinzer, 1949, p. 1).

Hydrologic data Records of observations and measurements ofphysical facts, occurrences, and conditions related to precipita-tion, stream flow, groundwater, quality of water, and water use(Rogers et al., 1981, p. 90).

Hydrologic equation An expression of the law of mass conservationfor purposes of water budgets. It may be as inflow equals outflowplus or minus changes in storage (Fetter, 2001).

Hydrologic model A scaled reproduction (mechanical device) orrepresentation (electrical system) of hydrologic data (Rogers etal., 1981, p. 235).



Hydrologic properties Those properties of a rock that govern theentrance of water and the capacity to hold, transmit, and deliverwater, e.g., porosity, effective porosity, specific retention, perme-ability, and direction of maximum and minimum permeability(Bates and Jackson, 1987).

Hydrologic regime The characteristic behavior and the total quan-tity of water involved in a drainage basin, determined by mea-suring such quantities as rainfall, surface and subsurface storageand flow, and evapotranspiration (Bates and Jackson, 1987).

Hydrologic system A complex of related parts (physical, concep-tual, or both) forming an orderly working body of hydrologicunits, and their man-related aspects, such as the use, treatment,reuse, and disposal of water, the costs and benefits thereof, andthe interaction of hydrologic factors with those of sociology,economics, and ecology (Bates and Jackson, 1987).

Hydrology (1) The science that relates to the water of the earth.The science treating the waters of the earth, their occurrence,distribution, and movement (Langbein and Iseri, 1960). (2) Thescience encompassing the behavior of water as it occurs in theatmosphere, on the surface of the ground, and underground(American Society of Civil Engineers, 1949, p. 1). (3) The studyof the occurrence, distribution, and chemistry of all waters ofthe earth (Fetter, 2001).


Glossary 143

I

Igneous rock A rock that solidified from molten or partly moltenmaterial; igneous rocks constitute one of the three main classesinto which all rocks are divided (U.S. Geological Survey, 1993).

Image well An imaginary well that can be used to simulate the effectof a hydrologic barrier, such as a recharge boundary or a barrierboundary, on the hydraulics of a pumping or recharge well (Fetter,2001).

Impervious bed Bed or stratum through which water cannot move(Rogers et al., 1981, p. 192).

Impervious boundary An aquifer boundary, such as is formed by atight fault or impermeable wall of a buried stream valley that cutsoff or prevents groundwater flow (Ferris et al., 1962, p. 145).

Induced infiltration When a surface-water body is in hydraulic con-nection with an aquifer, and the cone of depression of a pumpingwell in that the aquifer reaches the water body, the source of someof the pumped water will be stream flow that is induced into thegroundwater body under the influence of gradients set up by thewell. When steady-state conditions are reached, the source of allthe pumped groundwater is stream flow (Freeze and Cherry, 1979).

Industrial wastes The wastes from industrial processes, as distinctfrom domestic or sanitary wastes (Rogers et al., 1981, p. 196).

Inlet well (1) Well or opening at the surface of the ground con-structed to receive surface water that is then conducted to a sewer.(2) A chamber that serves as a suction well for pumps in awastewater pumping station (Rogers et al., 1981, p. 1990).

Inorganic Composed of material other than plant or animal materials(U.S. Army Corps of Engineers, 1991).

Interflow The lateral movement of water in the unsaturated zoneduring and immediately after rainfall (Fetter, 2001).

Intermittent spring A spring that discharges only periodically. A gey-ser is a special type of intermittent spring (Meinzer, 1923, p. 54).

Intrusive rock A rock that was emplaced as magma in preexistingrock.

Intrinsic permeability A measure of the relative ease with which aporous medium can transmit a liquid under a potential gradient.



Intrinsic permeability is a property of the medium alone that isdependent on the shape and size of the openings through whichthe liquid moves (Cohen and Mercer, 1993).

Ion An atom that has lost or gained one or more electrons andtherefore has acquired an electrical charge.

Ion exchange Reversible chemical replacement of an ion bonded atthe liquid-solid interface by an ion in solution. A process by whichan ion in a mineral lattice is replaced by another ion that waspresent in an aqueous solution (Fetter, 2001). It includes waterrequired to satisfy surface evaporation and other economicallyunavoidable loss (Rogers et al., 1981, p. 206).


Glossary 145

J

Jacob straight line method A graphical method using semiloga-rithmic paper and the Theis equation for evaluating the results ofan aquifer test (Fetter, 2001).

Junior water rights One who holds rights that are temporarily morerecent than senior rights holders. All water rights are defined inrelation to other users, and a water rights holder acquires the rightto use a specific quantity of water only under specified conditions.Thus, when limited water is available, junior rights are not metuntil all senior rights have been satisfied (U.S. Army Corps ofEngineers, 1991).



K

Kaolinite A common clay mineral of the kaolin group (Bates andJackson, 1987).

Karst A terrain, generally underlain by limestone, in which thetopography is formed by the dissolving rock and subsequentcollapse, and which is commonly characterized by closed depres-sion subterranean drainage and caves (Monroe, 1970, p. Kll). Thetype of geologic terrain underlain by carbonate rock where sig-nificant solution of the rock has occurred due to flowing ground-water (Fetter, 2001).

Karst hydrology (1) The drainage phenomena of karstified lime-stone, dolomite, and other slowly soluble rocks (Monroe, 1970,p. K11). (2) The study of water occurring in karsts.

Kriging A statistical procedure that geologists use to characterizethe subsurface. Kriging maximizes the information obtained froma given number of samples (National Academy, 1994).


Glossary 147

L

Landfill A facility for disposal of solid wastes or sludge by placingthe waste on land and compacting and covering it as appropriatewith a thin layer of soil (Rogers et al., 1981, p. 213).

Landsat An unmanned earth-orbiting National Aeronautics andSpace Administration satellite that transmits multispectral imagesin the 0.4 to 1.1 mm region to Earth-based receiving stations. Itwas formerly called Earth Resource Technology Satellite, orERTS (Bates and Jackson, 1987).

Leachate Water that contains a high amount of dissolved solids asa result of liquid seeping from a landfill (Fetter, 2001).

Leachate collection system A system installed in conjunction witha liner to capture the leachate that may be generated from alandfill so that it may be removed and treated (Fetter, 2001).

Leaching (1) The removal of soluble constituents from soil, landfills,mine wastes, sludge deposits, or other material by percolatingwater. (2) The disposal of excess liquid through porous soil orrock strata (Rogers et al., 1981, p. 214).

Leakage (1) The uncontrolled loss of water from artificial structuresas a result of hydrostatic pressure. (2) The uncontrolled loss ofwater from one aquifer to another. The leakage may be natural,as through a semipervious confining layer, or man-made, asthrough an uncased well (Rogers et al., 1981, p. 215).

Leakance (1) The rate of flow across a unit (horizontal) area of asemipervious layer into (or out of) an aquifer under one unit ofhead difference across this layer (U.S. Department of Interior,1989). (2) The ratio K’/b’ in which K’ and b’ are the verticalhydraulic conductivity and the thickness, respectively, of the con-fining bed (ASTM, 1994).

Leaky confining bed (1) A confining bed that transmits water atsufficient rates to furnish some recharge to a well pumping froman underlying aquifer (Fetter, 2001). (2) A confining bed thatunder natural conditions transmits water vertically between twoaquifers because of hydraulic head differences between aquifers.

Leaky aquifer Confined aquifer whose confining beds will conductsignificant quantities of water into or out of the aquifer (Batesand Jackson, 1987).



Limestone A consolidated sedimentary rock composed largely of thecarbonate minerals calcite or, less frequently, aragonite. Lime-stones are important as aquifers, as reservoir rocks for hydrocar-bons, as building stone and aggregate and, with clay, for makingcement (Allaby, 1977, p. 291).

Lithologic log A record of the sequence of lithologic characteristicsof the rocks penetrated in drilling a well, compiled from exami-nation of well cuttings and cores. The information is referred todepth of origin and is plotted on a strip log form (Bates andJackson, 1987).

LNAPL Acronym for less-dense-than-water nonaqueous-phase liq-uid. LNAPLs do not mix well with water and are less dense thanwater. Gasoline and fuel oil are common LNAPLs (NationalAcademy, 1994).

Loam Soil containing 7 to 27% clay, 28 to 50% silt, and less than52% sand (American Society of Agricultural Engineers, 1967,p. 21).

Losing stream Stream or reach of stream that contributes water to theaquifer. The water surface of such a stream stands at a higher levelthan the water table or potentiometric surface of the groundwaterbody to which it contributes water (Rogers et al., 1981, p. 198).


Glossary 149

M

Magnetometer An equation that can be used to locate items thatdisrupt the earth’s localized magnetic field; it can be used forfinding buried steel (Fetter, 2001).

Maximum contaminant level (MCL) The highest concentration ofa solute permissible in a U.S. public water supply as specified inthe National Interim Primary Drinking Water standards (Fetter,2001).

Measuring point An arbitrary permanent reference point fromwhich the distance to the water surface in a well is measured toobtain the water level.

Metamorphic rock Any rock derived from preexisting rocks inresponse to marked changes in temperature, pressure, shearingstress, and chemical environment at depth in the earth’s crust.Metamorphic rocks constitute one of the three main classes intowhich all rocks are divided.

Micrograms per liter A measure of the amount of dissolved solidsin a solution in terms of micrograms of solute per liter of solution(Fetter, 2001).

Mineral water Water that contains a large quantity of mineral salts(Rogers et al., 1981, p. 234).

Model A conceptual, mathematical, or physical system obeying cer-tain specified conditions, whose behavior is used to understandthe physical system to which it is analogous in some way(Groundwater Subcommittee, 1989).

Model calibration The process by which the independent variablesof a digital computer model are varied in order to calibrate adependent variable such as hydraulic head against observedwater-table elevations (Fetter, 2001).

Model verification The process by which a digital model that hasbeen calibrated against a steady-state condition is tested to see ifit can generate a transient response, such as the decline in thewater table with pumping, that matches the known history of theaquifer (Fetter, 2001).

Modeling The simulation of some physical or abstract phenomenonor system with another system believed to obey the same physicallaws or abstract rules of logic, in order to predict the behavior of



the former (main system) by experimenting with the latter (anal-ogous system) (Rogers et al., 1981, p. 235).

Monitoring

A type of sampling program designed to determine timetrend changes in water level, water quality, and stream flow (U.S.Army Corps of Engineers, 1991).


Glossary 151

N

NAPL

Acronym for nonaqueous phase liquids. A liquid solution thatdoes not mix easily with water. Many common groundwatercontaminants, including chlorinated solvents and many petroleumproducts, enter the subsurface in nonaqueous-phase solutions(National Academy, 1993).

Natural water table

A water table in its natural condition and posi-tion, not disturbed by artificial additions or extractions of water(Rogers et al., 1981, p. 243).

Natural well

An abrupt depression in the land surface, not made byhuman activity which extends into the saturation zone but fromwhich water does not flow to the surface except by artificialprocesses. It is distinguished from such features as ponds,swamps, lakes, and other bodies of impounded surface water,which also extend into the saturation zone, by having a smallerwater surface, being deeper in proportion to its water surface area,and having steeper sides.

Nonpoint pollution source

Natural or man-induced alteration of thechemical, physical, biological, or radiological integrity of water,originating from any source other than a point source (Rogers etal., 1981, p. 247).

Nonuniform flow

A flow in which the slope, cross-sectional area,and velocity change from section to section in the channel (Rog-ers et al., 1981, p. 248).

Numerical model

(1) A model whose solution must be approxi-mated by varying the values of controlling parameters and usingcomputers to solve approximate forms of the model’s governingequations (National Academy, 1994). (2) The analytical modeluses classical mathematical tools, such as differential equations(National Academy, 1994).



O

Observation well

A nonpumping well used to observe the elevationof the water table or potentiometric surface (Fetter, 2001).

Outcrop

That part of the formation that appears at the surface of theground (U.S. Army Corps of Engineers, 1991).

Outwash

Stratified detritus (chiefly sand and gravel) carried awayfrom a glacier by meltwater streams and deposited in front of orbeyond the end moraine or the margin of an active glacier. Thematerial deposited near the ice is coarser than that depositedfarther downstream (Bates and Jackson, 1987).


Glossary 153

P

Packer test

An aquifer test performed in an open borehole; the seg-ment of the aquifer to be tested is sealed off by inflating seals inthe borehole, called packer, both above and below the segment(Fetter, 2001).

Partially penetrating well

Well that does not penetrate the entirethickness of the aquifer (Fetter, 2001).

Particle size

A linear dimension, usually designated as “diameter,”used to characterize the size of a particle. The dimension may bedetermined by any of several different techniques, including sed-imentation, sieving, micrometric measurement, or direct mea-surement (Interagency Advisory Committee, 1977).

Pathogenic bacteria

Bacteria that cause disease in the host organismby their parasitic growth (Rogers et al., 1981, p. 262).

Pathogen

Pathogenic or disease-producing organism (Rogers et al.,1981, p. 262).

PCB

Acronym for polycychlorinated biphenyl compounds. PCBs areextremely stable, nonflammable, dense, and viscous liquids thatare formed by substituting chlorine atoms for hydrogen atoms ona biphenyl molecule. PCBs were manufactured by MonsantoChemical Company for use as dielectric fluids for electrical trans-formers (Cohen and Mercer, 1993).

Perched groundwater

Groundwater separated from an underlyingbody of groundwater by an unstaturated zone. Its water table is aperched water table. Perched groundwater is held up by a perchingbed whose permeability is so low that water percolating downwardis not able to bring water in the underlying unsaturated zone aboveatmospheric pressure (Groundwater Subcommittee, 1989).

Perched water table

The water table of a body of perched ground-water. (AGE, 1980, p 465).

Permeability

The property of soil or rock that allows passage ofwater through it when subjected to a difference in head. It dependsnot only on the volume of the openings and pores but also onhow these openings are connected to each other (U.S. Army Corpsof Engineers, 1991). The property or capacity of a porous rock,sediment, or soil for transmitting a fluid; it is a measure of the



relative ease of fluid flow under unequal pressure. The customaryunit of measurement is the millidarcy (Bates and Jackson, 1987).

Permeability coefficient

The rate of flow of water in gallons per daythrough a cross-section of one square foot under a unit hydraulicgradient, at the prevailing temperature (field permeability coeffi-cient) or adjusted for a temperature of 60

°

F (Stearns, 1927, p.148; Bates and Jackson, 1987).

Permit system

A general term referring to a system of acquiringwater rights under state law whereby the state must issue a permitfor a new use of water. Although permit systems were, at onetime, generally associated with eastern states using the ripariandoctrine, they are now found in the south and west (NationalAcademy, 1992).

Pesticide

Any substance, organic or inorganic, used to kill plant oranimal pests; major categories of pesticides include herbicidesand insecticides.

pH

Hydrogen-ion concentration.

Phosphate

Salt or ester of phosphoric acid (Rogers et al., 1981,p. 268).

Phreatic

Of or pertaining to groundwater.

Phreatophyte

Plant that obtains its water supply from the water tableor from the capillary fringe and is characterized by a deep rootsystem (AGE, 1980, p. 473).

Physical analysis

The examination of water and wastewater to deter-mine physical characteristics, such as temperature, turbidity,color, odors, and taste (Rogers et al., 1981, p. 270).

Piezometer

Instrument for measuring pressure head in a conduit,tank, or soil. Usually consists of a small pipe or tube tapped intothe side of the container, with its inside end flush with, and normalto, the water face of the container, and connected with a manom-eter pressure gage, mercury or water column, or other device forindicating pressure head (Rogers et al., 1981, p. 271).

Piezometer nest

A set of two or more piezometers set close to eachother but screened to different depths (Fetter, 2001).

Piezometric head

The elevation plus the pressure head. Above adatum, the total head at any cross section minus the velocity headat that cross section. It is equivalent to the elevation of the water


Glossary 155

surface in open channel flow; it is the elevation of the hydraulicgrade line at any point (Rogers et al., 1981, p. 271).

Playa

Dry, vegetation-free, flat area at the lowest part of an undraineddesert basin, underlain by stratified clay, silt, or sand, and com-monly by soluble salts. The term is also applied to the basincontaining an expanse of playa, which may be marked by ephem-eral lakes (AGE, 1981, p. 483). It is broadly used to describeareas occupied by temporary shallow lakes that are the focus ofan area of internal drainage. They usually occur in arid andsemiarid areas. Playa lakes are not part of an integrated surfacedrainage system. They are found in New Mexico, Utah, Nevada,and Texas (Stone and Stone, 1994).

Plume

A zone of dissolved contaminants. A plume usually will orig-inate from the DNAPL zone and extend downgradient for somedistance, depending on site hydrogeologic and chemical condi-tions (Cohen and Mercer, 1993; National Academy, 1994).

Pollution

The condition caused by the presence of substances of suchcharacter and in such quantities that the quality of the environ-ment is impaired (Bates and Jackson, 1987). Presence of anysubstance in water or addition of any substance to water that isor could become injurious to the public health, safety, or welfare,or that is or could become injurious to domestic, commercial,industrial, agriculture, or other uses being made of the water.

Point source of pollution

Pollution originating from any discretesource, such as the outflow from a pipe, ditch, tunnel, well,concentrated animal-feeding operation, or floating craft (NationalAcademy, 1992).

Pore

The volume between mineral grains that is occupied by fluidin a porous medium. A small space between the grains of sandor soil. Groundwater is stored in pores (National Academy, 1994).

Pore pressure

The stress transmitted by the fluid that fills the voidsbetween particles of soil or rock mass, e.g., that part of the totalnormal stress in a saturated soil caused by the presence of inter-stitial water (AGE, 1980, p. 422.)

Pore water

Interstitial water.

Porosity

Property of containing interstices or voids; may be expressedquantitatively as the ratio of the volume of interstices to the total



volume of material, either as a decimal fraction or percentage(Meinzer, 1923, p. 19).

Porous

Having numerous interstices, whether connected or isolated.“Porous” usually refers to openings of smaller size than those ofa cellular rock (AGE, 1980, p. 492).

Potable water

Water that does not contain objectional pollution,contamination, minerals, or infective agents and is consideredsatisfactory for domestic consumption (Rogers et al., 1981, p.279).

Potential evaporation

Evapotranspiration potential.

Potentiometric surface

The surface that represents the level towhich water will rise in tightly cased wells. If the head variessignificantly with depth in the aquifer, then there may be morethan one potentiometric surface. The water table is a particularpotentiometric surface (Fetter, 2001).

Precipitation

(1) As used in hydrology, precipitation is the dischargeof water, in liquid or solid state, out of the atmosphere, generallyupon a land or water surface (Langbein and Iseri, 1960).

(2) Waterthat falls to the surface from the atmosphere as rain, snow, hailor sleet. It is measured as a liquid-water equivalent regardless ofthe form in which it falls (AGE, 1980, p. 496).

Precipitation gage

Rain gage.

Pressure gage

A device for registering the pressure of solids, liquids,or gases. It may be graduated to register pressure in any unitsdesired. (Rogers et al., 1981, p. 282). See also

piezometer

.

Pressure head

The head represented by the expression of pressureover weight. The head is usually expressed as height of liquidin a column corresponding to the weight of the liquid per unitarea; for example, feet head of water corresponding to poundsper square inch (Rogers et al., 1981, p. 282).

Price current meter

A current meter with a series of conical cupsfastened to a flat framework through which a pin extends. Thepin sits in the framework of the meter, and the cups are rotatedaround it in a horizontal plane by the flowing water, registeringthe number of revolutions by acoustical or electrical devices, fromwhich the velocity of the water may be computed (U.S. ArmyCorps of Engineers, 1991).


Glossary 157

Primary porosity

The porosity that represents the original poreopenings when a rock or sediment is formed (Fetter, 2001).

Prior-appropriation doctrine

A concept in water law stating thatthe right to use water is separate from other property rights andthat the first person to withdraw and use the water holds the seniorright. The doctrine has been applied to both surface water andgroundwater (Fetter, 2001).

Pulsed pumping

An enhancement of the pump and treat system inwhich extraction wells are periodically not pumped (NationalAcademy, 1994).

Pump

A mechanical device for causing flow, for raising or liftingwater or other fluid, or for applying pressure to a fluid (Rogerset al., 1981, p. 288).

Pump and treat system

Most commonly used type of system forcleaning contaminated groundwater. Pump and treat systems con-sist of a series of wells used to pump contaminated water to thesurface and a surface treatment facility used to clean the extractedgroundwater (National Academy, 1993).

Pumpage

The total quantity of liquid pumped in a given interval,usually a day, month, or year (Rogers et al., 1981, p. 288).

Pumped well

Well that discharges water at the surface through theoperation of a pump or other lifting device (Rogers et al., 1981,p. 290).

Pumping test

A test made by pumping a well for a period of timeand observing the change in hydraulic head in the aquifer. Apumping test may be used to determine the capacity of the welland the hydraulic properties of the aquifer (Fetter, 2001). See also

aquifer test.



Q

Qanat

A term used in the Middle East, primarily in Iran, for anancient, gently inclined underground channel or conduit, dug soas to conduct groundwater by gravity from alluvial gravel at thefoot of hills to an arid lowland; a type of horizontal well (AGE,1980, p. 512).

Quality assurance

Programs and sets of procedures, including butnot limited to quality control, that are used to assure productquality or data reliability.

Quality control

Procedures used to regulate measurements and pro-duce data that meet the needs of the user.


Glossary 159

R

Radial flow

The flow of water in an aquifer toward a verticallyoriented well (Fetter, 2001).

Radial well

A special adaptation of infiltration galleries when thewell screen extends horizontally from a large vertical caissonconstructed adjacent to a stream, river, or lake (Wilson andMoore, 1998).

Radioactivity

The spontaneous decay or disintegration of an unsta-ble atomic nucleus, accompanied by the emission of radiation(Rogers et al., 1981, p. 293).

Radionuclide

A species of atom that emits alpha, beta, or gammarays for a measurable length of time. Radionuclides are distin-guished by atomic weight and atomic number.

Radius of influence of a well

Distance from the center of the wellto the closest point at which the potentiometric surface is notlowered when pumping has produced the maximum steady rateof flow (Wilson and Moore, 1998).

Rain

Particles of liquid water that have become too large to be heldby the atmosphere. Their diameter generally is greater than 0.02in (0.5 mm), and they usually fall to the earth at velocities greaterthan 10 fps (3.05 m/s) in still air (Rogers et al., 1981, p. 293).

Rating curve

A graph of the discharge of a river at a particularpoint as a function of the elevation of the water surface (Fetter,2001).

RCRA

Acronym for Resources Conservation and Recovery Actwhich regulates monitoring, investigation, and corrective actionactivities at all hazardous treatment, storage, and disposal facili-ties (Cohen and Mercer, 1993).

Recharge

(1) Addition of water to the zone of saturation fromprecipitation, infiltration from surface streams, and othersources. (2) To inject water underground to replenish ground-water and/or prevent land collapse or saltwater intrusion. (Rog-ers et al., 1981, p. 299).

Recharge area

An area in which water reaches the zone of saturationby surface infiltration. An area in which there are downwardcomponents of hydraulic head in the aquifer. Infiltration moves



downward into the deeper parts of an aquifer in a recharge area(Fetter, 2001).

Recharge well

(1) A well constructed to conduct surface water orother surplus water into an aquifer to increase the groundwatersupply. Sometimes called infusion well (Rogers et al., 1981,p. 300). (2) A well specifically designed so that water can bepumped into an aquifer in order to recharge the ground-waterreservoir (Fetter, 2001).

Recovery

The rate or amount of water-level rise in a well afterthe pump has been shut off. It is the inverse of drawdown(Fetter, 2001).

Redox potential

Describes the distribution of oxidized and reducedspecies in a solution at equilibrium. Redox potential is importantfor predicting the likelihood that metals will precipitate fromgroundwater upon pumping, for estimating the capacity of micro-organisms to degrade contaminants, and for predicting other sub-surface reactions (National Academy, 1995).

Relief well

A well used to relieve excess hydrostatic pressure, inorder to reduce waterlogging of soil or to prevent blowouts onthe land side of a levee or dam at times of high water (AGE,1980, p. 530).

Remedial investigation

A study carried out at a hazardous wastesite covered under the CECLA to determine the extent of con-tamination and the risks it poses (National Academy, 1994).

Remote sensing

The collection of information about an object by arecording device that is not in physical contact with the object.The term is usually restricted to methods that record reflected orradiated electromagnetic energy, rather than methods that involvesignificant penetration into the Earth. The technique employs suchdevices as cameras, infrared detectors, microwave frequencyreceivers, and radar systems (AGE, 1980, p. 530).

Residual drawdown

The difference between the projectedprepumping water-level trend and the water level in a well orpiezometer after pumping or injection has stopped (Wilson andMoore, 1998).

Resistivity survey

Any electrical exploration method in which cur-rent is introduced into the ground by two contact electrodes, and


Glossary 161

potential differences are measured between two or more otherelectrodes (AGE, 1980, p. 532).

RFI

Acronym for RCRA Facility Investigation (Cohen and Mercer,1993).

River

(1) A general term for a natural freshwater surface streamof considerable volume and a permanent or seasonal flow,moving in a definite channel toward a sea, lake, or anotherriver; any large stream or one larger than a brook or a creek,such as the trunk stream and the larger branches of a drainagesystem. (2) A term applied in New England to a small water-course which elsewhere in the U.S. is known as a creek (AGE,1980, p. 541).



S

Safe Drinking Water Act

A law passed in 1974 that required thesetting of standards to protect the public from exposure to con-taminants in drinking water (National Academy, 1995).

Safe yield

The rate at which water can be withdrawn from an aquiferfor human use without depleting the supply to such an extent thatwithdrawal at this rate is no longer economically feasible (Mein-zer, 1923, p. 55). Use of the term is discouraged because thefeasible rate of withdrawal depends on the location of wells inrelation to aquifer boundaries and rarely can be estimated inadvance of development (AGE, 1980, p. 550).

Saline-water system

A system of water mains, separate from theregular distribution system, that conveys saltwater for fightingfires (Rogers et al., 1981, p. 319).

Salinity (1) The relative concentration of dissolved salts, usuallysodium chloride, in a given water. It is often expressed in termsof mg/L chlorine. (2) A measure of the concentration of dissolvedmineral substances in water (Rogers et al., 1981, p. 318).

Sample log Lithologic log.Sampling The systematic gathering of specimens for appraisal. Such

appraisal may consist of the chemical, physical, or biologicalcontent of the specimen.

Sand (1) A loose material consisting of small but easily distinguish-able grains, most commonly of quartz, resulting from disintegra-tion of rocks. (2) Sediment particles having diameters between0.062 and 2.0 mm. (3) A size classification of sediment trans-ported by water, air, or ice (Rogers et al., 1981, p. 320).

Sandstone Consolidated sedimentary rock composed mainly ofcemented sand and recognized by a gritty feeling; depending onmineral content, it may be referred to as quartzose sandstone(mainly quartz), arkosic sandstone (>20% feldspar), or graywacke(Wilson and Moore, 1998).

Sanitary landfill A solid-waste burial site operated to minimizeenvironmental hazards. The wastes are continuously compactedand are covered daily with a layer of soil to minimize blowing,odors, fire hazards, and fly and rat problems; provisions are also


Glossary 163

made to minimize leaching of dissolved solids to groundwater(Rogers et al., 1981, p. 321).

Saturated zone The zone in which the voids in the rock or soil arefilled with water at a pressure greater than atmospheric. The watertable is the top of the saturated zone in an unconfined aquifer(Fetter, 2001). See also zone of saturation.

Screen A device with openings, generally having a relatively uniformsize, that permits liquid to pass but retain larger particles. Thescreen may consist of bars, coarse to fine wire, rods, gratings,membranes etc., depending upon particle size to be retained (U.S.Army Corps of Engineers, 1991)

Screened well Well into which water enters through one or morescreens (Rogers et al., 1981, p. 323).

Sea level In general, the surface of the sea used as a reference forelevation. A curtailed form of mean sea level (Rogers et al.,1981, p. 325).

Secondary porosity The porosity that has been caused by fracturesor weathering in a rock or sediment after it has been formed(Fetter, 2001).

Sedimentary rock A rock resulting from the consolidation of loosesediment that has accumulated in layers; a general term for anysedimentary material, unconsolidated or consolidated (AGI, 1980).

Seep (1) A poorly defined area where water oozes from the earth insmall quantities. (2) To appear or disappear, as water or otherliquid, from a poorly defined area of the earth’s surface. (3)According to some authorities, the type of movement of water inunsaturated material (Rogers et al., 1981, p. 329).

Seepage loss The loss of water by capillary action and slow perco-lation (Rogers et al., 1981, p. 329).

Seepage spring Spring in which the water percolates from numeroussmall openings in permeable material. Also called filtration spring(Rogers et al., 1981, p. 329).

Seep water Water that has passed through or under a levee or dam(Rogers et al., 1981, p. 330).

Seismic Pertaining to an earthquake or Earth vibration, including onethat is artificially induced (AGE, 1980, p. 568).



Seismic refraction A method of determining subsurface geophysicalproperties by measuring the length of time it takes for artificiallygenerated seismic waves to pass through the ground (Fetter,2001).

Septic tank An underground vessel for treating wastewater from asingle dwelling or building by a combination of settling andanaerobic digestion. Effluent is usually disposed of by leaching.Settled solids are pumped out periodically and hauled to a treat-ment facility for disposal (Rogers et al., 1981, p. 332).

Sink General term for a closed depression. It may be shaped like abasin, funnel, or cylinder (Monroe, 1970, p. 16).

Site investigation The collection of basic facts and the testing ofsurface and subsurface materials (including their physical prop-erties, distribution, and geologic structure) at a site, for the pur-pose of preparing suitable designs for an engineering structureor other uses (AGE, 1980, p. 585).

Slug test An aquifer test made either by instantaneously adding avolume of water into a well or by instantaneously withdrawing avolume of water from a well. A synonym for this test, when a slugof water is removed from the well, is a bail-down test (Fetter, 2001).

Soil Unconsolidated mineral and organic surface material that hasbeen sufficiently modified and acted upon by physical, chemical,biological agents so that it will support plant growth (Bates andJackson, 1987).

Soil type A phase or subdivision of a soil series based primarily ontexture of the surface soil to a depth at least equal to plow depth(about 15 cm). In Europe, the term is roughly equivalent to theterm great soil group (AGE, 1980, p. 593).

Soil water Water diffused in the soil, the upper part of the zone ofaeration from which water is discharged by the transpiration ofplants or by direct evaporation (Langbein and Iseri, 1960, p. 17).

Soil-water table The upper surface of a body of soil water (Rogerset al., 1981, p. 354).

Specific capacity The rate at which water may be drawn from aformation through a well, to cause a drawdown. The usual unitsof measurement are gallons per minute per foot of drawdown(U.S. Army Corps of Engineers, 1991). An expression of theproductivity of a well, obtained by dividing the rate of discharge


Glossary 165

of water from the well by the drawdown of the water level in thewell. Specific capacity should be described on the basis of thenumber of hours of pumping prior to the time the drawdownmeasurement is made. Specific capacity will generally decreasewith time as the drawdown increases (Fetter, 2001).

Specific conductance A measure of the ability of a sample of waterto conduct electricity. Measurement in micromohs. Used to esti-mate total dissolved solid content in water (U.S. Geological Sur-vey, 1993, p. 533).

Specific conductivity With reference to the movement of water insoil, a factor expressing the volume of transported water per unitof time in a given area (AGE, 1980, p. 598).

Specific discharge An apparent velocity calculated from Darcy’slaw; represents the flow rate at which water would flow in anaquifer if the aquifer were an open conduit (Fetter, 2001).

Specific gravity The ratio of a substance’s density to the densityof the same standard substance, usually water (Cohen andMercer, 1993).

Specific weight The weight of a substance per unit volume. The unitsare newtons per cubic meter (Fetter, 2001).

Specific yield The ratio of the volume of water that a given mass ofsaturated rock or soil will yield by gravity to the volume of thatmass. The ratio is stated as a percentage (AGE, 1980, p. 598).

Split-spoon sample A sample of unconsolidated material taken bydriving a sampling device ahead of the drill bit in a boring(Fetter, 2001).

Spring A place where groundwater flows naturally from a rock orthe soil onto the land surface or into a body of surface water.Its occurrence depends on the nature and relationship of rocks,especially permeable and impermeable strata, on the positionof the water table, and on the topography (AGE, 1980, p. 604).

Spring water Water derived from a spring (Rogers et al., 1981,p. 361).

Spontaneous potential log A borehole log made by measuring thenatural electrical potential that develops between the formationand the borehole fluids (Fetter, 2001).

Step drawdown test A test for examining the performance of a well.In the test, the well is pumped at several successively higher



pumping rates and the drawdown for each step is recorded (Wil-son and Jackson, 1998).

Stiff pattern A graphical means of presenting the chemical analysisof major cations and anions in a water sample (Fetter, 2001).

Storage coefficient The volume of water an aquifer releases from ortakes into storage per unit surface area of the aquifer per unitchange in head. In a confined water body, the water derived fromstorage with decline in head comes from expansion of the waterand compression of the aquifer.

Stream gage A device for measuring the elevation of the watersurface in a channel, ordinarily by the position of a float in atube, the change in pressure at some datum, or a visual readingon stakes or boards along channel sides. The datum is com-monly arbitrary, as is the case where zero is an estimate, pos-sibly many years old, of the lowest stage probable (Wilson andMoore, 1998).

Storage coefficient The volume of water released by pressurechanges per unit area during pumping of a confined aquifer(National Academy, 1994).

Submarine spring Large offshore emergence of fresh water, usuallyassociated with a coastal karst area but sometimes with lava tubes(AGE, 1980, p. 623).

Submersible pump Centrifugal pump, usually electrical, capable ofoperating entirely submerged under water.

Subsurface water Water in the lithosphere. It may be in liquid, solid,or gaseous state. It comprises unsaturated zone water and ground-water (Rogers et al., 1981, p. 378).

Surficial aquifer An aquifer near the earth’s surface, in the mostrecent of geologic deposits (National Academy, 1994).


Glossary 167

T

Test hole Circular hole made by drilling to explore for valuableminerals or to obtain geological or hydrological information(AGE, 1980, p. 188).

Test well A well constructed for test purposes as opposed to opera-tional water-supply purposes.

Theis equation An equation that describes the flow of groundwaterin a fully confined aquifer under certain idealized conditions(Fetter, 2001).

Thiessen method A process used to determine the effective uniformdepth of precipitation over a drainage basin with a nonuniformdistribution of rain gages (Fetter, 2001).

Trace element A chemical element dissolved in water in minutequantities, always or almost always in concentrations less than 1mg of trace element in 1 L of water (U.S. Geological Survey,1993, p. 584).

Tracer (1) A foreign substance mixed with or attached to a givensubstance for subsequent determination of the location or distri-bution of the substance. (2) An element or compound that hasbeen made radioactive so that it can be easily followed (traced)in biological and industrial processes. Radiation emitted by theradioisotope pinpoints its location (Rogers et al., 1981, p. 398).

Tracer test A method used to determine the flow of groundwater inthe subsurface (National Academy, 1994).

Transmissivity The rate at which groundwater of the prevailing kine-matic viscosity is transmitted through a unit width of aquiferunder a unit hydraulic gradient. It is a function of properties ofthe liquid, the porous media, and the thickness of the porousmedia (Fetter, 2001).

Transpiration (1) The quantity of water absorbed and transpired andused directly in the building of plant tissue, in a specified time.It does not include soil evaporation (U.S. Army Corps of Engi-neers, 1991). (2) The process by which plants give off water vaporthrough their leaves (Fetter, 2001).

Tributary Stream or other body of water, surface or underground,that contributes its water to another and larger stream or body ofwater (Rogers et al., 1981, p. 401).



U

Unconfined aquifer An aquifer having a water table; an aquifercontaining unconfined groundwater (AGE, 1980, p. 675). See alsowater table aquifer.

Underflow The downstream flow of groundwater through perme-able deposits that underlie a stream and that are more or lesslimited by rocks of lower permeability (Langbein and Iseri,1960, p. 201).

Unsaturated flow Flow of water in the unsaturated zone. Movementof water in a soil, the pores of which contain both air and water(Hutchinson, 1970, p. 50).

Unsaturated zone That part of the lithosphere in which the func-tional interstices of permeable rock or earth are not (except tem-porarily) filled with water under hydrostatic pressure.

Unsteady flow Flow in which the velocity and the quantity of waterflowing per unit of time at every point along the conduit varywith respect to time and position (Rogers et al., 1981, p. 408).

Upconing (1) The cone-shaped rise of saltwater beneath freshwater in an aquifer as fresh water is produced from a well. (2)The cone-shaped rise of water underlying oil or gas in a res-ervoir as the oil or gas is withdrawn from a well (AGE, 1980,p. 133).


Glossary 169

V

Vadose water Subsurface water that partially occupies the intersticesin the zone of aeration. It comprises hygroscopic, pellicular,mobile, and fringe water (Rogers et al., 1981, p. 384).

Vacuum extraction Forced extraction of gas (with volatile contam-inants) from the vadose zone, typically to prevent uncontrolledmigration of contaminated soil gas and to augment a site cleanup(Cohen and Mercer, 1993).

Venting, soil Remove volatile organic compounds from the unsatur-ated zone by vacuum pumping, which causes large volumes ofair to circulate through the spill. The presence of the circulatingair promotes volatilization and possibly biodegradation(Dominico and Schwartz, 1990)

Verification The process of testing a model to an observed set ofdata using the model parameters derived during calibration.Model calibration and verification must be performed on separatesets of data (Alley et al., 1976).

Virus The smallest (10 to 300 µm in diameter) life form capable ofproducing infection and diseases in man or other large species(Rogers et al., 1981, p. 414).

Volcanic spring Spring with water derived at considerable depths andbrought to the surface by volcanic forces (Rogers et al., 1981,p. 415).

Volcano (1) Vent in the surface of the Earth through which magmaand associated gases and ash erupt; also, the form or structure,usually conical, that is produced by the ejected material. (2) Anyeruption of material, e.g., mud, that resembles a magmatic vol-cano (AGE, 1981, p. 690).

Volatile organic compounds (VOC) A group of lightweight syn-thetic organic compounds, many of which are aromatic; sometimesreferred to as “purgeable organic compounds” because of their lowsolubility in water (U.S. Geological Survey, 1986, p. 552).



W

Wadi A valley, ravine, or watercourse that is dry except during therainy season. Term usually used in reference to northern Africanand Arabian locales (Rogers et al., 1981, p. 416).

Water hole (1) Natural hole or hollow containing water; a hole inthe dry bed of an intermittent stream; a spring in a desert; also,a pool, pond, or small lake. (Rogers et al., 1981, p. 423). (2) Anatural or artificial pool, pond, or small lake that stores water(Department of the Army, 1986, p. 12).

Water level (1) Water surface elevation or stage (U.S. Army Corpsof Engineers, 1991). (2) The free surface of a body of water. (3)The elevation of the free surface of a body of water above orbelow any datum. (Rogers et al., 1981, p. 423). (4) The surfaceof water standing in a well usually indicative of the position ofthe water table or other potentiometric surface.

Water-level fluctuation (1) Movement of the free-water surface ofa body of water. (2) Change in the elevation of the free-watersurface of a body of water above or below any datum (Rogers etal., 1981, p. 423).

Water-level recorder Device for producing, graphically or other-wise, a record of the rise and fall of a water surface with respectto time (Rogers et al., 1981, p. 423).

Water resources The supply of groundwater and surface water in agiven area (National Academy, 1992).

Water requirement The quantity of water, regardless of its source,required by a crop in a given period of time, for its normal growthunder field conditions. It includes surface evaporation and othereconomically unavoidable states.

Water reuse Application of appropriately treated wastewater to aconstructive purpose (Rogers et al., 1981, p. 308).

Water right The legal right to use a specific quantity of water, on aspecific time schedule, at a specific place, and for a specificpurpose (National Academy, 1992).

Water-supply system (1) Collectively, all property involved in awater utility, including land, water source, collection systems,wells, dams and hydraulic structures, water lines and appurte-nances, pumping systems, treatment works, and general proper-


Glossary 171

ties. (2) In plumbing, the water distribution system in a buildingand its appurtenances (Rogers et al., 1981, p. 21).

Water table The upper surface of the zone of saturation. The surfacein an unconfined aquifer or confining bed at which the pore-waterpressure is atmospheric. Its position can be identified by measur-ing the water level in shallow wells extending a few feet into thezone of saturation (Meinzer, 1923, p. 22; Langbein and Iseri,1960, p. 21). It can be measured by installing shallow wellsextending a few feet into the zone of saturation and then measur-ing the water level in those wells (Fetter, 2001).

Water table aquifer Unconfined aquifer.Water-table decline The downward movement of the water table.

Also called phreatic decline (Rogers et al., 1981, p. 429).water-table fluctuation The alternate upward and downward move-

ment of the water table. Also called phreatic fluctuation (Rogerset al., 1981, p. 429).

Water-table gradient The rate of change of altitude per unit ofdistance in the water table at a given place and in a given direction.If the direction is not mentioned, it is generally understood to bethe direction along which the maximum rate of change occurs.Where the rate of change is uniform between two points, thegradient is equal to the ratio of the difference of altitude betweenthe two points to the horizontal distance between them (Rogerset al., 1981, p. 429).

Water-table map A specific type of potentiometric surface map foran unconfined aquifer that shows lines of equal elevation of thewater table (Fetter, 2001).

Water treatment (1) The filtration or conditioning of water to renderit acceptable for a specific use. (2) A series of chemical andphysical processes to remove dissolved and suspended solidsfrom a raw water to produce potable water for distribution anduse (Rogers et al., 1981, p. 430).

Water use A system of classifying the purposes for which water isused, such as potable water supply, recreation and bathing, fishculture, industrial processes, waste assimilation, transportation,power production (Rogers et al., 1981, p. 430).

Water yield The runoff from the drainage basin including ground-water outflow that appears in the stream plus groundwater outflow



that bypasses the gaging station and leaves the basin underground.Water yield is the precipitation minus the evapotranspiration(Corps of Engineer, 1991).

Well (1) Artificial cylindrical excavation that derives fluid (oil, gas,or water) from the saturated zone (Rogers, 1981, p. 433). (2) Anartificial excavation or shaft that collects water from the inter-stices of the soil or rock (U.S. Army Corps of Engineers, 1991).

Well capacity The maximum rate at which a well will yield waterunder a stipulated set of conditions, such as a given drawdown,pump and motor, or engine size (Rogers et al., 1981, p. 434).

Well casing Material, usually pipe, used to line the borehole of awell (Rogers et al., 1981, p 434). A solid piece of pipe, typicallysteel or PVC plastic, used to keep a well open in either uncon-solidated materials or unstable rock (Fetter, 2001).

Well cuttings A type of drilling sample in which the material iscrushed and broken into particles.

Well data A concise statement of the available data regarding a well;a full history or day-by-day account, from the day the locationwas surveyed to the date production ceased (AGE, 1980, p. 699).

Well development Application of a surging or brushing process toa well for the purpose of drawing fine material from the aquifernext to the well and increasing well yield (U.S. Army Corps ofEngineers, 1991).

Well efficiency Ratio of the actual specific capacity after 24 hoursof pumping to the theoretical specific capacity at that time (U.S.Army Corps of Engineers, 1991).

Well function Mathematical function by means of which theunsteady drawdown can be computed at a given point in anaquifer at a given time due to a given constant rate of pumpingfrom a well (UNESCO, 1974, p. 286).

Wellhead protection A protected surface and subsurface zone sur-rounding a well or well field supplying a public water system tokeep contaminants from reaching the well water (U.S. Environ-mental Protection Agency, 1994).

Well intake The well screen, perforated sections of casing, bottomof casing, or other openings through which water from awater-bearing formation enters a well (Rogers et al., 1981,p. 434).


Glossary 173

Well log A chronological record of the soil and rock formationsencountered in the operation of sinking a well, with either theirthickness or the elevation of the top and bottom of each formationgiven. It also usually includes statements about the lithologic com-position and water-bearing characteristics of each formation, staticand pumping water levels, and well yield (Rogers et al., 1981,p. 434).

Well point A hollow vertical tube, rod, or pipe terminating in aperforated pointed shoe and fitted with a fine mesh wire screen,sometimes connected with others in parallel to a drainage pumpand driven into or beside an excavation, to remove undergroundwater, to lower the water level and thereby minimize floodingduring construction, or to improve stability (AGE, 1980, p. 699).Also used to obtain a small water supply from a shallow uncon-fined aquifer.

Well screen A tubular device with either slots, holes, gauze, orcontinuous wire wrap; used at the end of a well casing tocomplete a well. The water enters the well through the wellscreen (Fetter, 2001).

Well yield The rate at which a well will yield water either by pump-ing or free flow (Rogers et al., 1981, p. 439).

Withdrawal The act of removing water from a source for use or theamount removed (AGE, 1980, p. 703).



X

Xerophyte (1) A plant adapted to dry conditions; a desert plant(AGE, 1980, p. 706). (2) A desert plant capable of existing byvirtue of a shallow and extensive root system in an area of min-imal water (Fetter, 2001).


Glossary 175

Y

Yield (1) The quantity of water, expressed as a rate of flow, thatcan be collected for a given use or uses from surface or ground-water sources. The yield may vary with the use proposed, withthe plan of development, and also with economic consider-ations. (2) Total runoff. (3) The stream flow in a given intervalof tine derived from a unit area of watershed, usually expressedin cubic feet per second per square mile. (4) The amount ofmaterial ultimately produced by a given process, for example,volume or weight of sludge produced, BOD removed (Rogers,1981, p. 440). (5) The rate of pumping water from a well orwell field without lowering the water level below the pumpintake. See also water yield, well capacity.



Z

Zone of capture The area surrounding a pumping well that encoun-ters all areas or features that supply groundwater recharge to thewell (National Academy, 1994).

Zone of influence The area surrounding a pumping or rechargingwell within which the water table or potentiometric surface hasbeen changed due to the well’s pumping or recharge (NationalAcademy, 1944).

Zone of saturation The zone in which the permeable rocks are sat-urated with water under hydrostatic pressure. Water in the zoneof saturation will flow into a well and is called groundwater.That part of the earth’s crust beneath the regional water tablein which all voids, large and small are filled with water underpressure less than atmospheric (Langbein and Iseri, 1960). Seealso saturated zone.


Glossary 177

References

Allaby, Michael, 1977, A Dictionary of the Environment, Van Nostrand ReinholdCompany, New York, 532 p.

Alley, W.H. et al., 1999, Sustainability of Ground-Water Resources, U.S. GeologicalSurvey, 79 p., Denver, CO.

American Society of Testing and Material, 1994, ASTM Standards on Groundwaterand Vadose Zone Investigations, ASTM Philadelphia, 432 p.

American Society of Agricultural Engineers, 1967, Glossary of Soil and Water Terms,Nomenclature Committee, Soil and Water Division, Special Pub, 45 p.

American Society of Civil Engineers, 1949, Hydrology Handbook, American Societyof Civil Engineers, Manual of Engineering Practices, no. 28, 184 p.

Bates, R.L. and Jackson, J. A., Eds., 1987, Glossary of Geology, 3rd ed., AmericanGeological Institute, Alexandria, VA.

Bowen, Robert, 1980, Groundwater, Halsted Press Division, John Wiley & Sons,New York, 227 p.

Bryan, Kirk, I922, Erosion and sedimentation in the Papago country, Arizona, witha sketch of the geology, U.S. Geological Survey Bull. 730-B: 19–90.

Cohen, R.M. and Mercer, J.W., 1993, DNAPL Site Evaluation, CRC Press, BocaRaton, FL.

Colby, B.R., Hembree, C.H., and Jochens, E.R., 1953, Chemical quality of waterand sedimentation in Moreau River drainage basin, South Dakota, U.S. Geo-logical Survey Circ. 270, 53.

Dominico, P.A. and Schwartz, F.W., 1990, Physical and Chemical Hydrogeology,John Wiley & Sons, New York, 824 p.

Dunne, T. and Leopold, L.B. 1978, Water in Environment Planning, W.H. Freemanand Company, San Francisco, 818 p.

Durfor, C.N., and Becker, Edith, 1964, Public Water Supplies of the 100 LargestCities in the United States, 1962, U.S. Geological Survey Water-Supply Paper1812, 364 p.

Erbe, N.A., and Flores, D.T., 1957, Iowa drainage laws (annot.), Iowa HighwayResearch Board, Bulletin 6, 70 p.

Ferris, J. G., Knowles, D.B., Brown, R.H., and Stallman, R.W., 1962, Theory ofAquifer Tests, U.S. Geological Survey Water-Supply Paper 1536-E, 174 p.

Fetter, C.W., 2001, Applied Hydrogeology, McMillan College Publishing Co., NewYork, 691 p.

Freeze, A.R, and Cherry, J. A., 1979, Groundwater, Englewood Cliffs, N.J., PrenticeHall, Inc., 604 p.

Flick, G.W., Ed. 1980, Environmental Glossary, Government Institutes, Washington,D.C., 196 p.

Gilpin, Alan, 1976, Dictionary of Environmental Terms, Routledge and Kegan Paul,London, 189 p.



Glover, R.E., 1964, The pattern of fresh-water flow in a coastal aquifer. In Cooper,H.H., Jr., et al., Seawater in Coastal Aquifers, U.S. Geological Survey Water-Supply Paper 1613W, 84 p.

Gorden, N.D., McMahon, T.A., Finlayson, B.B., 1992, Stream Hydrology, an Intro-duction for Ecologists, John Wiley & Sons, NY, 526 p.

Groundwater Subcommittee of the Federal Interagency Committee of Water Data,1989, U.S. Geological Survey, Office of Water Coordination, 38 p.

Horton, R.E., 1933, The role of infiltration in the hydrologic cycle, American Geo-physical Union: 446–460.

Hutchinson, D.E., 1970, Resource conservation glossary, J. Soil and Water Conser.25(1).

Lamb, T.W. and Whitman, R.V., 1969, Soil Mechanics, John Wiley & Sons.Langbein, W.S., and Hoyt, M. G, 1959, Water Facts for the Nation’s Future, The

Ronald Press Company, New York, 288 p.Langbein, W.S., and Iseri, K.T., 1960, General introduction and hydrologic defini-

tions, U.S. Geological Survey Water-Supply Paper 1541-A, 29 p.Linsley, R.K., Jr., Kohler, M.A., and Paulhus, J. L.H., 1949, Applied Hydrology, New

York, McGraw-Hill Book Co., 689 p.Liptak, Bella G., Ed., 1974, Environmental Engineers’ Handbook, Vol. 1: Water

Pollution, Radnor, Pennsylvania, Chilton Book Company, 2018 p.Lohman, S W. et al., 1972, Definitions of selected ground-water terms, revisions

and conceptual refinements, U.S. Geological Survey Water-Supply Paper 1988,21 p.

Maxey, G.B., 1964, Hydrostratigraphic units, J. Hydrology 2: 124–129.Meinzer, 0.E., 1923, Outline of ground-water hydrology, U.S. Geological Survey

Water-Supply Paper 494, 71 p.Meinzer, O.E. 1927, Plants as indicators of groundwater, U.S. Geological Survey

Water-Supply Paper 577, 95 p.Monroe, W.H., 1970, A glossary of karst terminology, U.S Geological Survey

Water-Supply Paper 1899-K, 26 p.National Academy, National Research Council, 1994, Alternatives for groundwater

cleanup, National Academy Press, Washington, D.C., 315 p.Paylore, Patricia, Ed., 1974, Phreatophytes: A Bibliography, U.S. Department of

Interior office of Water Resources Research, 277 p.Pfannkuch, Hans Olaf, 1969, Elsevier’s Dictionary of Hydrogeology, Elsevier Pub-

lishing Company, New York, 168 p.Rantz, S.E. et al., 1982, Measurement and Computation of Streamflow: Measurement

of Stage and Discharge, Vol. 1, U.S. Geological Water Supply Paper 2175.Robinson, T.W., 1958, Phreatophytes, U.S. Geological Survey Water Supply Paper

1423, 84 p.Rogers, B.G. et al., 1981, Glossary — Water and Wastewater Control Engineering,

American Water Works Association, 75 p.


Glossary 179

Seaber, P.R., 1986, Evaluation of classification and nomenclature of hydrostrati-graphic units, EOS Trans. Am. Geophys. Union 67(16): 281.

Solley, W.B., Chase, E.B., Mann, W.B., IV, 1983, Estimated use of water in theUnited States, U.S. Geological Survey Circ. 1001, 56 p.

Stanger, Gordon, 1994, Dictionary of Hydrology and Water Resources, Lochan,Adelaide, South Australia, 208 p.

Stone, A.W. and Stone, A., 1994, Wetlands and Groundwater in the United States,American Groundwater Trust, 100 p.

Stringfield, V.T., 1966, Hydrogeology — definition and application, Groundwater4(4): 2–4.

Studdard, G.J., 1973, Common Environmental Terms — A Glossary, U.S. Environ-mental Protection Agency, EPA Region IV, Atlanta, Georgia, 23 p.

Titelbaum, 0.A., 1970, Glossary of Water Resource Terms, Federal Water PollutionControl Administration, 39 p.

UNESCO, 1970, International Legend for Hydrogeological Maps, InternationalAssociation of Scientific Hydrology, Publication No. 98, 101 p.

UNESCO, 1974, International Glossary of Hydrology, QM/OMM/BMO-No. 385,393 p.

U.S. Army Corps of Engineers, 1991, Glossary of Hydrologic Engineering Terms,Davis, CA, Hydrologic Engineering Center, 135 p.

U.S. Department of the Interior, 1986, Glossary of Selected Water-Resource andRelated Terms, Water Resource Division, U.S. Geological Survey, Reston, VA,141 p.

U.S. Environmental Protection Agency, 1975, Manual of Individual Water SupplySystems, EPA 430/9–74–007, 153 p.

U.S. Environmental Protection Agency, 1994, Terms of Environment: Glossary,Abbreviations, and Acronyms, U.S. Environmental Protection Agency EPA175-B-94–015.

U.S. Geological Survey, 1985, National Water Summary 1985, U.S. GeologicalSurvey Water Supply Paper 2300.

U.S. Geological Survey, 1986 National Water Summary 1986, U.S. GeologicalSurvey Water Supply Paper 2325.

U.S. Geological Survey, 1989, Federal Glossary of Selected Terms Subsurface-WaterFlow and Solute Transport, U.S. Geological Survey, 38 p.

U.S. Geological Survey, 1993, National Water Summary 1990–91, U.S. GeologicalSurvey Water Supply Paper 2400.

Wang, L.K., Ed., 1974, Environmental Engineering Glossary, Over 3800 Definitions,Calspan Corporation, Buffalo, N.Y., 439 p.

Wilson, W.E. and Moore, J.E., 1998, Glossary of Hydrology, American GeologicalInstitute, Alexandria, VA, 248 p.

Wisler, C.L, and Brater, E.P., 1959, Hydrology, John Wiley & Sons, Inc., New York,408 p.



World Meteorological Organization, 1974, International Glossary of Hydrology,WMO Publication.


181

Appendix: “The Ideal Project — Its Planning and Supervision”*

Introduction

Project orientation, planning, supervision, and timely completion areall areas that are receiving increasing attention at regional, division,and director levels. This emphasis has been strongly indicated by thedirector’s public statements regarding improving the usefulness ofsurvey reports and by the publication of priority guidelines in waterresources division memorandums. Valid criticism has been directed atthe geological survey regarding lack of timeliness and relevance ofreports. This can be corrected by improved project design, supervision,and management.

Assume that funds and personnel will be assigned to those projectsthat meet the criteria of technical quality, relevance to current andpotential needs, and adequate management to assure that these needsare fulfilled.

Before getting into specifics, the following is given for perspective.Within the total water resources division program there are about 1500projects. The number of reports from these projects that were preparedfor the director’s approval in 1970 was more than 800. In 1950, therewere only 300.

* By John E. Moore and Hugh H. Hudson, staff hydrologists, Lakewood, CO, USGS, 1991, WRD projectand report management guide, USGS Open File Report, 91–224, p. 152.

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In the 12-state Rocky Mountain region, there are about 230 inter-pretive projects that will produce reports. The total funding of workin this region in fiscal year 1972 was $19 million. Interpretive projectsuse $10 million of the money (area appraisal and applied research).Area appraisal projects consumed nearly $4.5 million in 1972. Clearly,project planning and management represent substantial investments inpeople and money and call for a business-like approach.

The purpose of this appendix is to list guidelines for better projectplanning and supervision. Obviously these guidelines should not beconsidered as a panacea to resolve all the problems related to projects.Before presenting these guidelines, we offer the following as ourdefinition of the "ideal project."

Characteristics of the Ideal Project

Specific Objectives

The objectives should point to the salutations of specific problems. Ifthe objectives are not clear, the approach cannot be determined andthe project is in danger of aimless roaming in search of its objective.Fuzzy definition of the project goal leads to uncertainty about themerits of each step taken during the project execution. Uncertaintyfrequently leads to time misspent in collecting, cataloging, and inter-preting trivia.

Limited Duration

Ideally, the length of a project should be 24 to 36 months. Longerprojects frequently run into problems of completing reports on sched-ule and maintaining staff continuity. If this span of time appearsimpracticable, the project should be broken into phases of relativelybrief duration with a specified goal and report for each phase.

Full-time and Continuous Staffing

Full-time and continuous staffing is essential to efficient project oper-ation and management. The probability of staffing interruptions bytransfer and priority changes by the cooperator is decreased withshorter projects. Full-time participation, particularly by the project


Appendix 183

chief, is almost essential. For the project chief to be required to dividehis or her time between projects is patently inefficient, and he or shemay be tempted to play one deadline off against the other and delaycompletion of both projects. If possible, an interdisciplinary teamapproach is recommended. Many of the new projects in the waterresources division include full- or part-time input from ground water,surface water, and water quality disciplines. An ideal project requiresa widely diversified experience, interest, and capability. The projectleader is responsible for assembling, guiding, and using the technicaltalents of his staff.

Adequate Funding

Lack of adequate funds is probably the major cause of failure.Although the absolute necessity of adequate funding cannot be denied,inadequate funding is a surprisingly common pitfall. We tend to besomewhat overzealous in "selling" projects and succumb to the temp-tation to make the job more attractive to the cooperator by cuttingcosts to the bone. Financing must be at a level adequate for achievingstated goals. Continuing surveillance of progress by the district chiefis required so that the cooperator can be advised if the original goalsare within budget constraints. If financing is a basic problem to suc-cessful completion, efforts should be made immediately to revise eitherthe objective or the budget level. Symptoms of an under funded projectare frequent cost overruns, slippage of completion date, and substan-dard technical report.

Meeting Objectives

It goes without saying that the ideal project is completed on schedule, istechnically acceptable, and meets the stated objectives. The project shouldproduce reports that reach and are understood by the intended audience.

Is the ideal project attainable? Emphatically yes, with proper attentionto the details that go into planning, supervision, and report management.

Project Planning

There are no hard and fast rules for planning a project. Many planningdetails depend on the uniqueness or difficulty of the job and the



experience available within the district from similar projects. If theproject under consideration is a county study adjacent to a just com-pleted county, the planning phase may be a relatively simple modifi-cation of the earlier study, provided the earlier experience wassuccessful and documented. Documentation is a requirement for ade-quate management and will be discussed under “Supervision.”

Project planning usually begins when the project proposal is pre-pared for the cooperator. The district should list specific objectives,point out the hydrologic complexities in the area, and list the majorwater problems. The district should obtain assistance from the regionaloffice, research projects, or other districts for review of these proposals.

Planning Report

Many districts prepare a pre-project planning report before any field-work is started. Some districts prepare the report as a separate projectwhile others put aside the first 3 to 6 months of the project to preparea planning report. A planning report is highly recommended forprojects that have had no predecessor in the district, and for those thatare above average in difficulty.

The basic planning report should include (as a minimum) a clearstatement of the objectives, the proposed approach, a conceptualhydrologic description, available data, data needs, work schedule,report plans, and references. The report should receive a detailedreview by the cooperator, regional office, and in some cases Divisionstaff members. Some districts have had success in using a brain-storming technique to prepare pans of the report. For example, a groupof hydrologists with diverse interests and backgrounds is assembled.They express the possible objectives, approaches, and project priori-ties. The cost of a project planning report ranges from $3000 to $8000and commonly requires 1 week to 3 months to complete.

The North Dakota district recently prepared such a report. Projectsthat had been routinely requested by the cooperator were the traditionalcounty groundwater reconnaissance studies. Then, the Corps of Engi-neers came up with plans for a reservoir on the Cheyenne Riveroverlying an important aquifer. The question the Corps asked was“what effects the reservoir would have on the local and regionalground-water environment?” A secondary question was “what wouldbe the effects of the proposed reservoir on nearby seeps and springs?”.

The district office developed a planning report to prepare for thisproject. It included the following: introduction, purpose of study,


Appendix 185

hydrogeology, method of study, available data, data needs, estimatedcosts, work schedule, selected references, a map showing the locationof the study area and a hydrogeologic section.

After the report was initially drafted, a meeting was held in Denverinvolving representatives of the Bismarck office, the regional staff, andtwo consultants from the Arkansas district who were chosen becauseof their experience with a similar problem. The original work planwas then modified on the basis of advice and recommendationsobtained at this meeting. The revised work plan served as the basisfor preparing (and became a part of) the formal project proposal. About3 months elapsed between the inception of the project and its approval.The time could have been shortened considerably, if necessary.

Planning major projects in New Mexico is done in a slightlydifferent way. The method used is a pre-project. The purpose of thisproject is specifically for planning. The project chief is assigned thejob of assessing the problem, the hydrologic situation, developing theconceptual model, reviewing the literature and the state of the art.assessing the data base. Determining data needs, and preparing a workplan. The end product is a highly detailed project proposal that servesas the basis of the agreement with the cooperator as to costs, approach,duration of study, and type of report. The detailed project proposal isabstracted for and becomes a part of the formal project proposal. Suchan approach costs about $6000 to $12,000 and is money well spentwhen the final project may cost in the $300,000 to $900,000 range.Moreover, cost overruns from inadequately planned projects may con-sume several times the cost of detailed planning.

Technical Assistance

The North Dakota district’s project report was substantially changedand improved because of consulting assistance provided by theregional office and by the Arkansas district. Much of the cost of theassistance was paid from the Region’s consulting fund. Districtsshould make use of the funds to review project plans during theformulation stage.

Project personnel should enlist the aid of other district personnel,the branches, and research specialists, in the design of quantitativestudies. Where predictive models are contemplated, the Analog ModelUnit, the Hydrologic Systems Laboratory Group, or similar researchgroup should be consulted for technical advice beginning with theproject planning. Where technical expertise in the project needs bol-



stering, consultations or short assignments by appropriate individualsshould be sought. Such needs should be identified during the projectplanning phase.

Identification of Specific Objectives

The definition of specific project objectives is probably the mostimportant part of planning. It is recommended that a list of desirableobjectives be prepared, then those objectives that are practical toachieve be selected. Finally, the objectives should be balanced withthe need for information in the study area. The selection of goalsshould be based on an awareness of the complexity of hydrologicand water supply problems. The most critical unknowns should betackled first. The limits of the project area, the information needed,and the type of report should be established during the first fewweeks of the project.

Documentation of Project

The preparation of a formal project description should be made by theproject chief. There are times when the project chief is not on boardor is not selected. He should be given the opportunity to review,modify, and otherwise imprint the project with his own personal touch.The preparation of project documents, as an administrative chore,remote from the project chief, is strongly discouraged. These docu-ments should be used to prepare the work plan and budget.

Project Supervision

The ideal project is now underway and its plan becomes a manage-ment tool. The following is a list of general guidelines for thesupervision of projects. It includes guidelines for the project chiefand district supervisors.

Work Plan

A detailed work plan containing a list of the major items of projectwork, completion dates, manpower requirements, and expenses should


Appendix 187

be prepared by the project chief during the first part of the project (1to 3 months). It is prepared after the needs for data, research support,and special studies have been defined. The work effort should first besubdivided into logical units with realistic completion dates for each.The work plan should include a listing of maps, tables, and other itemsto be generated by the project.

Project Control

The project chief should be required to give an oral or written progressreport to his or her supervisor on a regular schedule. Some districtsrequire a report on progress and plans each month. One very usefulmethod of keeping track of progress is to prepare a project progresschart. Actual progress is charted against the listed completion dateshown on the work plan. The chart serves two purposes: (1) it providesa visual display of progress, and (2) gives an early warning of scheduleslippage. Another use of the chart is to provide a basis for estimatingcost and time requirements for future projects.

Reconnaissance Phase

Reconnaissance work during the early phases of a project shouldidentify variability of hydrologic systems, data availability, and theprincipal controls on the occurrence and movement of water. Recon-naissance information should be used to update project work plans,guiding intensity, and distribution of field effort to define the signifi-cannot unknowns.

Technical Quality Control

A systematic technical review schedule is an essential element ofeffective project management. It is the responsibility of the supervi-sor to review the technical aspects of the project frequently. The re-view should consider the progress, plans, and resolution of objec-tives. If needed, the work plan should be revised and work effortand goals rescheduled.

You have no doubt heard of the district chief who gave a projectleader an assignment and said, “Here’s your project. Now don’t letme see you again for three years.” It probably never happened, butthere are indications of infrequent or irregular internal project reviews



within the district. Effective management requires close contact withthe project staff. This contact consists mainly of periodic and regulartechnical reviews. A team approach to review has merit, particularlyif the problem is interdisciplinary.

Review at three- to six-month intervals, especially during the firstyear, is an effective way to sense problems, progress, and to utilizedecision points if changes appear to be in order. Such reviews may beapart of regular staff meetings or at district technical seminar sessions.These reviews not only provide technical guidance, but also identifythe amount of time being expended on each phase of the project. Someproject chiefs frequently expend too much effort on that phase of theproject where they personally have the greatest interest or expertise.

The supervisor should also visit the field. There is no substitutefor understanding the field problems. The district chief should seekoutside assistance from the region, the branches, research, or outsidethe survey to assist in technical review. Outside help is especiallyneeded on projects that present a new approach for the district.

Oral Presentation

The project personnel should be encouraged to present talks to coop-erators, t echnica1 societies, and community groups. The advantagesgained from this are many. For example, it provides good publicrelations for the district, should improve the report, and may result inexpansion or change in project objectives.

Professional Environment

It is the basic responsibility of the district chief to provide a productiveenvironment for the employee. Key points here are the opportunity forthe project personnel to take an active part in project planning, tofreely exercise imagination in obtaining, interpreting, and presentingresults, and to communicate freely on technical problems with peersin other projects, districts, and agencies. Stated in a slightly differentway, project personnel should be given an opportunity for professionalgrowth through assigned responsibility rather than through a tightlyrestricted set of duties.

Project personnel should be made aware of their responsibilitiesby frequent consultations with the supervisor, continuing review ofproject progress by district officials results in commendations, where


Appendix 189

warranted. Project personnel should be surrounded by an attitude thatstresses getting the job done.

Report Management

Report management is a subject that should receive separate treat-ment all its own, however, reports cannot be separated or ignored inproject planning or supervision. Reports can be improved by givingmore attention to colleague review and making them less stereotyped,releasing them more rapidly, and preparing more reports related tothe water user.

Report Planning

Report planning is a continuing process. Some suggestions for plan-ning reports are as follows. A preliminary report should be preparedduring the first 10% of project life, which outlines main hydrologicfeatures of study area (using data available) and suggests workneeded to eliminate deficiencies and analytical techniques to beapplied. A series of short internal reports covering successive phasesof project work are valuable for training in report writing and canbe added to the final report.

Report preparation should never be handled as a rechore to be donejust before the project is concluded. Work on the outline and parts ofthe final report should be done in steps as fieldwork reaches identifiableconclusions throughout the life of the project. The project chief shouldsubmit the first drafts of the report not later than 6 months before theend of the project.


191

Index

A

Activated charcoal, 77Aerial photographs, 42Agencies, 42Alluvial aquifers, 4American Geological Institute, 42American Institute of Hydrology, 15American Society of Testing and Materials,

49, 81Aquifer(s)

alluvial, 4confined, 5, 48definition of, 3functions of, 7groundwater movement through, 7–8hydraulic connectivity of, 4isotropic, 5limestone, 6materials, 5–6permeability of, 4pore spaces for, 3properties of, 3recharge of, 8sandstone, 4stream relations with, 92–93subsurface mapping of, 63types of, 3unconfined, 5, 48, 84

Aquifer testASTM standards and guidelines for, 81computer program for, 85–87conditions necessary for, 81–82data analysis methods, 84–85design of, 80–82, 85–87hydrogeologic maps, 87objectives of, 80slug, 83–84specific capacity, 82

step-drawdown, 82–83types of, 82–84

Artesian springs, 52–53

B

Bar charts, 33Basalt aquifers, 6Borehole geophysical measurements, 60Budget, project, 21–22, 30

C

Case studiesCentral Valley, California, 107–108Chicago, Illinois, 118–119Las Vegas Valley, Nevada, 119–120Tucson and Phoenix, Arizona, 120–121

Central Valley of California case study, 107–108

Charcoal, activated, 77Chicago, Illinois case study, 118–119Chloride, 75Clay, 4Client

communication with, 35–36correspondence with, 36

Climactic data, 43Collection pipe, 54Comprehensive investigation, 38–39Computerized databases, 42Concurrent review, 106Confined aquifer, 5, 48Consecutive review, 106Contact spring, 53

L1587_Frame_IDX Page 191 Tuesday, May 21, 2002 11:26 AM


Contamination investigation, 39Contingency planning, 20Continuous staffing, 182–183Cooper-Jacob straight line method, 84–85

D

Darcy’s law, 7Depression spring, 53Discharge, 8–9Dissolved oxygen, 69Drill cuttings

description of, 67examination of, 67–68

Drinking waterfrom groundwater, 1–2from springs, 51, 53–54

Dye, 75–77

E

Editorial review, 30, 106–109Electrical resistivity measurements, 59Electrical tape, 71Electromagnetic induction measurements,

59Elevation head, 7

F

Field investigationhazardous waste, 56–58phase I, 57phase II, 57–58planning of, 49–50site reconnaissance and visit, 49–50springs

artesian, 52–53definition of, 50discharge rate of, 52drinking water from, 51, 53–54flow modifications, 54–55gravity, 52historical uses of, 51local, 52questions about, 55–56regional, 52thermal, 53types of, 51–52, 53

Field notebook, 16Field notebook items, 65Fracture, 11Fracture spring, 53Fracture traces, 11

Fractured rocksdescription of, 6permeability of, 5

Full-time staffing, 182–183Funding, 183

G

Gaining stream, 9Gantt charts, 33Geographic information system, 44Geologic mapping, 63–64Geologic-hydrologic-chemical-biologic

system, 18Geophysical maps, 42Geophysical surveys, 58–60Geyser spring, 53Grain size, 79–80Gravity measurements, 60Gravity springs, 52Ground penetrating radar measurements, 59Groundwater,

See also

Wateraquifer storage of,

See

Aquifer(s)collection sites for, 2contamination of, 53depth of, 2description of, 1–2discharge of, 8–9drinking water from, 1–2facts regarding, 12geologic mapping of, 63–64investigations,

See

Investigationslocating of, 11movement of, 4, 6–8replenishment of, 2sampling of, 68–69seepage run measurements, 92tracing techniques,

See

Tracingwater level measurements, 69–72to well, 9–10

Group review, 106Grout curtain, 54–55

H

Hazardous waste site investigation, 56–58Horizontal permeability, 4–5Hydraulic connectivity, 4, 79–80Hydraulic-head distribution, 8–9Hydrogeologic maps, 87Hydrogeologic reports

description of, 95elements of

abstract, 100–101, 111body of report, 103, 111–112conclusions, 103–104, 112


Index 193

description of, 184executive summary, 100–101, 111illustrations, 112–113introduction, 101, 111previous studies, 103purpose, 101–102recommendations, 103–104, 112references, 112scope, 101–102study area, 102study methods, 102summary, 103, 112tables, 112title, 99–100, 110

management of, 189organization of, 98–99outline of, 98planning of, 95–99, 184–185, 189review of

areas assessed, 107–109description of, 97editorial, 106–109methods, 106objectives, 104–105peer reviewers, 105process for, 110–113technical, 109–113, 187–188

verification of, 113work plan, 96, 186–187writing of

guidelines for, 97–98process, 99–104

Hydrogeologistsfield notebook used by, 16responsibilities of, 17–18rules for professional conduct, 15

Hydrologic cycle, 2Hydrologic information reports, 43Hydrologic system, 47–48Hydrology

data sources, 41–43web sites for, 43–44

I

"Ideal Project—Its Planning and Supervision," 181–189

Internal review, 30Investigations

comprehensive, 38–39contamination, 39data collection and sources, 41–43field,

See

Field investigationobjectives of, 40–41phase 1, 39, 57phase 2, 40, 57–58purpose of, 37reconnaissance, 38, 187steps involved in, 37–38

Isotopesfield methods for, 76radioactive, 74, 76stable, 73–74, 76

J

Joints, 11

L

Label tracing, 73Las Vegas Valley, Nevada case study,

119–120Limestone aquifer, 6Long-term project, 24Losing streams, 9

M

Magnetometry measurements, 60Management by objectives, 26–27Manpower,

See also

Staffingdescription of, 22projections for, 29–30

Metal detector measurements, 60Microscopic particulate analysis, 56Milestone charts, 32Monitor wells, 64, 66

O

Open-ended project, 25Organic dyes, 75–77

P

Peer review, 105Perched spring, 53Permeability, 4PERT, 33pH, 69Phase 1 investigation, 39, 57Phase 2 investigation, 40, 57–58Pore spaces

connections among, 4types of, 3–4

Porosity, 3–4Pressure head, 7



Pressure transducer, 72Primary porosity, 3Program Evaluation and Review Technique,

See

PERTProject

budget for, 21–22, 30completion of, 33–36contingency planning, 20controls for, 28definition of, 20–21deliverables, 21documentation of, 186duration of, 182elements of, 19failure of, 25final report of, 34funding of, 183"ideal," 181–189long-term, 24objectives of, 182, 186open-ended, 25personnel involved in, 188–189phases of, 26planning of, 19–26, 183–186postcompletion analysis of, 33–35professional environment, 188–189progress of,

See

Project progressproposal for, 20–21, 24–25report outline, 22–23review of, 27, 37schedule for, 22, 29short-term, 23staffing for, 22supervision of, 186–189technical assistance for, 185–186types of, 23–24

Project managementdefinition of, 26file for, 28, 37by objectives, 26–27

Project managerdescription of, 19–20responsibilities of, 34–35, 37

Project progresscharting of, 187evaluation of, 31–33milestone completion, 31–32monitoring of, 32, 187reports of, 32technical, 30–31

Public water supplyhydrogeologic setting for, 55springs for, 51, 53–54

Pulse tracing, 73

R

Radioactive isotopes, 74, 76Recharge, 8

Reconnaissance investigation, 38, 187Report,

See

Hydrogeologic reportsReviews

hydrogeologic reportareas assessed, 107–109description of, 97editorial, 106–109methods, 106objectives, 104–105peer reviewers, 105process for, 110–113technical, 109–113, 187–188

project, 27, 37

S

Salts, 74–75Sampling

dye analysis, 77groundwater, 68–69springs, 68

Sandcementation of, 4composition of, 5–6grain size, 79–80permeability of, 4

Sandstone aquifer, 4Secondary porosity, 4Sediment, 4Seep spring, 53Seismic refraction and reflection

measurements, 59Short-term project, 23Site

hazardous waste investigation, 56–58investigations of, 49landfill, 56reconnaissance of, 49–50visiting of, 50

Slug test, 83–84Soils, 42Specific capacity test, 82Specific conductance, 69Spring(s)

artesian, 52–53definition of, 50description of, 9discharge rate of, 52drinking water from, 51, 53–54flow modifications, 54–55gravity, 52historical uses of, 51local, 52questions about, 55–56regional, 52thermal, 53types of, 51–52, 53water-quality sampling, 68

Spring box, 54


Index 195

Stable isotopes, 73–74, 76Staffing

continuous, 182–183description of, 22full-time, 182–183projections for, 29–30

Statement of work, 34Step-drawdown test, 82–83Storyboard review, 106Stream

description of, 9gaging of

definition of, 91equipment for, 91measurement procedure, 91–92stream–aquifer relations, 92–93

groundwater withdrawal effects on, 9Streamflow hydrographs, 93Subsurface hydrologic systems, 18, 81Subsurface investigations, 63–64

T

Technical progress of project, 30–31Technical quality report, 187–188Test drilling, 67–68Theis equation, 84Topographic data sources, 42Total quality management, 36–37Tracers

artificial, 74–75natural, 73–74organic dyes, 75–77qualities of, 74radioactive isotopes, 74, 76salts, 74–75stable isotopes, 73–74

Tracingclassification of, 73field methods for, 75–77label, 73

pulse, 73streamflow hydrographs, 93techniques for, 72–73

Tubular spring, 53Tucson and Phoenix, Arizona case study,

120–121

U

Unconfined aquifer, 5, 48, 84U.S. Geological Survey, 41–42

V

Volcanic rocks, 6

W

Water,

See also

Drinking water; Groundwater

level measurements of, 69–72quality sampling, 68–69

Water table, 2Water-table contour map, 8, 87, 93Web sites, 43–44Well

failure of, 11inventory of, 64–65monitor, 64, 66observation, 69–70spring flow extraction by, 55water level measurements, 69–70water source to, 9–10water level measurements, 64

Wetted steel tape, 70–71Work plan, 96, 186–187


[john e. moore] field hydrogeology- a guide for si(bookfi.org)

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