1987. water supply sources and general considerations

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ARMY TM 5-813-1 NAVY AIR FORCE AFM 88 10, Vol. 1 WATER SUPPLY SOURCES AND GENERAL CONSIDERATIONS DEPARTMENTS OF THE ARMY, THE NAVY, AND THE AIR FORCE 4 JUNE 1987

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Page 1: 1987. Water supply sources and general considerations

ARMY TM 5-813-1NAVY

AIR FORCE AFM 88 10, Vol. 1

WATER SUPPLYSOURCES AND GENERAL CONSIDERATIONS

DEPARTMENTS OF THE ARMY, THE NAVY, AND THE AIR FORCE4 JUNE 1987

Page 2: 1987. Water supply sources and general considerations

REPRODUCTION AUTHORIZATION/RESTRICTIONS

This manual has been prepared by or for the Government and is public property and not subject to copyright.

Reprints or republications of this manual should include a credit substantially as follows: ‘.Joint Departments of the Armyand Air Force USA, Technical Manual TM 5813-1/AFM 88-10, Volume 1, Water Supply, Sources and GeneralConsiderations, 4 June 1987.

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*TM 5-813-1/AFM 88-10, Vol. 1

TECHNICAL MANUAL HEADQUARTERSNo. 5-813-1 DEPARTMENTS OF THE ARMYAIR FORCE MANUAL AND THE AIR FORCENo. 88-10, Volume 1 WASHINGTON, DC 4 June 1987

WATER SUPPLYSOURCES AND GENERAL CONSIDERATIONS

Paragraph PageChapter 1. GENERAL

Purpose...................................................................................................................................... 1-1 1-1Scope......................................................................................................................................... 1-2 1-1Definitions .................................................................................................................................. 1-3 1-1

Chapter 2. WATER REQUIREMENTSDomestic requirements .............................................................................................................. 2-1 2-1Fire-flow requirements ............................................................................................................... 2-2 2-1Irrigation ..................................................................................................................................... 2-3 2-1

Chapter 3. CAPACITY OF WATER-SUPPLY SYSTEMCapacity factors ......................................................................................................................... 3-1 3-1Use of capacity factor ................................................................................................................ 3-2 3-1System design capacity ............................................................................................................. 3-3 3-1Special design capacity ............................................................................................................. 3-4 3-1Expansion of existing systems ................................................................................................... 3-5 3-1

Chapter 4. WATER SUPPLY SOURCESGeneral ...................................................................................................................................... 4-1 4-1Use of existing systems ............................................................................................................. 4-2 4-1Other water systems .................................................................................................................. 4-3 4-1Environmental considerations .................................................................................................... 4-4 4-1Water quality considerations ...................................................................................................... 4-5 4-1Checklist for existing sources of supply ..................................................................................... 4-6 4-2

Chapter 5. GROUND WATER SUPPLIESGeneral ...................................................................................................................................... 5-1 5-1Water availability evaluation ...................................................................................................... 5-2 5-1Types of wells ............................................................................................................................ 5-3 5-3Water quality evaluation ............................................................................................................. 5-4 5-6Well hydraulics ........................................................................................................................... 5-5 5-6Well design and construction ..................................................................................................... 5-6 5-9Development and disinfection .................................................................................................... 5-7 5-19Renovation of existing wells ....................................................................................................... 5-8 5-20Abandonment of wells and test holes ........................................................................................ 5-9 5-20Checklist for design.................................................................................................................... 5-10 5-22

Chapter 6. SURFACE WATER SUPPLIESSurface water sources ............................................................................................................... 6-1 6-1Water laws ................................................................................................................................. 6-2 6-1Quality of surface waters............................................................................................................ 6-3 6-1Watershed control and surveillance ........................................................................................... 6-4 6-1Checklist for surface water investigations .................................................................................. 6-5 6-2

Chapter 7. INTAKESGeneral ...................................................................................................................................... 7-1 7-1Capacity and reliability ............................................................................................................... 7-2 7-1Ice problems .............................................................................................................................. 7-3 7-1Intake location ............................................................................................................................ 7-4 7-2

Chapter 8. RAW WATER PUMPING FACILITIESSurface water sources ............................................................................................................... 8-1 8-1Ground water sources................................................................................................................ 8-2 8-2Electric power............................................................................................................................. 8-3 8-2Control of pumping facilities ....................................................................................................... 8-4 8-2

Chapter 9. WATER SYSTEM DESIGN PROCEDUREGeneral ...................................................................................................................................... 9-1 9-1Selection of materials and equipment ........................................................................................ 9-2 9-1Energy conservation .................................................................................................................. 9-3 9-1

*This manual supersedes TM 5813-1/AFM 88-10, Chap. 1; and TM 5-813-2/AFM 88-10, Chap. 2, each dated July, 1965.i

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Page

Appendix A. REFERENCES ..................................................................................................................... A-1Appendix B. SAMPLE WELL DESIGN...................................................................................................... B-1Appendix C. DRILLED WELLS ................................................................................................................. C-1

BIBLIOGRAPHY ................................................................................................................... Biblio 1Index.............................................................................................................................................................. INDEX 1

List of Figures

Figure Page5-1 Water availability evaluation ................................................................................................. 5-25-2 Driven well ............................................................................................................................ 5-45-3 Collector well ........................................................................................................................ 5-55-4 Diagram of water table well .................................................................................................. 5-75-5 Diagram of well in artesian aquifer ....................................................................................... 5-85-6 Diagrammatic section of gravel-packed well ........................................................................ 5-105-7 Well in rock formation ........................................................................................................... 5-115-8 Sealed well ........................................................................................................................... 5-21B-1 Plan of proposed site ............................................................................................................ B-1

List of Tables

Table Page2-1 Domestic Water Allowances for Army and Air Force Projects .............................................. 2-23-1 Capacity Factors ................................................................................................................... 3-14-1 Water Hardness Classification ............................................................................................. 4-25-1 Types of Wells ...................................................................................................................... 5-35-2 Minimum distances from pollution sources ........................................................................... 5-65-3 Well diameter vs. anticipated yield ...................................................................................... 5-95-4 Change in yield for variation in well diameter ....................................................................... 5-125-5 Characteristics of pumps used in water supply systems ...................................................... 5-17

ii

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*TM 5-813-1/AFM-88-10, Vol. 1

CHAPTER 1GENERAL

1-1. PurposeThis manual provides guidance for selecting watersources, in determining water requirements for Army andAir Force installations including special projects, and fordeveloping suitable sources of supply from ground orsurface sources.

1-2. ScopeThis manual is applicable in selection of all watersources and in planning or performing construction ofsupply systems. Other manuals in this series are:

TM 5-813-3/AFM 88-10, Vol. 3--Water TreatmentTM 5-813-4/AFM 88-10, Vol. 4- Water StorageTM 58135/AFM 88-10, Vol. 5--Water DistributionTM 5-813-6/AFM 88-10, Chap. 6-Water Supply for

Fire ProtectionTM 5813-7/AFM 88-10, Vol. 7-Water Supply for

Special ProjectsTB MED-229-Sanitary Control and Surveillance of

Water Supplies at Fixed and FieldInstallations

AFR 161 11 Management of the Drinking WaterSurveillance Program

1-3. Definitionsa. General definitions. The following

definitions, relating to all water supplies, are established.(1) Water works. All construction

(structures, pipe, equipment) required for the collection,transportation, pumping, treatment, storage anddistribution of water.

(2) Supply works. Dams, impoundingreservoirs, intake structures, pumping stations, wells andall other construction required for the development of awater supply source.

(3) Supply line. The pipeline from thesupply source to the treatment works or distributionsystem.

(4) Treatment works. All basins, filters,buildings and equipment for the conditioning of water torender it acceptable for a specific use.

(5) Distribution system. A system ofpipes and appurtenances by which water is provided fordomestic and industrial use and firefighting.

(6) Feeder mains. The principal pipelinesof a distribution system.

(7) Distribution mains. The pipelines thatconstitute the distribution system.

(8) Service line. The pipeline extendingfrom the distribution main to building served.

(9) Effective population. This includesresident military and civilian personnel and dependentsplus an allowance for nonresident personnel, derived asfollows: The design allowance for nonresidents is 50gal/person/day whereas that for residents is 150gal/person/day. Therefore, an "effective-population"value can be obtained by adding one-third of thepopulation figure for nonresidents to the figure forresidents.

Nonresident PopulationEffective Population =

3+ Resident Population

(10) Capacity factor. The multiplier whichis applied to the effective population figure to provide anallowance for reasonable population increase, variationsin water demand, uncertainties as to actual waterrequirements, and for unusual peak demands whosemagnitude cannot be accurately estimated in advance.The Capacity Factor varies inversely with the magnitudeof the population in the water service area.

(11) Design population. The populationfigure obtained by multiplying the effective-populationfigure by the appropriate capacity factor.Design Population = [Effective Population]

x [Capacity Factor](12) Required daily demand. The total

daily water requirement. Its value is obtained bymultiplying the design population by the appropriate percapita domestic water allowance and adding to thisquantity any special industrial, aircraft-wash, irrigation,air-conditioning, or other demands. Other demandsinclude the amount necessary to replenish in 48 hoursthe storage required for fire protection and normal

1-1

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operation. Where the supply is from wells, the quantityavailable in 48 hours of continuous operation of the wellswill be used in calculating the total supply available forreplenishing storage and maintaining fire and domesticdemands and industrial requirements that cannot becurtailed.

(13) Peak domestic demand. For systemdesign purposes, the peak domestic demand isconsidered to be the greater of-

(a) Maximum day demand, i.e., 2.5times the required daily demand.

(b) The fire flow plus fifty percent ofthe required daily demand.

(14) Fire flow. The required number ofgal/min at a specified pressure at the site of the fire for aspecified period of time.

(15) Fire demand. The required rate offlow of water in gal/min during a specified fire period.Fire demand includes fire flow plus 50 percent of therequired daily demand and, in addition, any industrial orother demand that cannot be reduced during a fireperiod. The residual pressure is specified for either thefire flow or essential industrial demand, whichever ishigher. Fire demand must include flow required forautomatic sprinkler and standpipe operation, as well asdirect hydrant flow demand, when the sprinklers areserved directly by the water supply system.

(16) Rated capacity. The rated capacity ofa supply line, intake structure, treatment plant orpumping unit is the amount of water which can bepassed through the unit when it is operating underdesign conditions.

(17) Cross connection. Two typesrecognized are:

(a) A direct cross connection is aphysical connection between a supervised, potable watersupply and an unsupervised supply of unknown quality.An example of a direct cross connection is a pipingsystem connecting a raw water supply, used for industrialfire fighting, to a municipal water system.

(b) An indirect cross connection isan arrangement whereby unsafe water, or other liquid,may be blown, siphoned or otherwise diverted into a safewater system. Such arrangements include unprotectedpotable water inlets in tanks, toilets, and lavatories thatcan be submerged in unsafe water or other liquid. Underconditions of peak usage of potable water or potablewater shutoff for repairs, unsafe water or other liquid maybackflow directly or be back-siphoned through the inletinto the potable system. Indirect cross connections areoften termed "backflow connections" or "back-siphonageconnections." An example is a direct potable waterconnection to a sewage pump for intermittent use forflushing or priming. Cross connections for Air Forcefacilities are defined in AFM 8521, Operations andMaintenance of Cross Connections Control and BackflowPrevention Systems.

b. Ground water supply definitions. Themeanings of several terms used in relation to wells andground waters are as follows:

(1) Specific capacity. The specificcapacity of a well is its yield per foot of drawdown and iscommonly expressed as gallons per minute per foot ofdrawdown (gpm/ft).

(2) Vertical line shaft turbine pump. Avertical line shaft turbine pump is a centrifugal pump,usually having from 1 to 20 stages, used in wells. Thepump is located at or near the pumping level of water inthe well, but is driven by an electric motor or internalcombustion engine on the ground surface. Power istransmitted from the motor to the pump by a verticaldrive shaft.

(3) Submersible turbine pump. Asubmersible turbine pump is a centrifugal turbine pumpdriven by an electric motor which can operate whensubmerged in water. The motor is usually locateddirectly below the pump intake in the same housing asthe pump. Electric cables run from the ground surfacedown to the electric motor.

1-2

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CHAPTER 2

WATER REQUIREMENTS

2-1. Domestic requirementsThe per-capita allowances, given in table 2-1, will beused in determining domestic water requirements.These allowances do NOT include special purpose wateruses, such as industrial aircraft-wash, air-conditioning,irrigation or extra water demands at desert stations.

2-2. Fire-flow requirementsThe system must be capable of supplying the fire flowspecified plus any other demand that cannot be reducedduring the fire period at the required residual pressureand for the required duration. The requirements of eachsystem must be analyzed to determine whether thecapacity of the system is fixed by the domesticrequirements, by the fire demands, or by a combinationof both. Where fire-flow demands are relatively high, orrequired for long duration, and population and/orindustrial use is relatively low, the total required capacitywill be determined by the prevailing fire demand. Insome exceptional cases, this may warrant considerationof a special water system for fire purposes, separate, inpart or in whole, from the domestic system. However,such separate systems will be appropriate only underexceptional circumstances and, in general, are to beavoided.

2-3. IrrigationThe allowances indicated in table 2-1 include water forlimited watering or planted and grassed areas. However,these allowances do not include major lawn or otherirrigation uses. Lawn irrigation provisions for facilities,such as family quarters and temporary structures, in allregions will be limited to hose bibbs on the outside ofbuildings and risers for hose connections. Wheresubstantial irrigation is deemed necessary and water isavailable, underground sprinkler systems may beconsidered. In general, such systems should receiveconsideration only in arid or semiarid areas where rainfallis less than about 25 inches annually. For ArmyProjects, all proposed installations require specificauthorization from HQDA (DAEN-ECE-G), WASH, DC20314. For Air Force projects, refer to AFM 88 15 andAFM 8810, Vol. 4. Each project proposed must include

thorough justification, detailed plans of connection towater source, estimated cost and a statement as to theadequacy of the water supply to support the irrigationsystem. The use of underground sprinkler systems willbe limited as follows: Air Force Projects-Areas adjacentto hospitals, chapels, clubs, headquarters andadministration buildings, and Army Projects-Areasadjacent to hospitals, chapels, clubs, headquarters andadministration buildings, athletic fields, parade grounds,EM barracks, Boo’s, and other areas involving improvedvegetative plantings which require frequent irrigation tomaintain satisfactory growth.

a. Backflow prevention. Backflow preventiondevices, such as a vacuum breaker or an air gap, will beprovided for all irrigation systems connected to potablewater systems. Installation of backflow preventers will bein accordance with AFM 85-21, Operation andMaintenance of Cross Connection Control and BackflowPrevention Systems (for Air Force facilities) and theNational Association of Plumbing-Heating-CoolingContractors (NAPHCC) "National Standard PlumbingCode," (see app. A for references). Single or multiplecheck valves are not acceptable backflow preventiondevices and will not be used. Direct cross connectionsbetween potable and nonpotable water systems will notbe permitted under any circumstances.

b. Use of treated wastewater. Effluent fromwastewater treatment plants can be used for irrigationwhen authorized. Only treated effluent having adetectable chlorine residual at the most remotedischarge point will be used. Where state or localregulations require additional treatment for irrigation,such requirement will be complied with. The effluentirrigation system must be physically separated from anydistribution systems carrying potable water. A detailedplan will be provided showing the location of the effluentirrigation system in relation to the potable waterdistribution system and buildings. Provision will be madeeither for locking the sprinkler irrigation control valves orremoving the valve handles so that only authorizedpersonnel can operate the system. In

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addition, readily identifiable "nonpotable" or"contaminated" notices, markings or codings for allwastewater conveyance facilities and appurtenances willbe provided. Another possibility for reuse of treatedeffluent is for industrial operations where substantialvolumes of water for washing or cooling purposes arerequired. For any reuse situation, great care must beexercised to avoid direct cross connections between thereclaimed water system and the potable water system.c. Review of effluent irrigation projects. Concept plansfor proposed irrigation projects using wastewatertreatment plant effluent will be reviewed by the engineerand surgeon at Installation Command level and the AirForce Major Command, as appropriate. EM 1110-1-501will serve as the basic criteria for such projects, asamended by requirements herein. This publication isavailable through HQ USACE publications channels (seeapp. A, References). Such projects will only beauthorized after approval by HQDA (DAEN-ECE-G),WASH DC 20314 and HQDA (DASG-PSP-E), WASHDC 20310 for Army projects and by HQUSAF (HQUSAF/LEEEU), WASH DC 20332 and The SurgeonGeneral, (HQ AFMSC/SGPA), Brooks AFB, TX 78235for Air Force projects.

Table 2-1. Domestic Water Allowances for Army and AirForce Projects.1

Gallons/Capita/Day2

Permanent Field TrainingConstruction Camps

USAF Bases and Air ForceStations 1503 -

Armored/Mech. Divisions 150 75Camps and Forts 1504 50POW and Internment

Camps - 504

Hospital Units5 600/Bed 400/BedHotel6 70 -Depot, Industrial, Plant 50 gal/employee/8-hr shift;

and Similar Projects 150 gal/capita/day forresident personnel

Notes:1For Aircraft Control and Warning Stations, NationalGuard Stations, Guided Missile Stations, and similarprojects, use TM 5-813-7/AFM 88-10, Volume 7 forwater supply for special projects.2The allowances given in this table include water usedfor laundries to serve resident personnel, washingvehicles, limited watering of planted and grassed areas,and similar uses. The allowances tabulated do NOTinclude special industrial or irrigation uses. The percapita allowance for nonresidents will be one-third thatallowed for residents.3An allowance of 150 gal/capita/day will also be usedfor USAF semi-permanent construction.4For populations under 300, 50 gal/capita/day will beused for base camps and 25 gal/capita/day for branchcamps.5Includes hotels and similar facilities converted tohospital use.6Includes similar facilities converted for troop housing.

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CHAPTER 3

CAPACITY OF WATER-SUPPLY SYSTEM

3-1. Capacity factorsCapacity factors, as a function of "Effective Population,"are shown in table 3-1, as follows:

Table 3-1. Capacity Factors.Effective Population Capacity Factor

5,000 or less 1.5010,000 1.2520,000 1.1530,000 1.1040,000 1.05

50,000 or more 1.00

3-2. Use of capacity factorThe "Capacity Factor" will be used in planning watersupplies for all projects, including general hospitals. Theproper "Capacity Factor" as given in table 3-1 ismultiplied by the "Effective Population" to obtain the"Design Population." Arithmetic interpolation should beused to determine the appropriate Capacity Factor forintermediate project population. (For example, for an"Effective Population" of 7,200 in interpolation, obtain a"Capacity Factor" of 1.39.) Capacity factors will beapplied in determining the required capacity of the supplyworks, supply lines, treatment works, principal feedermains and storage reservoirs. Capacity factors will NOTbe used for hotels and similar structures that areacquired or rented for hospital and troop housing.Capacity factors will NOT be applied to fire flows,irrigation requirements, or industrial demands.

3-3. System design capacityThe design of elements of the water supply system,except as noted in paragraph 32, should be based on the"Design Population."

3-4. Special design capacityWhere special demands for water exist, such as thoseresulting from unusual fire fighting requirements,irrigation, industrial processes and cooling water usage,consideration must be given to these special demands indetermining the design capacity of the water supplysystem.

3-5. Expansion of existing systemsFew, if any, entirely new water supply systems will beconstructed. Generally, the project will involve upgradingand/or expansion of existing systems. Where existingsystems are adequate to supply existing demands, plusthe expansion proposed without inclusion of the CapacityFactor, no additional facilities will be provided exceptnecessary extension of water mains. In designing mainextensions, consideration will be given to planned futuredevelopment in adjoining areas so that mains will beproperly sized to serve the planned developments.Where existing facilities are inadequate for currentrequirements and new construction is necessary, theCapacity Factor will be applied to the proposed totalEffective Population and the expanded facilities plannedaccordingly.

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CHAPTER 4

WATER SUPPLY SOURCES

4-1. GeneralWater supplies may be obtained from surface or groundsources, by expansion of existing systems, or bypurchase from other systems. The selection of a sourceof supply will be based on water availability, adequacy,quality, cost of development and operation and theexpected life of the project to be served. In general, allalternative sources of supply should be evaluated to theextent necessary to provide a valid assessment of theirvalue for a specific installation. Alternative sources ofsupply include purchase of water from U.S. Governmentowned or other public or private systems, as well asconsideration of development or expansion ofindependent ground and surface sources. Acombination of surface and ground water, while notgenerally employed, may be advantageous under somecircumstances and should receive consideration.Economic, as well as physical, factor must be evaluated.The final selection of the water source will be determinedby feasibility studies, considering all engineering,economic, energy and environmental factors.

4-2. Use of existing systemsMost water supply projects for military installationsinvolve expansion or upgrading of existing supply worksrather than development of new sources. If there is anexisting water supply under the jurisdiction of theDepartment of the Army, Air Force, or other U.S.Government agency, thorough investigation will be madeto determine its capacity and reliability and the possiblearrangements that might be made for its use with orwithout enlargement. The economics of utilizing theexisting supply should be compared with the economicsof reasonable alternatives. If the amount of water takenfrom an existing source is to be increased, the ability ofthe existing source to supply estimated waterrequirements during drought periods must be fullyaddressed. Also, potential changes in the quality of theraw water due to the increased rate of withdrawal mustreceive consideration.

4-3. Other water systemsIf the installation is located near a municipality or otherpublic or private agency operating a water supplysystem, this system should be investigated to determineits ability to provide reliable water service to theinstallation at reasonable cost. The investigation mustconsider future as well as current needs of the existingsystem and, in addition, the impact of the military projecton the water supply requirements in the existing waterservice area. Among the important matters that must beconsidered are: quality of the supply; adequacy of thesupply during severe droughts; reliability and adequacyof raw water pumping and transmission facilities;treatment plant and equipment; high service pumping;storage and distribution facilities; facilities fortransmission from the existing supply system to themilitary project; and costs. In situations where a longsupply line is required between the existing supply andthe installation, a study will be made of the economicsize of the pipeline, taking into consideration cost ofconstruction, useful life, cost of operation, and minimumuse of materials. With a single supply line, the on-sitewater storage must be adequate to support the missionrequirement of the installation for its emergency period.A further requirement is an assessment of the adequacyof management, operation, and maintenance of thepublic water supply system.

4-4. Environmental considerationFor information on environmental policies, objectives,and guidelines refer to AR 200-1, for Army Projects andAFRs 19-1 and 19-2 for Air Force Projects.

4-5. Water quality considerationsGuidelines for determining the adequacy of a potentialraw water supply for producing an acceptable finishedwater supply with conventional treatment practices aregiven in paragraph A-2 of TM 5-813-3/AFM 88-10, Vol.3.

a. Hardness. The hardness of water suppliesis classified as shown in table 4-1.

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Table 4-1. Water Hardness Classification.

Total Hardness Classificationmg/1 as CaCO3

0-100 Very Soft to Soft100-200 Soft to Moderately Hard200-300 Hard to Very Hardover 300 Extremely Hard

Softening is generally considered when the hardnessexceeds about 200 to 250 mg/1. While hardness can bereduced by softening treatment, this may significantlyincrease the sodium content of the water, where zeolitesoftening is employed, as well as the cost of treatment.

b. Total dissolved solids (TDS). In addition tohardness, the quality of ground water may be judged onthe basis of dissolved mineral solids. In general,dissolved solids should not exceed 500 mg/1, with 1,000mg/1 as the approximate upper limit.

c. Chloride and sulfate. Sulfate and chloridecannot be removed by conventional treatment processesand their presence in concentrations greater than about250 mg/1 reduces the value of the supply for domesticand industrial use and may justify its rejection ifdevelopment of an alternative source of better quality isfeasible. Saline water conversion systems, such aselectrodialysis or reverse osmosis, are required forremoval of excessive chloride or sulfate and also certainother dissolved substances, including sodium andnitrate.

d. Other constituents. The presence of certaintoxic heavy metals, fluoride, pesticides, and radioactivityin concentrations exceeding U.S. EnvironmentalProtection Agency standards, as interpreted by theSurgeon General of the Army/Air Force, will makerejection of the supply mandatory unless unusuallysophisticated treatment is provided. (For detaileddiscussion of EPA water standards, see 40 CFR-Part141, AR 420-46 and TB MED 229 for Army Projects andAFR 161-44 for Air Force Projects.)

e. Water quality data. Base water qualityinvestigations or analysis of available data at or near theproposed point of diversion should include biological,bacteriological, physical, chemical, and radiologicalparameters covering several years and reflectingseasonal variations. Sources of water quality data areinstallation records, U.S. Geological Survey District orRegional offices and Water Quality Laboratories, U.S.Environmental Protection Agency regional offices, stategeological surveys, state water resources agencies, stateand local health departments, and nearby water utilities,including those serving power and industrial plants,

which utilize the proposed source. Careful study ofhistorical water quality data is usually more productivethan attempting to assess quality from analysis of a fewsamples, especially on streams. Only if a thoroughsearch fails to locate existing, reliable water quality datashould a sampling program be initiated. If such aprogram is required, the advice and assistance of anappropriate state water agency will be obtained. Specialprecautions are required to obtain representativesamples and reliable analytical results. Great cautionmust be exercised in interpreting any results obtainedfrom analysis of relatively few samples.

4-6. Checklist for existing sources of supplyThe following items, as well as others, if circumstanceswarrant, will be covered in the investigation of existingsources of supply from Government-owned or othersources.

a. Quality history of the supply; estimates offuture quality.

b. Description of source.c. Water rights.d. Reliability of supply.e. Quantity now developed.f. Ultimate quantity available.g. Excess supply not already allocated.h. Raw water pumping and transmission

facilities.I. Treatment works.j. Treated water storage.k. High service pumping and transmission

facilities.l l. Rates in gal/min at which supply is available.

m. Current and estimated future cost per 1,000gallons.

n. Current and estimated future cost per 1,000gallons of water from alternative sources.

o. Distance from military installation site toexisting supply.

p. Pressure variations at point of diversion fromexisting system.

q. Ground elevations at points of diversion anduse.

r. Energy requirements for proposed system.s. Sources of pollution, existing and potential.t. Assessment of adequacy of management,

operation, and maintenance.u. Modifications required to meet additional

water demands resulting from supplying water to militaryinstallation.

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CHAPTER 5

GROUND WATER SUPPLIES

5-1. GeneralGround water is subsurface water occupying thesaturation zone. A water bearing geologic formationwhich is composed of permeable rock, gravel, sand,earth, etc., is called an aquifer. Unconfined groundwater is found in aquifers above the first impervious layerof soil or rock. Confined water is found in aquifers inwhich the water is confined by an overlying imperviousbed. Porous materials such as unconsolidatedformations of loose sand and gravel may yield largequantities of water and, therefore, are the primary targetfor location of wells. Dense rocks such as granite frompoor aquifers and wells constructed in them do not yieldlarge quantities of water. However, wells placed infractured rock formations may yield sufficient water formany purposes.

a. Economy. The economy of ground waterversus surface water supplies needs to be carefullyexamined. The study should include an appraisal ofoperating and maintenance costs as well as capitalcosts. No absolute rules can be given for choosingbetween ground and surface water sources. Wherewater requirements are within the capacity of an aquifer,ground water is nearly always more economical thansurface water. The available yield of an aquifer dictatesthe number of wells required and thus the capital costs ofwell construction. System operating and maintenancecosts will depend upon the number of wells. In general,ground water capital costs include the wells, disinfection,

pumping and storage with a minimum of other treatment.Surface water supply costs include intake structures,sedimentation, filtration, disinfection, pumping andstorage. Annual operating costs include the costs ofchemicals for treatment, power supply, utilities andmaintenance. Each situation must be examined on itsmerits with due consideration for all factors involved.

b. Coordination with State and LocalAuthorities. Some States require that a representative ofthe state witness the grouting of the casing and collectan uncontaminated biological sample before the well isused as a public water supply. Some States require apermit to withdraw water from the well and limit theamount of water that can be withdrawn.

c. Artic well considerations. Construction ofwells in artic and subartic areas requires specialconsiderations. The water must be protected fromfreezing and the permafrost must be maintained in afrozen state. The special details and methods describedin TM 5-852-5/AFM 88-19, Chap. 5 should be followed.

5-2. Water availability evaluationAfter water demand and water use have beendetermined, the evaluation of water availability and waterquality of ground water resources will be made. Thefollowing chart is used to illustrate step-by-stepprocedures.

5-1

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*TM 5-813-1/AFM-88-10, Vol. 1

Figure 5-1. Water availability evaluation.

5-2

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5-3. Types of WellsWells are constructed by a variety of methods. There isno single optimum method; the choice depends on size,depth, formations encountered and experience of localwell contractors. The most common types of wells arecompared in table 5-1.

Table 5-1. Types of Wells.

Maximum Lining or Method ofType Diameter Depth (ft) Casing Suitability Disadvantages Construction

Dug 3 to 20 40 wood, ma- Water near sur- Large number of Excavation fromfeet sonry, con- face. May be con- manhours required within well.

crete or structed with for construction.metal hand tools. Hazard to diggers.

Driven 2 to 4 50 pipe Simple using Formations must be Hammering a pipeinches hand tools. soft and boulder into the ground.

free.

Jetted 3 or 4 200 pipe Small dia. wells Only possible in High pressureinches on sand. loose sand forma- water pumped

tions. through drill pipe.

Bored up to 36 50 pipe Useful in clay Difficult on loose Rotating earth au-inches formations. sand or cobbles. ger bracket.

Collector 15 feet 130 Reinforced Used adjacent to Limited number of Caisson is sunkconcrete surface recharge Installation Con- into aquifer. Pre-caisson source such as tractors formed radial

river, lake or pipes are jackedocean. horizontally

through portsnear bottom.

Drilled Up to 60 4000 pipe Suitable for vari- Requires experi- a. Hydraulic ro-inches ety of forma- enced Contractor & tary*

tions. specialized tools. b. Cable tool per-cussion*

c. reverse circula-tion rotary

d. hydraulic-per-cussion

e. air rotary

*For detailed description, see Appendix C.

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Figure 5-2. Driven well.

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Figure 5-3. Collector well.

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5-4. Water quality evaluationBoth well location and construction are of majorimportance in protecting the quality of water derived froma well.

a. Sanitary survey. Prior to a decision as towell or well field location, a thorough sanitary survey ofthe area should be undertaken. The followinginformation should be obtained and analyzed:

(1) Locations and characteristics ofsewage and industrial waste disposal.

(2) Locations of sewers, septic tanks andcesspools.

(3) Chemical and bacteriological quality ofground water, especially the quality of water fromexisting wells.

(4) Histories of water, oil, or gas wells ortest holes in area.

(5) Industrial and municipal landfills anddumps.

(6) Direction and rate of travel of usableground water.Recommended minimum distances for well sites, underfavorable geological conditions, from commonlyencountered potential sources of pollution are as shownin table 5-2. It is emphasized that these are minimumdistances which can serve as rough guides to goodpractice when geological conditions are favorable.Conditions are considered favorable when the earthmaterials between the well location and the pollutionsource have the filtering ability of fine sand. Where theterrain consists of coarse gravel, limestone ordisintegrated rock near the surface, the distance guidesgiven above are insufficient and greater distances will berequired to provide safety. Because of the widegeological variations that may be encountered, it isimpossible to specify the distance needed under allcircumstances. Consultation with local authorities will aidin establishing safe distances consistent with the terrain.

Table 5-2. Minimum Distances from Pollution Sources.

MinimumSource Horizontal Distance

Building Sewer 50 ft.Septic Tank 50 ft.Disposal Field 100 ft.Seepage Pit 100 ft.Dry Well 50 ft.Cesspool 150 ft.

Note: The above horizontal distances apply to all depths ofwells.

b. Sampling and analysis. It is mandatory toreview the stipulations contained in the current U.S.Environmental Protection Agency’s drinking waterstandards and state/local regulations as interpreted bythe Surgeon General of the Army/Air Force and to collectsamples as required for the determination of allconstituents named in the drinking water standards. Themaximum chemical concentrations mandated in thedrinking water standards are given in TM 5-813-3/AFM88-10, Vol. 3.

Heavy metals are rarely encountered in significantconcentrations in natural ground waters, but may be aconcern in metamorphic rock areas, along with arsenic.Radioactive minerals may cause occasional highreadings in granite wells.

c. Treatment. Well water generally requiresless treatment than water obtained from surfacesupplies. This is because the water has been filtered bythe formation through which it passes before being takenup in the well. Normally, sedimentation and filtration arenot required. However, softening, iron removal, pHadjustment and disinfection by chlorination are usuallyrequired. Chlorination is needed to provide residualchloride in the distribution system. The extent oftreatment must be based upon the results of thesampling program. For a detailed discussion oftreatment methods, see TM 5813-3/AFM 88-10, Vol. 3,and Water Treatment Plant Design.

5-5. Well hydraulicsa. Definitions. The following definitions are

necessary to an understanding of well hydraulics:-Static Water Level. The distance from the ground

surface to the water level in a well when no water isbeing pumped.

-Pumping Level. The distance from the groundsurface to the water level in a well when water is beingpumped. Also called dynamic water level.

-Drawdown. The difference between static waterlevel and dynamic water level.

-Cone of Depression. The funnel shape of thewater surface or piezometric level which is formed aswater is withdrawn from the well.

-Radius of Influence. The distance from the well tothe edge of the cone of depression.

-Permeability. The rate of flow through a squarefoot of the cross section of the aquifer under a hydraulicgradient of 100 percent at a water temperature of 60°F.

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(The correction to 60°F is usually neglected.) Usuallymeasured in gallons per day per square foot.

b. Well discharge formulas. The followingformulas assume certain simplifying conditions.However, these assumptions do not severely limit theuse of the formulas. The aquifer is of constantthickness, is not stratified and is of uniform permeability.The piezometric surface is level, laminar flow exists andthe cone of depression has reached equilibrium. Thepumping well reaches the bottom of the aquifer and is100 percent efficient. There are two basic formulas(Ground Water & Wells) one for water table wells andone for artesian wells. Figure 5-4 shows the relationshipof the terms used in the following formula for availableyield from a water table well:

Where:Q = well yield in gpmP = permeability in gpd per square footH = thickness of aquifer in feeth = depth of water in well while pumpingin feetR = radius of influence in feetr = radius of well in feet

Figure 5-5 shows the relationship of the terms used inthe following formula for available yield from an artesianwell:

where:m = thickness of aquifer in feetH = static head at bottom of aquifer in feetall other terms are the same as for Equation 5-1.

Figure 5-4. Diagram of water table well.

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Figure 5-5. Diagram of well in artesian aquifer.

c. Determination of values. The well driller’slog provides the dimensions of H and h. The value of Rusually lies between 100 and 10,000. It may bedetermined from observation wells or estimated. A valueof R = 1000 may be used; large variations makes smalldifference in the flow. P may be determined fromlaboratory tests or field tests. Existing wells or test wellsmay provide the values for all of these equations. Figure5-4 also shows the relationship of the terms used in theformula for calculating P:

For artesian conditions, again, as shown in fig. 5-5, theformula becomes:

d. Aquifer testing. Where existing wells orother data are insufficient to determine aquifercharacteristics, testing may be necessary to establish

values used for design. Testing consists of pumpingfrom one well and noting the change in watertable atother wells as indicated in figures 5-4 and 5-5.Observation wells are generally set at 50 to 500 feet froma pumped well, although for artesian aquifers they maybe placed at distances up to 1000 feet. A greaternumber of wells allows the slope of the drawdown curveto be more accurately determined. The three mostcommon methods of testing are:

-Drawdown Method. Involves pumping one welland observing what happens in observation wells.

-Recovery Method. Involves shutting down of apumped well and noting recovery of water level inobservation wells.

-Water Input Test. Involves running water into awell and determining the rate at which water flows intothe aquifer.The typical test, utilizing the drawdown method, consistsof pumping a well at various rates and noting thecorresponding drawdown at each step.

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e. Testing objectives. A simplified example isgiven in appendix B. When conducting tests by methodssuch as the drawdown method, it is important to noteaccurately the yield and corresponding drawdown. Agood testing program, conducted by an experiencedgeologists, will account for, or help to define, thefollowing aquifer characteristics:

(1) Type of aquifer-water table-confined-artesian

(2) Slope of aquifer(3) Direction of flow(4) Boundary effects(5) Influence of recharge

-stream or river-lake

(6) Nonhomogeneity(7) Leaks from aquifer

5-6. Well design and constructionWell design methods and construction techniques arebasically the same for wells constructed in consolidatedor unconsolidated formations. Typically, wellsconstructed in an unconsolidated formation require ascreen to line the lower portion of the borehole. Anartificial gravel pack may or may not be required. Adiagrammatic section of a gravel packed well is shownon figure 5-6. Wells constructed in sandstone, limestoneor other creviced rock formations can utilize an uncased

borehole in the aquifer. Screens and the gravel pack arenot usually required. A well in rock formation is shown infigure 5-7. Additional well designs for consolidated andunconsolidated formations are shown in AWWA A100.

a. Diameter. The diameter of a well has asignificant effect on the well’s construction cost. Thediameter need not be uniform from top to bottom.Construction may be initiated with a certain size casing,but drilling conditions may make it desirable to reducethe casing size at some depth. However, the diametermust be large enough to accommodate the pump andthe diameter of the intake section must be consistentwith hydraulic efficiency. The well shall be designed tobe straight and plump. The factors that control diameterare (1) yield of the well, (2) intake entrance velocity, (3)pump size and (4) construction method. The pump size,which is related to yield, usually dominates. Approximatewell diameters for various yields are shown in table 5-3.Well diameter affects well yield but not to a majordegree. Doubling the diameter of the well will produceonly about 10-15 percent more water. Table 5-4 givesthe theoretical change in yield that results from changingfrom one well diameter to a new well diameter. Forartesian wells, the yield increase resulting from diameterdoubling is generally less than 10 percent.Consideration should be given to future expansion andinstallation of a larger pump. This may be likely in caseswhere the capacity of the aquifer is greater than the yieldrequired.

Table 5-3. Well Diameter vs. Anticipated Yield.

Anticipated Nominal Size of Optimum Size Smallest SizeWell Yield Pump Bowls Well Casing Well Casing

(gallons/minute) (inches) (inches) (inches)

<100 4 6 ID 5 ID75-175 5 8 ID 6 ID150-00 6 10 ID 8 ID350-650 8 12 ID 10 ID600-900 10 14 OD 12 ID850-1300 12 16 OD 14 OD1200-1800 14 20 OD 16 OD1600-3000 16 24 OD 20 OD

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Figure 5-6. Diagrammatic section of a gravel-packed well.

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Figure 5-7. Well in rock formation.

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Table 5-4. Change in Yield for Variation in WellDiameter.

Original New Well DiameterWell

Diameter 6" 12" 18" 24" 30" 36" 48"6" 100% 110% 117% 122% 127% 131% 137%

12" 90 100 106 111 116 119 12518" 84 93 100 104 108 112 11724" 79 88 95 100 104 107 11230" 76 85 91 96 100 103 10836" 73 82 88 92 96 100 10548" 69 77 82 87 91 94 100

Note: The above gives the theoretical increase ordecrease in yield that results from changingthe original well diameter to the new welldiameter. For example, if a 12-inch well isenlarged to a 36-inch well, the yield will beincreased by 19 percent. The values in theabove table are valid only for wells inunconfined aquifers (water table wells) andare based on the following equation:

(Y2/Y1) = (log R/r1)/(log R/r2)where:

Y2 = yield of new wellY1 = yield of original wellR = radius of cone of depression,

in feet (the value of R used forthis table is 400 feet).

r2 = diameter of new well, in feetr1 = diameter of original well, in feet

b. Depth. Depth of a well is usually determinedfrom the logs of test holes or from logs of other nearbywells that utilize the same aquifer. The deeper the well isdriven into a water bearing stratum, the greater thedischarge for a given drawdown. Where the waterbearing formations are thick, there is a tendency to limitthe depth of wells due to the cost. This cost, however,usually is balanced by the savings in operations resultingfrom the decreased drawdown. Construction should sealoff water bearing formations that are or may be pollutedor of poor mineral quality. A sealed, grouted casing willextend to a depth of 20 feet or more from the groundsurface. Check local regulations to determine minimumrequirements. Where the depth of water of poor qualityis known, terminate the well above the zone of poorquality water.

c. Casing. In a well developed in a sand andgravel formation, the casing should extend to a minimumof 5 feet below the lowest estimated pumping level. Inconsolidated formations, the casing should be driven 5feet into bedrock and cemented in place for its full depth.

The minimum wall thickness for steel pipe used forcasing is V/4-inch. For various diameters, EPArecommends the following wall thicknesses:

Nominal Diameter (inch) Wall Thickness (inch)6 .2508 .250

10 .27912 .33014 .37516 .37518 .37520 .375

In the percussion method of drilling, and where sloughingis a problem, it is customary to drill and drive the casingto the lower extremity of the aquifer to be screened andthen install the appropriate size screen inside the casingbefore pulling the casing back and exposing the screento the water bearing formation.

d. Screens. Wells completed in sand andgravel with open-end casings, not equipped with ascreen on the bottom, usually have limited capacity dueto the small intake area (open end of casing pipe) andtend to pump large amounts of sand. A well designedscreen permits utilizing the permeability of the waterbearing materials around the screen. For a wellcompleted in a sand-gravel formation, use of a wellscreen will usually provide much more water than if theinstallation is left open-ended. The screen functions torestrain sand and gravel from entering the well, whichwould diminish yield, damage pumping equipment, anddeteriorate the quality of the water produced. Wellsdeveloped in hard rock areas do not need screens if thewall is sufficiently stable and sand pumping is not aproblem.

(1) Aperture size. The well screenaperture opening, called slot size, is selected based onsieve analysis data of the aquifer material for a naturallydeveloped well. For a homogeneous formation, the slotsize is selected as one that will retain 40 to 50 percent ofthe sand. Use 40 percent where the water is notparticularly corrosive and a reliable sample is obtained.Use 50 percent where water is very corrosive and/or thesample may be questionable. Where a formation to bescreened has layers of differing grain sizes andgraduations, multiple screen slot sizes may be used.Where fine sand overlies a coarser material, extend thefine slot size at least 3 feet into the coarser material.This reduces the possibility that slumping of the lowermaterial will allow finer sand to enter the coarse screen.

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The coarse aperture size should not be greater thantwice the fine size. For a gravel packed well, the screenshould retain 85 to 100 percent of the gravel. Screenaperture size should be determined by a laboratoryexperienced in this work, based on a sieve analysis ofthe material to be screened. Consult manufacturer’sliterature for current data on screens.

(2) Length. Screen length depends onaquifer characteristics, aquifer thickness, and availabledrawdown. For a homogeneous, confined, artesianaquifer, 70 to 80 percent of the aquifer should bescreened and the maximum drawdown should notexceed the distance from the static water level to the topof the aquifer. For a nonhomogeneous, artesian aquifer,it is usually best to screen the most permeable strata.Determinations of permeability are conducted in thelaboratory on representative samples of the variousstrata. Homogeneous, unconfined (water-table) aquifersare commonly equipped with screen covering the lowerone-third to one-half of the aquifer. A water-table well isusually operated so that the pumping water level isslightly above the top of the screen. For a screen lengthof one-third the aquifer depth, the permissible draw-downwill be nearly two-thirds of the maximum possibledrawdown. This drawdown corresponds to nearly 90percent of the maximum yield. Screens fornonhomogeneous water-table aquifers are positioned inthe lower portions of the most permeable strata in orderto permit maximum available drawdown. The followingequation is used to determine screen length:

where:L = length of screen (feet)Q = discharge (gpm)A = effective open area per foot of screen

length (sq. ft. per ft.) (approximately one-half of theactual open area which can be obtained from screenmanufacturers.)

V = velocity (fpm) above which a sand particleis transported; is related to permeability as follows:

P (gpd/ft2) V (fpm)5000 10 (Max)4000 93000 82500 72000 61500 51000 4500 3

0-500 2 (Min)

(3) Diameter. The screen diameter shallbe selected so that the entrance velocity through thescreen openings will not exceed 0.1 foot per second.The entrance velocity is calculated by dividing the wellyield in cubic feet per second by the total area of thescreen openings in square feet. This will ensure thefollowing:

(a) The hydraulic losses in thescreen opening will be negligible.

(b) the rate of incrustation will beminimal,

(c) the rate of corrosion will beminimal.

(4) Installation. Various procedures maybe used for installation of well screens.

(a) For cable-tool percussion androtary drilled wells, the pull-back method may be used. Atelescope screen, that is one of such a diameter that itwill pass through a standard pipe of the same size, isused. The casing is installed to the full depth of the well,the screen is lowered inside the casing, and then thecasing is pulled back to expose the screen to the aquifer.

(b) In the bail down method, thewell and casing are completed to the finished grade ofthe casing; and the screen, fitted with a bail-down shoe islet down through the casing in telescope fashion. Thesand is removed from below the screen and the screensettles down into the final position.

(c) For the wash-down method, thescreen is set as on the bail-down method. The screen islowered to the bottom and a high velocity jet of fluid isdirected through a self closing bottom fitting on thescreen, loosens the sand and allowing the screen to sinkto it final position. If gravel packing is used, it is placedaround the screen after being set by one of the abovemethods. A seal, called a packer, is provided at the topof the screen. Lead packers are expanded with aswedge block. Neoprene packers are self sealing.

(d) In the hydraulic rotary method ofdrilling, the screen may be attached directly to the bottomof the casing before lowering the whole assembly intothe well.

e. Gravel packing. Gravel packing is theprocess by which selected, clean, disinfected gravel isplaced between the outside of the well screen and theface of the undisturbed aquifer. This differs from thenaturally developed well in that the zone around thescreen is made more permeable by the addition ofcoarse material. Gravel-pack material must be cleanand fairly uniform with smooth, well-rounded grains.Gravel shall be siliceous material.

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(1) Size. Gravel size is based oninformation obtained by sieve analyses of the material inthe aquifer. The well screen aperture size will beselected so that between 85 and 100 percent of thegravel is larger than the screen openings. Criteria forsizing the gravel are as follows:

(a) Perform sieve analyses on allstrata within the aquifer. The sieve sizes to be used inperforming these analyses are:

3 in. No. 102 in. No. 2011/2 in. No. 401 in. No. 603/4 in. No. 140No. 4

The results of the analysis of any particular sampleshould be recorded as the percent (by weight) of thesample retained on each sieve and the cumulativepercent retained on each sieve (i.e., the total of thepercentages for that sieve and all larger sieve sizes).Based on these sieve analyses, determine the aquiferstratum which is composed of the finest material.

(b) Using the results of the sieveanalysis for the finest aquifer material, plot thecumulative percent of the aquifer material retainedversus the size of the mesh for each sieve. Fit a smoothcurve to these points. Find the size corresponding to a70 percent cumulative retention of aquifer material. Thissize should be multiplied by a factor between 4 and 6, 4if the formation is fine and uniform and 6 if the formationis coarse and nonuniform. Use 9 if the formationincludes silt. The product is the 70 percent retained size(i.e., the sieve size on which a cumulative 70 percent ofthe sample would be retained) of the gravel to be used inthe gravel pack.

(c) The uniformity coefficient of thegravel will be 2.5 or less, where the uniformity coefficientis defined as the ratio of the grain size for 40 percentretention to the grain size for 90 percent retention.

(d) The plot of cumulative percentretention versus grain size for the gravel should beapproximately parallel to same plot for the aquifermaterial, should pass through the 70 percent retentionvalue and should have 40 and 90 percent retentionvalues such that the uniformity coefficient is less than2.5. Gravel pack material will be specified bydetermining the sieve sizes that cover the range of thecurve and then defining an allowable range for thepercent retention on each sieve.

(2) Thickness. The thickness of thegravel pack will range from a minimum of 3 inches to

approximately 8 inches. A gravel envelope thicker thanabout 8 inches will not greatly improve yield and canadversely affect removal of fines, at the aquifer-gravelinterface, during well development.

(3) Pack length. Gravel pack will extenda minimum of 10 feet above the top of the screen. Ifpossible, well development should be completed beforeadditional material is placed above the gravel pack. Thatway, gravel can be added as the pack consolidates. Ifthis is not possible, a tremie may be placed prior to fillermaterial being added. Then additional gravel can beadded through the tremie to maintain gravel above thetop of the screen. A bentonite seal should be placeddirectly above the gravel pack to prevent infiltration fromfilter material. A gravel-pack well has been shownschematically in figure 5-6.

(4) Disinfection. It is important that thegravel used for packing be clean and that it also bedisinfected by immersion in strong chlorine solution (200mg/l or greater available chlorine concentration,prepared by dissolving fresh chlorinated lime or otherchlorine compound in water) just prior to placement.Dirty gravel must be thoroughly washed with clean waterprior to disinfection and then handled in a manner thatwill maintain it in as clean a state as possible.

f. Grouting and sealing. Grouting and sealingof wells are necessary to protect the water supply frompollution, to seal out water of unsatisfactory chemicalquality, to protect the casing from exterior corrosion andto stabilize soil, sand or rock formations which tend tocave. When a well is constructed there is normallyproduced an annular space between the drill hole andthe casing, which, unless sealed by grouting, provides apotential pollution channel.

(1) Prevention of contamination fromsurface. The well casing and the grout seal shouldextend from the surface to the depth necessary toprevent surface contamination via channels through soiland rock strata. The depth required is dependent on thecharacter of the formations involved and the proximity ofsources of pollution, such as sink holes and sewagedisposal systems. The grout seal around the casingshould have a thickness of at least 2 inches and agreater thickness is recommended where severecorrosive conditions are known to exist. Localregulations may govern the grout length and thickness.Materials for sealing and grouting should be durable andreadily placed. Normally, Portland cement grout willmeet these requirements. Grout is customarily specifiedas a neat cement mixture having a water-cement ration

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of not over 6 gallons per 94-pound sack of cement.Small amounts of bentonite clay may be used to improvefluidity and reduce shrinkage. Grout can be placed byvarious methods, but to ensure a satisfactory seal, it isessential that grouting be:

-done as one continuous operation-completely placed before the initial set occurs-introduced at the bottom of the space to begrouted

Establishment of good circulation of water through theannular space to be grouted is a highly desirable initialstep toward a good grouting job. This assures that thespace is open and provides for the removal of foreignmaterial.

(2) Prevention of subsurfacecontamination. Formations containing water of poorquality and located above or below the desired waterformation must be sealed to prevent upward ordownward migration of inferior quality water into the well.Sealing of formations above or below the aquifer to beutilized can be accomplished by grouting the annularspace between drill hole and casing for the entire lengthof the casing or by grouting this annular space onlythrough formations containing water of poor quality. Ifonly the formations containing poor quality water are tobe grouted, the sections of the annular space not filledwith grout must be filled with sand to prevent caving ofthe surrounding strata and to support the grout beforethe grout has set. To provide a satisfactory seal, thegrout may need to extend 10 to 25 feet above and belowthe formation producing the mineralized water andshould be 2 to 6 inches thick in all locations.

g. Accessibility. The well location shall bereadily accessible for pump repair, cleaning, disinfection,testing and inspection. The top of the well shall never bebelow surface grade. At least two feet of clearancebeyond any building projection shall be provided.

h. Details relating to water quality. In additionto grouting and sealing, features that are related to waterquality protection are:

(1) Surface grading. The well or wellsshould be located on the highest ground practicable,certainly on ground higher than nearby potential sourcesof surface pollution. The surface near the site should bebuilt up, by fill if necessary, so that surface drainage willbe away from the well in all directions. Where flooding isa problem, special design will be necessary to insureprotection of wells and pumping equipment from

contamination and damage during flood periods and tofacilitate operation during a flood.

(2) Surface slab. The well casing shouldbe surrounded at the surface by a concrete slab having aminimum thickness of 4 inches and extending outwardfrom the casing a minimum of 2 feet in all directions.The slab should be finished a little above ground leveland slope slightly to provide drainage away from thecasing in all directions.

(3) Casing. The well casing shouldextend at least 12 inches above the level of the concretesurface slab in order to provide ample space for a tightsurface seal at the top of the casing. The type of seal tobe employed depends on the pumping equipmentspecified.

(4) Well house. While not universallyrequired, it is usually advisable to construct a permanentwell house, the floor of which can be an enlarged versionof the surface slab. The floor of the well house shouldslope away from the casing toward a floor drain at therate of about 1/8 inch per foot. Floor drains shoulddischarge through carefully jointed 4 inch or larger pipeof durable water-tight material to the ground surface 20feet or more from the well. The end of the drain shouldbe fitted with a coarse screen. Well house floor drainsordinarily should not be connected to storm or sanitarysewers to prevent contamination from backup. The wellhouse should have a large entry door that opens outwardand extends to the floor. The door should be equippedwith a good quality lock. The well house design shouldbe such that the well pump, motor, and drop-pipe can beremoved readily. The well house protects valves andpumping equipment and also provides some freezeprotection for the pump discharge piping beyond thecheck valve. Where freezing is a problem, the wellhouse should be insulated and a heating unit installed.The well house should be of fire- proof construction. Thewell house also protects other essential items. Theseinclude:

-Flow Meter-Depth Gage-Pressure Gage-Screened Casing Vent-Sampling Tap-Water Treatment Equipment (if required)-Well Operating Records

If climatic or other conditions are such that a well houseis not necessary, then the well should be protected

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from vandals or unauthorized use by a security fencehaving a lockable gate.

(5) Pit construction. Pit construction isonly acceptable under limited conditions such astemporary or intermittent use installations where the wellpump must be protected from the elements when not inuse. The design must allow for cleaning anddisinfection. Underground pitless construction for pipingand wiring may be adequate for submersible pumpinstallations. These designs may be used only whenapproved by the responsible installation medicalauthority.

i. Spacing and location. The grouping of wellsmust be carefully considered because of mutualinterference between wells when their cones ofdepression overlap. Minimum well spacing shall be 250feet.

(1) Drawdown interference. Thedrawdown at a well or any other location on the watertable is a function of the following:

-number of wells being pumped-distance from point of measurement to pumping

wells-volume of discharge at each well-penetration of each well into aquifer.

For simple systems of 2 or 3 wells, the method of superposition may be used. The procedure is to calculate thedrawdown at the point (well) of consideration and then toadd the drawdown for each well in the field. For multiplewells, the discharge must be recalculated for eachcombination of wells, since multiple wells have the effectof changing the depth of water in equations 5-1 and 5-2.For large systems the following conditions should benoted:

-boundary conditions may change-change in recharge could occur-recharge may change water temperature,

an increase in water temperature increases thecoefficient of permeability

-computer analysis may be helpful to recalculatethe combinations.It is seldom practicable to eliminate interference entirelybecause of pipeline and other costs, but it can bereduced to manageable proportions by careful well fielddesign. When an aquifer is recharged in roughly equalamounts from all directions, the cone of depression isnearly symmetrical about the well and "R" is about thesame in all directions. If, however, substantially morerecharge is obtained from one direction; e.g., a stream,then the surface elevation of the water table is distorted,being considerable higher in the direction of the stream.

The surface of the cone of depression will be depressedin the direction of an impermeable boundary becauselittle or no recharge is obtained from the direction of theimpermeable boundary.

(2) Location. Where a source ofrecharge, such as a stream, exists near the proposedwell field, the best location for the wells is spaced outalong a line as close as practicable to and roughlyparallel to the stream. On the other hand, multiple watersupply wells should be located parallel to and as far aspossible from an impermeable boundary. Where thefield is located over a buried valley, the wells should belocated along and as close to the valley’s center aspossible. In hard rock country, wells are best locatedalong fault zones and lineaments in the landscape whererecharge is greatest. These are often visible using aerialphotographs. Special care should be exercised to avoidcontamination in these terrains since natural filtration islimited.

j. Pumps. Many types of well pumps are onthe market to suit the wide variety of capacityrequirements, depth to water and power source. Electricpower is used for the majority of pumping installations.Where power failure would be serious, the design shouldpermit at least one pump to be driven by an auxiliaryengine, usually gasoline, diesel or propane. The mostappropriate type is dictated by many factors for eachspecific well. Factors that should be considered forinstallation are:

-capacity of well-capacity of system-size of well-depth of water-power source-standby equipment-well drawdown-total dynamic head-type of well

(1) Type. There are several types of wellpumps. The most common are lineshaft turbine,submersible turbine, or jet pumps. The first two operateon exactly the same principal. The difference beingwhere the motor is located. Line-shaft turbine pumpshave the motor mounted above the waterline of the welland submersible turbine pumps have the motor mountedbelow the water line of the well. Jet pumps operate onthe principal of suction lift. A vacuum is createdsufficient to "pull" water from the well. This type of pumpis limited to wells where the water line is generally nomore than 25 feet below the pump suction. It also hassmall capacity capability.

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(2) Choice. Domestic systems commonlyemploy jet pumps or small submersible turbine pumpsfor lifts under 25 feet. For deeper wells with highcapacity requirements, submersible or lineshaft turbinepumps are usually used and are driven by electric

motors. A number of pump bowls may be mounted inseries, one above the other to provide the necessarydischarge pressure. Characteristics for various types ofpumps used in wells are listed in table 5-5.

Table 5-5. Characteristics of pumps used in water supply systems.Source: Manual of Individual Water Supply Systems, UDHEW.

Practical Usual well- UsualType of Pump suction pumping pressure Advantages Disadvantages Remarks

lift depths heads

Reciprocating:1. Shallow well... 22-26 ft. 22-26 ft 100-200 ft 1. Positive ac- 1. Pulsating dis- 1. Best suited for2. Deep well... 22-25 ft. Up to 600 Up to 600 tion. charge. capacities of 5-25

feet feet above 2. Discharge 2. Subject to vi- gpm against moder-cylinder. against variable bration and ate to high heads.

heads. noise. 2. Adaptable to3. Pumps water 3. Maintenance hand operation.containing sand cost may be high. 3. Can be installedand silt. 4. May cause de- in very small diame-4. Especially structive pres- ter wells (2" cas-adapted to low sure if operated ing).capacity and high against closed 4. Pump must belifts. valve. set directly over

well (deep wellonly).

Centrifugal:1. Shallow well 20 ft. maxi- 10-20 ft. 100-150 ft. 1. Smooth, even, 1. Loses prime 1. Very efficienta. straight centrifu- mum flow. easily. pump for capacitiesgal (single stage) 2. Pumps water 2. Efficiency de- above 50 gpm &

containing sand pends on operat- heads up to aboutand silt. ing under design 150 feet.3. Pressure on heads & speedsystem is even &free from shock.4. Low-startingtorque.5. Usually relia-ble and good ser-vice life.

b. Regenerative 28 ft. maxi- 28 ft. 100-200 ft. 1. Same as 1. Same as 1. Reduction invane turbine type mum straight centrifu- straight centrifu- pressure w/in-(single impeller) gal except not gal except main- creased capacity not

suitable for tains priming as severe aspumping water easily straight centrifugal.containing sandor silt.2. They are self-priming.

2. Deep well Impellers 50-300 ft. 100-800 ft. 1. Same as shal- 1. Efficiency de-a. Vertical line submerged low well turbine. pends on operat-shaft turbine ing under design(multi-stage) head & speed.

2. Requiresstraight welllarge enough forturbine bowlsand housing.3. Lubrication &alignment ofshaft critical.4. Abrasion fromsand.

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Table 5-5. Characteristics of pumps used in water supply systems.Source: Manual of Individual Water Supply Systems, UDHEW.

Practical Usual well- UsualType of Pump suction pumping pressure Advantages Disadvantages Remarks

lift depths heads

b. Submersible tur- Pump & 50-400 ft. 80-900 ft. 1. Same as shal- 1. Repair to mo- 1. Difficulty w/seal-bine motor sub- low well turbine. tor or pump re- ing has caused un-(multi-stage) merged 2. Easy to frost- quires pulling certainty as to

proof installa- from well. service life to date.tion. 2. Sealing of3. Short pump electrical equip-shaft to motor. ment from water

vapor critical.3. Abrasion fromsand.

Jet:1. Shallow well 15-20 ft. Up to 15-20 80-150 ft. 1. High capacity 1. Capacity re-

below ejec- feet below at low heads. duces as lift in-tor ejector. 2. Simple in op- creases.

eration. 2. Air in suction3. Does not have or return lineto be installed will stop pump-over the well. ing.4. No movingparts in the well.

2. Deep well 15-20 ft. 25-120 ft. 80-150 ft. 1. Same as shal- 1. Same as shal- 1. The amount ofbelow ejec- 200 ft. low well jet. low well jet. water returned totor maximum ejector increase w/

increased lift-50%of total waterpumped at 50 ft. lift& 75% at 100 ft. lift.

Rotary:1. Shallow well 22 ft. 22 ft. 50-250 ft. 1. Positive ac- 1. Subject to(gear type) tion. rapid wear if

2. Discharge con- water containsstant under vari- sand or silt.able heads. 2. Wear of gears3. Efficient oper- reduces effi-ation. ciency.

2. Deep well Usually 50-500 ft. 100-500 ft. 1. Same as shal- 1. Same as shal- 1. A cutless rubber(helical rotary type) submerged low well rotary. low well rotary stator increases life

2. Only one mov- except no gear of pump. Flexibleing pump device wear. drive coupling hasin well. been weak point in

pump. Best adaptedfor low capacity &high heads.

1Practical suction lift at sea level. Reduce lift 1 foot for each 1,000 feet above sea level.

(3) Capacity selection. The designcapacity of the pump must exceed the systemrequirements. However, the capacity of the pump mustnot exceed the capacity of the well. Pumpmanufacturers publish charts giving the pump discharge

capacity for their particular pumps at various operatingpressures. The total dynamic head (TDH) of the systemmust be calculated accurately from the physicalarrangement and is represented by the followingequation:

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where:HS = suction lift; vertical distance from

the waterline at drawdown underfull capacity, to the pump center-line

HD = discharge head; vertical distancefrom the pump centerline to thepressure level of the discharge pipesystem

HF = friction head; loss of head on pipelines and fittings

V2 = velocity head; head necessary to2g maintain flow

The brake horsepower of the motor used to drive thepump may be calculated from the following equation:

where:P = brake horsepower requiredH = total dynamic head in feetQ = volume of water in gpme = combined efficiency of pump and motor

5-7. Development and disinfectionAfter the structure of the well is installed, there remaintwo very important operations to be performed before thewell can be put into service. Well development is theprocess of removing the finer material from the aquiferaround the well screen, thereby cleaning out and openingup passages in the formation so that water can enter thewell more freely. Disinfection is the process of cleaningand decontaminating the well of bacteria that may bepresent due to the drilling action.

a. Development. Three beneficial aspects ofwell development are to correct any damage or cloggingof the water bearing formation which occurred as a sideeffect of drilling, to increase the permeability of theformation in the vicinity of the well and to stabilize theformation around a screened well so that the well willyield sand-free water.

(1) A naturally developed well relies onthe development process to generate a highly permeablezone around the well screen or open rock face. Thisprocess depends upon pulling out the finer materialsfrom the formation, bringing them into the well, andpumping them out of the well. Development work shouldcontinue until the movement of fine material from theaquifer ceases and the formation is stabilized.

(2) Artificial gravel packing provides a

second method of providing a highly porous materialaround the screen. This involves placement of aspecially graded gravel in the annular space between thescreen and the wall of the excavation. Developmentwork is required if maximum capacity is to be attained.

(3) Development is necessary becausemany drilling methods cause densification of theformation around the hole. Methods utilizing drillingfluids tend to form a mud cake. Good development willeliminate this "skin effect" and loosen up the sandaround a screen. Removal of fines leaves a zone of highporosity and high permeability around the well. Watercan then move through this zone with negligible headloss.

(4) Methods of development inunconsolidated formations include the following:

(a) Mechanical surging is thevigorous operation of a plunger up and down in the well,like a piston in a cylinder. This causes rapid movementof water which loosen the fines around the well and theycan be removed by pumping. This may beunsatisfactory where the aquifer contains clay streaks orballs. The plunger should only be operated when a freeflow of water has been established so that the tool runsfreely.

(b) Air surging involves injecting airinto a well under high pressure. Air is pumped into a wellbelow the water level causing water to flow out. The flowis continued until it is free of sand. The air flow isstopped and pressure in an air tank builds to 100 to 150psi. Then the air is released into the well causing waterto surge outward through the screen openings.

(c) Overpumping is simply pumpingat a higher rate than design. This seldom brings bestresults when used alone. It may leave sand grainsbridged in the formation and requires high capacityequipment.

(d) Backwashing involves reversalof flow. Water is pumped up in the well and then isallowed to flow back into the aquifer. This usually doesnot supply the vigorous action which can be obtainedthrough mechanical surging.

(e) High velocity jetting utilizesnozzles to direct a stream of high pressure wateroutward through the screen openings to rearrange thesand and gravel surrounding the screen. The jetting toolis slowly rotated and raised and lowered to get the actionto all parts of the screen. This method works better oncontinuous slot well screens better than perforated typesof screens.

(5) Development in rock wells can beaccomplished by one of the surging methods listedabove or by one of the following methods.

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(a) Explosives can be used to breakrock formations. However it may be difficult to tell inadvance if the shooting operation will produce therequired result.

(b) Acidizing can be used in wells inlimestone formations. Fractures and crevices areopened up in the aquifer surrounding the well hole by theaction of the acid dissolving the limestone.

(c) Sand fracking is the action offorcing high pressure water containing sand or plasticbeads in to the fractures surround a well. This serves toforce the crevices open.

b. Disinfection of completed well. Thedisinfection of the completed well shall conform toAWWA A100.Bacteriological samples must be collected and examinedin accordance with Standard Methods for theExamination of Water and Wastewater.

c. Disinfection of flowing artesian wells.Flowing artesian wells often require no disinfection, but ifa bacteriological test, following completion of the well,shows contamination, disinfection is required. This canbe accomplished as follows. The flow from the well willbe controlled either by a cap or a standpipe. If a cap isrequired, it should be equipped with a one-inch valve anda drop-pipe extending to a point near the bottom of thewell. With the cap valve closed, stock chlorine solutionwill be injected, under pressure, into the well through thedrop-pipe in an amount such that when the chlorinesolution is dispersed throughout all the water in the well,the resultant chlorine concentration will be between 50and 100 mg/l. After injection of the required amount ofstock chlorine solution, compressed air will be injectedthrough the drop-pipe, while simultaneously partiallyopening the cap valve. This will permit the chlorinesolution to be mixed with the water in the well. As soonas chlorine is detected in the water discharged throughthe cap valve, the air injection will be stopped, the capvalve closed and the chlorinated water allowed to remainin the well for 12 hours. The well will then be allowed toflow to waste until tests show the absence of residualchlorine. Finally, samples for bacteriological examinationwill be collected in accordance with Standard Methodsfor the Examination of Water and Wastewater. If thewell flow can be controlled by means of a standpipe,disinfection can be accomplished as described for awater table well.

5-8. Renovation of Existing WellsWell yield can be maintained by proper operatingprocedures. The most common cause of dediningcapacity in a well is incrustation which results frommaterial being deposited on the well screen and thereby

clogging the openings. A second cause is corrosion ofthe screen which is a chemical reaction of the metal.This action results in the screen being dissolved andenlarging the openings, allowing caving to occur.Records of pump performance and pumping levels arevery important in a good maintenance program.

a. Incrustation. The effect of incrustation isusually decreased capacity due to clogging of the screenopenings. For incrustation due to calcium deposits orprecipitation of iron and manganese compounds,treatment with an acid solution will dissolve the depositsand open up the screen. For bacterial growths and slimedeposits, a strong chlorine solution has been foundeffective. In some instances, explosives may be used tobreak up incrustation from wells in consolidated rockaquifers.

b. Corrosion. The best method to preventcorrosion is to use a metal which is resistant to theattack. Once a screen has deteriorated, the only methodof rehabilitation may be to remove it and install a newscreen. The design of the initial installation should allowfor removal of the screen in the future. Corrosion is alsoa problem in pumps. The use of pumps constructed ofspecial non-corrosive materials will help. Care should betaken to use pumps with single metal types. Chemicalinhibitors can be injected into wells to prevent corrosion,but this is costly.

c. Downhole Inspections. Special televisionequipment has been developed to permit a visualinspection of a well. Special lighting will permit highresolution pictures even under water. Wells as deep as3000 feet, in casings as small as 4 inches diameter canbe inspected. The entire inspection can be videotapedfor later review.

d. Well cleaning. Where incrustation is aproblem, periodic well cleaning (also called "wellstimulation" or "well rehabilitation") may be practiced. Aneffective cleaning procedure should be developed andapplied annually or more often if necessary.Maintenance procedures are given in Ground Water andWells, and Water Well Technology.

5-9. Abandonment of wells and test holes.It is essential that wells, test wells, and test holes haveserved their purpose and are to be abandoned, beeffectively sealed for safety and to prevent pollution ofthe ground water resources in the area. Theabandonment of wells shall follow the guidance ofAWWA A100 and state/local regulations. Figure 5-6

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illustrates the configuration of a gravel-packed well in operational condition and figure 5-8 illustrates well aftersealing.

Figure 5-8. Sealed well.

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5-10. Check list for designa. Topographic maps of area where wells could

be located.b. Reports on area geology and ground water

resources from U.S. Geological Survey, StateGeological Survey, and other state and local agenciesthat have an interest in or have conducted ground waterinvestigations. Records obtained from drillingcontractors familiar with the area. Reports of test drillingand pumping.

c. Copies of logs of existing water supply wells,drawdown data, pumpage, water table elevations.Estimates of safe yield of aquifers.

d. Records of physical, chemical and

bacteriological analyses of water from existing wells.e. Assessment of probable treatment

requirements, such as iron-manganese removal,softening, corrosion control, sulfide removal.

f. Summary of sanitary survey findings,including identification of possible sources of pollution.

g. Probable location, number, type, depth,diameter and spacing of proposed water supply wells.Significant problems associated with well operation.

h. Energy requirement of proposed system.i. Summary of applicable State water laws,

rules, regulations, and procedures necessary to establishwater use rights. Impact of proposed use on establishedrights of others.

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CHAPTER 6

SURFACE WATER SUPPLIES

6-1. Surface water sourcesSurface water supply sources include streams, lakes,and impounding reservoirs. Large supplies of surfacewater are generally available throughout much of theeastern half of the United States where rainfall averagesabout 35 inches or more annually and is reasonably welldistributed through the year. On the other hand, goodsurface water sources are much more limited in manywestern regions with the exception of the PacificNorthwest, where surface water is plentiful.

6-2. Water lawsAny investigation directed toward development of new oradditional sources of supply must include considerationof applicable State water laws. Most of the States inroughly the eastern half of the United States follow theriparian law of water rights, and only a few have permitsystems. Under this doctrine, the right to use water isassociated with ownership of the land through which thestream flows. The riparian rights doctrine is essentially alegal principle which may be used, in some form, tosettle disputes. It does not automatically provide forState water management and record keeping. Planningfor water supply systems under the riparian doctrine isnot absolutely certain for present and future wateravailability and security. In contrast, western law isbased largely on the doctrine of "prior appropriation." Inthe 17 Western States where this doctrine prevails,sophisticated legal, administrative and managementmachinery exists. In these States, water rights and landownership are separable and most Western Statesauthorize a water-right owner to sell the right to another.The new owner is permitted to transfer the water toanother point of use or put it to a different use, providedthe transfer conforms to the State’s administrativerequirements.

6-3. Quality of surface watersThe quality of stream and lake waters varies

geographically and seasonally. Streams, in particular,often exhibit fairly wide seasonal fluctuations in mineralquality, principally as a result of variations in stream flow.In general, streams and lakes east of the 95th meridian,which includes most of Minnesota, Iowa, Missouri,Arkansas, Louisiana, and States east thereof, exhibitdissolved mineral solids in the range of 100 or less toabout 700 milligrams per liter (mg/l). The water fromthese sources, after conventional treatment in a well-designed filtration plant, will meet standards prescribedfor potable water (see appendix A of TM 5-8133/ AFM88-10, Vol. 3, for these standards). Unusual localconditions; e.g., pollution, may render some easternwaters unsuitable as a source of supply; but in general,eastern streams and lakes are a satisfactory raw watersource. Similar comments are applicable to surfacewaters of the Pacific Northwest area. Streams in manyother areas west of the 95th meridian are much lesssatisfactory, often showing dissolved mineral solids in therange of 700 to 1,800 mg/l. High concentrations ofhardness-producing and other minerals such as sulfateand chloride are found in some western surface waters.

6-4. Watershed control and surveillanceRaw water supplies should be of the best practicablequality even though extensive treatment, includingfiltration, is provided. Strict watershed control is usuallyimpractical in the case of water supplies obtained fromstreams. However, some measure of control can beexercised over adverse influences, such as wastewaterdischarges, in the vicinity of the water supply intake. Forsupplies derived from impounding reservoirs, it isgenerally feasible to establish and maintain a control andsurveillance program whose objective is protection of thequality of raw water obtained from the reservoir. Atreservoirs whose sole purpose is to provide a source ofwater supply, recreational use of the reservoir andshoreline areas should be rigorously controlled to protectthe water supply quality.

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6-5. Checklist for surface water investigationsThe investigations will cover the following items, as wellas others, as circumstances warrant.

a. Topographic maps showing pertinentdrainage areas.

b. Hydrologic data, as required for projectevaluations; e.g., rainfall, runoff, evaporation,assessment of ground water resources and theirpotential as the sole source or supplementary source ofsupply.

c. Sanitary survey findings.d. Intake location.e. Water quality data at or near proposed

intake site.

f. Feasibility of developing supply withoutreservoir construction.

g. Reservoir location if reservoir is required.h. Plans for other reservoirs on watershed.i. Pertinent geological data that may affect

dam foundation or ability of reservoir to hold water.j. Locations for pumping stations, supply lines,

treatment plant.k. Energy requirements for proposed system.l. State water laws, rules and regulations,

procedure for obtaining right to use water, impact ofproposed use on rights of other users.

m. Disposition of water supply sludge fromtreatment plant.

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CHAPTER 7

INTAKES

7-1. GeneralThe intake is an important feature of surface watercollection works. For fairly deep streams, whose flowalways exceeds water demands, the raw water collectionfacilities generally consist of an intake structure locatedin or near the stream, an intake conduit and a raw waterpumping station. Often the intake and pumping stationare combined in a single structure. On smaller, shallowstreams, a channel dam may be required to provideadequate intake submergence and ice protection. Inletcribs of heavy timber construction, surrounding multiple-inlet conduits, are frequently employed in large naturallakes. For impounding reservoirs, multipleinlet towers,which permit varying the depth of withdrawal, arecommonly used. Hydraulically or mechanically-cleanedcoarse screens are usually provided to protect pumpingequipment from debris. Debris removed from screensmust be hauled to a landfill or other satisfactory disposalsite. It may be necessary to obtain a permit forconstruction of an intake from both State and Federalagencies. If the stream is used for navigation, the intakedesign should include consideration of navigation useand of impact from boats or barges out of control. Apermit from the U.S. Army District Engineer is required ifnavigation is obstructed.

7-2. Capacity and reliabilityThe intake system must have sufficient capacity to meetthe maximum anticipated demand for water under allconditions during the period of its useful life. Also, itshould be capable of supplying water of the best qualityeconomically available from the source. Reliability is ofmajor importance in intake design because functionalfailure of the intake means failure of the water system.Intakes are subject to numerous hazards such asnavigation or flood damage, clogging with fish, sand,gravel, silt, ice, debris, extreme low water notcontemplated during design, and structural failure ofmajor components. Many streams carry heavysuspended silt loads. In addition to suspended silt, thereis also a movement of heavier material along the bed ofthe stream. The intake must be designed so that

openings and conduits will not be clogged by bed-loaddeposits. An additional problem, caused by suspendedsilt and sand, is serious abrasion of pumps and othermechanical equipment. Excessive silt and sand mayalso cause severe problems at treatment plants. Liberalmargins of safety must be provided against floodhazards and also against low-water conditions. Adepression dredged in the stream bed to providesubmergence is not a solution to the lowwater problembecause it will be filled by bedload movement. A self-scouring channel dam may be the only means ofassuring adequate water depth. As an alternative tounusually difficult intake construction, gravel-packedwells and horizontal collector infiltration systems locatedin the alluvium near the river are often worthy ofinvestigation. Water obtained from such systems willusually be a mixture of ground water and induced flowfrom the stream.

7-3. Ice problemsIn northern lakes, frazil ice (a slushy accumulation of icecrystals in moving water) and anchor ice (ice formedbeneath the water surface and attached to submergedobjects) are significant hazards, while on large rivers,floating ice has caused damage. Intake design mustinclude ample allowances for avoiding or coping withthese hazards. The intake location and inlet size areimportant aspects of design. Excessive inlet watervelocities have been responsible for major cloggingproblems caused by both sand and ice. Inlet velocities inthe range of 0.25 to 0.5 feet per second are desirable foravoiding ice clogging of intakes. Where ice is a problem,river intakes must have the structural stability to resistthe thrust of ice jams and the openings must be deepenough to avoid slush ice which has been reported asdeep as six to eight feet. Frazil and anchor ice can alsocause difficulties, but on rivers, floating ice is usually thegreater hazard. Steam heating has been employed tocope with ice problems at some northern lake intakes.Nonferrous materials are preferred for cold-climate inletconstruction because their lower heat conductivitydiscourages ice formation.

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7-4. Intake locationMeandering streams in deep alluviums pose especiallydifficult intake problems. Here, expensive dikes, jettiesand channel protection may be required to prevent theriver channel from moving away from the intake orcutting behind it. On such streams, careful considerationmust be given to intake location. Generally, the intakesite should be on the outside bank of a well establishedbend where the flow is usually swiftest and deepest. Ifthe outside bend site includes a rock bank, a reliableintake probably can be placed there. Inside bends are tobe avoided because of shallow water and sand bars.

Sufficient depth at extreme low stage must also be aconsideration. In addition to structural and hydraulicconsiderations, water quality is of major importance inconnection with intake design and location, and the waterquality aspects of a proposed location should be carefullyexamined. The location study should include a sanitarysurvey whose objective is evaluation of the effects ofexisting and potential sources of pollution on waterquality at the intake site. The survey should include asummary of historical water quality data at the site plusan assessment of the probable impact of all wastewaterdischarges likely to influence present or future quality.

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CHAPTER 8

RAW WATER PUMPING FACILITIES

8-1. Surface water sourcesa. Pumping station arrangement. The location

and arrangement of raw water pumping stations willdepend upon the requirements of the local situation andonly general comments can be given. Raw waterpumping stations and intakes are often combined in asingle structure, but this is not mandatory. The depth ofthe structure is a function of the type and arrangement ofthe pumps used. Horizontal centrifugal pumps are oftenemployed and will give satisfactory performance andgood operating economy. However, if the supply is froma variable stream and the pump suctions are to be underpositive pressure under all operating conditions, a stationof considerable depth probably will be required. Deepstations of the dry-pit type commonly used for horizontalcentrifugal pumps should be compartmented so thatrupture of pump discharge piping within the station willnot flood all other pumps and motors. The depth may bereduced, with some loss in reliability, by installing thepumps at an elevation such that suction lift prevailsunder some operating conditions. Equipment for primingis a requirement when suction lift is employed. Use ofvertical type wet-pit pumps, which requires less space inplan, permits a somewhat shallower station and does notrequire priming, may prove an economical alternative.Among other pumping arrangements that could be usedare: vertical-type pumps or end- or side-suctioncentrifugals, with their shafts in a vertical position,located on a submerged suction header. The latterpermits location of the pump drive units at an elevationwhere they are protected from flooding and readilyaccessible.

b. Pump protection. Pumps, particularly thoselocated on streams, must have protection against debris.In order to prevent or at least minimize screen clogging,the size of the screen openings should be consistent withthe capacity of the pump to pass solids. The pumpmanufacturer can supply information on the largestsphere that the pump will pass. Plants with flows of 1mgd or larger and obtaining their water from streams willuse hydraulically cleaned traveling screens. For smallerinstallations or those not obtaining water from streams, afixed bar screen or strainers can be used. For such

arrangements, provision must be made for cleaning.This can be accomplished by backflushing. In general,screening should be held to the minimum required forprotection of the pumps. Excessively fine screens,strainers or bar racks are sometimes subject to rapidclogging and will require frequent cleaning. Debrisremoved by mechanically cleaned screens must becollected and hauled to a landfill or other acceptabledisposal site. Screenings may be stored temporarily atthe station in dump carts from which they are dischargedto a truck for transport to a disposal site.

c. Structural considerations. Substructures willusually be of reinforced concrete. Superstructuresshould be of incombustible materials such as reinforcedconcrete, brick or other masonry. Wood frameconstruction should not be used except for temporary orminor installations. Structural design should includeconsideration of requirements for pump and motorservicing and removal for major repairs.

d. Ventilation. Where a gravity ventilationsystem is deemed inadequate to supply fresh air andremove fumes and heated air from the pump station, aforced ventilation system should be provided. Theventilation system should be capable of removing wasteheat from the motors without allowing more than a 10°Frise in the temperature of the air in the pump station. Foroccupied areas, the ventilation system will have acapacity of about six air changes per hour. If dust-producing chemicals are to be handled at the station,special dust exhaust systems will also be provided.Where chemicals are used in the pump station,precautions should be taken to ensure that the exhaustfrom the ventilation system complies with air pollutionprevention requirements.

e. Pumping equipment. In general, pumpingequipment shall be sized to conform to the rated capacityof the water treatment plant and will include a minimumof three electric motor driven pumps. With the largest ofthe three pumps out of service, the remaining

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two pumps will be capable of supplying raw water at arate equal to the rated capacity of the plant. To ensurewater service in the event of a major power outage, asufficient number of pumps must be equipped foroperation when normal electric power is not available.These pumps will be capable of supplying at least 50percent of the rated capacity of the treatment plant,except where greater capacity is essential. Standbypower for emergency operation can be provided bygasturbine or diesel engine generators or by enginesarranged to provide for pump operation by direct enginedrives during the emergency.

8-2. Ground water sourcesFor most applications, either vertical line shaft turbinepumps or submersible turbine pumps (see para 1-3b fordefinitions) will be used. For small-capacity or low-headapplications, rotary or reciprocating (piston) pumps maybe more appropriate. Factors influencing the selection ofpumping equipment include well size, maximumpumping rate, range in pumping rate, maximum totalhead requirements, range in total head requirements,and type of power available. Final selection of pumpingequipment will be based on life cycle cost considerations.If all pumps use electric power as the primary energy

source, a sufficient number of the pumps must beequipped for emergency operation when normal electricpower is not available. Emergency power can beprovided by gas-turbine or diesel engine generators or byengines arranged to provide for pump operation by directengine drives during the emergency. These standby-powered pumps will be capable of supplying at least 50percent of the required daily demand, except wheregreater capacity is essential.

8-3. Electric powerIf dual electric power feeders, breakers, transformersand switchgear can be provided, they will increase thestation’s reliability but may add appreciably to its cost. Ifa high degree of reliability is deemed necessary, thestation should be served by independent transmissionlines that are connected to independent power sourcesor have automatic switchover to direct drive engines.

8-4. Control of pumping facilitiesSupervisory or remote control of electric motor-drivenpumping units will be provided if such control willsubstantially reduce operator time at the facilities. Lifecycle cost will apply.

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CHAPTER 9

WATER SYSTEM DESIGN PROCEDURE

9-1. GeneralWater supply is an essential feature of any large projectand water system planning should be coordinated withthe design of the project elements in order to insureorderly progress toward project completion. Majorelements of the water system, such as supply works,usually can be located and designed in advance ofdetailed project site planning. On the other hand, thedesign of the distribution system must be deferred untilcompletion of topographic surveys and the developmentof the final site plan. The preparation of plans andspecifications for water supply works, pumping stations,treatment works, supply lines, storage facilities anddistribution systems requires the services of professionalengineers thoroughly versed in water works practice.

9-2. Selection of materials and equipmentSelection of materials, pipe, and equipment should beconsistent with system operating and reliabilityconsiderations, energy conservation, and the expecteduseful life of the project. For Air Force Projects refer toAFM 88-15, for material and component requirements.

Current policies of the Department of the Army andHeadquarters, U.S. Air Force, with respect to energyconservation and the use of critical materials will beobserved in the planning and construction of any watersystem. To avoid delivery delays, standard equipmentthat can be supplied by several manufacturers should bespecified. Delivery schedules must be investigated priorto purchase commitments for mechanical equipment. Asa general rule, patented equipment, furnished by a singlemanufacturer, should be placed in competition withfunctionally similar equipment available from othersuppliers. Equipment of an experimental nature orequipment unproved by actual, full-scale use should notbe used unless specifically approved by the Chief ofEngineers or Headquarters, U.S. Air Force.

9-3. Energy conservationFor each water supply alternative considered, energyrequirements will be clearly identified and the designanalysis will include consideration of all energyconservation measures consistent with system adequacyand reliability.

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APPENDIX A

REFERENCES

Government Publications

Departments of the Army and the Air ForceTM 5-813-3/AFM 8810, Vol. 3 Water Supply: Water TreatmentTM 5-813-4/AFM 8810, Vol. 4 Water Supply: Water StorageTM 5-813-5/AFM 88-10, Vol. 5 Water Supply: Water DistributionTM 5-813-6/AFM 88-10, Chap. 6 Water Supply: Water Supply for Fire ProtectionTM 5-813-7/AFM 88-10, Vol. 7 Water Supply for Special ProjectsTM 5-852-5/AFM 8819, Chap. 5 Engineering and Design Artic and Subartic Con-

struction-UtilitiesAR 200-1 Environmental Protection and EnhancementAR 42046 Water and SewageTB MED 229 Sanitary Control and Surveillance of Water

Supplies at Fixed and Field InstallationsAFM 85-21 Operation and Maintenance of Cross Connec-

tion Control and Backflow Prevention Sys-tems

AFM 88-15 Air Force Design Manual-Criteria and Stand-ards of Air Force Construction

AFR 19-1 Pollution Abatement and Environmental Qual-ity

AFR 19-2 Environmental Impact Analysis Process (EAIP)AFR 161-44 Management of the Drinking Water Surveil-

lance ProgramU.S. Army Corps of Engineers, USACE Publications Depot, 2803 52nd Avenue, Hyattsville, MD20781

EM 1110-1-501 Process Design Manual for Land TreatmentMunicipal Waste Water

General Services Administration (GSA)Superintendent of Documents, Government Printing Office, Washington, D.C. 20402

40 CFR Part 141 National Interim Primary Drinking Water Reg-ulations

Non-government Publications

American Water Works Association (AWWA), 6666 West Quincy Avenue, Denver, CO 80235A100 Standard for Deep Wells

Standard Methods for the Examination of Waterand Wastewater (1981)

Water Treatment Plant Design (1969)Johnson Division, Universal Oil Products Inc., St. Paul, MN 55165

Ground Water and WellsNational Association of Plumbing-Heating-Cooling Contractors (NAPHCC), 1016 20th Street,NW Washington, DC 20036

National Standard Plumbing Code

A-1

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APPENDIX B

SAMPLE WELL DESIGN

B-1. The situationThe Government has purchased approximately 100acres for use as a site for a light manufacturing plant inthe midwest. The site is generally situated between twosmall towns on the western bank at a large river.Existing roads from the boundaries of the north and westsides, a railroad is on the east and undeveloped land onthe south. A creek crosses from west to east along thenorthern portion and a large flat area exists for the

facility. The site is generally overgrown with hardwoodsand pines. The northern portion, at the base of theslope, is relatively flat and was once farmland. The smallcommercial area on the east and both towns are servedby wells located in the plains between the river and thehilly area. A search of records, review of aerial photosand discussions with local residents indicates that nodumps or other potential sources of pollution exist in thewatershed. A plan of the site is shown on figure B-1.

Figure B-1. Plan of proposed site.

B-1

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B-2. Site selectionFigure B-1 has been prepared from a U.S.G.S.topographic map. Contours, drainage and land use havebeen shown but vegetation has been omitted for clarity.The well must be located within the site boundary forsecurity and to minimize the length of pipelines. Sincethe existing towns use the river plains area as a sourceof ground water, the flatland in the northeast has beenchosen as a site for test drilling. It has good potential forrecharge from the surface drainage and from the river.Available records indicate the 100 year flood level to beapproximately at elevation 675 feet; therefore, the site isnot subject to flooding. Three test wells were driven inthe locations shown on figure B-1 and indicated by PW(pumping well), W1 and W2 (observation wells). A crosssection of these three wells is represented by figure 5-3.The depth to the bottom of the aquifer is found to be 150feet. Depth to static water level is 100 ft. A pumping testgives the following data.

Q = 200 gpmr1 = 50.0 fthl = 47.5 ftr2 = 300.0 fth2 = 49.0 ft

Calculate aquifer permeability using equation 5-3:

B-3. Size the wellA yield of 350 gpm is required. Table 53 indicates that apump of 6" diameter will be required and the smallestwell casing (and screen size) should be 8". (Currentpump manufacturers and screen manufacturersliterature should be reviewed to confirm this.) AssumingR = 1000 ft. and a maximum drawdown of 15 ft. asdepicted in figure 5-4, calculate the available yield:

The well should be designed to be drilled to the bottom ofthe aquifer. Screen manufacturer’s literature shows thatan 8" diameter telescoping screen has an intake area of113 sq. in. per ft. of length; calculate length of screenrequired using equation 5-5:

Note that the pumping water level will be above the topof the screen. Check screen entrance velocity:

B-4. LocationThe well should be installed near the test pumping well(PW) and observation well (W1) as shown on figure B-1.The exact location may be influenced by location ofaccess roads, fences and other details. This leavesroom for construction of an additional well for futureexpansion of the facility, north of the observation well(W2) which would be beyond the 250 ft. minimumspacing required.

B-5. Water qualitySamples are taken and analyzed in accordance withStandard Methods. Although the water quality is suchthat no treatment is required, chlorine will be added as adisinfectant in accordance with standard practice.

B-6. Pump selectionAn elevated storage tank will be installed in the area ofthe facility to maintain a 40 psi minimum distributionsystem pressure at the maximum ground elevation of820 ft. Approximately 1500 lin. ft. of 6" pipe will berequired from the well to the tank. Calculate the TDHusing equation 5-6.

a. Suction head is the distance from the ground(pump level) to the lowest elevation of water in the well.Assume this would be at the top of the screen. Add thedistance to the water table plus depth of top of screen.

HS = 100 + 20 = 120 ft.b. Discharge head is the difference in elevation

from the pump to the water level in the storage tank.Calculate the difference in ground elevation and add therequired pressure. Assume the well is at El. 695.

HD = (820 - 695) + (40) (2.31) = 217 ft.c. Friction head is calculated by methods

presented in TM 5-813-5. Add head loss in pipe plusloss in fittings.

HF = (18 ft/1000) (1.5) + 10 = 37 ft.d. Velocity loss is calculated from the equation.

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e. Total dynamic head is the sum of the above.TDH = 120 + 217 + 37 + 0.25 = 374 ft.

Calculate the pump horsepower using equation 5-7.Efficiency can be found in manufacturer’s literature.

B-7. Specification preparationGiven the above information, the designer can reviewmanufacturer’s literature and consult with theirrepresentatives to determine types of pumps and motordrives which are available to meet the operatingconditions. The calculations can then be refined toaccount for actual pump and well characteristics.Although not a function of well design, the engineer maywant to oversize the transmission main from the well tothe storage tank to allow for future expansion or make

other modifications in the design. The calculationsshould be reviewed when all systems are finally sized.The well diameter may be oversized to allow for futureinstallation of a larger pump, but the pump installedshould not exceed the capacity of the well. Thisprocedure gives sufficient information to specify a waterwell.

B-8. Construction detailsSince this area is subject to freezing temperatures andother climatic conditions which would be detrimental toan exposed pump and motor, a small building should beerected for protection. The floor of the building shouldbe raised above grade and the foundation extendedbelow frost depth. A separate room with access onlyfrom the outside should be provided for the chlorinationequipment. The well casing should be extended abovethe floor approximately 12 inches and concrete placed tothis level for the pump base. Electric power can beprovided from the main facility. Some small partsstorage may be provided.

B-3

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APPENDIX C

DRILLED WELLS

C-1. MethodsDrilled wells are normally constructed by one of thefollowing methods:

-Hydraulic Rotary-Cable Tool Percussion-Reverse Circulation Rotary-Hydraulic-Percussion-Air Rotary

These methods are suitable for drilling in a variety offormations. Diameters may be as large as 60 inches forwells constructed by the reverse circulation method.Smaller diameter wells may be constructed by drilling todepths of 3000 or 4000 feet. For a detailed discussion ofthese methods, see Ground Water and Wells byJohnson Division, UOP Inc. The first two methods listedare the most common in well construction and a briefdescription of each follows:

a. In the hydraulic-rotary method of drilling, thehole is formed by rotating suitable tools that cut, chip,and abrade the rock formations into small particles. Theequipment consists of a derrick, a hoist to handle thetools and lower the casing into the hole, a rotary table torotate the drill pipe and bit, pumps to handle mud-ladenfluid, and a suitable source of power. As the drill pipeand bit are rotated, drilling mud is pumped through the

drill pipe, through openings in the bit, and up to thesurface in the space between the drill pipe and the wallof the hole, washing the drill cuttings out of the hole atthe same time. The borehole is kept full of a relativelyheavy mud fluid. Due to its viscosity, this fluid exerts agreater pressure against the walls of the hold than thewater flowing in from the water-bearing bed. Therefore,the mud tends to penetrate and seal the pore spaces inthe walls, and prevents caving. Water under low hydro-static pressure (pressure exerted by the weight of thewater in the water zone) cannot force its way into thehole.

b. In the cable tool percussion method ofdrilling, the hole is formed by the pounding and cuttingaction of a drilling bit that is alternately raised anddropped. This operation is known as spudding. The drillbit is a club-like, chisel-type tool, suspended from acable. As the bit is raised and lowered, the cableunwinds and rewinds, which gives the bit a grindingmotion as well as a chisel-type action. It breaks hardformations into small fragments and loosens softformations. The reciprocating motion of the drilling toolsmixes the loosened material into a slurry that is removedfrom the hole at intervals by a bailer or sand pump.

C-1

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BIBLIOGRAPHY

Alsay-Pippin. Handbook of Industrial Drilling Procedures and Techniques, Alsay-Pippin Corp. (1980).American Society of Civil Engineers. Ground Water Management, (ASCE Manual 40), New York, N.Y. (1972).American Water Works Association. Ground Water, (AWWA Manual M21), Denver, Colorado (1973).Anderson, K. E. Missouri Water Well Handbook.Barlitt, H. R. Rotary Sampling Techniques. Industrial Drilling Contractors. (Undated).Bennison, E. W. Ground Water, Its Development, Uses and Conservation. Edward E. Johnson, Inc. St. Paul, Minnesota

(1947).Beskid, N. J. Hydrological Engineering Considerations for Ranney Collector Well Intake Systems, Division of

Environmental Impact Studies of the Argonne National Laboratory.Campbell, M. D. and Lehr, J. H. Water Well Technology, McGraw-Hill Book Co., New York, N.Y. (1973).Civil Engineering. Uranium in Well Water, ASCE (Oct. 1982).Committee on Hydraulic Structures of the Hydraulics Division. Nomenclature for Hydraulics, Manual No. 43, ASCE

(1962).Department of the Army. TM 5-545 Geology, (July 1971).Fair, Geyer and Okun. Water Supply and Wastewater Removal, Vol. 1.Fair, Gordon M.; Geyer, John C.; Okun, Daniel A. Elements of Water Supply and WastewaterDisposal, John Wiley &

Sons, Inc., New York, N.Y. (1971).Gibson, Ulric P. and Singer, Rexford D. Water Well Manual, Premier Press, Berkeley, California (1971).Hardenbergh, W. A. and Rodie, E. B. Water Supply and Waste Disposal. International Textbook Co. (1963).Harr, M. E. Groundwater and Seepage. McGraw-Hill Book Co. (1962).Huisman, L. Groundwater Recover, Winchester Press, (1972).Joint Departments of the Army and Air Force USA. Well Drilling Operations. TM5297/AFM 85-23, (1965).Lacina, W. V. A Case History in Ground Water Collection. Public Works (July 1972).Larson, T. E. and Skold, R. V. "Laboratory Studies Relating Mineral Quality of Water to Corrosion of Steel and Cast

Iron," Corrosion 14:6, 285 (1958).Lehr, J. H. and Campbell, M. D. Water Well Technology. McGraw-Hill Book Co. (1973).Meinzer, O. E. Water Supply Paper 489, USGS (1923).Missouri Department of Natural Resources. Missouri Public Drinking Water Regulations, MO DNR (1979).Rhoades, J. F. Ranney Water Collection Systems, Annual Meeting of the Technical Association of the Pulp and Paper

Industry (1942).Spiridonoff, S. V. Design and Use of Radial Collector Wells, Journal, AWWA, Vol. 56, No. 6 (June 1964)*Tolman, C. F. Ground Water, McGraw-Hill Book Co. (1937).United States Geological Survey. A Primer on Ground Water. (1963).Walker, W. R. Managing Our Limited Water Resources: The Ogallala Aquifer. Civil Engineering, ASCE (Oct. 1982).Water Systems Handbook. Sixth Edition. Water Systems Council, Chicago, Illinois.

Bibliography-1

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INDEX

Abandoned wells, 5-9 Disposal field (minimum distance from wells),Analyses (water quality) Table 5-1

ground water, 5-4b Distribution mainssurface water, 6-3 capacity, 3-2, 3-5

Aquifer definition, 1-3a(7)characteristics related to well design, 5-6 Distribution systemdefinition, 5-1 capacity, 3-2, 3-3, 3-4, 3-5recharge, 5-3a definition, 1-3a(5)sieve analysis, 5-6c(1)(a) design, 9-1yield, 5-5b Domestic water requirements, 2-1

Arsenic (drinking water standard), Table 5-2 Drawdown, 5-5a, 5-6i(1)Artesian wells Drinking water standards, 5-4b

discharge, 5-5b Energy usagediameter, 5-6a conservation, 9-3disinfection, 5-7c existing systems, 4-6r

Backflow ground water supplies, 5-10hconnections, 1-3a(17) surface water supplies, 6-5kprevention, 2-3a water supply alternatives, 4-1, 9-3

Bacteriological analyses (see Analyses) Environmental considerations, 4-4Barium (drinking water standard), Table 5-2 Environmental Protection Agency, 5-4bCadmium (drinking water standard), Table 5-2 Equipment (selection of), 9-2Calcium Existing systems

incrustation effects, 5-8a expansion, 3-5Capacity use of, 4-2

distribution system, 3-5, 3-2 Feeder mains, 1-3a(6)rated, 1-3a(16) Fire demand, 1-3a(15)storage (finished water), 3-2 Fire flowsupply lines, 3-2 definition, 1-3a(14)supply works, 3-2 effect on system capacity, 3-2, 3-4treatment works, 3-2 requirements, 2-2water supply system, 3-2, 3-3, 3-4, 3-5 Fluoride, Table 5-2

Capacity factor Gravel pack, 5-6e, 5-7a(2)application, 1-3a(11), 3-2, 3-5 Ground waterdefinition, 1-3a(10) availability, 5-1, 5-3list of, 3-1 definitions, 5-1

Cesspool, 5-4a economy, 5-1alocation by sanitary survey, 5-4a(2) quality, 5-4minimum distances from wells, 5-4a recharge, 5-6i(2)

Chloride sampling, 5-4bcriteria, 4-5c test drilling, 5-3, 5-9in surface waters, 6-3 treatment, 5-4c

Chlorine, 5-4c(2), 5-7e wells (see Wells)Chromium (drinking water standard), Grouting (water supply wells), 5-6f

Table 5-2 HardnessCone of depression, 5-5a, 5-6d(1) criteria, 4-5aCorrosion, 5--8b surface water, 6-3Cross connection, 1-3a(17) Heavy metals, 5-4bCyanide (drinking water standard), Table 5-2 Hospitals (water supply capacity), 3-2Disinfection Horsepower (brake), 5-6

gravel pack, 5-6e(4) Hydrogen sulfide, 5-2water supply wells, 5-7 Hydrologic data, 6-5b

Index-1

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Incrustation (well screens), 5-8a structural considerations, 8-1cIndustrial water types and applications, 8-1a

effect on system capacity, 3-2, 3-4 ventilation, 8-1drequirements, 2-3, 3-4 Pumping level (dynamic water level), 5-5a

Intakes Pumps (ground water)capacity, 7-2 control, 8-4clogging by sand or silt, 7-2 emergency power, 8-2, 8-3flood hazards, 7-2 reciprocating, 8-2ice problems, 7-1, 7-3 rotary, 8-2inlet cribs, 7-1 selection factors, 8-2inlet velocities, 7-3 sizing, 5-6jlocation, 6-5d, 73, 7-4 submersible turbine, 1-3b(3), 8-2low water depth, 7-2, 7-4 vertical line shaft turbine, 1-3b(2), 8-2multiple-inlet towers, 7-1 Pumps (surface water)natural lakes, 7-1 centrifugal, 8-1apermits for construction, 7-1 control, 8-4reliability, 7-2, 7-4 emergency power, 8-1e, 8-3reservoirs, 7-1 protection, 8-1bscreens, 7-1 reliability, 8-1e, 8-3size, 7-3 sizing, 8-1estreams, 7-1, 7-2, 7-3, 7-4 Purchase of water, 4-1, 4-3Irrigation Radioactivity (drinking water standard), 4-5d,backflow prevention, 2-3a 5-4beffect on system capacity, 3-2, 3-4 Radius of influence of well, 5-5a, 5-6i(1)planted and grassed areas, 2-3 Required daily demand, 1-3a(12)with treated wastewater, 2-3b, 2-3c, 2-7 Reservoirs (raw water)

Landfills, 8-1b geological considerations, 6-5iLead (drinking water standard), Table 5-2 location, 6-5gLife cycle cost analyses recreational use, 64

pumping equipment selection, 8-2 water quality control, 6-4water supply alternatives, 4-1 Rock wells, 5-6

Materials (selection of), 9-2 Saline water conversion, 4-5cMercury (drinking water standard), Table 5-2 SamplingMunicipal water systems (purchase of water), general, 4-5e

4-3 ground water, 5-4bNational Interim Primary Drinking Water Sand-gravel wells, 5-6

Standards, 4-4d Sand pumping, 5-6dNitrate-Nitrogen, Table 5-2 Sanitary surveyNitrite-Nitrogen, Table 5-2 for evaluation of surface water supplies, 6-Peak domestic demand, 1-3a(13) 5c, 7-4Permeability, 5-5a, 5-6i(2) for location of wells, 5-4aPesticides (drinking water standard), Table 5- Screens

2 bar, 8-1bPollution of existing source of supply, 4-6s cleaning of, 8-1bPopulation disposal of screenings, 8-1b

design, 1-3a(11), 3-2, 3-3 ground water (see Well screens)effective, 1-3a(9), 1-3a(10), 1-3a(11), 3-2, size of openings, 8-1b

3-5 surface water, 7-1, 8-lbPumping facilities (surface water) traveling, 8-lb

arrangement, 8-1a Sealing (water supply wells)combined with intake, 7-1, 8-1a abandoned wells, 5-9control, 8-4 purpose, 5-6fdepth of structure, 8-1a Seepage pit (minimum distance from well), Ta-design, 9-1 ble 5-1location, 8-1a Selenium (drinking water standard), Table 5-2screens, 8-1b

Index-2

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*TM 5-813-1/AFM-88-10, Vol. 1

Septic tanks Water levellocation by sanitary survey, 5-4a(2) dynamic, 5-5aminimum distances from wells, Table 5-1 static, 5-5a

Service line, 1-3a(8) Water qualitySewers chloride, 4-5c

location by sanitary survey, 5-4a(2) data, 4-5eminimum distance from wells, Table 5-1 EPA drinking water standards, 4-5d, 5-4b

Sieve analysis, 5-6e(1) ground water, 5-4Silver (drinking water standard), Table 5-2 hardness, 4-5aSludge disposal (water treatment), 6-5m raw water guidelines, 4-5Softening sampling, 4-5e, 5-4b

general, 4-5a sulfate, 4-5cground water, 5-4c surface waters, 6-3, 6-5e

Specific capacity total dissolved solids (TDS), 4-5b, 6-3definition, 1-3b(1) Water requirements

Sprinkler systems (irrigation), 2-3 domestic, 2-1Static water level, 5-5a fire-flow, 2-2Storage (distribution) industrial, 2-1

capacity, 3-2, 4-3 irrigation, 2-3design, 9-1 Water reuseevaluation, 4-6j industrial, 2-3

Sulfate irrigation, 2-3criteria, 4-5c Water rightssurface waters, 6-3 existing sources, 4-6

Supply line ground water supplies, 5-1, 5-10capacity, 3-2 prior appropriation, 6-2definition, 1-3a(3) riparian, 6-2design, 9-1 Water workslocation, 6-5j capacity, 3-2

Supply works definition, 1-3a(1)capacity, 3-2 expansion, 3-5definition, 1-3a(2) Wellsdesign, 9-1 abandoned (see Abandoned wells)expansion, 3-5 accessibility, 5-6glocation, 9-1 alluvial, 7-2

Surgeon General, 5-4b artesian (see Artesian wells)Television inspection, 5-8c capacity, 5-1aTotal dissolved solids (TDS) casing, 5-6c, 5-6h(3)

criteria, 4-5b cleaning, 5-7Total dynamic head, 5-6j collector-type, Table 5-1, Figure 5-3Treatment works construction, 5-3, 5-6

capacity, 3-2 depth, 5-6bdefinition, 1-3a(4) design, 5-6, 5-10design, 9-1 development, 5-7aexisting supplies, 4-6i diameter, 5-6alocation, 6-5j disinfection, 5-7b

Uniformity coefficient, 5-6b distance from pollution sources, 5-4aWaste disposal ponds (as sources of ground water drilling methods, 5-3

pollution), 5-4 gravel pack (see Gravel pack)Wastewater grouting (see Grouting)

disposal (location by sanitary survey), 5- interference, 5-6i(1)4a(1) location 5-6i(2)

reuse, 2-3 rock wells (see Rock wells)Water law sand-gravel wells (see Sand-gravel wells)

prior appropriation, 6-2 screen (see Well screens)riparian, 6-2 sealing (see Sealing)

Index-3

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*TM 5-813-1/AFM-88-10, Vol. 1

spacing, 5-6i diameter, 5-6d(3)surface-slab, 5-6h(2) incrustation, 5-8atesting, 5-5d, 5-5e installation, 5-6d(4)waste disposal, 5-4a length, 5-6d(2)yield, (see Well yield) purpose, 56d

Well house, 5-6h(4) Well yieldWell screens definition, 1-3b

aperture size, 5-6d(1) design for, 5-5bcleaning, 5-8 maintenance, 5-8corrosion, 5-8b quantities, 5-5bdesign, 5-6

Index-4

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*TM 5-813-1/AFM-88-10, Vol. 1

The proponent agency of this publication is the Office of the Chief of Engineers, United States Army. Users areinvited to send comments and suggested improvements on DA Form 2028 (Recommended Changes toPublications and Blank Forms) direct to HQDA (DAEN-ECE-G), WASH, DC 20314-1000.

By Order of the Secretaries of the Army and the Air Force.

JOHN A. WICKHAM, JR.General, United States Army

Official: Chief of StaffR. L. DILWORTH

Brigadier General, United States ArmyThe Adjutant General

LARRY D. WELCH, General, USAFOfficial: Chief of StaffNORMAND G. LEZY, Colonel USAF

Director of Administration

Distribution:Army: To be distributed in accordance with DA Form 1234B, requirements for Water Supply-General

Considerations.Air Force: F

*U.S. GOVERNMENT PRINTING OFFICE: 1993 - 342-421/62116

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Page 53: 1987. Water supply sources and general considerations

PIN: 005341-000