water sources final 1

Water Sources

Presented by:

New England Water Works Association

Instructor: Sam Elliot, CET 703-403-6313

[email protected]

Water Sources

Introduction– Course will cover:

• Hydrologic cycle – Description

» Terms» Water ownership rights

– Groundwater– Surface water– Water quality concerns for water sources– Conservation methods and water use– Watershed protection

Water Sources

Water Quality Concerns for Water Sources1. Physical2. Biological3. Chemical4. Radiological

Source Protection Concepts5. Wellhead protection6. Surface water protection7. Watershed protection

Water Sources

Groundwater– Terms and well construction– Types of wells– Springs and infiltration galleries– Well construction– Aquifer types and performance – Well operation and pumping

Water Sources

Surface Water– Water rights– Watershed sources and characteristics

• Runoff and types of pollution• Storage• Challenges using surface water sources

– Alternative sources– Use and conservation of water

Water Sources

Water Sources – Hydrologic Cycle

The Hydrologic Cycle– Evaporation and transpiration– Condensation– Precipitation– Infiltration, percolation surface runoff


Evaporation– Water becomes a gas – evaporation– Heat from the sun causes most evaporation– Sublimation – ice directly to vapor

Transpiration– Water is absorbed by plants– Returns to air from leaves and blades of grass


Condensation– Results from water vapor cooling– Forms clouds

Precipitation– Drops in clouds become to heavy to remain airborne– Falls as rain, snow, sleet, hail– Results in redistribution of water supply


Groundwater– Infiltration

• The movement of water through the soil• Some moves upward due to capillary action

– Percolation• The downward movement of water in the soil

– Downward below root zone– Reaches water table (saturated area)


Surface runoff– When soil can hold no more water it is saturated– Excess precipitation flows downhill– Eventually reaches rivers, lakes and the ocean– Cycle continues


Aquifers – Unconfined aquifers

• Surface of saturated zone free to rise and fall– Confined aquifers

• Also called an artesian aquifer• A permeable layer confined by an upper and lower

layer• Results is the water is under pressure• Well water rises, not necessarily to the surface


Aquifer materials– A variety of materials

• Sand – small or large grains• Limestone or fractured rock

– Important• Porosity - How much the aquifer can hold• Permeability – How well the water can flow


Impurities– In precipitation mostly effects surface water

• Dissolves gases from the atmosphere• Picks up dust and other solids• Generally soft, low in total solids, low to neutral pH• Can be corrosive

– Groundwater• Effected by materials picked up in run off• Effected by materials in the water table

Water Sources – Surface Water

Surface water sources– Primarily lakes and rivers– Relied on by large urban areas in most cases– Canals, aqueducts and pipelines

• Bring water in from distant sources

Water Sources - Groundwater

Groundwater sources– Springs

• Rarely used by utilities– Infiltration galleries

• Collect water from surface sources– Wells

• Drilled into water table– Serves 48% of general population– Servers 95% of rural population


Parts of a well– Sanitary seal– Air vent– Well casing– Grout– Screen– Discharge pipe– Pump– Gravel packing


Well terms– Static water level– Pumping level– Drawdown– Cone of depression

– Zone of influence– Residual drawdown– Well yield– Specific capacity


Static water level– Water level when no water level is being withdrawn– Measured from ground surface to water level– Monitors changes in water table

Pumping water level– Water level when pump is on– Pump must be below this level

Drawdown– Level between static level and pumping level


Cone of depression– In unconfined aquifer, water flows from all directions– Free water surface takes the shape of a cone

Zone of influence– Zone affected by drawdown– Distance depends on ground porosity– Low porosity equals large zone of influence


Residual drawdown– After pumping, water rises in the well– If rise does not reach original level

Well yield– What the well can produce over a long period of time– Measured in gpm or gphr– If pumping exceeds recharge, safe yield will be reduced– Pump will be damaged if sucks air– To correct problem, well can be left to “rest”


Specific yield (Specific capacity)– Specific yieldgpm/ft = Well yieldgpm ÷ Drawdownfeet

– Calculation used to monitor well operation– Should be done frequently– Indicates

• Pump wear• Screen plugging• Other problems


Well location– Where maximum yield possible is obtained– Where can be protected from contamination– How to select location

• Existing data• Likely locations• Exploration


Existing data– State and Federal geological agencies

• Likely water quality– Hardness, iron and manganese, sulfur, nitrates, etc– Contamination possibilities

• Owners of surrounding wells• Local well drillers

Water Snmources - Groundwater

Likely locations– More likely under valleys than on hills– Material washed down from mountains – likely aquifers– Presence of surface water

• Streams• Springs• Seeps • Swamps• Lakes


Exploration– Do underground exploration before drilling a full sized well– Tests

• Seismic and resistivity tests– Shock waves from dynamite– The lower the ground’s electrical resistivity, the great

the probability of water presence• Test wells

– Earth samples taken– Checked electrically or with gamma rays


Exploration– Computer modeling

• Measures complex stresses and effect on aquifer• Calculates withdrawal and recharge rates• Location of additional wells• Possible contamination


Sources of contamination– Landfills– Hazardous-waste sites– Liquid waste storage– Septic tanks, leachfields– Deep well injection

– Agriculture– Sludge application– Infiltration from runoff– Deicing activities– Radioactive waste– Abandoned wells


Types of wells– Dug wells– Bored wells– Driven wells– Jetted wells– Drilled


Dug wells– Can supply large amounts of water from shallow source– Dug with

• Pick and shovel, Clamshell, Backhoes– May be lined with concrete liners called curbs– Public utility dug wells may be

• 8 to 30 feet in diameter• 20 to 40 feet deep

– Vulnerable to contamination


Bored wells– Can be constructed quickly– Soil must be suitable– Limited to 3 feet in diamter and 25 to 60 feet deep– Casing is forced down as hole is bored– Cement grout surrounds the casing to block surface water


Driven wells– Simple to install– Water must be neat the surface– No rock layers or boulders in the way– The point has a steel tip– Diameters from 1 ¼ to 4 inches– Maximum depth is30 to 40 feet– For suction pump, static water level of at least 15 feet


Jetted Well– Soil must be appropriate – not hardpan, boulders– Water is pumped down to the point– Well screen on smaller diameter pipe is then placed in well– Outer casing is withdrawn


Drilled well– Cable tool method– Rotary hydraulic method– Reverse-circulation rotary method– California method– Rotary air metho– Down-the-hole hammer method


Cable tool method– Percussion drilling – wells of all sizes and depth– Clublike chisel is driven into the earth– Every 3 to 6 feet, a bailer is used to clean out hole– Casing is used as necessary– Operator adjusts tool blows for soil conditions– At desired depth, a screen is lowered and pump installed


Rotary hydraulic method– Well is drilled with rapid rotation of a bit– Drill pipe is hollow

• Fluid is pumped down – carries borings to surface• Clay may be added to liquid to adhere to hole sides

Reverse-circulation method– As above, fluid circulates in the opposite direction– Fluid returns to surface through drill pipe


California method (stovepipe method)– Used in unconsolidated material– Similar to cable tool method but uses a special bucket– When bit is dropped, bucket is filled with cuttings– Steel casing forced down as well is deepens

Rotary hammer method– Similar to rotary hydraulic method– Air is used instead of water– Suitable only for drilling in consolidated rock– Large drill rigs usually equipped to do both


Down-the-hole hammer method– Uses a pneumatic hammer– Air also cleans away cutting from the bit– For most rock, this is the fastest way to drill


Special types of wells– Radial wells– Gravel-wall wells– Bedrock wells


Radial wells– Commonly used near lakes or rivers– Consists of central well with horizontal screened wells

projecting outward from the bottom– Central well serves as water collector– Central cassion is generally 15 to 20 feet in diameter– Each horizontal well is constructed with a gate valve– Superstructure protects the well

Bedrock well– Well is drilled into bedrock – water flows through fractures


Well construction procedures– Well components

• Well casing– Steel, iron, fiberglass, plastic– Some have drive shoe on lower end– Rotary drilled well casing installed after drilling


Gravel-wall well or gravel packed well– Best in fine grain material with uniform size– Built with large casing with smaller casing with well screen– Area around screen is filled with gravel– Outer casing is withdrawn– There are variations on the above


Well components– Well screens

• Used in unconsolidated formations• Proper size:

– Minimum resistance– Prevents sand from entering well

• Openings between 0.1 and 0.3 feet• Must be sized to allow for buildup of headloss• Plastic, mild steel, bronze, stainless steel


Well components– Grouting

• Seals out water to prevent surface pollution• Seal out water from poor quality strata• Protects casing against corrosion• Restrains unstable soil and rock formations

– Annular space is filled– Hole larger than casing when corrosion likely for 2’” grout


Well development– High rate pumping– Surging– Increased-rate pumping and surging– Use of explosives– High velocity jetting– Chemical agents– Pressure acidizing– Hydraulic fracturing


High rate pumping– Where no screen is used – flushes out bore and

aquiferSurging

– Employs a plunger or surge block– Also achieved by using compressed air

— Increased rate pumping– Develops wells in unconsolidated limestone– Pumping rates increased in steps


Use of explosives– May be used to fracture massive rock formations– Might be used to clear material that is plugging bore face– Light charge used to agitate materials surrounding bore

High velocity jetting– Uses clean water under high pressure– Breaks up compacted materials– Wells is pumped in the meantime


Chemical agents– Chemicals frequently enhance some development methods– Used with hexametaphospahtes to improve jetting– May also be used where to disperse iron or carbonate

Pressure acidizing– May be used when good isolation from overlying

formations to increase well productivityHydraulic fracturing

– Fluid under pressure to open strata separations– Gelling agents and sand added to hold fractures open


Pumping tests– To confirm that well produces water at design capacity– Typically:

• 24 hours for confined aquifer• 72 hours for unconfined aquifer

– Pumping rate is held constant– Drawdown is measured frequently


Sanitary considerations– For shallow wells, surround with:

• 50 feet radius of clay• Layer 2 feet deep

– Grout used to fill in annular space– Disinfection

• Extended pumping removes most• With 50 mg/L of chlorine with surging• HTH included with gravel in gravel packed well


Aquifer evaluation– Observations wells located on map– Routine measure of drawdown in observation wells

• Steel tape measure• Air bubbler tube• Electronic sensors

– Performance evaluated by:• Drawdown method• Recovery method• Specific capacity method


Well operation and maintenance– Important base line data

– Static water level– Pumping water level– Drawdown– Well production– Well yield– Time required for recovery after pumping– Specific capacity


Well abandonment and sealing– Goal is restoration of geologic and hydrologic conditions

• To prevent physical hazard• To prevent groundwater contamination• To conserve the aquifer• To avoid mixing water from different aquifers

– Work is best done by company who constructed the well


Summary– Wells often supply water to smaller communities– Water quality generally consistent– Minerals can be a problem– Droughts may not effect as much as surface sources– Proper maintenance and record keeping are important


Surface water– Primary source for larger communities and cities– Cities have grown up around sources

• Great lakes• Major rivers

– When groundwater insufficient, surface water from a distance carried to cities with aqueducts, pipelines


— Surface runoff– Rain

• Runs off quickly toward streams etc.– Snow

• Form of water storage• Extremely important for western US and Canada

— Groundwater– Springs and seeps– Many streams would dry up without these


— Influences on runoff– Rainfall

• Intensity and duration– Soil

• Composition and moisture– Ground slope– Vegetation cover– Human influences


— Watercourses– Natural

• Brooks, streams, creeks, rivers– Perennial streams

• Run year round– Ephemeral streams

• Flow occasionally, brief existence– Intermittent streams

• May run for weeks or months at a time• Dry at some times


— Constructed watercourses– Ditches, channels, canals, aqueducts etc.– Used to divert water from one watershed to another– May be used to prevent ponding from impeding growth– Other uses

• Potable water• Shipping, boat access• Irrigation

— Water Bodies – Lakes, ponds and reservoirs


— Considerations for public use1. Quantity of water available (allow for growth)

• Required amount must be available• Summer usually greatest use• Safe yield

– Amount used during lowest flow• Source

– Impoundment– Watershed– Rain or snow fall


Considerations– Water quality

• Almost any water can be made potable• Expense considerations• Political and legal issues

– Whose water is it?» Supply and demand» Salt water


— Considerations – Water quality continued

• Temperature• Taste, odor, color• Algae• Turbidity• Microbiological contamination• Chemical/radiological contamination


— Water storage– Natural storage– Impoundments

• Dams– Utility is responsible for maintenance– Failure

» Water loss» Downstream destruction

– Maintenance record keeping important


— Groundwater recharge– Create basins to provide recharge aquifers– Injecting water into aquifer

• Must equal drinking water standards• Turbidity an clog injection area

– EPA making it difficult to create new impoundments


— Surface intakes– Spillway– Disadvantages

• Warm water• Ice in winter• Floating debris• Varying water levels


— Submerged intakes– Best water usually at some depth– Do not obstruct surface activity– Floating debris not a problem– Raised off of the bottom – prevents intake of silt/sand– Typically water is pumped to treatment plant


Operating Problems1. Stream contamination

• Spills from barges and ships• Spills from industrial installations• Fertilizer• Broken pipe lines• Swamps after heavy rain


Operating Problems2. Lake Contamination

• Vulnerable to human and natural contamination• Nitrates from farmland• Algae growth, aquatic weeds• Organisms – zebra and quagga mussels• Lake straification


Operating Problems 3. Icing

• Rapid cooling to freezing – frazil ice– Small, disc shaped crystals– Can plug intake– Favorable conditions

» Clear sky at night» Air temperature less than 19.4 degrees» Day time temperature less than 32.4 degrees» Winds greater than 10 mph


Operating problems – icing continued – Overcoming frazil ice problems

• Backflush with:– Settled water– Air – Steam

• Switch intakes4. Multiple intakes for slow flow

• Use of non-ferrous intake materials


Operational problems5. Evaporation

• Large surface can lose 6 to 8 feet to evaporation• Cover with plastic or other material

6. Seepage• Through bottom and sides• Line reservoir


Operational Problems 7. Siltation

– Streams carry sediment– Serious problem for dams– Cannot be prevented but can be limited

• Good farming procedures• Controls on logging, road building• Artificial wetlands

– Correction• Dredging• New source


Emergencies and alternative sources• Supply to public – continuous and uninterrupted• Loss of pressure = contamination• Lack of water for sanitation = spread of disease• Emergency plans are important• Below is discussion of possible situations and solutions


Use and conservation of water– Water, our most important natural resource– Use has declined since 1980

• Less used by agriculture, industry, power companies• More is used by public water suppliers• Domestic use about 105 gallons per day per capita• Fire use

– Small across the country– Maybe largest flow met by any given utility


Causes of source disruption– Natural disasters

• Earthquakes• Storms• Landslides• Vandalism• Spills• Leaks• Contamination

– Equipment failure


Source contamination– Chemical spills

• Some short term, some longer term effects– Most chemical contamination can be dealt with

• Carbon adsorption


Loss of water source– Short term

• Conservation, rationing• Use tank trucks• Bottled water• Water from neighboring system


Long term options– Drill new wells– Construct new surface water sources– Clean up contamination– Connect to near-by town– Impose permanent conservation requirements– Reuse wastewater for non-potable uses– Dual potable- nonpotable system– New reservoir– Aquifer recharge


Evaluate the options– Required procedures to implement option – Is technology available – How much water can option provide– Can it meet systems total needs– Can it be expanded to meet future needs– What equipment and supplies are needed


Reliability– How reliable is option– Does it require special operation and maintenance skills

Political considerations– What administrative procedures are needed– Is property ownership a problem– Will option be accepted by public


Cost considerations– What is initial investment– What will be operating costs– Who will pay for:

• Design• Construction• Operation


— Alternative water sources– Surface water

• Two or more intakes at different locations• Intakes in more than one source• Construct wells for back up

– Groundwater• Provide extra wells• Locate wells in different aquifers• Provide emergency source water supply

– All systems tie in with other systems


Use and conservation of water– Variations in water use

• Time of day and day of the week• Climate and season of the year• Type of community • System water pressure• Presence or absence of meters• Quality of water


Time and day of week– Rapid rise early in the morning– Significant rise early evening– Industries may not operate on weekends– Monday might be “wash day”


Climate and season– Most places higher in summer

• Some air conditioners use water• Lawn and garden watering, bathing

– Usually lower in winter unless water is run to avoid freezing


Type of community– Industrial communities use can be higher than

average– Type of housing

• Individuals homes use more due to lawns and gardens• Economically depressed areas generally use less


Water pressure– Normal pressure – 25 to 50 psig– Increase of 25 psi to 45 psi = maybe 30% increase in use

Metering– Unmetered customers use 25% more than average

• Let hoses run• Let faucets run• Ignore leaks


Sewers– Customers with sewer connections tend to use 50 to 100%

more water than those with septic systems

Condition of the Distribution System– Leaks result loss of revenu– Poor condition results in:

• Taste and odor problems• Reduced use and customer support for utility


Conservation– Gradual acceptance by public of need to conserve– Efforts most effective in areas on minimal supply– Benefits

• Reduced demand on source• Energy savings• Reduction in wastewater flow• Reduced costs• Protection of environment


Drawbacks to conservation– Loss of revenue– Possible delay in developing new source– Possible stimulation of water service growth– Difficulty in dealing with drought conditions


Loss of revenue– Some offsetting expenses - power, chemicals– May require increased rates– Financial planning necessary before program starts– In case of drought, hard to raise rates on short notice

Delay in developing new sources– If conservation successful, lack of public support for new

source– Delay can increase cost of new source development


Stimulation of system growth– More water available can attract more users– Can be a system until new sources developed

Drought conditions– Drought after conservation is hard to explain asking for

even less use– Emphasizes need for good planning– Utility must plan for future use


Supply management techniques– Careful management of all resources– Analysis of water use data– Complete source and customer metering– Reduction of unaccounted for water


Demand management techniques– Public education– Distribution of water-saving devices– Management of water use demand– Modification of rate structure– Promotion of low water use agriculture and gardening– Promotion of conservation by industry and business


Drought conditions management– Response

• Conservation• Additional supply

– Emergency plan in place– Identify additional sources ahead of time– In extreme cases, fines for misuse of water


Allocation of Water rights:— Riparian Doctrine— Appropriation Doctrine

— Most eastern states have a combination of the two— Western and dry states tend to use Appropriation Doctrine


Riparian Doctrine– Common law doctrine based on civil cases– Rule of “reasonable sharing” by abutting land owners– Sharing rather than a right to a specific amount of water

• Uses not allocated a specific amount– Use cannot interfere with others use

Drought conditionsLength of ownership or previous use is not a basis for use under these conditions


Greater water use has resulted in:– More frequent conflicts especially during droughts– Increasing number of state statutes

• Gradual move toward Appropriation Doctrine


Appropriation Doctrine– “First in time, first in right”– Water for irrigation greatest use in west– Most laws relate to this type of use– Two basic principals

• Priority use• Beneficial use


Priority use– When less water than demand, who has used the longest– No shared suffering

Beneficial use• Opposite of Riparian Rights – Land ownership not a

factor• User must prove used is beneficial• Non-use for period of time can lead to loss of right• This type of use tends to be settled in courts


Legal complications– Land boundries are clear, water use is not– Water rights are highly independent and relative– Many variables to consider

• Use may have to be adjusted– Drought conditions– Seasonal use for crops– Nature of the source


Rights for the use of Groundwater– Absolute right– Reasonable use– Correlative rights– Appriation-Permit systems


Absolute ownership– Owner of the land owns what is under it– For all practical purposes = law of capture– Water can be used for owner’s purpose or sold– No liability if dries up neighbor’s well


Reasonable use– Interference with neighbor only ok if use is reasonable– Owner is liable if use harms others– Off site use is considered unreasonable it if interferes with

others use of the water


Correlative rights


Appropriation-Permit systems– Basically a permit system– Most important issue is Rule of Priority

• Based on who has use the water the longest– Adjustments to use not so necessary as with surface water– Main control is limiting pumping


SummaryThe evolution of water rights is more advanced in the western states than if the east.Control of water sources remains in under the control of the states.

Principles of Source Protection

Surface and groundwater in watershed area to be protected– Some utilities hire a consultant – work closely with him– Federal funding may be available– Organize a watershed management team

• Watershed delineation• Potential and existing threats to water quality• Set goals• Control stategies• Implement a source protection plan


Ten steps to preparing plan:

Organize community team Delineate watershed Review zoning Determine critical areas Inventory potential treats

Prioritize potential threatsEstablish goalsPrepare Source Protection PlanReach out and educateImplement plan


Community planning team– Good when financial resources are limited– Involves community people and their expertise– Begins to educate the public to the need for source

protection– Public education may be most important part of plan– Team might be:

• Municipal officials • Public organizations• Appropriate agency staff• Farmers, developers, residents, business leaders


Delineate your watershed– Some states have done this with GIS– Topo maps may be enough for small systems– Use large scale map i.e. 1:5,000– Watershed may include other towns– Physically go out an inspect boundary lines– Some towns put up signs indicating watershed area


Review zoning– Get information from code enforcement officer– Evaluate restrictions already in place– Consider:

• Permitted land uses• Conditional land uses• Town’s long range plan for directing growth• Existing performance standards


Determine critical areas– Identify sensitive areas – personal tour important

• Steep slopes• Unvegetated or disturbed areas• Various soil conditions• Forest areas• Streams, brooks, ponds and lakes• Wetlands

– Review USGS history of precipitation and stream flow recordsL=


Inventory potential threats– Important to identify pollutants and their sources– On a 1:5,000 map mark out areas– Use zoning maps and town master plans– Double check information from state agencies to be sure

information is current– Update information over time


For potential pollution sources:– Permitted discharges– Solid waste facilities– Residential development– Industrial/commercial development– Agricultural activities– Water demand– Use lists of relative risk from various uses


Prioritize potential threats• Use list of potential sources of pollution• Consider

– Amounts of pollutants– Toxicity– Water quality impacts– Cooperation needed from abutting towns

• Review periodically


Source protection plan should consist of:– Control measures– Education and outreach strategies– Implementation strategy

Control measures may be regulatory or non-regulatory– Regulatory – bylaws, ordinances– Non-regulatory – buffer zones, detention basins, erosion

controls


Reach out and educate– Non-regulatory measures rely on education and outreach– Regulatory measures rely on support from public and

town officials– Use of “Best Management Practices” good guideline


Implement the plan– Need PUBLIC SUPPORT– Establish individual who will enforce the plan– Pick people with proper expertise (spetic systems, zoning)– Consider a “Water Supply Advisor Committee”

• Review projects that threaten watersupply• Work closely with the Planning Board• Keep program updated

water sources final 1

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