3.0 SOURCE DEVELOPMENT - RECOMMENDED STANDARDS FOR WATER WORKS 1997

In selecting the source of water to be developed, the designing engineer must prove to the satisfaction of the reviewing authority that an adequate quantity of water will be available, and that the water which is to be delivered to the consumers will meet the current requirements of the reviewing authority with respect to microbiological, physical, chemical and radiological qualities. Each water supply should take its raw water from the best available source which is economically reasonable and technically possible.

3.1 SURFACE WATER

A surface water source includes all tributary streams and drainage basins, natural lakes and artificial reservoirs or impoundments above the point of water supply intake. A sourcewater protection plan for continued protection of the watershed from potential sources of contamination shall be provided as determined by the reviewing authority.

3.1.1 Quantity

a. be adequate to meet the maximum projected water demand of the service area as shown by calculations based on the extreme drought of record while not significantly affecting the ecology of the water course downstream of the intake.,

c. be adequate to compensate for all losses such as silting, evaporation, seepage, etc.,

3.1.2 Quality

A sanitary survey and study shall be made of the factors, both natural and man made, which may affect quality. Such survey and study shall include, but not be limited to

c. assessing degree of hazard to the supply by accidental spillage of materials that may be toxic, harmful or detrimental to treatment processes,

d. assessing all waste discharges (point source and non point sources) and activites that could impact the water supply. The location of each waste discharge shall be shown on a scale map.

e. obtaining samples over a sufficient period of time to assess the microbiological, physical, chemical and radiological characteristics of the water,

f. assessing the capability of the proposed treatment process to reduce contaminants to applicable standards,

g. consideration of currents, wind and ice conditions, and the effect of confluencing streams.

3.1.3 Minimum treatment

a. The design of the water treatment plant must consider the worst conditions that may exist during the life of the facility.

b. The minimum treatment required shall be determined by the reviewing authority.

c. Filtration preceded by appropriate pretreatment shall be provided for all surface waters. Exemptions may be approved by the reviewing authority on a case-by-case basis.

3.1.4 Structures

3.1.4.1 Design of intake structures

c. where frazil ice may be a problem, holding the velocity of flow into the intake structure to a minimum, generally not to exceed 0.5 feet per second,

d. inspection manholes every 1000 feet for pipe sizes large enough to permit visual inspection,

g. ports located above the bottom of the stream, lake or impoundment, but at sufficient depth to be kept submerged at low water levels,

h. where shore wells are not provided, a diversion device capable of keeping large quantities of fish or debris from entering an intake structure.

i. where deemed necessary, provisions shall be made in the intake structure to control the influx of zebra mussels or other aquatic nuisances. Specific method to control zebra mussels must be approved by the reviewing authority.

j. when buried surface water collectors are used, sufficient intake opening area must be provided to minimize inlet headloss. Particular attention should be given to the selection of backfill material in relation to the collector pipe slot size and gradation of the native material over the collector system.

3.1.4.2 Shore wells

a. have motors and electrical controls located above grade, and protected from flooding as required by the reviewing authority,

d. be equipped with removable or traveling screens before the pump suction well,

e. provide for introduction of chlorine or other chemicals in the raw water transmission main if necessary for quality control,

f. have intake valves and provisions for backflushing or cleaning by a mechanical device and testing for leaks, where practical,

3.1.4.3 An upground reservoir

is a facility into which water is pumped during periods of good quality and high stream flow for future release to treatment facilities. Upground reservoirs shall be constructed to assure that

3.1.5 Impoundments and reservoirs

3.1.5.1 Site preparation

c. abandonment of all wells which will be inundated, in accordance with requirements of the reviewing authority.

3.1.5.2 Construction

a. approval from the appropriate regulatory agencies of the safety features for stability and spillway design,

b. a permit from an appropriate regulatory agency for controlling stream flow or installing a structure on the bed of a stream or interstate waterway.

3.2 GROUNDWATER

A groundwater source includes all water obtained from dug, drilled, bored or driven wells, and infiltration lines.

3.2.1 Quantity

3.2.1.1 Source capacity

The total developed groundwater source capacity shall equal or exceed the design maximum day demand and equal or exceed the design average day demand with the largest producing well out of service.

3.2.1.2 Number of sources

3.2.1.3 Standby power

a. To ensure continuous service when the primary power has been interrupted, a power supply shall be provided through

b. When automatic pre-lubrication of pump bearings is necessary, and an auxiliary power supply is provided, the pre-lubrication line shall be provided with a valved by-pass around the automatic control, or the automatic control shall be wired to the emergency power source.

3.2.2 Quality

3.2.2.1 Microbiological quality

After disinfection, one or more water samples shall be submitted to a laboratory satisfactory to the reviewing authority for microbiological analysis with satisfactory results reported to such agency prior to placing the well into service.

3.2.2.2 Physical and chemical quality

a. Every new, modified or reconditioned groundwater source shall be examined for applicable physical and chemical characteristics by tests of a representative sample in a laboratory satisfactory to the reviewing authority, with the results reported to such authority.

b. Samples shall be collected at the conclusion of the test pumping procedure and examined as soon as practical.

c. Field determinations of physical and chemical constituents or special sampling procedures may be required by the reviewing authority.

3.2.2.3 Radiological quality

Every new, modified or reconditioned groundwater source shall be examined for radiological activity as required by the reviewing authority by tests of a representative sample in a laboratory satisfactory to the reviewing authority, with results reported to such agency.

3.2.3 Location

3.2.3.1 Well location

The reviewing authority shall be consulted prior to design and construction regarding a proposed well location as it relates to required separation between existing and potential sources of contamination and groundwater development. The well location should be selected to minimize the impact on other wells and other water resources.

3.2.3.2 Continued sanitary protection

Continued sanitary protection of the well site from potential sources of contamination shall be provided either through ownership, zoning, easements, leasing or other means acceptable to the reviewing authority. Fencing of the site may be required by the reviewing authority.

3.2.3.3 Wellhead protection

A wellhead protection plan for continued protection of the wellhead from potential sources of contamination shall be provided as determined by the reviewing authority.

3.2.4 Testing and records

3.2.4.1 Yield and drawdown tests

a. be performed on every production well after construction or subsequent treatment and prior to placement of the permanent pump,

c. have a test pump capacity, at maximum anticipated drawdown, at least 1.5 times the quantity anticipated, and

d. provide for continuous pumping for at least 24 hours or until stabilized drawdown has continued for at least six hours when test pumped at 1.5 times the design pumping rate,

1. test pump capacity-head characteristics,

2. static water level,

3. depth of test pump setting,

4. time of starting and ending each test cycle; and

5. the zone of influence for the well or wells.

f. provide recordings and graphic evaluation of the following at one hour intervals or less as may be required by the reviewing authority:

1. pumping rate,

2. pumping water level,

3. drawdown, and

4. water recovery rate and levels.

3.2.4.2 Plumbness and alignment requirements

a. Every well shall be tested for plumbness and alignment in accordance with AWWA standards.

b. The test method and allowable tolerance shall be clearly stated in the specifications.

c. If the well fails to meet these requirements, it may be accepted by the engineer if it does not interfere with the installation or operation of the pump or uniform placement of grout.

3.2.4.3 Geological data

a. be determined from samples collected at 5-foot intervals and at each pronounced change in formation,

c. be supplemented with information on accurate records of drillhole diameters and depths, assembled order of size and length of casing and liners, grouting depths, formations penetrated, water levels, and location of any blast charges.

3.2.5 General well construction

3.2.5.1 Drilling fluids and additives

a. not impart any toxic substances to the water or promote bacterial contamination,

3.2.5.2 Minimum protected depths

Minimum protected depths of drilled wells shall provide watertight construction to such depth as may be required by the reviewing authority, to

b. seal off formations that are, or may be, contaminated or yield undesirable water.

3.2.5.3 Temporary steel casing

Temporary steel casing used for construction shall be capable of withstanding the structural load imposed during its installation and removal.

3.2.5.4 Permanent steel casing pipe

a. be new single steel casing pipe meeting AWWA Standard A-100, ASTM or API specifications for water well construction,

c. have additional thickness and weight if minimum thickness is not considered sufficient to assure reasonable life expectancy of a well,

3.2.5.5 Nonferrous casing materials

a. Approval of the use of any nonferrous material as well casing shall be subject to special determination by the reviewing authority prior to submission of plans and specifications.

b. Nonferrous material proposed as a well casing must be resistant to the corrosiveness of the water and to the stresses to which it will be subjected during installation, grouting and operation.

3.2.5.6 Packers

Packers shall be of material that will not impart taste, odor, toxic substances or bacterial contamination to the well water. Lead packers shall not be used.

3.2.5.7 Screens

a. be constructed of materials resistant to damage by chemical action of groundwater or cleaning operations,

b. have size of openings based on sieve analysis of formation and/or gravel pack materials,

c. have sufficient length and diameter to provide adequate specific capacity and low aperture entrance velocity. Usually the entrance velocity should not exceed 0.1 feet per second,

d. be installed so that the pumping water level remains above the screen under all operating conditions,

e. where applicable, be designed and installed to permit removal or replacement without adversely affecting water-tight construction of the well, and

f. be provided with a bottom plate or washdown bottom fitting of the same material as the screen.

3.2.5.8 Grouting requirements

All permanent well casing, except driven Schedule 40 steel casing with the approval of the reviewing authority, shall be surrounded by a minimum of 1 1/2 inches of grout to the depth required by the review authority. All temporary construction casings shall be removed. Where removal is not possible or practical, the casing shall be withdrawn at least five feet to insure grout contact with the native formation.

1. Cement conforming to ASTM standard C150 and water, with not more than six gallons of water per sack of cement, must be used for 1 1/2 inch openings.

2. Additives may be used to increase fluidity subject to approval by the reviewing authority.

1. Equal parts of cement conforming to ASTM Standard C150, and sand, with not more than six gallons of water per sack of cement may be used for openings larger than 1 1/2 inches.

2. Where an annular opening larger than four inches is available, gravel not larger than one-half inch in size may be added.

Where an annular opening greater than six inches is available a clay seal of clean local clay mixed with at least 10 per cent swelling bentonite may be used when approved by the reviewing authority.

1. Sufficient annular opening shall be provided to permit a minimum of 1 1/2 inches of grout around permanent casings, including couplings.

2. Prior to grouting through creviced or fractured formations, bentonite or similar materials may be added to the annular opening, in the manner indicated for grouting.

3. When the annular opening is less than four inches, grout shall be installed under pressure by means of a grout pump from the bottom of the annular opening upward in one continuous operation until the annular opening is filled.

4. When the annular opening is four or more inches and less than 100 feet in depth, and concrete grout is used, it may be placed by gravity through a grout pipe installed to the bottom of the annular opening in one continuous operation until the annular opening is filled.

5. When the annular opening exceeds six inches, is less than 100 feet in depth, and a clay seal is used, it may be placed by gravity.

6. After cement grouting is applied, work on the well shall be discontinued until the cement or concrete grout has properly set.

The casing must be provided with sufficient guides welded to the casing to permit unobstructed flow and uniform thickness of grout.

3.2.5.9 Upper terminal well construction

a. Permanent casing for all groundwater sources shall project at least 12 inches above the pumphouse floor or concrete apron surface and at least 18 inches above final ground surface.

b. Where a well house is constructed, the floor surface shall be at least six inches above the final ground elevation.

c. Sites subject to flooding shall be provided with an earth mound to raise the pumphouse floor to an elevation at least two feet above the highest known flood elevation, or other suitable protection as determined by the reviewing authority.

d. The top of the well casing at sites subject to flooding shall terminate at least three feet above the 100 year flood level or the highest known flood elevation, whichever is higher, or as the reviewing authority directs.

3.2.5.10 Development

a. Every well shall be developed to remove the native silts and clays, drilling mud or finer fraction of the gravel pack.

b. Development should continue until the maximum specific capacity is obtained from the completed well.

c. Where chemical conditioning is required, the specification shall include provisions for the method, equipment, chemicals, testing for residual chemicals, and disposal of waste and inhibitors.

d. Where blasting procedures may be used, the specifications shall include the provisions for blasting and cleaning. Special attention shall be given to assure that the grouting and casing are not damaged by the blasting.

3.2.5.11 Capping requirements

a. A welded metal plate or a threaded cap is the preferred method for capping a well.

b. At all times during the progress of work, the contractor shall provide protection to prevent tampering with the well or entrance of foreign materials.

3.2.5.12 Well abandonment

a. Test wells and groundwater sources which are not in use shall be sealed by such methods as necessary to restore the controlling geological conditions which existed prior to construction or as directed by the appropriate regulatory agency.

1. be sealed to prevent undesirable exchange of water from one aquifer to another,

2. preferably be filled with neat cement grout,

3. have fill materials other than cement grout or concrete, disinfected and free of foreign materials, and

4. when filled with cement grout or concrete, these materials shall be applied to the well hole through a pipe, tremie, or bailer.

3.2.6 Aquifer types and construction methods -- Special conditions

3.2.6.1 Sand or gravel wells

a. If clay or hard pan is encountered above the water bearing formation, the permanent casing and grout shall extend through such materials.

b. If a sand or gravel aquifer is overlaid only by permeable soils the permanent casing and grout shall extend to at least 20 feet below original or final ground elevation, whichever is lower.

c. If a temporary outer casing is used, it shall be completely withdrawn as grout is applied.

3.2.6.2 Gravel pack wells

a. Gravel pack shall be well rounded particles, 95 per cent siliceous material, that are smooth and uniform, free of foreign material, properly sized, washed and then disinfected immediately prior to or during placement.

c. Gravel refill pipes, when used, shall be Schedule 40 steel pipe incorporated within the pump foundation and terminated with screwed or welded caps at least 12 inches above the pump house floor or concrete apron.

d. Gravel refill pipes located in the grouted annular opening shall be surrounded by a minimum of 1 ½ inches of grout.

e. Protection from leakage of grout into the gravel pack or screen shall be provided.

f. Permanent inner and outer casings shall meet requirements of Section 3.2.5.3.

g. Minimum casing and grouted depth shall be acceptable to the reviewing authority.

3.2.6.3 Radial water collector

a. Locations of all caisson construction joints and porthole assemblies shall be indicated.

b. The caisson wall shall be reinforced to withstand the forces to which it will be subjected.

c. Radial collectors shall be in areas and at depths approved by the reviewing authority.

d. Provisions shall be made to assure that radial collectors are essentially horizontal.

f. All openings in the floor shall be curbed and protected from entrance of foreign material.

3.2.6.4 Infiltration lines

a. Infiltration lines may be considered only where geological conditions preclude the possibility of developing an acceptable drilled well.

b. The area around infiltration lines shall be under the control of the water purveyor for a distance acceptable to or required by the reviewing authority.

3.2.6.5 Dug wells

a. Dug wells may be considered only where geological conditions preclude the possibility of developing an acceptable drilled well.

c. Minimum protective lining and grouted depth shall be at least ten feet below original or final ground elevation, whichever is lower.

3.2.6.6 Limestone or sandstone wells

a. Where the depth of unconsolidated formations is more than 50 feet, the permanent casing shall be firmly seated in uncreviced or unbroken rock. Grouting requirements shall be determined by the reviewing authority.

b. Where the depth of unconsolidated formations is less than 50 feet, the depth of casing and grout shall be at least 50 feet or as determined by the reviewing authority.

3.2.6.7 Naturally flowing wells

c. If erosion of the confining bed appears likely, special protective construction may be required by the reviewing authority.

3.2.7 Well pumps, discharge piping and appurtenances

3.2.7.1 Line shaft pumps

a. have the casing firmly connected to the pump structure or have the casing inserted into a recess extending at least one-half inch into the pump base,

b. have the pump foundation and base designed to prevent water from coming into contact with the joint, and

3.2.7.2 Submersible pumps

a. the top of the casing shall be effectively sealed against the entrance of water under all conditions of vibration or movement of conductors or cables, and

b. the electrical cable shall be firmly attached to the riser pipe at 20 foot intervals or less.

3.2.7.3 Discharge piping

1. be designed so that the friction loss will be low,

2. have control valves and appurtenances located above the pumphouse floor when an above-ground discharge is provided,

3. be protected against the entrance of contamination,

4. be equipped with a check valve, a shutoff valve, a pressure gauge, a means of measuring flow, and a smooth nosed sampling tap located at a point where positive pressure is maintained,

5. where applicable, be equipped with an air release-vacuum relief valve located upstream from the check valve, with exhaust/relief piping terminating i a down-turned position at least 18 inches above the floor and covered with a 24 mesh corrosion resistant screen,

6. be valved to permit test pumping and control of each well,

7. have all exposed piping, valves and appurtenances protected against physical damage and freezing,

8. be properly anchored to prevent movement, and

9. be protected against surge or water hammer.

b. The discharge piping should be provided with a means of pumping to waste, but shall not be directly connected to a sewer.

3.2.7.4 Pitless well units

a. The reviewing authority must be contacted for approval of specific applications of pitless units.

1. be shop-fabricated from the point of connection with the well casing to the unit cap or cover,

2. be threaded or welded to the well casing,

3. be of watertight construction throughout,

4. be of materials and weight at least equivalent and compatible to the casing,

5. have field connection to the lateral discharge from the pitless unit of threaded, flanged or mechanical joint connection, and

6. terminate at least 18 inches above final ground elevation or three feet above the 100 year flood level or the highest known flood elevation, whichever is higher, or as the reviewing authority directs.

1. access to disinfect the well,

2. a properly constructed casing vent meeting the requirements of Section 3.2.7.5,

3. facilities to measure water levels in the well (see Section 3.2.7.6),

4. a cover at the upper terminal of the well that will prevent the entrance of contamination,

5. a contamination-proof entrance connection for electrical cable,

6. an inside diameter as great as that of the well casing, up to and including casing diameters of 12 inches, to facilitate work and repair on the well, pump, or well screen, and

7. at least one check valve within the well casing or in compliance with requirements of the reviewing authority.

d. If the connection to the casing is by field weld, the shop-assembled unit must be designed specifically for field welding to the casing. The only field welding permitted will be that needed to connect a pitless unit to the casing.

3.2.7.5 Casing vent

Provisions shall be made for venting the well casing to atmosphere. The vent shall terminate in a downturned position, at or above the top of the casing or pitless unit in a minimum 1 ½ inch diameter opening covered with a 24 mesh, corrosion resistant screen. The pipe connecting the casing to the vent shall be of adequate size to provide rapid venting of the casing.

3.2.7.6 Water level measurement

a. Provisions shall be made for periodic measurement of water levels in the completed well.

b. Where pneumatic water level measuring equipment is used it shall be made using corrosion resistant materials attached firmly to the drop pipe or pump column and in such a manner as to prevent entrance of foreign materials.

3.2.7.7 Observation wells

a. constructed in accordance with the requirements for permanent wells if they are to remain in service after completion of a water supply well, and

SIZE	DIAMETER (inches)		THICKNESS (inches)	WEIGHT PER FOOT (pounds)
	EXTERNAL	INTERNAL		PLAIN ENDS (calculated)	WITH THREADS AND COUPLINGS (nominal)
6 id.	6.625	6.065	0.280	18.97	19.18
8	8.625	7.981	0.322	28.55	29.35
10	10.750	10.020	0.365	40.48	41.85
12	12.750	12.000	0.375	49.56	51.15
14 od.	14.000	13.250	0.375	54.57	57.00
16	16.000	15.250	0.375	62.58
18	18.000	17.250	0.375	70.59
20	20.000	19.250	0.375	78.60
22	22.000	21.000	0.500	114.81
24	24.000	23.000	0.500	125.49
26	26.000	25.000	0.500	136.17
28	28.000	27.000	0.500	146.85
30	30.000	29.000	0.500	157.53
32	32.000	31.000	0.500	168.21
34	34.000	33.000	0.500	178.89
36	36.000	35.000	0.500	189.57