SECTION 02520PUBLIC WATER SUPPLY WELL DRILLING

PART 1 -GENERAL

1.01 SUMMARY

A. This section includes drilling, casing, screening, developing and testing of water wells for public water supply in Oklahoma.

B. It is anticipated that the well will be in unconsolidated material.

1.02 RELATED WORK

A. Section 01330 – Submittals

B. Section 02517 – Well House Piping

C. Section 02521 - Community Well Pumps

D. Section 02522 – Well Abandonment

E. Section 16402 – Well House Electrical

F. Section 03200 – Concrete Reinforcement

G. Section 03310 - Cast in Place Concrete (Structural)

1.03 REFERENCES

A. ASTM A53 – Standard Specification for Pipe, Steel, Black and Hot Dipped, Zinc Coated Welded and Seamless.

B. ASTM A139 – Standard Specification for Electric-Fusion (Arc)-Welding

C. AWWA C200 – Standard for Steel Water Pipe – 6 in. and Larger.

D. AWWA C206 – Standard for Field Welding of Steel Water Pipe.

E. AWWA C654 – Standard for Disinfection of Wells.

F. ASTM C33 – Standard Specification for Concrete Aggregates.

G. ASTM C150 – Standard Specification for Portland Cement.

H. ASTM D 1784 – Standard Specification for Rigid PVC Compounds and Chlorinated PVC Compounds

I. ASTM D2837 – Standard Test Method for Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials

J. ASTM F480 – Standard Specification for Thermoplastic Well Casing Pipe and Couplings Made in Standard Dimension Ratios (SDR), SCH 40 and SCH 80.

K. ASTM A276 – Stainless steel well screen

L. NSF61 – Drinking Water System Components – Health Effects

M. NSF14 – Plastic Piping System Components and Related materials

N. American Water Works Association (AWWA) publication A-100 and appendices.

O. Oklahoma Department of Environmental Quality (DEQ)

P. Oklahoma Water Resources Board (OWRB)

Q. Underwriters Laboratory (UL)

R. National Sanitation Foundation (NSF)

S. American Petroleum Institute (API)

T. American Society for Testing and Materials (ASTM)

1.04 SUBMITTALS

A. Conform to Section 01330 – Submittals

B. Type of drilling equipment

C. Well drilling rig operator license number

D. Drilling mud and plan for use (if applicable)

E. Well screen and method of installation

F. Gravel, sand pack material and method of installation

G. Surface casing

H. Well casing and couplings

I. Centralizers

J. Well house

K. Water level meter

L. Method of disinfection

M. Method of development

N. Grout and method of installation

O. Water testing lab (if applicable)

1.05 LICENSURE

A. Currently Licensed by the OWRB.

B. Be in compliance with OWRB rules.

1.06 CONFLICTS WITH STATE WELL CODES

A. The materials and construction methods specified herein are minimum requirements. Where the appropriate ORWB or DEQ well codes require more stringent materials or execution methods, they shall apply.

B. Notify the Project Officer of any planned deviation from these specifications before proceeding so any price changes or quantity adjustments may be made.

1.07 DRILLING EQUIPMENT

A. The drilling may be accomplished by an air rotary drilling machine, or a combination air-mud rotary machine.

B. Cable-tool or solely mud-rotary drilling machines are not allowed.

C. The equipment used shall be in good repair and be capable of drilling to a depth of 500 feet.

1.08 TYPE OF WELLS

A. Community Wells

1. Cased and screened holes in consolidated rock or unconsolidated material.

B. Test Wells

1. Preliminary holes drilled for community wells.

1.09 FINAL INSPECTION AND ACCEPTANCE

A. Minimum final yield approved by the Project Officer.

B. Test results from a laboratory showing the results of the complete test for all substances listed currently listed in the EPA National Drinking Water Standards and Secondary National Drinking Water Standards.

C. Test results from a laboratory showing two consecutive days of safe bacteriological testing following initial disinfection of the new well.

D. Copy of the well driller’s log.

E. A completed and signed copy of the Groundwater Well Completion Report (OWRB form.)

PART 2 -PRODUCTS

2.01 GENERAL APPROVED PRODUCTS

A. All materials that will come in contact with potable water must be approved by the NSF, API, UL, or AWWA for use in public drinking water supplies.

B. Made of material that that will not impart taste, odor, toxic substances or bacterial contamination to the water.

2.02 DRILLING FLUID (AIR-MUD ROTARY METHOD)

A. Conform to standard accepted well drilling practice for water wells.

2.03 SURFACE CASING

A. Steel Casing

1. Conform to ASTM A53, Grade B, Type E, electric resistance welded or Type S, seamless.

2. Each length of pipe shall be clearly marked.

a. Markings shall include manufacturers name, type of pipe, ASTM number and pipe length.

b. Mill certificates shall be supplied if the Project Officer deems the casing pipe or markings to be of questionable condition.

3. Pipe shall be new, clean and free of oil, grease, rust, or other detrimental materials and sanitized.

4. Pipe shall meet the following requirements:

a. Nominal Diameter: 14-inches

b. Thickness: 0.375-inches

c. Meet ASTM, NSF, or API specifications for water well construction.

2.04 WELL CASING

A. Steel Casing

1. Conform to ASTM A53, Grade B, Type E, electric resistance welded or Type S, seamless.

2. Each length of pipe shall be clearly marked.

a. Markings shall include manufacturers name, type of pipe, ASTM number and pipe length.

b. Mill certificates shall be supplied if the Project Officer deems the casing pipe or markings to be of questionable condition.

3. Pipe shall be new, clean and free of oil, grease, rust, or other detrimental materials and sanitized.

4. Pipe shall meet the following requirements:

a. Nominal Diameter: 8-inches

b. Thickness: 0.3125-inches

c. Meet ASTM, NSF, or API specifications for water well construction.

2.05 CENTRALIZERS

A. Provide centralizers for the surface casing, well casing, and drop pipe.

1. Surface casing: 0.375 thick and 1.5-inch wide steel straps welded to the surface casing.

2. Well casing: provide either

a. 0.3125 thick (minimum) and 1.5-inch wide steel straps welded to the casing.

b. Commercially manufactured

(1) Kwikzip, model 380, Atokan Drilling Technologies, Inc.

(2) Or approved equal.

2.06 SAFETY ROPE

A. 0.25-inch, 1200 lb test polypropylene.

1. Permanently attach to the interior of the sanitary seal.

2. Attach a safety rope to the drop pipe and drawn down tube.

3. Disinfect rope before installation using 50 ppm chlorine solution.

2.07 WELL SCREEN

A. General

1. Material resistant to damage by chemical action of ground water or cleaning operations.

2. Openings based on sieve analysis of formation and filter pack (gravel pack) materials to permit maximum transmitting ability without clogging or jamming.

a. Sufficient diameter and length to provide adequate specific capacity.

b. Aperture entrance velocity less than or equal to 0.1 feet per second.

c. Vertical velocity: less than 4 feet per second.

d. The screen manufacturer will size/design the screen based on sieve analysis of aquifer sample provided by the well driller and the required specific capacity.

B. Stainless Steel Screen

1. Continuous slot design, with outer windings and internal longitudinal bars.

2. Type 304 stainless steel conforming to ASTM A276.

3. Provide a bottom plate or wash down bottom fitting of the same material as the screen.

4. Manufacturers:

a. The Johnson Division, Universal Oil Products Company, St. Paul, MN.

b. Howard Smith of Houston, TX.

c. Or approved equal.

2.08 FILTER (GRAVEL) PACK

1. Clean, well-rounded, 95% siliceous material, smooth and uniform, free of foreign material, properly sized, washed and disinfected immediately prior to or during placement.

2. Weight loss by the acid test than 20%.

3. Gradation specified by the manufacturer of the well screen based on the gradation of the submitted water bearing formation.

4. Disinfected by submersion in a chlorine solution not less than 50 ppm of available chlorine.

a. Disinfect immediately prior to or during placement

5. Submit

a. The manufacturer's gravel pack gradation recommendation for each screen size.

b. The weight loss by the acid test.

2.09 GROUT

A. Surface Casing: When the opening between the surface casing and the side of the bore hole annular opening is:

1. Annular space of 1.5 inches:

a. Cement that conforms to ASTM Standard C-150.

b. Water not over 6 gallons per 94 lb. sack of cement.

c. additives may not be used to increase the cements fluidity.

2. Annular space greater than1.5 but less than 4 inches:

a. Concrete Grout

(1) Ratio not more than one part sand to one part cement.

(2) Water not over 6 gallons per 94 lb. sack of cement.

b. Annular space Greater than 4 inches:

(1) Ratio not more than one part sand to one part cement.

(2) Water not over 6 gallons per 94 lb. sack of cement.

(3) ½-inch or smaller gravel may be added.

B. Well Casing

1. Bentonite Grout

a. High-solids bentonite grout and water mixture with 20 percent solids mixed and placed in accordance with the manufacturer’s written instructions.

b. Swelling bentonite clay 10% minimum.

c. Conventional bentonite drilling clay and water mixtures are not allowed.

2.10 WELL FLOOR

A. Reinforced concrete 3,000 psi minimum.

B. 6-inches thick (minimum).

C. Place over 6-inches of mechanically compacted sand.

1. Compact to 95% of maximum density.

D. Extend minimum of 24 inches from the outside of the well casing in any direction.

E. Extend at least 6 inches above final grade.

F. Slope 1/8-inch per foot (minimum) away from casing toward floor drain.

G. Slope finished ground away from well floor 1:10 for a minimum of 10 feet in all directions.

H. Provide drainage so there is no standing water within 20 feet of well head.

2.11 WELL HOUSE

A. Base: 8 ft. by 8 ft.

B. Height: 8 ft.

C. Doorway: 5 ft. by 3 ft.

1. Provide weather stripping.

2. Hinges: heavy duty.

3. Door handle: freezer type door handle with inside push rod.

D. Insulation: 1-inch thick foam.

E. Body: Fiberglass with gel coat.

F. Sliding Window: 2 ft. by 2 ft.

G. Manufacturer: KBK Industries (www.kbkfiberglass.com/WellHouses.html).

H. Water Level Meter

1. Battery operated

2. 500 foot reel

3. Tape marked in feet and 1/10ths of feet

4. Stainless steel submersible probe ½ -inch in diameter

5. Provide carrying case

6. Solinst Model 101 or approved equal.

PART 3 -EXECUTION

3.01 SCOPE OF WORK

A. Proposed Well #3

1. Drill well at the location staked by the Project Officer.

2. Construct, test, and disinfect the well in strict accordance with these specifications.

3. Complete the well including all controls, piping, chemical feed pump, and appurtenances so that it is approved and ready for operation before starting work on the existing well #2.

4. Provide well house

5. Provide water level meter

6. The expected operating capacity is 125 gpm.

a. Pump test the well at 1.5 times the operating capacity.

B. Existing Well #2

1. Location is shown on the Drawings.

2. Notify the owner 72 hours in advance of starting work.

3. Remove existing pump and drop pipe.

4. The expected operating capacity is 100 gpm.

a. Pump test the well at 1.5 times the operating capacity.

5. Install a new pump as specified in Section 02521 - Community Well Pumps.

6. Disinfect the well in strict accordance with these specifications.

3.02 GENERAL

A. Locate all existing underground utilities.

B. Permanently prevent contaminated water or water with undesirable physical or chemical characteristics from entering the well.

1. This includes water contaminants entering the well through the opening made by the Contractor during drilling operations or entering the stratum from which the well draws its water supply.

2. Take all necessary and practical precautions to prevent contaminating or polluting substances from entering the well either through the opening or by seepage through the ground surface.

C. Provide water with at least 50-ppm chlorine during well drilling and development.

D. Wash all drill pipes, bits, and any other drilling equipment used down-hole with water containing at least 50-ppm chlorine before drilling operations begin.

E. Locate wells as shown on the plans or staked by the Project Officer.

F. Drill wells to the depth specified, unless otherwise approved by the Project Officer.

1. If satisfactory yield is obtained at a lesser depth, terminate drilling and develop at that depth.

3.03 DRILLING

1. Surface Casing

2. Drill the annular opening at least 3 inches wider than the outside diameter of the surface casing (including couplings) to accommodate the sanitary grout seal.

3. Depth of annular space:

a. From the ground surface a depth of 20 feet, unless additional depth is necessary due to the character of the formation, type of aquifer(s)

(1) Project Officer to approve, in advance, any additional depth.

B. Well Casing:

1. Drill the annular opening at least 3 inches wider than the outside diameter of the well casing (including couplings) to accommodate the sanitary grout seal and/or filter pack.

C. Approved method

1. Rotary or reverse rotary using:

a. Airb. Waterc. Mudd. Foam

2. Drilling Fluid Properties and Tests: Meet current AWWA - A110-06 Wells requirements.

3.04 SAMPLING OF FORMATIONS

A. General

1. Samples:

a. Do not wash samples.

b. Keep samples in cloth bags.

(1) Each bag should contain 1.1 lbs. of material (minimum.)

(2) Tag each bag with the well location, depth of sample, type of sample, and date collected.

c. Provide Project Officer with samples as the drilling progresses.

d. If directed by the Project Officer, collect and lay out samples of each stratum encountered during drilling for inspection and verification of the well log.

2. Sample every 10 feet maximum and at every change in formation.

a. Take particular care when sampling water bearing formations.

(1) Take a representative sample of the aquifer of sufficient volume to be analyzed.

(2) The manufacturer of the well screen to mechanically analysis the sample to determine the required slot size of the well screen, length, and diameter.

3.05 DRILLERS LOG

A. Maintain a complete log, setting forth the following items as they apply.

1. Reference point for all depth measurements.

2. Depth at which each change of formation occurs.

3. Depth at which the first water was encountered, when applicable to the drilling method.

4. Location and thickness of each aquifer

5. Identification of the stratigraphy and litho logy encountered in the bore hole.

6. Depth interval from which each water and formation sample was taken.

7. Depth for each bore hole diameter.

8. Depth to the static water level and observable changes with well depth.

9. Total depth of completed well.

10. Location limits of lost circulation zones.

11. Depth of the surface or sanitary seal.

12. Nominal hole diameter of the well bore, above and below the casing seal

13. Quantity, type, and mixture of the grout installed for the seal.

14. Depth, length, diameter, wall thickness, material, and the type of connection of the well casing.

15. Well screen type, diameter, wall thickness, material, aperture, type of connection, and depth interval in the bore hole.

16. Sealing off of water-bearing strata, if any, and the exact location thereof.

17. Any and all other pertinent information required by these specifications.

18. Rate of penetration and type of bit used in each portion of the well.

B. Stratigraphic Log

1. Prepare to accompany the set of drilling samples, noting:

a. Depth

b. Strata thickness

c. Litho logy using the USGS standard gradation of grain sizes, including:

(1) Size(2) Range(3) Shape(4) Smoothness(5) Rock type(6) Rate of penetration.

C. File an official construction report; using state approved form, with the designated state agency within 30 days from when well is completed.

3.06 CASING

A. General

B. Install casing in wells to a depth appropriate for the formation and minimum yield required.

C. Well protection

1. At all times during the progress of the work, protect the well to prevent tampering or the entrance of foreign matter.

2. Provide a temporary cap after setting the casing.

3. Do not leave the well unattended with out the cap in place.

4. Keep the cap in place until the well is finished.

D. Steel Casing

1. New, clean and free of oil, grease, rust, or other detrimental materials and disinfected.

a. Meet NSF 61 standard for contact with potable water.

b. Meet ASTM, or API specifications for water well construction.

2. Connect steel casing lengths with either screwed couplings or approved welds.

3. Welds:

a. Full circumferential welds.

b. Ends to be welded shall be factory cut and beveled.

c. Welding will not be allowed when the base metal temperature is below 0 degrees Fahrenheit.

d. Heat areas within 3 inches of the weld when the base metal temperature is between 0 and 32 degrees Fahrenheit.

e. Casing sections having twists, bends, offsets, and openings will not be accepted.

f. Make all joints watertight.

4. Drive shoes: use if driving the casing.

5. If the top of the casing is torch cut, grind all rough surfaces smooth.

6. Surface Casing:

a. Steel casing is required.

b. Extend 1.5 feet above finish grade and 1 foot above the top of the well floor (minimum.)

c. Extend 20 feet below existing grade.

(1) Additional surface casing may be required at the direction of the Project Officer.

d. Weld steel centralizers to casing at 20-foot intervals (but no less than 2 sets of centralizers) with 3 centralizers per set (minimum) evenly spaced around the circumference of the pipe to keep the surface casing centered in the annual space.

(1) Centralizers may be made from 1.5 inch wide metal straps, 0.375 inches thick.

(2) Centralizers may not impede grouting operations.

7. Well Casing

a. Extend the casing 3 feet above existing grade.

b. Provide centralizers at 60 foot (maximum) intervals, but not less than 2 sets of centralizers.

(1) Centralizers may be made from 1.5 inch wide metal straps, 0.315 (minimum) inches thick or purchased from a manufacturer.

E. Plumb and Alignment

1. Maximum horizontal deviation (drift) from vertical in any 100 feet of depth is 5.33 inches.

2. Conduct an alignment test on all wells after casing as per AWWA A-100-06 section 4.7.93 Alignment tolerance.

a. The test will consist of running piece of pipe 40 feet long whose diameter is 1/2 inch smaller than the inside diameter of the casing to the bottom of the well.

(1) In lieu of the pipe a dummy meeting the requirements of AWWA 100-6, Section 4.7.9.3 may be used.

b. No payment will be made for testing procedure or materials.

3. If the test pipe binds or is bent as a result of testing procedure or does not pass through the well casing freely the well will not be accepted and no payment will be made.

3.07 WELL SCREEN

A. Screen Slot Design

1. By well screen manufacturer as determined by sieve analysis or aquifer material supplied by the well driller.

B. Well Screen Dimensions

1. Length: 20 feet.

2. Diameter: 7 inches IPS (minimum) unless otherwise approved by the Project Officer.

C. Well Screen Installation

1. Place to utilize the full depth of the water-bearing formation as approved by the Project Officer.

2. Provide a centralizer on casing just above the screen so an even thickness of filter pack can be installed.

a. For screens longer than 10 feet place a centralizer at the bottom of the screen.

D. Acceptable methods for installing stainless steel well screens:

1. Pull back method

a. Provide a 1 1/2-foot section of riser pipe and neoprene type packer.

b. Packer material approved by NSF.

2. Open hole method

3. Bail down method

4. Wash down method

5. Welding the screen to the casing.

a. Diameter equal to the casing.

E. Bottom of well screen. Seal the bottom of the deepest well screen using one of the following methods

1. Attach a threaded or welded stainless steel endplate on screen.

2. Self closing valve installed at the bottom of the screen with a 1 ft thick cement plug above the valve.

3.08 FILTER (GRAVEL) PACKING

A. Use the screen manufacturer’s recommended filter pack material.

1. The manufacturer recommended filter pack material will be determined using the aquifer samples supplied by the well driller.

2. Filter pack material.

a. Well rounded.

b. 95% siliceous material.

c. Smooth and uniform.

d. Properly sized.

e. Washed and disinfected immediately before or during placement.

f. Minimum thickness of filter pack: 3 inches.

g. Maximum thickness of filter pack: 12 inches.

h. Extend 20 feet above the highest slot in the well screen.

3. Artificial filter packing will be placed in the well by either the Tremie or the reverse-circulation methods in a manner that will not allow hydraulic separation.

4. Free dropping of the filter pack material into the drill hole from the ground surface will not be allowed.

5. Install in one continuous operation throughout each screened interval.

6. Artificial filter pack shall be placed from the bottom of the well to a point 20 feet above the upper most slots in the screen.

7. Disinfect filter pack by adding 1 lb of 65 percent available chlorine as pelletized tablets or liquid water mixture to achieve 50 ppm free chlorine to 1 yd3 of gravel pack during placement.

8. The Project Officer may direct that the annular space from 20 feet above the upper most screen slot in the well to 20 ft below the surface be filled with gravel pack or cement or bentonite grout.

3.09 SEALING

A. Seal unsuitable shallow aquifers and/or shallow unstable soil formations with steel casing and swelling bentonite clay.

3.10 GROUTING

A. Pump grout under pressure from the bottom of the annular space to the surface.

B. Place grout in a single uninterrupted operation.

C. Minimum thickness of grout seal is 1-1/2 inches.

1. Surface Casing:

a. Grout from the surface to bottom of the surface casing.

b. Cement or Concrete grout as required.

2. Well Casing:

a. Grout as shown on the detail drawings or as approved by the Project Officer

b. Bentonite clay grout as required.

D. No work on the well will be allowed within 72 hours after completion of grouting.

3.11 WELL DEVELOPMENT

A. Develop the well using a method that extracts the maximum practical quantity of drilling mud, fine sand, silt or other fine material.

1. Maximum allowable sands and fine material: less than or equal to 5 ppm (by weight) during a 2 hour pumping cycle.

2. Maximum allowable turbidity of less than 10 NTU under all conditions.

a. Failure to meet the turbidity requirement may cause the well to be abandoned by fault of the Contractor.

3. Development by continuous over pumping shall not be allowed.

B. Acceptable development methods include surge plungers, compressed air or high velocity jetting.

1. Bailing or pumping is not acceptable.

2. Compressed air must be delivered at a minimum rate of 75 cfm at a minimum pressure of 100 psi.

C. Conduct development to prevent settlement of the stratum above the water bearing formation.

D. High velocity jetting with phosphates may be required.

1. Follow established procedures for this type of development.

3.12 TESTING FOR YIELD AND DRAW DOWN

A. Proposed Well #3

1. Pump at 188 gpm (1.5 times the proposed production rate of 125 gpm.)

B. Existing Well #2

1. Test pump after well #3 is complete and on line.

2. Pump at 150 gpm (1.5 times the proposed production rate of 100 gpm.)

C. Contact Project Officer two working days prior to the start of test pumping.

D. Do not begin test pumping until development is complete and accepted by the Project Officer.

E. Provide all necessary labor, equipment, materials and power required for test pumping.

1. Supply measuring equipment to determine water levels and the rate of pump discharge to the nearest 0.1-foot and 1-gpm.

a. Equipment approved for water level measurements: electrical probes or an air line.

b. Equipment approved for flow measurements are a 50 gal barrel, weirs, or calibrated meters.

2. Provide all piping necessary to convey water away from test pump site.

F. Test pump wells at the rate specified by the Project Officer based on the estimated well capacity.

G. Do not use the actual pumps to be installed in the well for the test pump operation.

H. Duration of draw down test

1. Pump until at least six hours after the water level draw down stabilizes in the well or 24 hours, which ever is less.

I. Take draw down measurements from well #2 during the testing of well #3.

1. Record the measurements (drawn down and recovery) at the same frequency and accuracy as well #3

2. Provide data to the Project Officer.

J. Take draw down measurements from well #1 during the test pumping of well #2.

1. Record the measurements (drawn down and recovery) at the same frequency and accuracy as well #2

2. Provide data to the Project Officer.

K. Take draw down and pump discharge measurements every 5 minutes for the first half-hour.

L. Take draw down and pump discharge measurements every 10 minutes for the remainder of the test.

M. Start recording recovery measurements immediately upon completion of test pump and continue for four hours or until the static water level is within 1 inch of initial static water level which ever is less.

1. Take recovery readings every minute for the first 10 minutes.

2. Take recovery readings every 5 minutes for the remainder of the first hour

3. Take recovery reading every 20 minutes for the remainder of the test.

N. Take water samples for field chemical analysis test after test pumping.

O. Remove all temporary-pumping facilities at the conclusion of test pumping.

P. Submit test pump results to the Project Officer within 5 days of completion.

1. Include the following additional information.

a. Test pump capacity-head characteristics and overall efficiency.

b. Static water level and water level at design pumping rate.

c. Depth of test pump setting.

d. Time of starting and ending each test cycle.

e. Zone of influence for the well

3.13 DISINFECTION

A. Disinfect as per AWWA 100-06, Section 4.9 Well Disinfection.

B. Disinfect drilling equipment and casing by washing with a 50 ppm free chlorine solution prior to drilling or placing casing.

C. Filter Pack

1. Disinfect filter pack by adding 1 lb of 65 percent available chlorine as pelletized tablets or liquid water mixture to achieve 50 ppm free chlorine to 1 yd3 of gravel pack during placement.

D. After test pumping and construction is complete, thoroughly clean the well of all foreign material (i.e. cement, oil, grease, joint dope, scum, etc.)

E. Disinfect well with a liquid chlorine solution.

1. Prepare solution prior to injection into well.

2. Mix volume and strength such that a minimum concentration of 50 ppm of free residual chlorine is obtained in all parts of the well for a minimum of 12 hours after injection.

3. Flush casing above static water level with solution.

3.14 CHEMICAL AND BACTERIOLOGICAL ANALYSIS

A. Take two bacteriological samples from each well.

1. Sample immediately after disinfection and flushing of each well.

2. Take the second sample 24 hours after the first sample.

B. Submit bacteriological samples to State Department of Health or Indian Health Service approved lab.

1. Provide copy of results within 10 days of receipt of the report.

2. If a sample tests positive, notify Project Officer immediately and repeat chlorination of the well and the sampling procedure listed above until two consecutive samples from each well test negative.

3. Take water sample for chemical analysis.

4. Conform to sampling and preservation requirements of laboratory.

5. Parameters to be analyzed:

a. The following is a list of most of the parameters to be analyzed; however, the entire list of parameters to be measured must meet the current National Primary Drinking Water Standards list determined by the EPA.

Inorganic Chemicals1. Antimony 2.   Arsenic3.  Asbestos (fiber >10 micrometers) 4.   Barium5. Beryllium 6.   Cadmium7.  Chromium (total) 8.   Copper9.  Cyanide (as free cyanide) 10. Fluoride11. Lead 12. Inorganic Mercury13. Nickel 14. Nitrate (measured as Nitrogen)15. Nitrite (measured as Nitrogen) 16. Selenium

17. Thallium  Organic Chemicals

18.  Acrylamide 19.  Alachlor20.  Aldicarb 21.  Aldicarb Sulfoxide22.  Aldicarb Sulfone 23.  Atrazine24.  Benzene 25.  Benzo(a)pyrene26.  Carbofuran 27.  Carbon tetrachloride28.  Chlordane 29.  Chlorobenzene30.  2,4-D 31.  Dalapon32.  1,2-Dibromo-3-chloropropane (DBCP) 33.  o-Dichlorobenzene34.  p-Dichlorobenzene 35.  1,2-Dichloroethane36.  1-1-Dichloroethylene 37.  cis-1, 2-Dichloroethylene38.  trans-1,2-Dichloroethylene 39.  Dichloromethane40.  1-2-Dichloropropane 41.  Di(2-ethylhexyl)adipate42.  Di(2-ethylhexyl)phthalate 43.  Dinoseb44.  Dioxin (2,3,7,8-TCDD) 45.  Diquat46.  Endothall 47.  Endrin48.  Epichlorohydrin 49.  Ethylbenzene50.  Ethelyne dibromide 51.  Glyphosate52.  Heptachlor 53.  Heptachlor epoxide54.  Hexachlorobenzene 55.  Hexachlorocyclopentadiene56.  Lindane 57.  Methoxychlor58.  Oxamyl (Vydate) 59.  Polychlorinated biphenyls(PCBs)60.  Pentachlorophenol 61.  Picloram62.  Simazine 63.  Styrene64.  Tetrachloroethylene 65.  Toluene66.  Total Trihalomethanes (TTHMs) 67.  Toxaphene68.  2,4,5-TP (Silvex) 69.  1,2,4-Trichlorobenzene70.  1,1,1-Trichloroethane 71.  1,1,2-Trichloroethane72.  Trichloroethylene 73.  Vinyl chloride74.  Xylenes (total)  

Radionuclides75.  Beta particles and photon emitters 76.  Gross alpha particle activity77.  Radium 226 78.  Radium 22879.  Uranium  

Microorganisms80.  Total Coliforms (including fecalcoliform and E. Coli)  

Secondary Contaminants81.  Alkalinity 82.  Aluminum83.  Chloride 84.  Color85.  Conductivity 86.  Corrosivity

87.  Foaming Agents 88.  Iron89.  Manganese 90.  Odor91.  pH 92.  Silver93.  Sodium 94.  Sulfate95.  Total Dissolved Solids 96.  Total Hardness97.  Zinc  

b. As part of the testing requirements noted above, the date, time and temperature of each sample are recorded.

C. Submit chemical analysis results to Project Officer within 30 days of completion of test pumping.

1. Submit a copy to the Project Officer.

3.15 WELL FLOOR

A. Construct a 9-foot by 9-foot by 6-inch thick concrete well floor

1. Footing 12 inch minimum.

2. Steel reinforcement: reinforce footing and floor as shown on the drawings.

3. Subgrade:

a. Excavate to a depth of 6 inches below final grade.

b. Mechanically compact

c. Back fill with imported sand and compact to 95% of maximum density.

4. Footings:

a. Excavate to grade and thoroughly compact before placing concrete.

5. Reinforcement steel:

a. Conform to Section 03200 – Concrete Reinforcement

b. Place as shown in the detail drawing.

6. Concrete:

a. Conform to Section 03310 - Cast in Place Concrete (Structural)

b. Place as shown in the detail drawings.

7. Provide a water tight joint between concrete floor and cement/concrete grout seal of surface casing.

8. Provide water tight joints between concrete floor and all electrical conduit, posts, and water lines.

9. Construct the top of the floor slab at least 6 inches above finish grade.

10. Extend the floor slab 24 inches (minimum) from the well excavation line in all directions.

11. Slope the floor slab 1/8-inch per foot away from the well casing and toward the floor drain.

12. Install 2-inch PVC floor drain and PVC drain line as shown in the Drawings.

a. Pipe to daylight.

b. Provide 1% fall in piping.

c. Provide a concrete discharge structure.

d. Sandwich #24 stainless steel mesh between two flanges at discharge.

13. Terminate the surface casing 12 inches above the top of the floor slab.

14. Terminate the well casing 24 inches above the top of the floor slab.

3.16 SANITARY SEAL

A. Seal the top of the well casing with a sanitary well seal to properly protect against entrance of contamination into the well.

3.17 WELL HOUSE

A. Place a 1.5 inch wide by ½-inch foam tape between the well house and floor slab.

B. Center well house on floor slab.

C. Bolt well house to floor slab with stainless steel anchor bolts.

1. Bolt at each corner and 12 inches on center around the perimeter.

2. Provide the owner with a ½ drive, professional quality ratcheting socket wrench and socket that will fit the bolt or nuts.

3.18 WELL HOUSE PIPING

A. Conform to Section 02514 – Well House Piping.

3.19 WELL PUMPS

A. Conform to Section 02521 - Community Well Pumps

3.20 WELL HOUSE ELECTRICAL

A. Conform to Section 16402 – Well House Electrical

3.21 UNACCEPTED DRILLED WELLS

A. Drilled wells will not be accepted due to insufficient capacity, unsatisfactory chemical or bacteriological quality, poor alignment, and loss of tools or any other cause.

B. Obtain Project Officer’s approval prior to abandoning wells.

C. Well abandonment shall be in accordance with Section 02522 – Well Abandonment.

END OF SECTION