SECTION 02520
PUBLIC 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 A100 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 airmud rotary machine.
B. Cabletool or solely mudrotary 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 downhole 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. Air
b. Water
c. Mud
d. 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