B09_Amd8_-_Spec_33_11_13_-_POTABLE_WATER_SUPPLY_WELLS_0008.pdf

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POTABLE WATER SUPPLY WELLS

SECTION 33 11 13 – POTABLE WATER SUPPLY WELLS

PART 1 - GENERAL

1.1 SUMMARY

A. This Section includes the requirements for drilling, construction and testing of a new water supply well at the National Park Service (NPS) Death Valley National Park and commissioning in accordance with the requirements of the authority having jurisdiction (AHJ); the Inyo County

Department of Environmental Health (ICDEH), the California Department of Water Resources

(DWR), and the California Lahontan Regional Water Quality Control Board (LRWQCB). The supply well specified herein will consist of a final diameter of 5 inches (nominal) or larger, an open borehole well completion with a 6.625-inch-outside-diameter casing or larger, installed to top of water bearing unit.

Based on geologic conditions at the site, the supply well will be drilled using a rotary drilling method. In 2010, the U.S. Department of Energy installed another flowing artesian well into the same aquifer unit near the proposed location of the new supply well. During drilling of the 2010 well, high aquifer pressures (in excess of 6 pounds per square inch at ground surface, or over 14 feet of water above ground surface) were encountered in the aquifer. The DRILLER must be prepared in advance for similar conditions occurring at the location of the new supply well. A well design schematic, included as Figure 1, shows proposed design depths and expected lithology. Figure 2 shows the proposed location for the new supply well.

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1.2 SUBMITTALS

A. Items to be submitted before the project

1. The DRILLER shall provide documentation they are a licensed water well driller in Califor-nia and has completed similar wells in California.

2. Work Plan: The DRILLER shall submit a Work Plan for review and approval by the COR that describes:

a) The drilling and sampling methods.

b) The traffic requirements and security measurements as required by NPS, if necessary.

c) The environmental characterization, transportation, and disposal of the drilling fluid and drill cuttings, and well disinfectant materials, if determined necessary by the COR.

d) Provide a plot plan describing the space needed for equipment, discharge of groundwa-ter, etc.

e) Provide drilling and testing schedule including mobilization and demobilization.

f) Provide description of methods to secure work area unless site is staffed for 24 hours per day for duration of project.

3. Health and Safety Plan: The DRILLER shall submit a Health and Safety Plan for review and approval by the COR. In addition, the DRILLER shall complete health and safety training as required for work at NPS facilities including a site, equipment, and emergency response ori-entation from DEVA Fire. Provide safety data sheets for all materials being brought on site.

4. Under-An-Acre Pollution Prevention Plan (UPPP): The DRILLER shall submit a pollution prevention plan, including protocols for erosion and sediment control and discharge and miti-gation of pollution from disinfectant materials, in the Denver Service Center UPPP format for review and approval by the COR and NPS.

B. Items to be submitted during the project

1. Well Design: Submit for approval all the items listed below before construction of the new supply well.

2. Well design is to include the following:

a) Drilling method and borehole size changes needed to complete nominal 5-inch-diame-ter open hole well completion.

b) Total length and depth interval of open hole completion.

c) Length, depth, diameter, and wall thickness of production casing.

d) Length, depth, diameter, and wall thickness of outside conductor casing, if used.

e) Method to be used to assemble casing (factory beveled ends, type of welding rod, weld-ing method, and number of weldment passes.

f) Length, elevation, and depth of grout below ground surface (bgs) to fill borehole annu-lus between minimum 6.625-inch-outside-diameter production casing and borehole, and between production casing and conductor casing and conductor casing and bore-hole, if conductor casing used.

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3. Flow Tests Plan

a) Provide flow control valve at top of casing stick-up. A pump will likely not be required for the well testing with anticipated artesian flowing conditions. If a pump is required, provide pump and pump column.

b) Diameter of discharge piping.

c) Size and location of flow control valves on discharge piping. Provide two valves in se-ries, in addition to the permanent flow control valve at wellhead.

d) Size, location, and specifications of in-line water flow meter.

e) Well development equipment that meets requirements of Section 3.7.

f) Discharge location and permitting requirements, as determined and approved by NPS and COR.

C. Documentation: Provide the COR with written documentation of all work activities upon com-pletion of the Work and before final payment. Documentation shall include, but is not limited to, the items listed below:

1. Daily written reports shall be submitted with information describing the Work as follows:

a) Summary of Work completed and work to be performed for next two days.

b) Subcontracted employees.

c) Equipment used, including drilling rig and sampling equipment.

d) Location of all areas in which work was conducted.

e) Well construction methods and materials.

2. Well Construction Log: Provide four copies of completed well construction log indicating all of the pertinent lengths, drilled depths, diameters, wall thickness, and other materials used to construct the test well.

3. Plumbness and Alignment Results: Summarizes the methods, procedures, and results of the plumbness and alignment test.

4. Well Development Log: Summarizes the data collected and methods used to develop the well. This shall also include documentation of the specific capacity and sand content of the well every hour during well development.

5. The DRILLER shall provide to COR a well completion log describing details of well drilling and construction materials and methods, and any other requested material required for

ICDEH and LRWQCB permits.

PART 2 - PRODUCTS

2.1 Surface Seal – A continuous surface seal will be installed to a minimum depth of beyond the drilled depth of the production casing (approximately 280 feet) using either a separate conductor casing of minimum drilled depth 50 feet, and/or against the final production

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casing, such that is meets the seal requirements set forth in DWR drilling regulations, including diametrical size, drilled depth, and grout installation requirements.

2.2 Initial borehole size will be minimum 11-inch diameter and casing will be minimum

6.625-inch outside-diameter or larger, at the driller’s discretion in order to guarantee a final nominal 5-inch-diameter open hole completion to a total drilled depth of up to 400 feet. If permanent conductor casing is used, the initial borehole size will need to be larger, minimum 16-inch diameter, to ensure minimum 3-inch annular space of seal. The casing shall be of size and construction to hold back and support the material surrounding the casing, as well as sufficient tensile strength, column, and collapse strength to withstand the stresses of the formation during drilling, construction and grouting operations.

2.3 Conductor Casing – if permanent conductor casing is used, the casing shall be minimum

¼-inch thickness for single casing or minimum No. 10 U.S. Standard Gage for double casing.

2.4 Production Casing – The final completion or inner casing shall be minimum 6.625-inch outside-diameter and be welded with continuous weldment without gaps. The welds shall be made by certified welders to the standards of ANSI/AWWA C206. Joints shall be aligned with an alignment tool, butt-welded, and watertight. Welds shall be continuous and fillets shall be as deep as the thickness of the material.

2.5 Cement Grout – Cement grout shall consist of Portland cement conforming to ASTM C

150 Type I or II. Cement grout shall be proportioned not to exceed 6 gallons of water per

94-pound sack of cement and well-mixed prior to pumping, yielding a mixture of such consistency that it can be easily pumped through a tremie pipe to ensure proper placement without bridging. Not more than 3% by weight of bentonite powder may be added to reduce shrinkage.

2.6 Drums – New drums shall be used at all times, be 55-gallon capacity and U.S. Department of Transportation-approved or an approved substitution. DRILLER to remove all containers, packaging, etc., that are brought on site.

PART 3 - EXECUTION

3.1 The DRILLER shall be responsible for:

A. Mobilizing equipment to the site.

B. Safety and security of equipment and personnel at all times.

C. Compliance with all state, county, and local laws, including traffic laws.

D. Obtain approval for proposed drilling schedule and site plan from NPS and COR.

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3.2 LOCATING THE PRODUCTION WELL

A. The production well shall be located on the site identified and approved by the OWNER’S

REPRESENTATIVE. The enclosed Figure 2 provides the proposed location for the replacement well.

3.3 DRILLING THE INITIAL DIAMETER BOREHOLE

Based on geologic conditions at the site, the production well will be drilled using a Dual Rotary or similar approved casing advance drilling method.

A. Drill a final nominal 5-inch-diameter open hole completion borehole or larger to a maximum of

400 feet drilled depth bgs or the drilled depth identified by the COR. Normally, the drilling may start with a larger diameter borehole and casing and end up with nominal 5-inch borehole at the open hole completion interval. The drilling method shall be approved by the COR. Collect grab soil samples at maximum 10-foot intervals and as directed by the COR. Final diameter of the borehole will not be less than 5 inches. Store drilling cutting samples in a solid-sided container with hinged locking lid that has COR name, test well number, and the drilled depth range of soil samples stored in each box; or use approved equivalent.

B. Drilling fluid and cuttings shall be contained and collected in a temporary pit or portable roll-off bins, such that the drilling fluid and cuttings may be removed from the site and the conclusion of the Work.

C. The well will be geophysically logged prior to completion. Geophysical logging shall include natural gamma, caliper, temperature, and fluid resistivity. The DRILLER shall prepare the borehole for logging as directed by the COREF and shall be on site to assist as required.

3.4 WELL CONSTRUCTION AND INSTALLATION

A. Assemble, weld, and install the 6.625-inch-outside-diameter steel production casing or larger as the borehole is advanced during drilling to the bottom of the borehole, advancing the well casing simultaneously. The total drilled depth of production casing shall be a minimum of approximately

280 feet, or as approved by the COR. As the borehole and casing are advanced, remove the drill cuttings and place the cuttings into a DRILLER-provided roll-off bin or excavated soil pit as specified by the COR.

B. Fill annular space between outer steel casing and borehole wall with cement grout using a side discharging conductor pipe, if a larger diameter casing is present. A conductor pipe or tremie pipe shall be lowered to the bottom of the larger diameter borehole between the steel casing and the borehole wall. The grout shall be pumped at uniform rates as the grout fills the annulus from the bottom up. Grout shall be installed continuously until the grout reaches land surface. As grout is placed, the temporary tremie pipe shall be removed from the well annulus, maintaining the tremie pipe submerged in the grout until the operation is complete. Volume of grout installed to be monitored and compared to theoretical volume required. Maintain accurate record of cement, water, and bentonite volumes used.

C. Extend the outer steel casing at least 2 feet above concrete pad and equip with flow control valve to prevent artesian flowing groundwater from flowing out of well.

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D. Install a 2-inch-diameter capped threaded access port, equipped with globe valve, at the wellhead, to allow installation of temporary standpipe for manual water level observations, as necessary.

E. A concrete pad shall be installed at the ground surface around the top of the well casing. The concrete pad shall extend a minimum of 2 feet from the outside of the well casing in all directions, be sloped away from casing, have a minimum thickness of 6 inches, and be in contact with the sanitary annular seal and be installed prior to the sanitary annular seal has set, such that the contact is water tight.

3.5 EROSION CONTROL AND ARTESIAN FLOW DISCHARGE

A. The DRILLER shall control artesian flows during well drilling and construction, such that erosion of surface soils at the wellhead is mitigated.

B. The DRILLER shall collect and/or discharge groundwater in accordance with the NPS- and COR-approved UPPP, such that significant erosion or displacement of material does not occur in the vicinity of or down-gradient of the well site.

3.6 PLUMBNESS AND ALIGNMENT

A. Conduct a plumbness and alignment test according to the procedures outlined in Appendix D of the American Water Works Association Standard for Water Wells (AWWA A100-97).

B. The maximum allowable horizontal deviation (drift) of the well from the vertical shall not exceed two-thirds of the smallest inside diameter of that part of the well being tested per 100 feet of drilled depth.

C. The maximum misalignment or “dog leg” permissible is one that will allow a 40-foot-long section of pipe, or a dummy, to pass freely through. The outside diameter of the pipe or dummy shall be no smaller than ½-inch less than the inside diameter of the casing or hole being tested.

D. If one or both of the specified tolerances are exceeded, the DRILLER shall fix or replace the well at no additional cost to the Government.

3.7 WELL DEVELOPMENT

A. Initially develop the test well by airlifting. The water shall be conveyed to an approved location near the well as determined by the COR. Development will be determined to be complete when the well produces the maximum yield of water per foot of drawdown and produces less than 100 parts per million (ppm) of fine sand or silt, as measured with an Imhoff Cone, when the well is discharged under maximum conditions of drawdown by airlifting.

B. Begin development at low flow rates and bring up the flow rate slowly over two 8-hour days.

After 16 hours of development, the flow rate should be brought up to the maximum capacity allowable by airlifting.

C. Develop the well sufficiently such that the turbidity shall be below 1 NTU. 1

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D. Notify COR of development activities each day and provide COREF the opportunity to witness and verify total suspended solids readings and water production rates and to take water quality samples and such measurements the COR may require.

E. Record the static water level in the well at the start of each day prior to pumping or airlifting. In addition, determine the 30-minute specific capacity of the well at the start of each day by airlifting or pumping the well for 30 minutes.

F. Monitor the progress of well development by taking a series of sand samples upon every startup following a rest. These samples shall be shown to the COREF. A minimum of three samples at 1 minute, 5 minutes, and 30 minutes shall be obtained from a sampling port on the pump discharge.

The sample containers, provided by the DRILLER, shall be a 1,000-milliliter minimum, wide-mouth, clear glass jar with a threaded plastic cap.

G. Upon completion of well development or achieving less than 100 ppm total suspended solids, notify the COR that the well is ready to test.

H. The well will be video inspected prior to completion. The DRILLER shall prepare the well for video inspection as directed by the COR and shall be on site to assist as required. The well must pass the video inspection prior to acceptance of the well. Any defects observed during the video inspection shall be corrected by the DRILLER at no additional cost to the Government. Three copies of the video will be provided as a Windows Media Player compatible format to the

Government in a physical and/or digital form, as determined by the Government.

I. The well shall test for all Safe Water Drinking Act (SWDA) requirements including turbidity, primary organics, secondary contaminants/general mineral, synthetic organic contaminants, volatile organic contaminants, per- and polyfluoroalkyl substances, and radionuclides).

J. After development is complete, well shall be disinfected with chlorine solution in accordance with procedure specified by AWWA C645-03 (California Code of Regulations §64583).

3.8 BACKGROUND WATER LEVEL MONITORING

A. Allow installation of water level pressure transducers, or equivalent, in the new supply well and existing wells Nevares Springs Monitoring Well #1 and Nevares Springs Deep Research Well #2 to automatically collect water levels during the pre-test background period and subsequent well testing periods. A transducer shall be installed minimum 50 feet below the static water level in

Well #1, and a transducer shall be installed in temporary standpipes at Well #2 and the new supply well.

B. Assist with collection of manual water level measurements in the new supply well and observation wells for a period of up to 36 hours before the start of the flow testing.

C. COREF will configure all dataloggers to collect water level measurements every 1 to 5 minutes or as specified by NPS or COR. COREF will download of the data from the dataloggers at the end of the background monitoring period prior to start of test pumping.

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3.9 STEP-DRAWDOWN TEST

A. Conduct a step-drawdown test to determine the pumping rate for the constant rate aquifer performance test. The step-drawdown test shall be up to 8 hours in length.

B. Furnish and install discharge piping of sufficient size and length to convey the water being pumped to the approved point of discharge without creating excess back pressure that may interfere with control of the flow rate. Install an in-line (totalizing) water meter and/or a discharge orifice with pressure manometer sufficiently sized to accurately measure the well flow rate. Install two gate or globe valves in series at the well head, in addition to the permanent flow control valve, to permit coarse and fine control of the flow rate.

C. Measure depth to water below top of casing in all wells, or in temporary standpipes, prior to testing but after dataloggers have been configured and checked for proper operation. Collect automated water level measurements from the test well at maximum 10-second intervals during the step drawdown test. COREF will configure dataloggers and pressure transducers according to the manufacturer’s instructions to collect water level measurements. Conduct the step test with four consecutive steps of increasing flow rate, each consisting of at least 90 minutes of continuous flow. The flow rates are expected to increase up to at least 200 gallons per minute. The flow rates for each step will be determined by the COREF. The flow rate will be measured with a flow meter and/or an orifice and manometer and controlled with two gate-valves. A constant flow rate shall be maintained for each step and valve adjustments should be frequently made to minimize pumping rate deviations from the specified rate. Water level measurements shall be collected with a manual water level meter at the frequency outlined below from the start of each step from the test well.

Elapsed Time (minutes) Frequency of Measurements (minutes)

1 to 10 1

11 to 30 2

31 to 60 5

61 to 90 10

D. Measure the flow rate before collecting each water level measurement. If the flow rate changes, promptly adjust the valves to maintain a constant flow rate.

3.10 AQUIFER TEST

A. Conduct a constant rate aquifer performance test on the new supply well for 72 hours as specified by the COREF. The flow rate for the constant rate test will be determined by the COREF based on the results of the step test. Manually measure the water level in the test well at a logarithmic frequency shown below. Measure and record the flow rate before each manual water level measurement. If the flow rate changes, attempt to maintain the original constant rate by valve adjustments as necessary. Water levels should be recorded at 1-minute intervals until the readings stabilize. The flow rate shall be maintained at a constant rate throughout the duration of the flow test without interruption. It is expected that frequent valve adjustments may be required to maintain a constant flow rate. If the flow rate is not maintained at a constant rate, and the rate varies more than 5% from the specified or original flow rate, the test will be terminated by the

COREF. Should the flow test be terminated by the COREF due to failure of the DRILLER to

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maintain a constant flow rate, the flow test will be restarted, after a 24-hour recovery period, and after correcting the mechanical deficiencies, at no additional cost to the Government.

Elapsed Time (minutes) Frequency of Measurements (minutes)

1 to 10 1

11 to 30 2

31 to 60 5

61 to 120 10

121 to 180 20

181 to 360 (3 to 6 hours) 30

361 to 4,320 (6 to 72 hours) 60

B. Collect automated water level measurements from the new supply well and all observation wells at 1-minute intervals starting at the beginning of the aquifer test. The COREF will set up the datalogger according to the manufacturer’s instructions to collect water level measurements.

Download data from the dataloggers per manufacturer’s instructions. Do not disturb the sensor depth or setting during data downloads.

C. Install a 1-inch-diameter valve/spigot in the discharge pipe to collect water quality samples.

COREF will collect a sample of water from the well prior to completion of the constant rate flow test and send them to a State of California-approved laboratory for analysis.

3.11 RECOVERY TEST

A. DRILLER to manually measure the water level in the test well at a logarithmic frequency shown above. Allow COREF to collect automated water level measurements at 1-minute intervals from the test well and observation wells for at least 72 hours after the constant rate flow period has concluded.

B. DRILLER will allow up to 72 hours of recovery measurements with no cost to the Government.

3.12 CLEANUP

A. The DRILLER shall be responsible for the cleaning up the site and restoring the surface to its original condition. The DRILLER shall be responsible for containerizing drill cuttings, empty containers, cement and gravel sacks, litter and leaving the site in a good condition.

3.13 QUALITY ASSURANCE

Reference Standards: Comply with applicable provisions and recommendations of the following, except as otherwise shown or specified.

A. American Water Works Association Standards for Water Wells (ANSI/AWWA A100-20).

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B. American Water Works Association Standard for Field Welding of Steel Water Pipe

(ANSI/AWWA C206).

C. American Society for Testing and Materials Standard Test Method for Sieve Analysis of Fine and

Coarse Aggregates (ASTM C136).

D. American Society for Testing and Materials Standard Specification for Portland Cement (ASTM

C150).

E. California Water Code, as related to well drilling and construction (Water Code Division 7

Chapter 10), and California Well Standards, Combined (Bulletin 74-81 and Bulletin 74-90).

F. Safe Water Drinking Act (SWDA) for testing well

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