AMERICAN SAMOA POWER AUTHORITY

Transcription

1 AMERICAN SAMOA POWER AUTHORITY A Scope of Work for Construction Management Supervision of Directionally Drilled Wells for American Samoa Power Authority. For the Benefit of the Territory of American Samoa This project will benefit the water supply on the Island of Tutuila in the Territory of American Samoa. The project will focus on improvements to the ASPA-owned water supply as stipulated under USEPA Administrative Orders. Submitted by the American Samoa Power Authority December 2016

2 Scope of Work (SOW) Outline Proposed Wells nos. 9, 10, 11, 12 and 153 Drilling Project. 1. Project Background: This project involves the drilling of five (5) new directional wells in the Island of Tutuila in American Samoa. Some of the existing wells on Tutuila Island have chloride levels exceeding EPA minimum standards and some are under the influence of surface water contamination. Groundwater under the influence of surface water contamination (GUDI wells) is a critical issue on Tutuila Island and is the reason for the Boil Water Notice issued for affected areas. The American Samoa Power Authority (ASPA) is in urgent need of more good water sources to remove the BWN and also have better water supply coverage with areas of low pressure and supply shortage. The topography in American Samoa is very steep, some areas are very hard to access and areas easily accessible to drilling are not recommended due to dense residential settlements and Right of Way issues and close proximity to the ocean. Hence directional drilling is recommended to tap into new groundwater sources without need of mass excavation or delays in construction work from land rights issues and also to keep the extraction point far away from the coast. 2. Scope of Services Description This SOW covers the Construction Management supervision for the directional drilling of five (5) new directional wells. The well locations and details are described in Section 3 of this document. The tasks and services required of the Construction Manager for this project is outlined below. A. Construction Manager Responsibilities: 1. Ensure and organize that all standard erosion control measures (e.g. silt fencing, barricades, retaining walls and silt ponds) on project site are in place to control any runoff and sedimentation during construction works. 2. Ensure safety procedures are in place and that employees have and are wearing Personal Protective Equipment (PPE) onsite, as well as conduct safety briefings. All onsite incidents must be reported by CM to the Project Engineer and to ASPA Safety. 3. The CM is expected to have background experience in Directional Drilling and can assist with reviewing and making recommendations on the procurement of tooling and drilling supplies for directional drilling and give feedback and assistance during construction activities. 4. The CM is to provide a QA/QC plan to ASPA and ensure implementation of the QA/QC Plan and that the driller follows standard drilling standards/procedures for directional drilling. 2

3 5. Document all drilling works carried out on site and must produce a daily report for all drilling works and construction work on site. Weekly reports must be submitted to project manager and project engineer at the beginning of the new week and month reports to USEPA must be prepared and submitted to Project Manager for review on the first week of the new month prior to submitting to USEPA. 6. Record and keep track and stock of all materials ordered and materials used on site and expenses. A record of all drilling materials received and materials used during construction must be recorded in the weekly progress reports. All tooling and supplies must be accounted for. A final stock take of materials must be carried out by the CM after construction work and signed off by Project Engineer. 7. Collect and record drill cuttings during drilling and produce a lithology log for new well at the end of drilling. The CM is expected to have background knowledge of the geologic formations in the project area and must have sound hydrogeologic knowledge to contribute to drilling works. 8. Ensure that the neat cement for grouting has a consistent density and that the process and procedures for installing the wells grout seal are correct and efficient and make recommendations if there s any for better procedures for installing. 9. Test and record chloride concentrations for the new well and produce salinity profile for the new well. Also, carry out water quality sampling and arrange with ASPA Water Quality operations for baseline tests and any other necessary tests to ensure a good quality source. 10. Assist and complete any other necessary tasks given by the Project Engineer or Project Manager. 11. Must have input in reverse circulation techniques and assist as required. 12. Submit a Final Well Drilling Construction Management Report no less than 30 working days at the end of directional drilling works to the Project Engineer. A copy of well drilling and construction photographs, reports and other related materials must be handed over to ASPA-ESD with submission of CM s final report. 3. PROJECT LOCATION This project will have five different well site locations, Well 9 will be drilled in the Pago Pago area, Well 10 will be drilled in the Aua area, Well 11 will be drilled in the Lauli i area, Well 12 will be drilled in the Alega area and Well 153 will be at Aoa area. Below are the site description and location maps. A. Proposed New Well Site # 9 Pago Pago Drilling Works This proposed site is at elevation 290 ft. amsl and is 1,203 ft. (0.23 mi) from Vaipito Reservoir, 1,089 ft. (0.20 mi) from south east of Well 183 in Vaipito. The well site is 1,203 ft. (0.23 mi) from the main road and the closest distance to the coast on the Fagasa side is 4,812 ft. (0.91 mi) and 4,630 ft. (0.88 mi) on the Pago Pago harbor side. This Pago Pago well will help provide additional water to the canneries. This well will be angle drilled at an angle of 50 o from ground level towards the easterly direction (refer to Figure 1) down to a depth of 50 ft. below groundwater table and will have casing from ground 3

4 level to 100ft below surface level in the vertical direction, hence will require at least 160 ft. of casing if drilled at the proposed angle. The well is expected to produce 150 gallons per minute (gpm). Figure 1 shows the proposed well location. The existing road to Well # 9 site will need to be widened and graded from the main road leading up to the project area to allow the drilling rig and other vehicles to access the new drilling site. The 100 x 100 ft. drilling project area requested for drilling works will allow for maneuvering the drill rig into/and around the project area, and for casings, equipment, water tank, drilling crew vehicle and any other necessary materials needed on site during drilling works. After, the drilling site has been cleared and prepared, we will then select a suitable drilling spot within the 100 x 100 ft. project area. The design for this well is shown in Appendix B of this document. A Construction Manager (CM) that has been hired via ASPA s competitive bidding process will be supervising the directional drilling of this well to ensure Quality Control and Assurance. When drilling works have been completed, the well must undergo pumping test procedures (see Appendix C) to determine the sustainable yield. Once a sufficient yield has been obtained from this well, the Well Connections Project will then commence to prepare our well heads and fence off the area for the well. Figure 1: Location of Proposed Well 9 in PagoPago B. Proposed New Well Site # 10 Aua Drilling Works This proposed site is at elevation 285 ft. amsl and is 101 ft. (0.02 mi) from the main road and the closest distance to the coast is 2,249 ft. (0.43 mi). This site is 233 ft. (0.044 mi) 4

5 North East of the Aua 100,000 gallon tank. The new well site is 259 ft. (0.049 mi) from operational Well 99, and 626 ft. (0.19 mi) from operational Well 97. Figure 2: Location of Proposed Well 10 in Aua Wells 99 and 97 are high in chloride and we aim to shut down these two wells if the new Aua well is successful. This well will be angle drilled at an angle of 50 o from ground level towards the north easterly direction (refer to Figure 2) down to a depth of 50 ft. below groundwater table and will have casing from ground level to 100ft below surface level in the vertical direction, hence will require at least 160 ft. of casing if drilled at the proposed angle. The well is expected to produce 100 gallons per minute (gpm). This new well will contribute water to Aua area and eastern side. Figure 2 shows proposed well location. 5

6 The existing road to Well # 10 site will need to be widened and graded from existing road leading to the project area to allow the drilling rig and other vehicles to access the new drilling site. The 100 x 100 ft. drilling project area requested for drilling works will allow for maneuvering the drill rig into/and around the project area, and for casings, equipment, water tank, drilling crew vehicle and any other necessary materials needed on site during drilling works. After, the drilling site has been cleared and prepared, we will then select a suitable drilling spot within the 100 x 100 ft. project area. The design for this well is shown in Appendix B of this document. A Construction Manager (CM) that has been hired via ASPA s competitive bidding process will be supervising the directional drilling of this well to ensure Quality Control and Assurance. When drilling works have been completed, the well must undergo pumping test procedures (see Appendix C) to determine the sustainable yield. Once a sufficient yield has been obtained from this well, the Well Connections Project will then commence to prepare our well heads and fence off the area for the well. C. Proposed New Well Site # 11 Lauli i Drilling Works This proposed site is at elevation 91 ft. amsl and is 2,702 ft. (0.51 mi) from the main road and the closest distance to the coast is 2,317 ft. (0.44 mi). There is a small perennial stream that runs 150 ft. (0.028 mi) from the project boundary area. This well will be angle drilled at an angle of 55 o from ground level towards the north westerly direction (refer to Figure 3) down to a depth of 30 ft. below groundwater table and will have casing from ground level to 100ft below surface level in the vertical direction, hence will require at least 160 ft. of casing if drilled at the proposed angle to prevent any surface infiltration. The well is expected to produce 70 gallons per minute (gpm). Figure 3 shows proposed well location. The existing road to Well # 11 site will need to be widened and graded from existing road leading to the project area to allow the drilling rig and other vehicles to access the new drilling site. The 100 x 100 ft. drilling project area requested for drilling works will allow for maneuvering the drill rig into/and around the project area, and for casings, equipment, water tank, drilling crew vehicle and any other necessary materials needed on site during drilling works. After, the drilling site has been cleared and prepared, we will then select a suitable drilling spot within the 100 x 100 ft. project area. The design for this well is shown in Appendix B of this document. 6

7 Figure 3: Location of Proposed Well 11 in Laulii A Construction Manager (CM) that has been hired via ASPA s competitive bidding process will be supervising the directional drilling of this well to ensure Quality Control and Assurance. When drilling works have been completed, the well must undergo pumping test procedures (see Appendix C) to determine the sustainable yield. Once a sufficient yield has been obtained from this well, the Well Connections Project will then commence to prepare our well heads and fence off the area for the well. D. Proposed New Well Site # 12 Alega Drilling Works This proposed site is at elevation 135 ft. amsl and is 537 ft (0.10 mi) from the main Alega road and the closest distance to the coast is 579 ft (0.11 mi). 7

8 Figure 4: Location of Proposed Well 12 in Alega. This well will be angle drilled at an angle of 55 o from ground level towards the northern direction (refer to Figure 4) down to a depth of 40 ft. below groundwater table and will have casing from ground level to 100ft below surface level in the vertical direction, hence will require at least 160 ft. of casing if drilled at the proposed angle. The well is expected to produce 60 gallons per minute (gpm). This new well site is located on the eastern side of Tutuila Island as shown on Figure 4, and if successful will contribute to alleviating water pressure, water quality and supply issues on the East side. 8

9 The existing road to Well # 12 site will need to be widened and graded from existing road leading to the project area to allow the drilling rig and other vehicles to access the new drilling site. The 100 x 100 ft. drilling project area requested for drilling works will allow for maneuvering the drill rig into/and around the project area, and for casings, equipment, water tank, drilling crew vehicle and any other necessary materials needed on site during drilling works. After, the drilling site has been cleared and prepared, we will then select a suitable drilling spot within the 100 x 100 ft. project area. The design for this well is shown in Appendix B of this document. A Construction Manager (CM) that has been hired via ASPA s competitive bidding process will be supervising the directional drilling of this well to ensure Quality Control and Assurance. When drilling works have been completed, the well must undergo pumping test procedures (see Appendix C) to determine the sustainable yield. Once a sufficient yield has been obtained from this well, the Well Connections Project will then commence to prepare our well heads and fence off the area for the well. E. Proposed New Well Site # 153 Aoa Drilling Works This proposed site is at elevation 185 ft. amsl and is 187 ft. (0.035 mi) from the main road and the closest distance to the Aoa coastline is 1806 ft. (0.34 mi) towards the Aoa coastline and 2665 ft. (0.50 mi) towards the Amouli coastline. This new well will be angle drilled at an angle of 60 o towards the central part of the island to target a more favorable hydrogeological area down to a vertical depth of 235 ft. and install casing from ground level to 100 ft. below surface level in the vertical direction. Angle drilling this well at 60 o will move the extraction point at least another 400 ft. towards the central part of the island. By drilling towards the south eastern side of the island at the proposed angle, ASPA will be able to tap into the thicker part of the freshwater lens further inland and move our extraction area further away from the coast thus reducing the risk of saline up-coning. The existing road to proposed Well 153 will require road works to widen the access path up to the tank site area. The existing security fence around the tank site area will be removed in some parts to allow for more room and space for project construction works. After completion of the project, the fence will be re-installed. 9

10 Fig 5: Location of proposed well in Aoa. After, the drilling site has been cleared and prepared, we will then select a suitable drilling spot within the 100 x 100 ft. project area. The design for this well is shown in Appendix B of this document. A Construction Manager (CM) that has been hired via ASPA s competitive bidding process will be supervising the directional drilling of this well to ensure Quality Control and Assurance. When drilling works have been completed, the well must undergo pumping test procedures (see Appendix C) to determine the sustainable yield. Once a sufficient yield has been obtained from this well, the Well Connections Project will then commence to prepare our well heads and fence off the area for the well. 4. KEY PERSONNEL William Spitzenberg, Chief Water Engineer; Joachim Fong, ESD Manager; Katrina Mariner, Project Engineer; Ioana Uli, Procurement Manager; Taylor Savusa, Water Operations Manager; David Addison, ASPA Archaeology. 5. KEY PARTNERS/AGENCIES AS-EPA and US-EPA are ASPA s key partners in this endeavor. ASPA will also work closely with the AS Department of Marine and Wildlife Resources, the Department of Commerce, the Historic Preservation Office and other government agencies and private interest groups that wish to participate. 10

11 6. ADMINISTRATION The procurement of materials will be the responsibility of the ASPA Procurement Manager. All purchases will be approved by EPA, the Executive Director and the ASPA Board of Directors. Construction of wells will be overseen by Project Manager and Engineer. Administrative tasks will be overseen by ASPA s Grants Manager. Administrative tasks will include, but not limited to tracking financial expenditures, financial reporting and project status appraisal for US-EPA. 7. ATTACHMENTS Appendix A: Directional Well Design. Appendix B: Pumping Test Procedures. 8. PROJECT MANAGEMENT As stipulated by EPA, the project will be managed by William Spitzenberg, P.E., ASPA s Sr. Water Engineer. 10/14/14 02/27/15 Signed: William E. Spitzenberg, Arizona P.E

12 AMERICAN SAMOA POWER AUTHORITY Appendix A: Directional Well Design. 12

13 Ground Elevation 12" hole to 160' 12" casing as needed Neat cement seal 10" casing if needed 8" hole to required depth 8" casing as needed 6" casing to required depth as needed perforated Note: This well will be drilled down to 50 ft. or less (depending on formations) below water table. The construction of the well and the size of the casings used will depend on the formations and information obtained from drilling. Final trajectory and direction of angled well will be surveyed after construction. Well ID 9 Pago Pago (50 Angle Well) Scale: Scale To Fit

14 Ground Elevation 12" Hole to 140'. 12" casing will be pulled out after pumping in cement. Neat cement seal 10" casing if needed 8" casing as needed 6" casing as needed Perforated Note: This well will be drilled down to 50 ft. or less (depending on formation) below the water table. The construction of the well and the size of the casings used will depend on the subsurface formations and information obtained from drilling. Final trajectory and direction of angled well will be surveyed after construction. Well ID 10 Aua (40 Angle Well) Scale: Scale To Fit

15 Ground Elevation 8" Hole to 160'. 8" casing will be pulled out after pumping in cement. Neat cement seal Note: This well will be drilled down to 30 ft. or less (depending on formations) below water table. The construction of the well and the size of the casings used will depend on the formations and information obtained from drilling. Final trajectory and direction of angled well will be surveyed after construction. Well ID 11 Laulii (40 Angle Well) Scale: Scale To Fit 6" casing as needed Perforated

16 Ground Elevation 12" Hole to 160'. 12" casing will be pulled out after pumping in cement. Neat cement seal 10" casing if needed Note: This well will be drilled down to 50 ft. or less (depending on formations) below water table. The construction of the well and the size of the casings used will depend on the formations and information obtained from drilling. Final trajectory and direction of angled well will be surveyed after construction. 8" casing as needed 6" casing as needed Perforated Well ID 12 Alega (55 Angle Well) Scale: Scale To Fit

17 Ground Elevation 12" Hole to 200'. 12" casing will be pulled out after pumping in cement. Neat cement seal Note: This well will be drilled down to 30 ft. or less (depending on formations) below water table. The construction of the well and the size of the casings used will depend on the formations and information obtained from drilling. Final trajectory and direction of angled well will be surveyed after construction. 10" casing if needed 8" casing as needed 6" casing if needed Perforated Well ID 153 Aoa (60 Angle Well) Scale: Scale To Fit

18 AMERICAN SAMOA POWER AUTHORITY A. Purpose and Scope Appendix B: Pumping Test Procedures. The purpose of this procedure is to describe the process for performing pumping tests to determine the hydraulic properties of water-bearing geologic materials for the American Samoa Power Authority (ASPA). B. Background and Precautions 1. Background A pumping test is a controlled field procedure to determine the hydraulic properties of water bearing geologic units. Aquifer characteristics that may be obtained from pumping tests include hydraulic conductivity (K), transmissivity (T), specific yield (Sy) for unconfined aquifers, the storage coefficient (S) for confined aquifers, and the vertical hydraulic conductivity of confining layers. Also, the occurrence and position of recharge or impermeable boundaries can be identified. These parameters can be determined by graphical solutions and calculations as well as computerized programs. Pumping tests consist of three main phases: 1) an initial phase before pumping whereby water levels in the well are measured to determine any fluctuations that are natural (tidal) or induced by other wells 2) a pumping phase resulting in water level drawdown; and 3) a recovery phase after the pump has been turned off. Water level monitoring is conducted throughout all three phases. The pumping test regime may include the following: 1) Pre-tidal water level monitoring 2) Multiple Flow Test 3) Recovery 4) Constant Rate Test 5) Post-tidal water level monitoring During pumping, water drawdown measurements during each step may be taken at the following intervals or as specified by the onsite engineer: 1) 0 to 10 minutes: every minute 2) 10 to 20 minutes: every 2 minutes 3) 20 to 60 minutes: every 5 minutes During the recovery period, water level measurements may be recorded as follows: 13

19 AMERICAN SAMOA POWER AUTHORITY 1) 0 to 10 minutes: every minute 2) 10 to 20 minutes: every 2 minutes 3) 20 to 60 minutes: every 5 minutes 4) 60 to 120 minutes: every 10 minutes 5) 120 to 360 minutes: every 15 minutes 2. Precautions Pumping tests are generally carried out by monitoring the water level over time in the pumping well and in each observation well (if available) while the pumping well is being discharged at a constant rate. All water from the pumping well must be discharged downstream at a distance determined by the onsite engineer to prevent recharge into the well that is being pump tested. Such tests provide results that are more representative of aquifer characteristics than those obtained by other methods. They can also be used to determine the hydraulics of secondary aquifer flow. However, pumping tests require a greater degree of labor activity and expense than other methods and may not always be justified for all levels of investigation. Refer to the site-specific work plan for the duration of the pumping test, the location of the observation well (if available), and the data to be collected. Collection of measurements and documentation of data will be performed C. Equipment and Tools 1) Water pressure transducers; 2) Discharge flow meter; 3) Electronic data logger; 4) Electric water level indicator (if transducer method is not used); 5) Manufacturer s operating manuals for equipment selected above; 6) Weighted tapes with plopper (plumb bob); 7) Steel tape (graduated in hundredths of a foot); 8) Stopwatch or watch with a second hand; 9) Tape measure (graduated in tenths of a foot); 10) Semi log graph paper (if required); 11) Laptop computer; 12) Waterproof ink pen; 13) Thermometer; 14) Appropriate references; 15) Calculator; 14

20 AMERICAN SAMOA POWER AUTHORITY 16) Barometer or recording barograph (for tests conducted in confined aquifers); 17) Pumping/recovery test data forms; 18) Groundwater elevation forms; 19) Daily activity logs; 20) Any PPE listed or required in the site-specific health and safety plan (SSHASP); and 21) Any additional supplies listed in associated procedures, as needed. D. Step-by-Step Process Description 1. Pre-Operation Activities 1) Field Team 2) Drilling Crew 3) Field Team: i. Ensure permission to discharge is obtained (Permit may be required) or that a containment system is available for collecting the water that will be pumped during the test. [NOTE: This is especially important for wells that may produce contaminated water.] ii. Confirm from the site drilling crew that well installation is complete and that the equipment necessary to conduct the pumping test is deployed. [NOTE: All wells should be properly developed before testing.] iii. Obtain the pumping test equipment, appropriate operating manuals, and information on equipment modifications necessary to conduct a pumping test. iv. Check the equipment for proper functioning. v. Install a submersible or turbine pump. vi. Install a flow meter in the discharge line of the pumping well to accurately measure and monitor the volume of discharge. vii. Install sufficient pipe to transport the discharge from the pumping well away from the area to prevent infiltration of extracted water into the pumped zone. viii. Install a gate valve along with a pressure regulator on the discharge pipe to control the pumping rate. ix. Place an outlet near the well head, but past the totalizer and flow meters, for water quality monitoring and sampling. x. Ensure all gauges, transducers, flow meters, and other equipment used in conducting pumping tests are properly calibrated before use. xi. Perform any on-site zero adjustment or calibration and document those procedures. xii. Monitor and record water levels at the test site for about one (1) week before performing the test using a continuous recording device. [NOTE: 15

21 AMERICAN SAMOA POWER AUTHORITY These records establish the barometric efficiency of the aquifer. The records also help determine if the aquifer is experiencing an increase or decrease in head over time that may be caused by recharge or pumping in the nearby area or by diurnal variations.] 2. Pumping and Recovery Test Options 1) Field Team: i. Manually measure static water levels in the test well and any observation well(s) using a water level meter when all equipment has been deployed ii. Read and record the totalizer value from the in-line flow meter prior to turning on the pump. iii. Initiate pumping at a specified discharge rate and immediately begin time series water level measurements in the test and observation wells at a predetermined time zero. iv. Measure all depths to water from a designated reference marker point (measuring point). v. Continue to monitor water levels during recovery phase of the test. vi. Connect the pressure transducer to a lap top computer to monitor drawdown and recovery changes in real time. vii. Record barometric pressure during the test. [NOTE: The barometric data, as well as projected pre-test water level trends, may be applied as corrections to water level readings so that the reduced data are representative of the hydraulic response in the aquifer to pumping from the test well.] 16