SCOPE OF WORK: RFB 6820 ON-CALL DRILLER

Transcription

1 SCOPE OF WORK: RFB 6820 ON-CALL DRILLER RFB Exhibit A: Scope of Work On-Call Driller San Joaquin County Purchasing Department

2 CONTENTS A. GENERAL... 1 B. NOTICE FOR WORK... 1 C. SELECTION OF DRILLING METHODS... 1 D. DEFINITIONS... 1 E. WORK LOCATION... 2 F. SITE CONDITIONS... 2 G. USE OF SITE... 3 H. MOBILIZATION AND DEMOBILIZATION... 4 PHOTOGRAPHS 1. Typical Acceptable Monitoring Well and Bollards FIGURES 1. Figure 1: County Map-All Sites 2. Figure 2: Site Map-Corral Hollow Landfill 3. Figure 3: Site Map-Harney Lane Landfill 4. Figure 4: Site Map-Foothill Landfill 5. Figure 5: Site Map-North County Landfill 6. Figure 6: Bollard Detail ATTACHMENTS Attachment 1: Soil Gas Monitoring Well Specifications Figures: Figure 7: Soil Gas Well Figure 8: Soil Gas Well Probe Detail Figure 9: Soil Gas Well Enclosure Figure 10: Soil Gas Well Enclosure-Plan View Figure 11: Soil Gas Well Enclosure Detail Attachment 2: Groundwater Monitoring Well Specifications Figures: Figure: 12: Groundwater Monitoring Well Detail RFB Exhibit A: Scope of Work On-Call Driller i San Joaquin County Purchasing Department

3 SCOPE OF WORK A. GENERAL San Joaquin County Public Works Department (COUNTY) seeks an on-call drilling Contractor to install groundwater monitoring wells and soil gas monitoring wells as needed at County owned solid waste facilities. The Contractor shall comply with the work plan and construct the new monitoring wells per the construction drawings and specifications. B. NOTICE FOR WORK 1. County will provide Contractor a written and or verbal notice to start work. Work shall start within 10 working days after receipt of notice, unless mutually scheduled to a different date based on the workload of the Contractor or other factors beyond the control of the Contractor. The Contractor shall accommodate the County as much as possible based on Contractor s work schedule. Contractor shall complete work within the number of working days initially agreed in writing with the County. 2. Failure by the Contractor to finish the work within the agreed time may result in contract cancellation. In cased of contract cancellation, Contractor shall pay penalties to the County equal to the additional cost to the County to hire an outside Contractor to complete the work. C. SELECTION OF DRILLING METHODS 1. The County will provide the Contractor existing well logs of each site after the award of contract. Contractor shall choose the drilling methods to install groundwater monitoring and soil gas wells at each landfill based on the site lithology as shown in the well logs. Contractor shall notify the County of the drilling method selected 2. Contractor shall mobilize equipment by the chosen drilling method. Contractor shall charge the County for one mobilization for each project. 3. If the first drilling method chosen by the Contractor is not successful, then the Contractor may choose the other drilling method and mobilize equipment as needed. However, the Contractor may not charge mobilization for the alternate equipment. 4. Contractor shall follow other specific instructions from the County when doing work. Contractor shall call to the County s attention directives that do not, in the Contractor s opinion, fall within the scope or the work to which unit prices apply. Contractor shall make all such notifications to the County in writing. Failure to bring this to the attention of the Engineer will be considered agreement that the work requested is within the contract scope. D. DEFINITIONS 1. Engineer: The authorized representative of the County ( staff). RFB 6820 Exhibit A: Scope of Work On-Call Driller 1 San Joaquin County Purchasing Department

4 E. WORK LOCATION Work will be at the following landfills owned by the County: 1. Corral Hollow Sanitary Landfill, S. Corral Hollow Road, Tracy, CA Harney Lane Sanitary Landfill, E. Harney Lane, Lodi, CA Foothill Sanitary Landfill, 6484 N. Waverly Road, Linden, CA North County Sanitary Landfill, E. Harney Lane, Lodi, CA F. SITE CONDITIONS 1. Existing Site Conditions The existing terrain indentified in the site maps is approximate. Each landfill has perimeter roads. North County and Foothill perimeter roads have limited access during the winter months, while Corral Hollow and Harney Lanes are accessible year-round. The County will make the drilling locations accessible as much as possible at each work area. The County will schedule work when surface conditions permit access. Contractor shall bid based on accessible condition to the work areas on a dirt roadway. 2. Landfill Gas (LFG) Well installation will not include drilling in refuse; however, landfill gas (LFG) is known to travel through soil under some circumstances. When buried in a landfill, refuse and other organic material produces LFG, which is approximately 50 percent methane by volume and may contain other contaminants. LFG can move through soils, especially through sandy layers that exist at the site. The lower explosive limit of methane is 5 percent by volume. Before the start of the project, the Engineer will check the methane concentration of any confined work area. The Contractor shall verify with Engineer if the methane concentration is below the explosive limit before starting work. The Contractor may use other LFG analyzers to verify the LFG concentration in any confined work areas. Potential hazards associated with LFG are due to: Oxygen defiance in the landfill gas Combustible characteristics of landfill gas Potential for hydrogen sulfide in LFG RFB 6820 Exhibit A: Scope of Work On-Call Driller 2 San Joaquin County Purchasing Department

5 Potential hazards include: Fire Explosion Asphyxiation 3. Refuse a b Refuse is not anticipated to be excavated during well drilling. All landfills contain household refuse, demolition debris, tree trimmings, and miscellaneous refuse. To the best knowledge of the County, hazardous materials have not been disposed at any site. G. USE OF SITE 1. General 2. Contractor shall collect meal trash and other litter generated by the Contractor daily. 3. Contractor shall contain drilling mud when mud drilling. 4. Contractor shall not use site telephones. 5. The sites have perimeter fences and gates. 6. Contractor shall place a combination lock at the entrance gates of Corral Hollow and Harney Lane Landfill when working at these sites. Contractor shall place the lock in series with other existing locks. Contractor shall provide the Engineer the lock combination number before placing the lock on the entrance gate. Contractor shall remove the combination lock at the completion of each project. Key locks are not acceptable. 7. Contractor shall keep the entrance gates at Corral Hollow and Harney Lane Landfills locked during working hours. Contractor shall lock entrance gates at those sites at the end of each working day. Failure to lock gates may result in theft, vandalism or unauthorized dumping. The Contractor shall be responsible for any damages or costs to the County due to unlocked gates. 8. The County is not responsible for theft, vandalism or damage to Contractor s material and equipment left on site. 9. Water for well construction and development is available at each site from an overhead truck fill station or equivalent (See Site Maps). The Engineer will show the operation of the overhead fill station of each site. Contractor shall give the landfill staff priority for using the overhead fill station at North County and Foothill Landfill. Contractor shall bring the drill rig s water tank full on the first day for well installation. 10. Contractor shall provide drinking water for its workers. RFB 6820 Exhibit A: Scope of Work On-Call Driller 3 San Joaquin County Purchasing Department

6 11. Contractor may use the portable toilets at Harney Lane Landfill, Corral Hollow Landfill, and Foothill Landfill, and the permanent toilet at North County Landfill. 12. The Contractor is responsible for Contractor s materials and equipment. Contractor is responsible for drilling augers, rods, sampling spoons dropped, damaged or broken during drilling. 13. Smoking will be allowed only in Contractor's vehicles when located in an area not subject to fire as determined by the Engineer. Smoking materials shall be contained within Contractor s vehicle. Burning cigarettes shall not be thrown from vehicles. Failure to comply with this requirement will result in a smoking ban at the sites. 14. Site Safety a Safety Responsibility 15. Work Hours The Contractor is solely and wholly responsible for the safety of its workers and damage to his equipment. The Contractor shall take all appropriate measures for worker safety. All OSHA safety standards shall be practiced by the Contractor. The Contractor may access sites Monday through Friday excluding public holidays per the site opening schedule below. North County: 7:00 A.M. to 4:00 P.M. Harney Lane landfill, Foothill Landfill and Corral Hollow Landfill: 7:00 A.M. to 4:30 P.M Site access includes access by Contractor s workers, sub-contractors and delivery of material and equipment. Working means any time when Contractor staff is on site. 16. Coordination with Landfill Operation. The Contractor shall not inhibit or obstruct the flow of traffic or landfill operations when working at North County or Foothill Landfill. Contractor's foreman shall provide the Engineer a list of the workers that will be working on the site the first day. Contractor's workers shall park as directed by the Engineer. H. MOBILIZATION AND DEMOBILIZATION 1. Mobilization shall include: a Delivering to the landfill site and work areas all necessary equipment, tools, materials and supplies in good working order. Contractor s equipment shall be free from leaks of fuel, hydraulic fluid, and oil which may contaminate the borehole, the ground surface or drill tools. If a drill rig breaks down, the Contractor shall provide a replacement drill rig within 24 hours for the scheduled job. RFB 6820 Exhibit A: Scope of Work On-Call Driller 4 San Joaquin County Purchasing Department

7 b c d e f g Establishing a work force sufficient to commence and sustain the scope of work. Ensuring proper operation and safety of drill rigs for the drilling location. Providing the driller s job foreman with a working cell phone. Contractor shall provide the job foreman s phone number to the Engineer before the start of each project. Providing a container for the containment of construction debris and wastes, as needed. Providing hand-washing facilities for workers at the Foothill, Harney Lane and Corral Hollow landfills. Facilities available to the contractor at these sites do not include hand-washing. Maintaining a complete set of contract documents on site. Contract documents include: i ii iii Well details and specifications, Site maps Communication documents with the County regarding the particular project. 2. Failure for the Contractor to comply will result the Contractor to stop work until all needed documents are on site. 3. Demobilization shall include: a b c d Removing from the landfill site and work areas all equipment, tools, surplus materials, supplies, waste container and debris generated by the work. Distributing drill cuttings around the work area to match the existing contours as much as possible. Work shall be considered complete when all construction materials, debris, and equipment are removed from the site, and boring locations are left clean in condition. Within five workings days after installing groundwater monitoring wells, submitting the completed Well Completion Report to the State of California Department of Water Resources, with a copy of that report to the Engineer. RFB 6820 Exhibit A: Scope of Work On-Call Driller 5 San Joaquin County Purchasing Department

8 Photograph 1 Typical Acceptable Monitoring Well and Bollards N:\ContractsGen\1RFB & RFP Docs\On-Call_Driller\RFB 6820_On-Call Driller_Exhibit A-Scope of Work-Nov27.docx RFB 6820 Exhibit A: Scope of Work On-Call Driller 6 San Joaquin County Purchasing Department

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15 ATTACHMENT 1 TO SCOPE OF WORK SOIL GAS MONITORING WELL SPECIFICATIONS ON-CALL DRILLER RFB 6820 Revised November 27, 2012 RFB 6820_On-Call Driller_Soil Gas Well Specs.doc On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

16 PART I. GENERAL 1.01 SUMMARY A Section covers the installation of triple-probe soil gas monitoring well as shown on the contract figures and as specified herein. Providing soil gas wells accepted by the regulatory agencies as suitable for soil gas monitoring is of the essence in this contract SUBMITTALS A Submit sieve test results or samples of the following materials a minimum of 5 working days prior to well installation. 1 Pea Gravel B Submit drilling method to the Engineer within two (2) working days after receiving notice to proceed for a particular job QUALITY ASSURANCE A Contractor shall coordinate all construction with the Engineer. B Contractor shall maintain pipe probe identification throughout the well installation. Contractor shall not get the probe pipe mixed. C Contractor shall label each probe pipe with color coordination with respect to probe pipe depth INSPECTION A For the purpose of this section, installation refers to placing material in a borehole. Installation does not include drilling the borehole. B Installation of soil gas wells shall be in the presence of EHD inspectors. Lack of EHD inspection is cause to find the well unacceptable. C Contractor shall notify the Engineer a minimum three (3) days prior to the need for well inspection for a particular project. D The Engineer will schedule well inspection with EHD. Contractor shall not coordinate inspections with the EHD unless authorized by the Engineer. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

17 E EHD inspection hours are from 9.00 a.m. to 4.00 p.m. each working day. The Contractor shall install wells between EHD s inspection hours. 1 Contractor shall confirm with the Engineer the approximate time Contractor s crew will be ready for the first inspection for a project before 24 hours. 2 Contractor shall confirm consecutive inspections needed for the project with the Engineer based on the work progress after the first inspection. The Engineer will then schedule inspections with EHD inspector. PART II. PRODUCTS 2.01 GENERAL All materials shall be new and free of defects. Contractor shall inspect materials before installing. Contractor shall replace defective materials at no additional cost to the County PROBE PIPE Probe pipe shall be ¾ inch PVC Sch 80 flush thread COCK VALVE Cock valve shall be a ¼ inch Stopcock Valve, Hayward Industrial Products, LC12 or equivalent 2.04 POLYETHYLENE TUBE Polyethylene tube shall be ¼: OD x 1/8 ID. The color of tube shall be per the color code of shallow, intermediate, deep probe pipe PEA GRAVEL A Pea gravel shall: 1 Consist of rounded to subangular material from a natural source (not crushed). 2 Contain no limestone. 3 Comprise of maximum particle size of 3/8-inch. 4 Contain 50 to 90 percent by weight passing No. 4 Sieve. 5 Contain less than 3 percent by weight passing No. 200 Sieve. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

18 2.06 BENTONITE Bentonite shall be premium grade sodiumbentonite clay, 8 mesh granules, Benseal or approved equivalent NEAT CEMENT Neat cement shall be 6 gallons of water per 98 pound sack of cement with a 5 percent Bentonite mixture CONCRETE The concrete shall have minimum of 28-day compressive strength of 2500 psi WELL ENCLOSURE 1 Well enclosure shall be constructed as shown in the contract drawings. 2 Contractor shall: a b c Cut materials straight and square. Paint well enclsure with two coats of rust inhibitive paint, red in color. Contractor shall apply final coat in the field after placement. Drill ¼-inch diameter weep hole at the base of the enclosure. 3 Steel channel shall be 1 5/8 inch X 1 5/8 inch single channel: Unistrut or equivalent. 4 The well enclosure cover shall open and close smoothly. The Engineer will be the sole judge of smoothness of operation. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

19 PART III. EXECUTION 3.01 EXISTING SITE CONDITIONS A Contractor shall examine the areas and conditions under which work will be performed. Contractor shall notify the Engineers if site conditions are not in accordance with the Scope of Work or the specifications. Contractor shall not proceed until unsatisfactory conditions are corrected. B Contractor shall protect any existing survey monuments, groundwater wells, and bollards, other monitoring wells in or near the work. Existing items damaged by the Contractor shall be repaired or replaced by the Contractor to its original or better condition PERMITS A. Contractor shall notify underground service alert (USA) and have the work area cleared by underground utility companies before drilling. Contractor will be held liable for any damages caused by the Contractor by not following the guidelines set by USA. The Contractor shall provide the USA tickets numbers to the Engineer 24 hours before drilling. The County will notify USA as well. B. Contractor shall provide the Engineer the USA ticket number and its expiration date before drilling at each site. C. County will obtain permits for soil gas wells from San Joaquin County Environmental Health Department (EHD) DRILLING A. Drilling equipment shall be clean of contamination. Equipment will be inspected by the Engineer for fluid leaks that could mix with and contaminate site materials. Contractor shall replace contaminated equipment with acceptable equipment at no additional cost to the County. B. Contractor shall not use drilling mud or liquids. C. Contractor shall select drilling methods upon receiving notice to proceed for a particular well. Contractor shall notify the Engineer of the drill rig selected. The Engineer will provide boring logs of previously installed soil gas wells of each site. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

20 D. Contractor shall drill well borings at the staked locations by the Engineer. Contractor shall verify the well boring locations with the Engineer if any well boring stakes are missing or destroyed by livestock. E. Contractor shall remove any vegetation from the drilling area. Organic materials shall not fall into the borehole F. Drill the wells in the presence of the Engineer. G. Contractor shall coordinate drilling with the Engineer to allow the Engineer to compile a detailed written log showing the materials encountered at each depth and the time required for drilling. The Engineer will log the drilling at 5-foot intervals. The Contractor shall provide soil samples as determined by the Engineer for each drilling method. The Contractor shall adjust well construction as directed by the Engineer based on this information. H. Contractor shall drill to the depth specified. The County will not compensate for borings drilled deeper by the Contractor unless authorized by the Engineer. I. Contractor shall distribute spoils of well borings per the Engineer in the vicinity of the boring unless otherwise directed. J. Contractor shall dispose subsurface litter or wood wastes encountered during drilling in a contractor provided container, or remove it from the work area. The work area shall be left in a neat and orderly condition on a daily basis. K. Uncompleted Borings: 1 If there is an interruption in work, such as overnight shutdown or inclement weather, the Contractor shall: a b Measure and record depth of uncompleted borings at the end of the work day and again when drilling resumes. Cover the well opening with a watertight uncontaminated cover with the following methods: Contractor may leave the hollow stem auger in the boring and place the drill s drive shaft over it. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

21 Contractor may cover the boring with a ¾-inch thick 4x8 plywood or a 2ft x 2ft steel plate. Contractor shall place bentonite around plywood or steel covers if used. The plywood shall be secured in place or weighted down so that it cannot be tampered or blown away by the wind. c d Direct all surface runoff away from the work boring location. Cordon the work area with safety cones and caution tape to the satisfaction of the Engineer. 2 Contractor shall verify the depth of the well the next day by measuring with the weighted tape. If the boring has collapsed, then the Contractor shall re-drill the boring at no additional cost to the County. L. Abandoned Borings 3 If impenetrable obstructions are encountered during drilling, the Contractor shall cease drilling and promptly notify the Engineer. The Engineer will determine whether to abandon or to complete the well to the specified depth. 4 Abandoned borings shall be backfilled in the presence of the EHD inspector.with neat cement within two days PROBE PIPE ASSEMBLY A Engineer will provide the Contractor with dimensions of the probe pipes and perforated sections prior to installation. B The initial total probe pipe length shall be a minimum of two feet longer than the length indicated by the Engineer. C Contractor shall complete assembly of the probe pipe with the perforated sections per the dimensions provided by the Engineer. D Maintain the probe pipe identification throughout the work. Accurate probe pipe labeling is of the essence. Identify each probe pipe by placing colored duct tape on top of the probe pipe as shown on the Figures. E Place a PVC end cap on the top end of probe pipe and secure it by screwing SS No. 6 screws. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

22 3.05 SOIL GAS WELL INSTALLATION A General 1 Installation shall be in the presence of EHD inspector. 2 Contractor shall place items within the boring in the presence of the EHD inspector. 3 Any boring that collapses during well installation shall be re-drilled to the specified depth at no additional cost to the County. B Probe Pipe Installation 1 Measure the depth of the well drilled from surrounding grade in the presence of the Engineer and EHD inspector before probe pipe installation. 2 Insert each probe pipe carefully in the well borehole. 3 Do not bend or kink the probe pipe. 4 Probe pipes shall be to a near-straight position in the borehole. Check the the straightness of the probe pipe in the borehole with a flashlight. 5 Maintain probe pipe identification. C Backfilling 1 The depth and length of the pea gravel sampling zones may be adjusted by the Engineer based on geologic data obtained during drilling. 2 Place backfill materials in a controlled manner to avoid bridging, overfilling the boring, or damaging the probe pipes. 3 Confirm with the Engineer the required depths of sampling intervals. 4 Periodically measure depths of pea gravel backfill from the existing grade level with a weighted measuring tape. 5 Measure the final top pea gravel sampling interval depth of each pipe probe from surrounding grade with a weighted measuring tape in the presence of the EHD inspector and the Engineer. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

23 6 Place the bentonite plug as identifed in the soil gas well construction figures. 7 Measure the top depth of each bentionite plug from surrounding grade with a weighted measuring tape in the presence of the EHD inspector and the Engineer. Hydrate bentonite plug with 3 gallons of water. Allow 30 minutes for bentonite plug to hydrate. Provide the quantity of bentonite bags used for each bentonite plug to the Engineer. 8 Install well enclosure after hydrating the upper bentonite layer. If left overnight, protect the bore hole from soil falling into the hole. D Arrange the three probe pipes in the bore hole such that the pipes are in the correct order and can be easily attached to the steel channel when the enclosure is installed, E Probe Pipe Cock Valve Installation. 1 Probe pipe cock valve shall be installed after the well enclosure. 2 Cut probe pipes to install probe pipe cock valves. When installed, probe pipe cock valves shall have clearance from the top of the well enclosure lid as specified in the well enclosure details. 3 Install Polyethylene tubing inside the probe pipe. 4 Install PVC fittings on probe pipe as shown on the soil gas well figures. Apply Teflon tape on all threaded fittings. All fittings shall be secure and tight. 5 Connect Polyethylene tubing to the cock valve and then install cock valve on probe pipe. 6 Paint probe pipe cock valves per the depth of the probe pipe prior to installation as shown on the soil gas well figures WELL ENCLOSURE INSTALLATION A Brace enclosure plumb during concrete placement, until set. B Inscribe the concrete base with the designation of the well as shown on the plans. Inscription shall be neat and professional in appearance. C Once the concrete base of the enclosure has hardened, pour neat cement inside the protective enclosure to the finish grade level of the concrete base in the presence of the Engineer. When pouring cement slurry inside the enclosure, protect probes from contact with neat cement. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

24 D Clamp probe pipe to the steel channel at the identified clamping location. E Apply the final coat of paint in the field. F Well enclosure shall be labeled with the designated well number as shown on the contract figures using yellow paint. Labeling shall be by oil-based paint with brush, in a neat and professional manner with lettering a minimum of four (4) inches in height using stencils. G Well enclosures not installed to the satisfaction of the Engineer will be reinstalled at no additional cost to the County BOLLARDS A Install bollards at the location staked by the Engineer. The Engineer will determine the number of bollards for each well. Typically, there are two bollards for each well. B Remove wet concrete from the outside surface of the bollard after overfilling the steel pipe with cement. C Apply final coat of paint to the bollards in the field. PART IV. MEASUREMENT AND PAYMENT 4.01 GENERAL A Payment for each project will be on a lump sum basis. Partial payment will not be made. B The price quoted shall include full compensation for furnishing all labor, materials, tools, equipment, and incidentals, and for doing all the work involved in the work as shown on the contract figures and specified herein Mobilization/ Demobilization A Measurement Measurement for Mobilization/Demobilization shall be in accordance with Scope of Work. B Payment Payment for mobilization/demobilization will be based on the lump sum price quoted in the bid proposal. Payment shall be full compensation for submittal of materials, USA marking, distributing soil cuttings in the vicinity of the well and other work not part of other bid items. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

25 4.03 SOIL GAS WELL A Measurement Measurement for installing soil gas wells shall be by the linear foot. Contractor shall measure the depth from ground surface to the bottom of each well completed with a weighted tape in the presence of the Engineer. B Payment Payment for soil gas wells shall be by the unit price per linear foot quoted in the bid proposal. The unit price shall include full compensation for all the work involved in installing the triple-probe soil gas monitoring well as shown on the contract figures and specified herein SURFACE COMPLETION A Measurement Measurement for payment for soil gas surface completion shall be per the number installed. B Payment Payment for surface completion shall be per lump sum cost quoted in the bid proposal. The lump sum cost shall include full compensation for: 1 Fabricating the well enclosure pe the contract drawings 2 Painting the well enclusure 3 Installing the well enclosure with the concrete well shirt 4 Inscribing the date and well No. on the concrete well skirt 5 Labeling the well enclosure 6 Installing the Polyethylene tube and cock valve on probe pipe 7 Securing the pipe probe on the steel channel 8 Painting probe pipe cock valves with the color code 9 Placing A.B. around well skirt. 10 Doing all the work involved in installing the well enclosure completely as shown on the Contract figures and specified herein. On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

26 4.05 BOLLARDS A Measurement Measurement for payment for installing bollards shall be per the number of bollards installed per the contract figures. B Payment Payment for installing bollards shall be per the unit cost quoted in the bid proposal. The unit price quoted shall include full compensation for installing bollards completely as shown on the contract figures and specified herein. Payment is contingent on meeting minimum concrete dimensions above ground surface ABANDONED BORINGS A Measurement Measurement for payment for abandoned borings shall be per linear foot. B Payment Payment for each soil gas well shall be by the unit price per linear foot quoted in the bid proposal. END OF SECTION On-Call Driller RFB San Joaquin County-Public Works Soil Gas Monitoring Well Specifications

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32 ON-CALL DRILLER RFB 6820 GROUNDWATER MONITORING WELL SPECIFICATIONS Revised October 26, 2012 RFB 6820_On-Call Driller_GW Well Specs.doc On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specification i Public Works Dept

33 PART 1 GENERAL 1.01 SUMMARY A. Providing wells accepted by the regulatory agencies as suitable for sampling groundwater, as identified herein, is of the essence in this contract. B. Contractor shall install groundwater wells in accordance with these specifications and associated figures. C. Contractor shall be solely responsible for any damage to equipment, such as drill rigs, drilling augers, rods, etc SUBMITTALS A. Contractor shall submit the following to the Engineer before starting work. 1. Method of drilling: whether by mud-rotary, air-rotary, hollow stem auger, or other method. The drilling method shall prevent the collapse of formation material against the well screen and casing during installation of the well. The inside diameter of any temporary casing used shall be sufficient to allow accurate placement of the screen, riser, centralizers, filter pack, seal and neat cement grout. Contractor shall not use use drilling aids such as bentonite, other claybased agents, or any materials capable of affecting the characteristics of the ground water. Grease or oil on drill rods, casing, or auger joints are not permitted; however, PTFE tape or vegetable oil (in solid phase form) is acceptable. 2. Drilling fluid additive, if used. 3. Work schedule, identifying approximate drilling and well inspection time. 4. Health and Safety plan. The health and safety plan shall describe the safety procedures and emergency response procedures in case of an emergency. Contractor shall incorporate comments related to safety in the health and safety plan after review by the Engineer. 5. Bentonite description and particle size PERMITS A. Contractor shall notify underground service alert (USA) and have the work area cleared by underground utility companies before drilling. Contractor will be held liable for any damages caused by the Contractor by not following the guidelines set by USA. The Contractor shall provide the USA ticket numbers to the Engineer 24 hours before drilling. The County will also notify USA. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 1 Public Works Dept

34 B. Permits to drill and install groundwater monitoring wells will be obtained by the County from San Joaquin County Environmental Health Department (EHD). The Engineer will provide the Contractor a copy of the approved permit INSPECTION A. For the purpose of this section, installation refers to placing material in a borehole. Well Installation does not include drilling the borehole. B. Installation of groundwater wells shall be in the presence of EHD inspectors. C. The Engineer will be in charge of scheduling well installation inspections with EHD. Contractor shall not coordinate any inspections with the EHD unless authorized by the Engineer. D. EHD inspection hours are from 9.00 a.m. to 4.00 p.m. each working day. Well installation shall be during EHD s inspection hours. E. Contractor shall provide the Engineer three days notice for well installation. Engineer will provide two days notice to EHD. 1. Contractor shall confirm with the Engineer the approximate time Contractor s crew will be ready for the first inspection for a project before 24 hours. 2. Contractor shall confirm consecutive inspections needed for the project with the Engineer in the field based on the work progress after the first inspection. The Engineer will then schedule inspections with EHD inspector. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 2 Public Works Dept

35 PART 2 PRODUCTS 2.01 GENERAL All materials shall be new and free of defects. Contractor shall inspect materials before installing. Contractor shall replace defective materials at no additional cost to the County WELL CASING The well casing shall be schedule 80, flush-threaded polyvinylchloride (PVC) WELL SCREEN The well screen shall be PVC schedule 80, flush-threaded. Well screen shall be factory-cut slots SAND PACK The sand pack shall be free of debris or organic impurities BENTONITE SEAL The bentonite seal shall consist of sodium montmorillonite clay. Granular size shall be based on drilling method NEAT CEMENT The neat cement shall consist of Portland Type II cement, or equivalent, and bentonite mixture with a water-to-cement ratio that includes no more than 8 gallons of water per sack of cement and 5 percent bentonite by weight CONCRETE The concrete shall have minimum of 28-day compressive strength of 2500 psi WELL PLUG Well plug shall be expansion type plug which provides a water tight seal. Well plug shall be. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 3 Public Works Dept

36 2.09 WELL ENCLOSURE The well enclosure shall be a minimum 8 x 8 square, made of galvanized steel and shall have a lockable cover with a padlock. The cover shall open and close smoothly. The well enclosure shall be painted with etching primer, then painted with two (2) coats of YELLOW rust inhibitive paint. Etching primer may be applied at the Contractor s shop. Final coats of yellow rust inhibitive paint shall be applied in the field after installation of the enclosure in the presence of the Engineer. The well enclosure shall be labeled based on the well number. The labeling shall be with black paint and shall use stencils providing letters four inches in height CENTRALIZERS Centralizers shall be composed of plastic or stainless steel. Galvanized steel or black iron shall not be used WELL PUMP Well pump shall be Groundfos Rediflo 2, single phase, 230 Volts, stainless steel submersible pump. A. Discharge Tubing Pump discharge tubing shall be PE or equivalent. Tubing connections to the pump and to the well cap shall be made with stainless steel compression fittings. The tubing shall have a stainless steel check valve installed and at the bottom. B. Motor Lead Motor lead wire shall be of appropriate gauge. The length shall be based to the depth of each well. Lead wire shall be all-in-one, integrated with the safety cable and have electrical connectors for connection to the pump controller. C. Safety Cable Bracket Pump safety cable bracket and cable shall be stainless steel. D. Well Cap Well cap shall be of appropriate size to fit the well casing and shall have connections for the discharge tubing and the lead wire. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 4 Public Works Dept

37 PART 3 EXECUTION 3.01 GENERAL Groundwater well depths will have at least 15 feet of screen below the groundwater elevation at each site. The actual well depth will be determined in the field by the Engineer based on the groundwater level. Contractor shall leave well bores open for a minimum of 12 hours to allow water level to stabilize before installing the well EXISTING SITE CONDITIONS A. Contractor shall examine the areas and conditions under which work of this section will be performed. Contractor shall notify the Engineers if site conditions are not in accordance with the scope of work or the well specifications. B. The Contractor shall protect any existing survey monuments, groundwater wells, bollards and other monitoring wells in or near the work area. Any existing items damaged by the Contractor shall be repaired or replaced by the Contractor to its original or better condition DRILLING A. Drilling does not require EHD inspection. B. The Contractor shall drill at the location staked by the Engineer. Contractor shall verify drilling location with the Engineer before drilling. C. The Contractor shall decontaminate the drilling rig and drilling equipment before drilling. 1. Decontamination Decontamination shall be in accordance with ASTM D 5088 and ASTM D The drill rods, drill bits, augers, temporary casing, well developing equipment, tremie pipes, grout pumping lines, and other associated equipment shall be cleaned with high-pressure hot water/steam prior to drilling. Weighted measuring tapes shall be decontaminated as well. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 5 Public Works Dept

38 Decontamination shall be performed either at a central decontamination station or an area that is remote from, and cross- or down-gradient from, the well being drilled. 2. If any drilling equipment is found unclean by the Engineer, then the Contractor shall clean the equipment at the site without charging drill rig down time. D. Contractor shall clear the boring location of all brush and minor obstructions. E. Drilling shall be in the presence of the Engineer. F. Drilling shall be coordinated with the Engineer for soil samples. The Engineer will log the drilling at every 5-foot intervals. The Contractor shall provide soil samples as determined by the Engineer for each drilling method. G. If the borehole was over-drilled, the bottom of the hole shall be filled with sand to raise the bottom of the hole. H. Uncompleted Borings 1. If there is an interruption in work, such as overnight shutdown or inclement weather, the Contractor shall a. Measure and record depth of uncompleted borings left overnight. b. Cover the well opening a watertight uncontaminated cover with the following methods: Contractor may leave the hollow stem auger in the boring and place the drills drive shaft over it. Contractor may cover the boring with a ¾-inch thick 4x8 plywood or a steel plate 2ft x 2ft in size. Contractor shall place bentonite around plywood or steel covers if used. The plywood or steel cover shall be secured in place or weighted down so that it cannot be tampered or blown away by the wind. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 6 Public Works Dept

39 c. Direct all surface runoff away from the boring. d. Cordon the work area with safety cones and caution tape to the satisfaction of the Engineer. 2. Contractor shall verify the depth of the well the next day by measuring with the weighted tape. If the boring has collapsed, then the Contractor shall re-drill the boring at no additional cost to the County. I. ABANDONED BORINGS If an obstruction or other condition is encountered that prevents the drilling of a well at the location identified, the Engineer may request that the Contractor abandon the boring. If directed so, the Contractor shall fill the hole with neat cement. Neat cement backfill shall be in the presence of EHD inspector WELL INSTALLATION A. Well installation shall be in the presence of EHD inspectors. Contractor shall follow the guidelines for well inspection as specified herein. B. The Contractor shall measure the total depth of the borehole using a weighted sounding line or other method as agreed with the Engineer and EHD inspector. If heaving or cave-ins have taken place, then the Contractor shall clean out or re-drill the borehole before well installation. C. The Contractor shall ask for inspection by the Engineer of the casing, screen, and any other well construction materials prior to installation. D. The well screens, bentonite seals and neat cement seals shall be installed in accordance with the following sequence: 1. Contractor shall estimate the length of casings needed and verify with the Engineer before lowering into the boring. Well casing shall be at least 5 feet above grade. 2. Contractor shall not use couplings, or glue to join well casings. 3. Contractor shall install a PVC slip end cap or a well plug on the top of both well casings before placing the casing in the bore hole. 4. Contractor shall connect and lower the well casing assembly gently. 5. If the well casing assembly is dropped, lowered abruptly, or for any other reason suspected of being damaged during placement, the well casing assembly shall be removed from the borehole for inspection by the Engineer. The need to inspect the casing will be at the sole judgment of the Engineer. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 7 Public Works Dept

40 6. If the well casing rises after being placed in the borehole, the Contractor shall not place any drilling equipment such as drill pipe, hammers, etc. on the casing to prevent the casing from rising. Contractor shall notify the Engineer immediately of rising casing, and shall measure the amount of rise. 7. Contractor shall place the sand pack into the annular space around the screened interval. Clean water and a tremie pipe may be used to assist with sand pack placement. If the well assembly is installed through the hollow stem augers, the augers shall be pulled slowly during sand pack installation. 8. Contractor shall minimize bridging of the sand by pouring the sand in the bore hole gently and not in large quantity. Patience shall be exercised by the Contractor. 9. Contractor shall monitor the sand pack settlement by measuring the sand level with a weighted tape. Contractor shall also monitor the top of the well casing to detect any movement due to settlement or from drive casing removal. 10. Contractor shall periodically gently surge the water inside the well casing and screen to compress the sand pack while placing the sand. Contractor shall measure the top of the sand pack periodically 11. Contractor shall add sand shall until the sand pack is above the top of the screened interval as shown on the groundwater well figure. 12. Once the placement of the sand packed interval is completed, the contractor shall measure and record the depth to the top of the pack in the presence of the Engineer. 13. Contractor shall install a bentonite seal in the annular space above the sand pack. Add bentonite gradually to avoid bridging. Contractor shall measure the depth of the bentonite plug using a weighted tape. 14. Contractor shall hydrate the bentonite seal after placement with five (5) gallons of distilled or Engineer-approved water for each 2.5 vertical feet of seal. 15. Contractor shall add sufficient water to hydrate the bentonite. Contractor shall add water to the bentonite seal and allow the bentonite to hydrate for minimum of 30 minutes. Contractor shall measure the water elevation over the bentonite after adding water and again 30 minutes later. If water elevation has dropped during that time, then Contractor shall wait for another 30 minutes. before grouting with neat cement. 16. Contractor shall pump neat cement through a tremie pipe filling the annular space from the top of the bentonite seal upward. The bottom of the tremie pipe shall be maintained below the top of the cement to prevent free fall and bridging. 17. Contractor shall place neat cement in a single pour for wells up to 100 feet deep. For wells deeper than 100 feet, the Contractor shall pour neat cement in two pours, the second pour being at least 24 hours after the first pour. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 8 Public Works Dept

41 18. When drilling with hollow stem augers, the hollow stem of the auger may be substituted for the tremie pipe, provided the bottom of the augers are no more than 10 feet above the top of the neat cement layer within the well. 19. Contractor shall place neat cement in the boring up to the existing grade. Contractor shall allow neat cement to settle overnight. After neat cement settlement, Contractor shall place additional neat cement to a level as indicated in the Drawings. 20. Contractor shall install the well enclosure and do the surface completion only after the neat cement has hardened. E. Contractor shall record the following information on the Driller s Log: 1. Depth to water-bearing zones 2. Total depth of bore hole 3. Depth from ground surface to top and bottom of the well screen interval 4. Depth from ground surface to top of the sand pack interval 5. Depth from ground surface to top of the bentonite plug 6. Height above the ground surface of the top of the well casing 7. Height above the ground surface of the top of the steel protective casing WELL SURFACE COMPLETION A. Contractor shall clean well enclosure housing with high-pressure hot water/steam prior to installation to ensure that it is free of contamination. B. Contractor shall install well enclosure plumb. C. Contractor shall cut the well casing pipe to minimum required height. The well enclosure lid shall open and close smoothly providing space for pump discharge tubing and pump lead wires. D. Contractor shall remove the PVC end caps from the top of the casing and then install well plugs. E. Contractor shall place coarse sand in the annular space between the enclosure and the well casings. The sand shall be placed six inches below the top of the well casings. F. Contractor shall clean cement grout from the well casing and enclosure prior to painting. G. Contractor shall apply the final coat of paint on the enclosure and then shall label the enclosure with the well No provided by the Engineer after installation. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 9 Public Works Dept

42 H. Contractor shall install bollards plumb. PART 4 WELL DEVELOPMENT 4.01 GENERAL A. Contractor shall develop the new groundwater well within 7 days of completion of each new well, but no sooner than 48 hours after placing neat cement. B. Well development shall be in the presence of the Engineer. C. Contractor shall check if the well casing has collapsed or if the neat cement has seeped into the well casing. Contractor shall report any problems to the Engineer. D. Contractor shall not damage the well casing during well development. E. Contractor shall remove any tools or other parts dropped in the well casing. F. Contractor shall allow the Engineer to install hydrology meter during well development. G. Contractor shall develop well using mechanical surging or over pumping or a combination thereof per ASTM D Contractor shall purge the well until:. 1. Well water is clear to the unaided eye. 2. Sediment in the well casing is less than 0.1 foot thick. 3. Water removed during surging and purging shall be a minimum of three times the water volume in the well prior to the start of purging plus three times the volume of water added for purging and surging. 4. Contractor shall purge until: 5. Temperature is consistent within 0.2 deg F, 6. Specific conductivity is consistent within + 3 percent change in specific conductance. 7. ph varies less than 0.2 ph units 8. Turbidity varies not more than 10% On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 10 Public Works Dept

43 4.02 WELL DEVELOPMENT RECORDS A. Contractor shall submit to the Engineer in the writing the following well development data for each well development. Submittal shall be made within two business days of completing well development. Engineer may request any other data in the field. 1. Name of project, site, well identification number, date and time of development and name of person developing well. 2. Method used for development, to include size, type and make of equipment, bailer, and/or pump used during development. 3. Depth to bottom of well pre and post development 4. Static water level before and after well development 5. Time spent developing the well by each method, to include typical pumping rate, if pump is used in development. 6. Minimum purge volume 7. Amount of water purged. Provide physical character of water removed, to include changes during development in clarity, color, particulates, and odor. 8. Volume and source of water added to the well, if any. 9. Volume and physical character of sediment removed, to include changes during development in color orodor. 10. Readings of ph, specific conductance, turbidity, DO, oxidation / reduction potential (ORP), and temperature taken before, during, and after development. 11. Other information as requested by the Engineer. PART 5 PUMP INSTALLATION A. Contractor shall install the dedicated well pump in each groundwater monitoring well in accordance the manufacture s specification in the presence of the Engineer. Contractor shall tie the lead wire, safety cable and discharge tubing to the casing every five (5) feet with zip ties or as approved by the Engineer. Contractor shall install the well cap and hang the pump in the well casing at the appropriate depth as determined by the Engineer. On-Call Driller RFB 6820 San Joaquin County Groundwater Monitoring Well Specifications 11 Public Works Dept