100_Percent_Project_Manual_-_Well.pdf

SECTION 33 20 00 Page 1

SECTION 33 20 00

WATER WELLS

04/08

03/11/2016

PART 1 GENERAL

1.1 UNIT PRICES

Payment for each specified item will be made at the contract unit price for that item. Payment will include full compensation for equipment, materials and labor for drilling; removal and disposal of temporary casing, cuttings, and drill fluid; preparation of borehole logs; and sample handling, containers, storage, and testing. Depth, logging, installation, casing, riser pipe, and well screen shall be measured by linear distance. Payment will not be allowed for test holes or wells abandoned due to construction practices not in accordance with this specification, faulty construction practices or for the convenience of the Contractor.

1.1.1 Test Hole

Compensation for the test hole will be made at the contract unit price and will include material, equipment, and labor required to drill and perform tests on the test hole. Depth shall be measured as the total linear distance between ground surface and bottom of hole. If the total depth of hole is greater than that specified on the contract for "Test Hole," the additional depth will be paid for at the contract unit price for

"Additional Test Hole Depth." If the test hole is developed into the permanent well with no increase in diameter, the Contractor will be compensated as described below, and separate payment will not be made for the test hole.

1.1.2 Water Well

Compensation for the water well will be made at the contract unit price and will include material, equipment, and labor required to drill, develop, perform tests, and complete the permanent well. Depth shall be measured as the total linear distance between ground surface and bottom of hole. If the total depth of well is greater than that specified in the contract for

"Water Well," the additional depth will be paid for at the contract unit price for "Additional Water Well Depth."

1.1.3 Geophysical Logging

The "Geophysical Logging" unit price will include interpretation of the logs and their delivery to the Government.

1.1.4 Well or Test Hole Decommissioning/Abandonment

Permanent decommissioning/abandonment of wells or test holes will be paid for only if it becomes necessary to abandon a well or test hole as specified, and only for work completed and accepted as specified. Payment will include compensation for drilling, casing removal, well sampling, materials, cement, mixing of cement, bentonite, and water, pumping of grout, equipment, removal of foreign objects, and transportation necessary to abandon the well or test hole and for the required well or test hole abandonment records.

SECTION 33 20 00 Page 2

1.1.5 Site Cleanup

Separate payment will not be made for cleanup of the site. Cleanup will mean restoring the site to its pre-construction condition, in accordance with paragraph SITE CLEANUP. Cleanup will be considered part of and incidental to the drilling, construction, and/or decommissioning of the well.

1.2 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

AMERICAN WATER WORKS ASSOCIATION (AWWA)

AWWA 10084 (2005) Standard Methods for the

Examination of Water and Wastewater

AWWA A100 (2006; Errata 2007) Water Wells

AWWA B300 (2010; Addenda 2011) Hypochlorites

AWWA B301 (2010) Liquid Chlorine

AWWA C200 (2012) Steel Water Pipe - 6 In. (150 mm) and Larger

AWWA C206 (2011) Field Welding of Steel Water Pipe

AWWA C654 (2013) Disinfection of Wells

ASTM INTERNATIONAL (ASTM)

ASTM A139/A139M (2004; R 2010) Standard Specification for

Electric-Fusion (ARC)-Welded Steel Pipe

(NPS 4 and over)

ASTM A53/A53M (2012) Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless

ASTM C136 (2006) Standard Test Method for Sieve

Analysis of Fine and Coarse Aggregates

ASTM C150/C150M (2012) Standard Specification for Portland

Cement

ASTM D1586 (2011) Penetration Test and Split-Barrel

Sampling of Soils

ASTM D2487 (2011) Soils for Engineering Purposes

(Unified Soil Classification System)

ASTM D2488 (2009a) Description and Identification of

Soils (Visual-Manual Procedure)

ASTM D4750 (1987; R 2001) Determining Subsurface

SECTION 33 20 00 Page 3

Liquid Levels in a Borehole or Monitoring

Well (Observation Well)

ASTM D5521/D5521M (2013) Standard Guide for Development of

Ground-Water Monitoring Wells in Granular

Aquifers

1.3 SYSTEM DESCRIPTION

The well shall be located as indicated, and be constructed in accordance with these specifications. Each well shall be installed to prevent aquifer contamination by the drilling operation and equipment, intra- and inter-aquifer contamination, and vertical seepage of surface water adjacent to the well into the subsurface, especially the well intake zone.

1.3.1 Notification

The Contracting Officer shall be notified 14 days prior to drilling. The

Contractor shall be responsible for contacting the State of New Mexico in accordance with the applicable reporting requirements. Before beginning work, the New Mexico Office of the State Engineer and New Mexico

Environment Department shall be notified of the type and location of wells to be constructed, the method of construction and anticipated schedule for construction of the wells.

1.3.2 Abandonment of Wells

If the Contractor fails to construct a well of the required capacity, or if the well is abandoned because of loss of tools, or for any other cause, abandon the hole as specified in paragraph WELL DECOMMISSIONING/ABANDONMENT.

1.4 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for Contractor Quality Control approval. Submit the following in accordance with Section 01 33 00

SUBMITTAL PROCEDURES:

SD-02 Shop Drawings

Installation Diagrams; G

SD-03 Product Data

Permanent Well Pump; G

Well Installation Plan; G

Well Material; G

Qualifications

Site Conditions

Geophysical Logging

SD-06 Test Reports

Survey Maps and Notes

SECTION 33 20 00 Page 4

Well Development Records

Geophysical Logs

Decommissioning/Abandonment Record

Project Photographs

Water Source

Filter Pack; G

Tests

SD-07 Certificates

Casing

Cement Grout

Air line and gauge

Drilling mud

Well Screens

Graveling equipment list

Construction of Filter Pack

1.5 QUALITY ASSURANCE

1.5.1 Well Installation Plan

Submit a plan as specified herein describing the drilling methods, sampling, and well construction and well development 30 calendar days prior to beginning drilling operations. Mobilization activities may start prior to submittal of the plan. The plan shall be approved and signed by an experienced geologist as specified in paragraph QUALIFICATIONS.

Incorporate the following requirements into the Contractor's Well

Installation Plan and follow them in the field. The plan shall include, but shall not be limited to, a discussion of the following:

a. Description of well drilling methods, and installation procedures, including any temporary casing used, placement of filter pack and seal materials, drill cuttings and fluids disposal, and soil/rock sample disposition.

b. Description of well construction materials, including sizing/selection of well screen, riser pipe, centralizers, air line and gauge, tailpiece

(if used), pitless adapter unit, filter pack and filter pack gradation, bentonite or drilling mud, drilling fluid additives (if used), drilling water, cement grout, and well protective measures.

c. Description of quality control procedures to be used for placement of filter pack and seals in the boring, including depth measurements.

d. Forms to be used for written boring logs, installation diagrams of

SECTION 33 20 00 Page 5 wells, geophysical logs, well development records, well sampling data records, state well registration forms, and well abandonment records.

e. Description of contamination prevention and well materials and equipment decontamination procedures.

f. Description of protective cover surface completion procedures, including any special design criteria/features relating to frost heave prevention. The maximum frost penetration for the site shall be included in this description.

g. Description of well development methods to be used.

h. List of applicable publications, including state and local regulations, standards and New Mexico Office of the State Engineer required forms.

i. List of personnel assignments for this project, and personnel qualifications.

j. Description of well decommissioning/abandonment procedures.

k. Description of well capacity testing techniques.

l. Description and discussion of geophysical techniques to be employed at the site.

m. Description of permanent pump to be installed, and discussion of pump operating tests to be employed at the site.

n. Description of specific methods to be employed to control potential contamination or pollution arising from well installation activities.

1.5.2 Qualifications

Submit personnel qualification documentation. A geologist with at least 3 years experience in soil logging, and well installation, shall be on site and responsible for all geophysical and borehole logging, drilling, well installation, developing and testing activities. The driller shall be licensed in the state of New Mexico, according to the state requirements

(NMAC 19.27.4). Geophysical log interpretation shall be done by a qualified log analyst. The log analyst shall be able to demonstrate competence through background, training, and experience when so called upon. Document a minimum of 8 years of well installation experience.

1.5.3 Test Holes

Before starting construction of the well, a test hole of at least 4 inches in diameter shall be drilled at the location of the well into the target water bearing strata to a maximum depth of 125 feet as directed by the

Contracting Officer. Test holes should be drilled in a manner to protect the subsurface from surface contamination. Test holes should be carefully advanced and sampled to determine the presence of the upper aquiclude if one exists. The test hole shall be used to determine the optimum depth, and to log the strata encountered. Test holes shall be logged in accordance with paragraph BOREHOLE LOGS. A temporary casing may be used.

If the test hole is not used for the permanent well, the test hole shall be abandoned as specified in paragraph WELL DECOMMISSIONING/ABANDONMENT.

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1.5.4 Sampling

1.5.4.1 Sampling for Chemical Analysis

Sampling requirements for obtaining and preserving samples for chemical analysis shall be included in the Sampling and Analysis Plan.

1.5.4.2 Sampling for Geotechnical Analysis

Samples shall be taken of all materials penetrated by each drilled well/test hole. Wash bore return samples shall be collected on 5 foot invervals and at every change in formation. Soil sampling shall be done with a split tube sampler using standard sampling techniques in accordance with ASTM D1586 over the zone to be screened. Samples shall be extracted from their in-situ environment in as near an intact, minimally disturbed condition as technically practical. Split tube samples shall be obtained continuously through the area expected to be screened. Provide sieve analyses of all drive-sampled material. Sieve analyses shall be conducted in accordance with ASTM C136. The gradation of the natural formation shall be determined through the use of sieve analyses performed on formation samples taken from the areas to be screened. Sampled materials shall be placed in cloth geologic/sand sample bags and labeled as specified in paragraph SAMPLE CONTAINERS. Wash bore return samples shall be delivered to the Contracting Officer designated facility and to NMED & OSE.

Representative soil samples collected by split-screen shall be tested for grain-size distribution by mechanical means (sieves down to the No. 200 size according to ASTM C136). Description and identification of soils shall be done in accordance with ASTM D2488. Laboratory classification of soils shall be done in accordance with ASTM D2487. Sampling shall be performed to allow completion of the documents described in paragraph

BOREHOLE LOGS.

1.5.5 Geophysical Logging

Submit five prints of the graphic boring log prepared to scale showing the required details, within 7 working days after completion of the test hole.

This drawing shall be used for determining the well design, design of the filter pack, well screen location and screen openings. The total depth of each test hole drilled shall be geophysically logged. Geophysical logging shall be documented in accordance with paragraph Geophysical Logs. Run one successful natural gamma ray for the full depth, (top to bottom of test hole); one successful (top to bottom of test hole) spontaneous potential

(self-potential); and, one successful (top to bottom of test hole) resistivity log, for each test hole. Log analyses and interpretations shall be made by a person qualified in accordance with paragraph

QUALIFICATIONS.

1.6 DELIVERY, STORAGE, AND HANDLING

Store and maintain well materials in a clean, uncontaminated condition throughout the course of the project. Filter pack material shall not be allowed to freeze before installation.

1.7 SITE CONDITIONS

Access to each well site, including any utility clearance, permits, licenses, or other requirements and the payment thereof necessary for execution of the work, is the responsibility of the Contractor. A copy of all permits, licenses, or other legal requirements necessary for execution

SECTION 33 20 00 Page 7 of the work shall be furnished 14 working days before commencement of the work. Obtaining rights-of-entry and training necessary to enter Melrose

Air Force Rainge is the responsibility of the Contractor to coordinate with the Government. Visit each proposed well location to observe any condition that may hamper transporting equipment or personnel to the site. If clearing, or relocation is necessary, the Contractor, and the Contracting

Officer shall agree on a suitable clearing, or relocation plan, and the location of any required access road.

PART 2 PRODUCTS

2.1 CASING

All casing, screen, and other well material shall be of compatible materials to prevent galvanic reaction between components of the completed well. Submit catalog data, and name of supplier, for well screens (to include the screen slot size), casing, riser pipe, filter pack material, bentonite, cement grout, centralizers, pitless adapter units, surface protective covers, well vaults, locking caps, airline oil filters for pneumatic drilling, dedicated sampling equipment, pumps, and chemical specifications on drill lubricants, tracers, disinfecting agents, and drill fluid additives, if used. Catalog data shall include any information, written or otherwise, supplied by the manufacturers or suppliers of the above listed items.

2.1.1 Steel Casing and Couplings

Steel casing shall be new carbon steel, conforming to ASTM A139/A139M Grade

B, standard weight black steel pipe, conforming to ASTM A53/A53M, steel pipe conforming to AWWA C200. The protective outer casing shall be nominal

26 inch diameter, 0.500 inch wall thickness, as applicable. The inner well casing shall be nominal 10 inch diameter, 0.365 inch wall thickness schedule 40S meeting the requirements of ASTM A312/A312M, as applicable.

Joints shall be either threaded and coupled, or field welded in accordance with AWWA C206.

2.2 WELL SCREENS

Well Screens shall be a minimum of 10 inches nominal diameter, and shall be directly connected to the bottom of the inner casing by an approved method. The length of the screen shall be 12 feet to provide an intake area capable of passing not less than the minimum required yield of the well, at an entrance velocity not exceeding 0.1 fps. The opening, or slot size of the screen, shall be determined by the Contractor based on analysis of the distribution of the grain size of the artificial filter pack, be compatible with the material surrounding the screen, and shall be submitted for approval as part of the well installation plan. The well screen shall be of sufficient size and design to hold back and support the gravel used in the filter pack envelope. The screen and all accessories required for satisfactory operation shall be essentially standard products of manufacturers regularly engaged in the production of such equipment. Field constructed screen is not acceptable. The bottom section, below the screen, shall be sealed watertight by means of a flush threaded or welded end cap of the same material as the well screen.

2.2.1 Metal Screen

Metal screen shall be of an approved wire-wound type and shall be type 304 or type 316 stainless steel, conforming to the applicable requirements of

SECTION 33 20 00 Page 8

AWWA A100. A wire-wound screen manufactured with supporting bars or core of material different from the wire will not be acceptable. Joints shall be made of threaded couplings of the same material as the screens or by brazing or welding in accordance with AWWA C206.

2.3 FILTER PACK

Filter pack material shall be a product of a commercial sand and gravel supplier, shall be properly sized and graded for the surrounding soil encountered, and shall be composed of clean, round, hard, waterworn 95 percent siliceous material, free of flat or elongated pieces, organic matter, or other foreign matter. Submit filter pack material test results;

sieve and chemical analyses, within 15 working days after completion of the test hole. The filter material shall be of a size which will allow the maximum flow of water into the well and prevent the infiltration of sand and silt. The gradation of the filter material shall be such that the uniformity coefficient is not more than 2.5. The filter material shall be thoroughly sterilized with chlorine or hypochlorite immediately before or during being placed.

2.4 BENTONITE SEAL

The bentonite seal, intended to keep grout from entering the filter pack, shall consist of hydrated granular, or pelletized, sodium montmorillonite furnished in sacks or buckets from a commercial source and shall be free of impurities which adversely impact the water quality. If the bentonite seal is located above any borehole fluid levels, a layer of fine sand shall be placed at the top of the bentonite seal, to provide an additional barrier to any downward migration of grout.

2.5 CEMENT GROUT

2.5.1 Neat Cement Grout

Neat cement grout shall consist of Portland cement conforming to

ASTM C150/C150M, Type I or II. Cement grout shall be proportioned not to exceed more than 6 gallons of water per 94 lb bag of Portland cement, with a mixture of such consistency that the well can be properly grouted. No more than 5 percent by weight of bentonite powder may be added to reduce shrinkage.

2.5.2 Cement Grout

Cement grout may only be used where the annular opening is greater than 1.5 inches. Cement grout shall consist of equal parts of cement conforming to

AWWA A100 Section 7, and sand, with not more than six gallons of water per sack of cement.

2.6 PERMANENT WELL PUMP

Permanent pump shall be an approved electric submersible type with a capacity sufficient to deliver 167 gpm with 380 feet of head. The pump shall be connected to the pump controls by a three-wire drop line. Piping for the well drop line shall be 4 inch diameter galvanized steel pipe conforming to ASTM A53/A53M. The pump shall operate on 480 volts, 60 Hz, 3

-phase power, and the motor shall be of sufficient size to operate the pump under the maximum operating conditions without exceeding its rating. Motor shall be premium efficiency rated for variable speed operation. Pump shall be equipped with necessary controls to provide for automatic operation of

SECTION 33 20 00 Page 9 the pump. The pump and motor unit shall be no larger than 6 inches in diameter at any point. The drop line shall include at least one check valve.

2.7 PITLESS ADAPTER UNIT

Pitless adapter unit shall be a shop-fabricated from the point of connection to the inner well casing to the unit cap or cover. The pitless adapter unit shall be of materials and weight at least equivalent and compatible with the casing and be of watertight construction throughout.

The design of the pitless adapter unit should make provision for an electrical cable seal, access to disinfect the well, provide a casing vent, and include facilities to measure water level. The casing vent should terminate in a downturned position, at or above the top of the pitlers unit in a minimum 1-1/2 inch diameter opening covered with a 24 mesh, corrosion resistant screen. The pitles adapter shall also have installed a probe tube for drawdown line and an airline assembly with guage and stainless steel tubing.

2.8 SAMPLE CONTAINERS

Drill cuttings and driven samples for geotechnical purposes shall be placed in cloth geological/sand sample bags and labeled with the project name, date of sample, well number and depth at which the sample was taken. Both the container shall be labeled in permanent indelible ink. Bags shall be furnished by the Contractor.

PART 3 EXECUTION

3.1 PROTECTION OF EXISTING CONDITIONS

Maintain existing survey monuments and wells, and protect them from damage from equipment and vehicular traffic. Repair any items damaged during this work. Reinstall wells requiring replacement due to Contractor negligence according to these specifications. Wells scheduled for abandonment shall be protected from damage so that abandonment may be performed according to these specifications. Prior to excavation, obtain written approval from the local utility companies to drill at each site, to avoid disturbing buried utilities.

3.2 PREPARATION

3.2.1 Decontamination

The drill rig, drill rods, drill bits, augers, temporary casing, well developing equipment, tremie pipes, grout pumping lines, and other associated equipment shall be clean prior to drilling. Samplers shall be decontaminated in accordance with the Sampling and Analysis Plan. The water used for cleaning shall be from a Government approved source. The water source used for cleaning shall be sampled and tested for the constituents specified in the Sampling and Analysis Plan prior to use at the site.

3.2.2 Water Source

If well drilling/installation requires the use of water, prior to its use at the site, the water source approved by the Contracting Officer for the constituents specified in the Sampling and Analysis Plan. Submit drilling water source, within 5 working days before beginning drilling operations.

SECTION 33 20 00 Page 10

The Contractor is responsible for locating the source, obtaining the water from the source, transporting it to, and storing it at the site.

3.3 WELL CONSTRUCTION

The drilling method shall be as approved by the Contracting Officer and shall conform to all state and local standards for water well construction. The execution of the work shall be by competent workmen and shall be performed under the direct supervision of a State of New Mexico experienced well driller. 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, centralizer(s), filter pack, seal and grout. Any drilling fluid additive used shall be inorganic in nature. Grease or oil on drill rods, casing, or auger joints are not permitted; however, PTFE tape or vegetable oil (in solid phase form) are acceptable. The drill rig shall be free from leaks of fuel, hydraulic fluid, and oil which may contaminate the borehole, ground surface or drill tools. Casing pipe, well screens, and joint couplings shall be of compatible materials throughout each well. The well shall be a filter pack well activated in the stratum based on test hole data.

The well shall be drilled straight, plumb, and circular from top to bottom. The well shall be initially drilled from the ground surface to 20 feet and the bottom of the outer casing set at this elevation. The hole below the outer casing shall penetrate the water bearing stratum to the bottom of the High Plains aquifer to produce the required amount of water without causing excessive velocities through the aquifer. During construction of the wells, precautions shall be used to prevent tampering with the well or entrance of foreign material. Runoff shall be prevented from entering the well during construction. If there is an interruption in work, such as overnight shutdown or inclement weather, the well opening shall be closed with a watertight uncontaminated cover. The cover shall be secured in place or weighted down so that it cannot be removed except with the aid of the drilling equipment or through the use of drill tools.

3.3.1 Setting Outer Casing

The outer casing shall not be less than 26 inches in diameter. The hole shall be of sufficient size to leave a concentric annular space of not less than 1-1/2 inches and not more than 6 inches between the outside of the outer casing and the walls of the hole. The annular space between the outer casing and the walls of the holes shall be filled with neat cement grout or cement grout. Acceptable methods of grouting are detailed in

AWWA A100; the approved method shall specify the forcing of grout from the bottom of the space to be grouted towards the surface. A suitable grout retainer, packer, or plug shall be provided at the bottom of the inner casing so that grout will not leak into the bottom of the well. Grouting shall be done continuously to ensure that the entire annular space is filled in one operation. After grouting is completed, drilling operations shall not be resumed for at least 72 hours to allow proper setting of the grout.

3.3.2 Construction of Inner Casing and Screen

After the grout has set, the hole below the outer casing shall be reamed at the required diameter, to the required depth, by an approved method which will prevent caving of the hole before or during installation of the filter pack, well screen and inner casing. In lieu of reaming, the entire well may be drilled to the diameter of the filter pack with an annular space

SECTION 33 20 00 Page 11 between the inner casing and outer casing equal to the thickness of the filter pack. The outer casing shall be increased in size to provide for this space, if this option is elected. The well screen and inner casing shall be firmly attached, and lowered into the hole by a method which will allow for control of the rate of fall of the well screen and inner casing at all times. Well screen and inner casing shall not be dropped or allowed to fall uncontrolled into the hole. The inner casing shall extend up through the outer casing to 1 feet above the ground surface. Approved centering devices shall be installed at a spacing of 120 degrees, between the outer casing and inner casing prior to well construction at intervals not exceeding 25 feet along the length. Centering devices shall not be placed on the screened interval, or within the bentonite seal, if used.

3.3.3 Construction of Filter Pack

After the screen and inner casing have been concentrically set in the hole below the outer casing, the approved filter pack shall be constructed around the screen by filling the entire space between the screen and the wall of the hole in the water bearing stratum with filter pack material. A tremie pipe having an inside nominal diameter of not less than 1-1/2 inches shall be lowered to the bottom of the well between the hole and screen.

The tremie pipe shall be arranged and connected, at the surface of the ground, to water pumping and graveling equipment so that water and filter material, fed at uniform rates, are discharged as the filter material fills the hole from the bottom up. The tremie pipe shall be raised at a rate that will keep the bottom of the pipe no more than 3 feet above the filter material level at all times. If the Contractor desires to use methods of placing filter material other than those specified, the details of the method and equipment proposed shall be submitted to the Contracting

Officer, before filter pack placement is begun; however, dumping filter pack material from the surface of the ground and agitating the well in an effort to settle the filter will not be allowed. The filter pack shall be installed continuously and without interruption until the filter pack has been placed to within 38 feet above the top of the screen. The depth to the top of the filter pack shall be directly measured, and recorded. Any water added to the filter pack material shall be obtained in accordance with paragraph Water Source. Filter pack material shall be protected from contamination prior to placement by either storing it in plastic lined bags, or in a location protected from the weather and contamination on plastic sheeting. Filter pack material shall not be allowed to freeze before installation. Filter pack material shall be transported to the well site in a manner which prevents contamination by other soils, oils, grease, and other chemicals. Frequent measurements shall be made inside the annulus during retraction to ensure that the filter pack is properly placed.

3.3.4 Bentonite Seal

After the inner casing well screen and filter pack have been installed, and after predevelopment of the well, the annular space between the inner and outer casings shall be sealed by use of a bentonite seal. A minimum 3 foot thick hydrated bentonite seal shall be placed on top of the filter pack in a manner which prevents bridging of the bentonite in the annulus. The bottom of the bentonite seal shall be a minimum of 5 feet above the top of the well screen. The depth to the top of the bentonite seal shall be directly measured, and recorded immediately after placement, without allowance for swelling. Bentonite pellets shall be allowed 4 hours to hydrate before placement of grout. If the bentonite seal is located above any borehole fluid levels, a 1 foot layer of fine sand shall be placed at the top of the bentonite seal.

SECTION 33 20 00 Page 12

3.3.5 Grout Placement

After the inner casing well screen and filter pack have been installed, a non-shrinking cement grout, shall be mechanically mixed in accordance with paragraph CEMENT GROUT, and placed by tremie pipe, in one continuous operation into the annulus between the inner and outer casings above the bentonite seal to within 6 feet of the ground surface. Grout injection shall be in accordance with AWWA A100. The tremie pipe shall be thoroughly cleaned with high pressure hot water/steam before use in each well. The bottom of the tremie pipe shall be constructed to direct the discharge to the sides rather than downward. The discharge end of the tremie pipe shall be submerged at all times. Additional grout shall be added from the surface to maintain the level of the grout within 6 feet of the ground surface as settlement occurs. Work shall not be conducted in the well within 24 hours after cement grouting. The alignment of the well shall be verified by passing a 5 foot long section of rigid PVC, stainless steel or

PTFE pipe 1/4 inch smaller in diameter than the inside diameter of the casing through the entire well. If the pipe does not pass freely, the well will not be accepted. The pipe section shall be thoroughly cleaned with high pressure hot water/steam prior to each test.

3.4 WELL DEVELOPMENT

Within 7 days of completion of each well, but no sooner than 48 hours after cement grouting is completed, the well shall be developed. Predevelopment, or development after the filter pack has been installed, but before the bentonite pellet annular seal is installed, may be initiated before this minimum 48 hour period. The well shall be developed in accordance with the

Well Installation Plan, by approved methods until the water pumped from the well is substantially free from sand, and until the turbidity is less than

5 on the Jackson Turbidity Scale specified in AWWA 10084. Developing equipment shall be of an approved type and of sufficient capacity to remove all cutting fluids, sand, rock cuttings, and any other foreign material.

The well shall be thoroughly cleaned from top to bottom before beginning the well tests. Development shall be performed using only mechanical surging, over pumping, or jetting, or a combination thereof in accordance with ASTM D5521/D5521M. Details of the proposed development method shall be included in the Well Installation Plan. At the time of development of any well, the well shall be free of drawdown or surcharge effects due to pump testing, developing or drilling at another location. The Contractor is responsible for maintaining at the well site the needed access and work area and clearance, necessary to accomplish development. Furnish, install, or construct the necessary discharge line and troughs to conduct and dispose of the discharge a sufficient distance from the work areas to prevent damage. Development shall be conducted to achieve a stable well of maximum efficiency and shall be continued until a satisfactory sand test, as specified in paragraph Sand Test, is obtained. During predevelopment of the well, filter pack material shall be added to the annular space around the screen to maintain the top elevation of the filter pack to the specified elevation. Provide an open tube or other approved means for accurately determining the water level in the well under all conditions.

If, at any time during the development process it becomes apparent in the opinion of the Contracting Officer that the well may be damaged, development operations shall be immediately terminated. The Contracting

Officer may require a change in method if the method selected does not accomplish the desired results. The Contracting Officer may order that wells which continue to produce excessive amounts of fines after development for 8 hours be abandoned, plugged, and backfilled, and may

SECTION 33 20 00 Page 13 require the Contractor to construct new wells nearby. All materials pulled into the well by the development process shall be removed prior to performing the pumping test.

3.4.1 Jetting

Jetting should be performed using either a single or double ring jet. If a double ring jet is used the rings should be 2 feet apart. The jetting tool shall be constructed of high-strength material and conservatively designed and proportioned so that it will withstand high pressures. The jetting tool shall have two 3/16, 1/4, or 3/8 inch diameter hydraulically balanced nozzles spaced 180 degrees or four 3/16, 1/4, or 3/8 inch diameter holes spaced 90 degrees apart and which shall exert the jetting force horizontally through the screen slots. The rings shall be constructed such that the tips of the jets shall be within 1/2 inch from the inner surface of the well screen. The pump used in conjunction with the jetting tool shall be capable of providing pressures up to 250 psi or a minimum jetting fluid exit velocity of 150 f/s. Prior to commencing jetting, and following each jetting cycle, all sand and/or other materials shall be removed from inside the screen. The jetting process shall start at the bottom of the screen and consist of rotating the jetting tool slowly while rotating the pipe 90 degrees for two minutes at each location then raising the pipe 6 inches. All wells, more than 4 inches in diameter, shall be pumped during the jetting cycle to remove incoming sand and other material. Such pumping shall be at a rate not less than 115 percent of the rate at which fluid is introduced through the jetting tool. This will allow a flow of material into the well as it is being developed. Water used for development shall be free of sand. The contracting officer may require other means of developing the well such as intermittent pumping method, variation of the intermittent pumping method, or surge block if it appears that the development of the well is not producing the desired results.

3.4.2 Intermittent Pumping

Intermittent pumping shall be performed by pumping the well at a capacity sufficient to produce a rapid drawdown of approximately 6 feet stopping the pump (backflow through pump will not be permitted) to permit the water surface to rise to its former elevation, and repeating this procedure.

Cycle time for this procedure will vary as directed but will not be more than 3 cycles per minute. A pump discharge in excess of 250 gpm will be required. A deep well turbine pump, or electric submersible pump with check valve, shall be used with any attachment necessary to accomplish rapid starting and stopping for intermittent pumping. The intake shall be set at least 10 feet below the maximum expected drawdown in the well.

Prior to commencing intermittent pumping, and periodically during development by this method, all sand and/or other materials shall be removed from inside the screen. The amount of drawdown may be decreased if, in the opinion of the Contracting Officer, the efficiency of the well might otherwise be impaired.

3.4.3 Surging

Surging of the well shall require use of a circular block, or multiple blocks, which are approximately 1 inch smaller in diameter than the inside diameter of the well and is constructed of a material which will not damage the screen if the block comes in contact with the screen, and a bailer or pump to remove materials drawn into the well. The surging shall be continued for a period of approximately one hour, or until little or no additional material from the foundation or filter pack can be pulled

SECTION 33 20 00 Page 14 through the screen. The surge block shall be moved by a steady motion up and down the full length of the well screen. Prior to commencing surging, and periodically during development by this method, all sand and/or other materials shall be removed from inside the screen. All materials pulled into the well by the surging process shall be removed by the Contractor.

3.4.4 Well Development Criteria

A well development record shall be maintained in accordance with paragraph

Well Development Records. Development is complete when all of the following criteria are met:

a. Well water is clear to the unaided eye.

b. Sediment thickness in the well is less than 1 percent of the screen length.

c. A minimum of three times the standing water volume in the well is removed plus three times the volume of all added water and drilling fluid lost during drilling and installation of the well is removed, and

d. Water removed during development and testing operations shall be discharged to the ground surface at least50 feet from the well in a down gradient area.

3.5 TESTS

After the wells have been developed, notify the Government and make the necessary arrangements for conducting the capacity tests. If the capacity test indicates that the required capacity can be obtained, the tests for quality of water shall be made. If the capacity and quality tests indicate that the required capacity and quality can be obtained, the permanent well, as specified, shall be completed at that depth. Submit Test Reports within

24 hours following the conclusion of each test. Prior to making quality tests, drilling equipment, tools and pumps contacting well water shall be cleaned with live steam.

3.5.1 Capacity Test

Furnish and install an approved temporary test pump, with discharge piping of sufficient size and length to conduct the water being pumped to point of discharge at least 200 feet from the well, and equipment necessary for measuring the rate of flow and water level in the well. A 4 hour step drawdown capacity test shall be run at consecutive stepped rates of 100 gpm, 150 gpm, 200 gpm and 250 gpm for an hour at each rate. Pumping rate and drawdown in the pumped well shall be recorded at intervals of 0, 5, 10, 15, 30 and 45 minutes into each step. Once the pumped well has recovered from the step drawdown test for a minimum of 8 hours, a 24 hour constant rate capacity test shall be run with the pumping rate and drawdown at the pump well and observation wells recorded every 1/2 minute during the first

5 minutes after starting the pump; then every 5 minutes for an hour; then every 20 minutes for 2 hours. From this point on, readings taken at hourly intervals, until the water level stabilizes, shall be sufficient. The test shall begin at the rate of 150 gpm and at least that rate maintained throughout the duration of the test. When the pump is shut off, water level readings shall be taken during the rebound period for the same intervals of time as the drawdown test for a period of 8 hours. The record of the test, in triplicate, shall be delivered to the Contracting Officer.

SECTION 33 20 00 Page 15

3.5.2 Test for Plumbness and Alignment

Upon completion of the permanent well, plumbness and alignment shall be tested by lowering into the well, to the total depth of the well, a plumb 40 feet long or a dummy of the same length. The outer diameter of the plumb shall not be more than 1/2 inch smaller than the diameter of that part of the hole being tested. If a dummy is used, it shall consist of a rigid spindle with three rings, each ring being 12 inches wide. The rings shall be cylindrical and shall be spaced one at each end of the dummy and one in the center. The central member of the dummy shall be rigid so that it will maintain the alignment of the axis of the rings. The dummy shall be decontaminated as specified in paragraph Decontamination, before use. If the plumb or dummy fail to move freely throughout the length of the casing or well screen for the depth of well or should the well vary from the vertical in excess of two-thirds the inside diameter of that part of the well being tested for each 100 feet of depth, the plumbness and alignment of the well shall be corrected. If the faulty alignment and plumbness is not correctable, as determined by the Contracting Officer, the well shall be abandoned as specified in paragraph WELL DECOMMISSIONING/ABANDONMENT and a new well drilled at no additional cost to the Government.

3.5.3 Test for Quality of Water

After the yield in the permanent well and drawdown test or capacity test have been completed, secure samples of the water in suitable containers, and of sufficient quantity, to have bacterial, physical, and chemical analyses made by a recognized testing laboratory recognized by the New

Mexico Environment Department, except that the bacterial analysis may be made by the applicable State Board of Health, if desired. Water Quality

Analysis shall address each item specified in the Water Quality Analysis

Table at the end of this section. Expenses incident to these analyses shall be borne by the Contractor and the results of the analyses shall be furnished to the Contracting Officer. All sampling and analyses shall be performed using EPA and State approved methods, procedures, and holding times.

IOCs

Fluoride

Barium

Cadmium

Chromium

Mercury

Nitrate

Nitrite

Total Nitrate and Nitrite

Selenium

Antimony

Beryllium

Cyanide (as free Cyanide)

Thallium

Arsenic

Radionuclides

Radium-226

Radium-228

Gross Alpha Particle Activity

SECTION 33 20 00 Page 16

Secondary Contaminants

Aluminum

Chloride

Color

Dopper

Corrosivity

Fluoride

Foaming Agents

Iron

Manganese

Odor pH

Silver

Sulfate

Total Dissolved Solids (TDS)

Zinc

VOCs

Vinyl Chloride

Benzene

Carbon Tetrachloride

1,2-Dichloroethane

Trichloroethylene para-Dichlorobenzene

1,1-Dichloroethylene

1,1,1-Trichloroethane cis-1,2-Dichloroethylene

1,2-Dichloropropane

Ehtylbenzene

Monochlorobenzene o-Dichlorobenzene

Styrene

Tetrachloroethylene

Toluene trans-1,2-Dichloroethylene

Xylenes (total)

Dichloromethane

1,2,4-Trichloro-benzene

1,1,2-Trichloro-ethane

SOCs

Alachlor

Atrazine

Carbofuran

Chlordane

Dibromochlororpropane

2,4-D

Ethylene Dibromide

Heptachlor

Heptachlor epoxide

Lindane

Methoxychlor

Polychlorinated Biphenyls

Pentachlorophenol

Toxaphene

2,4,5-TP

SECTION 33 20 00 Page 17

Benzoapyrene

Dalapon

Di(2-theylhexyl) Adipate

Di(2-ethylhexyl) Phthalate

Dinoseb

Diquat

Endothall

Endrin

Glyphosphate

Hexachlorobenzene

Hexachlorocyclopentadiene

Oxamyl (Vydate)

Picloram

Simazine

3.5.4 Sand Test

As part of each capacity test, or at the end of each intermittent pumping, a determination of the amount of sand (filter pack and/or foundation material) a well is producing shall be performed. Prior to starting the sand test all material shall be removed from the bottom of the tailpipe.

Test each well by pumping at a rate of minimally 150 gpm. After the pump is at the desired pumping rate the flow from the discharge shall be diverted through a Rossum Sand Tester. Development of the well is satisfactory if the amount of sand collected is less than 1 pint per 25,000 gallons of water pumped at the specified rate. Upon completion of the test the amount of sand in the tailpipe shall be determined to verify that no material is being deposited in the bottom of the well.

3.6 INSTALLATION OF PERMANENT PUMP

The permanent well pump intake shall be installed in the well at a minimum depth of 101 feet below ground level. The pump shall be secured at the required elevation as recommended by the pump manufacturer. After installation of the pumping units and appurtenances is complete, operating tests shall be carried out to assure that the pumping installation operates properly. Tests shall assure that the pumping units and appurtenances have been installed correctly, that there is no objectionable heating, vibration, or noise from any parts, and that all manual and automatic controls function properly.

3.7 DISINFECTING

After completion of tests of well, or installation of permanent pump, or at time of tests for yield and drawdown test, whichever is later, the wells shall be disinfected by adding chlorine, conforming to AWWA B301, or hypochlorite, conforming to AWWA B300, in sufficient quantity so that a concentration of at least 50 ppm of chlorine shall be obtained in all parts of the well. Chlorine solution shall be prepared and introduced into the well in an approved manner and shall remain in the well for period of at least 12 hours but not more than 24 hours. Information on methods for preparing chlorine solution and introducing it into the well may be found in AWWA C654. After the contact period, the well shall be pumped until the residual chlorine content is not greater than 1.0 ppm. The well shall be pumped to waste for an additional 15 minutes with less than 1 ppm chlorine residual after which two samples shall be taken not less than 30 minutes apart and tested for the presence of coliform bacteria. The well shall be disinfected and redisinfected as may be required until two consecutive samples of water are found upon test to be free from Coli Acrogenes group

SECTION 33 20 00 Page 18 of organisms.

3.8 SURFACE COMPLETION

The inner well casing shall be cut off approximately 6 feet below grade and the pitless adapter unit field welded on so that the top of the pitless upper casing flange is minimally 18 inches above ground surface. The annulus between the out surface casing and the pitless unit shall be backfill with clean fill sand. The slab shall be constructed preventing the infiltration of surface water or precipitation into the well. The slab shall be 5 feet 6 inches square by 6 inches thick and constructed of reinforced concrete. The upper casing flange on the pitless adapter unit shall extend 12 inches above the top of the slab.

3.9 SITE CLEAN-UP

After completion of the work, remove tools, appliances, surplus materials, temporary drainage, rubbish, and debris incidental to work. Excavation and vehicular ruts shall be backfilled and dressed to conform with the existing landscape. Utilities, structures, roads, fences, or any other pre-existing item which must be repaired or replaced due to the Contractor's negligence shall be the Contractor's responsibility; repair or replacement shall be accomplished prior to completion of this contract.

3.10 DRILLING WASTE DISPOSAL

Slurry, drill cuttings, rock core; other solid or liquid material bailed, pumped, or otherwise removed from the borehole during drilling, installation, completion, and well development procedures; and fluids from material/equipment decontamination activities shall spread on site.

3.11 SURVEYS

Coordinates and elevations shall be established for each well/test hole.

Horizontal coordinates shall be determined to the closest 1.0 foot and referenced to the State Plane Coordinate System, or Universal Transverse

Mercator (UTM). If the State Plane Coordinate System/UTM is not readily available, an existing local grid system shall be used. A ground elevation to the closest 0.1 foot shall be obtained at each well. The highest point on the top of the riser pipe will serve as a measurement point. The elevation of the well shall reference this point, and shall be surveyed to the nearest 0.01 foot using the North American Vertical Datum of 1988. If the datum is not readily available, the existing local vertical datum shall be used. The location, identification, coordinates, and elevations of the well and monuments shall be plotted on maps with a scale large enough to show their location with reference to other structures.

3.12 WELL DECOMMISSIONING/ABANDONMENT

Any well disapproved by the Contracting Officer, or any well decommissioned/abandoned by the Contractor for any reason shall be decommissioned/abandoned according to the requirements of the New Mexico

Office of the State Engineer, and the requirements of these specifications. Well decommissioning/abandonment includes the removal of all materials left in the borehole/well, excluding the filter pack, and including backfill materials, casing, screen, and any other material placed into the hole before the decision was made to abandon the borehole/well.

Test holes decommissioned/abandoned for any reason shall be grouted from the bottom to within 2.5 feet of the top of the ground surface according to

SECTION 33 20 00 Page 19 the protocol for grout/bentonite placement established in paragraph Grout

Placement, using the grout mix specified in paragraph CEMENT GROUT. The top 2.5 feet shall be backfilled with material appropriate for the intended land use. Maintain a well decommissioning/abandonment record as specified herein.