California Water Well Standards, DWR Bulletin 74 ... - County of Glenn

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~ 1.Section 12. Casing.The term "casing" in its broadest sense includes all tubular materials that are permanent features of a well.Screens, collars, risers, liners, and blank casing in monitoring wells maintain the well bore and provide apassage for ground water level measurement and/or sample-collection devices.Protective casing serves to prevent accidental or intentional damage to a well. Protective casing normallyconsists of heavy gauge metallic pipe placed over the portion of the well casing that extends above groundsurface.Conductor casing usually functions as a temporary means of shoring the walls of a well boring to allow drillingand the placement of well construction materials. If used, temporary conductor casing is usually driven intoplace during drilling and is withdrawn at the same time filter pack and annular seal materials are installedaround the well casing. Sometimes conductor casing is left in place and is made a permanent feature of thecompleted well structure. Requirements for sealing permanent conductor casing in place are contained inSection 9.For the purpose of these standards, the term "casing" applies to screens, collars, risers, and blank casing, andother specialized products used to maintain the well bore. General discussion and standards for casingmaterials are contained in Section 12 of the Water Well Standards. Special considerations that apply tomonitoring well casing are described below:ACasinl! Material.Chemical ComRatibility. Special consideration shall be given to the selection of casingmaterials for monitoring wells installed in environments that are chemically "hostile".The selected casing shall resist chemical attack and corrosion.Special consideration should be given to the selection of casing materials for wells tobe used for sensitive water-quality determinations. Chemical interaction between casingmaterials and pollutants, contaminants, ground water, filter pack material, and geologicmaterials could bias ground-water quality determinations.2. Used Casing. Used casing may be acceptable in certain cases, at the approval of theenforcing agency.3. Plastic and Steel Casing. Plastic and steel well casing materials are commonly used formonitoring wells. The principal plastics used for water-quality monitoring wells arethermoplastics and fluorocarbon resins.Standards for thermoplastic well casing are in Section 12 of the Water Well Standards.The principal thermoplastic material used for water quality monitoring wells is polyvinylchloride (PVC).Fluorocarbon casing materials include fluorinated ethylene propylene (FEP) andpolytetrafluoroethylene (PTFE). Fluorocarbon resin casing materials are generallyconsidered immune to chemical attack. Fluorocarbon casing materials shall meet thefollowing specifications, including the latest revisions thereof:a. ASTM D3296, Standard Specification for FEP-FLuorocarbon Tube.b. ASTM D3295, Standard Specifications for PTFE Tubing.-47-
Stainless steel is the most common form of metallic casing used in monitoring wellsconstructed for sensitive water quality determinations. Stainless steel casing shall meetthe provisions of ASTM A312, Standard Specification for Seamless and WeldedAustenitic Stainless Pipe, and shall meet general requirements for tubular steel productsin Section 12 of the Water Well Standards.Multi~le Screens. Monitoring well casing strings shall not have openings in multiple waterbearingunits (multi-level monitoring wells), if poor-quality water, pollutants, or contaminantsin units penetrated by the well could pass through the openings and move to other unitspenetrated by the well and degrade ground water quality, unless otherwise approved by theenforcing agency.c. Bottom Plugs. The bottom of a monitoring well casing shall be plugged or capped to preventsediment or rock from entering the well.D.Casing Installation. Discussion and standards for the installation of casing materials are inSection 12 of the Water Well Standards. Special considerations for monitoring wells are:Cleanliness. Casing, couplings, centralizers, and other components of well casing shallbe clean and free of pollutants and contaminants at the time of installation.Joining Plastic Casinl!. Depending on the type of material and its fabrication, plasticcasing shall be joined (threaded or otherwise coupled) in a manner that ensures itswater tightness. Organic solvent welding cements or glues should not be used forjoining plastic casing if glues or cement compounds could interfere with water-qualitydeterminations.3. Im~act. Casing shall not be subjected to significant impact during installation that maydamage or weaken the casing.Section 13. Well Development.Monitoring well development, redevelopment, and reconditioning shall be performed with care so as to prevent.damage to the well and any strata surrounding the well that serve to restrict the movement of poor-qualitywater, pollutants, and contaminants. Development, redevelopment, and reconditioning operations shall beperformed with special care where a well has been constructed in an area of known or suspected pollution orcontamination. Such special care is necessary to prevent the spread of pollutants and contaminants in theenvironment and to protect public health and safety.Water, sediment, and other waste removed from a monitoring well for "development" operations shall bedisposed of in accordance with applicable federal, State, and local requirements. The enforcing agency shouldbe contacted concerning the proper disposal of waste from development operations.Appropriate methods of well development vary with the type and use of a monitoring well. Developmentmethods that may be acceptable under certain circumstances include:A Mechanical Surging. Plungers, bailers, surge blocks, and other surging devices shall incorporate2.safety valves or vents to prevent excessive pressure differentials that could damage casing orscreen..B. 1.-48-
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--1#~Water wells .1Cathodic protect
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. ~~Bulletin 74-81)N. KennedyResour
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~vState of CaliforniaPETE WILSON, G
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~ viiForewordOrganization.TABLE OF
Page 10 and 11: ~ ix(4) Glass Fiber Reinforced Resi
Page 12 and 13: E~B. Sealing Conditions. 421. Tempo
Page 14 and 15: ~CATHODIC PROTECTION WELL STANDARDS
Page 16 and 17: 5.~Introduction:Figure 1.Years DWR
Page 19 and 20: GENERAL INTRODUCTIONImproperly cons
Page 21 and 22: Figure 1. YEARS DWR WELL STANDARDSB
Page 24 and 25: .9-REVISIONS TO WATER WELL STANDARD
Page 26 and 27: ~STANDARDSPart I. GeneralSection 1.
Page 28: ~B. c.-13-Many variables are involv
Page 32 and 33: "8. 2.casing and the borehole wall
Page 34 and 35: d. ~c.water shall be used if less s
Page 36 and 37: 3. Foundation and Transition Seals.
Page 38 and 39: -23-otherwise approved by the enfor
Page 40 and 41: Thermoplastic well casing that may
Page 42 and 43: ~.Introducing.Combinationsspecifica
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Page 47: Advances in analytical and environm
Page 50 and 51: Nested monitoring wells consist of
Page 52 and 53: c.STANDARDSPart I.GeneralSection 1.
Page 54 and 55: 1.Part II.Monitoring Well Construct
Page 56 and 57: 1. 3.casing shall in turn be at lea
Page 58 and 59: c.Casing spacers shall be designed
Page 62 and 63: B. c. E.Over~um~ing and Pum~ Surgin
Page 64 and 65: 2. b.Section 19. Requirements for D
Page 66 and 67: 3. 5. E.freefall only where the int
Page 69 and 70: INTRODUCTIONMost wells in Californi
Page 72: Many cathodic protection wells have
Page 75 and 76: Need for Cathodic Protection Well S
Page 77 and 78: (Division 3, Chapter 9, California
Page 79 and 80: 3. B.E. c.consolidation after place
Page 81 and 82: for surface construction features a
Page 83 and 84: ~Part III.Destruction of Cathodic P
Page 85 and 86: E.these standards, or standards ado
Page 88 and 89: ~APPEN DIX ADefinition of Terms-A m
Page 91: National Association of Corrosion E
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California Water Well Standards, DWR Bulletin 74 ... - County of Glenn

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