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

The well shall be sounded immediately before it is destroyed to make sure that no obstructionsexist that will interfere with filling and sealing. The well shall be cleaned before destruction,as needed, to ensure that all undesirable materials, including obstructions to filling and sealing,debris, and pollutants and contaminants that could interfere with well destruction are removedfor disposal. The enforcing agency shall be notified as soon as possible if pollutants andcontaminants are known or suspected to be in a well to be destroyed. Well destructionoperations may then proceed only at the approval of the enforcing agency. The enforcingagency should be contacted to determine requirements for proper disposal of materials removedfrom a well to be destroyed.B.Filling and Sealin1! Conditions. The following minimum requirements shall be followed whenvarious conditions are encountered.1. Wells that onlv ~enetrate unconsolidated material and a sinl!le "zone" of I!round water.At a minimum, the upper 20 feet of the well casing and the annulus between the wellcasing and borehole wall (if not already sealed) shall be completely sealed with suitablematerial. Sealing material shall extend to a minimum depth of 50 feet below landsurface if the well to be destroyed is located in an urban area, or is within 100 feet ofany potential source of pollution or contamination. Additional sealing material maybe needed if adverse conditions exist. The remainder of the well below the minimumsurface seal shall be filled with suitable granular fill material, such as clean sand or peagravel, or with sealing material.Wells that l!enetrate several water-bearin2 strata. The upper portion of the well casingand annular space shall be filled with sealing material as described in Item 1, above.Strata encountered below the surface seal that contain poor-quality water, pollutants,or contaminants that could mix with and degrade water in other strata penetrated bythe well, shall be effectively isolated by sealing the well bore and annulus withinintervals specified in Section 10, above. The remainder of the well shall be filled withsuitable granular fill or sealing material.4.5.Wells l!enetrating fractured rock. Sealing material shall be installed as outlined inItems 1 and 2, above. Cement-based sealing material shall be used opposite fracturedrock. The remainder of the well shall be filled with fill or sealing material, asappropriate.Wells in nonfractured consolidated strata. Sealing material shall be installed asoutlined in Items 1 and 2, above. The remainder of the well shall be filled with fill orsealing material, as appropriate.Wells ~enetrating water-bearing zones or aguifers of s~ecial si2nificance. Theenforcing agency may require that specific water-bearing zones be sealed off for welldestruction.Placement of Material. The placement of sealing materials for cathodic protection welldestruction is generally described in Section 23 and Appendix B of the Water Well Standards.The following additional requirements shall be observed in destroying cathodic protection wells.. 2.3. c.Casing, cables, anodes, granular backfill, conductive backfill, and sealing material shall beremoved as needed, by redrilling, if necessary, to the point needed to allow proper placementof sealing materials within required sealing intervals. Removal of some or all well materials willlikely be required for cathodic protection wells that were not constructed in accordance with-72-