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

c. Where two strata containing poor-quality water, pollutants, or contaminants are separated by a stratumto be protected, the annular space opposite the stratum to be protected, the confining strata underlyingand overlying the stratum to be protected, and the upper stratum containing poor-quality water,pollutants, or contaminants shall be sealed off.~ -70-The supplementary seals described in the cases above shall be extended up to and contact the base of therequired minimum annular surface seal described in Section 7 above, if they are otherwise required to bewithin 10 feet of the surface seal. Sealing the entire annulus above the anode interval will often economicallyfulfill the conditions outlined above.Requirements for sealing materials and their placement are described in Section 7, above.Section 11. Repair of Cathodic Protection Wells.Materials used for repairing cathodic protection well casing shall meet the requirements of Section 9, above.Section 12. Temporary Cover.The well or borehole opening and any associated excavations shall be covered at the surface'to prevent theentry of foreign material, water, pollutants, and contaminants, and to ensure public safety whenever work isinterrupted by such events as overnight shutdown, poor weather and required waiting periods to allow settingof sealing materials and the performance of tests. The cover shall be held in place or weighted down in sucha manner that it cannot be removed except by equipment or tools.