WORK PLANS - Laserfiche WebLink

Home Browse Search

Part II. Cathodic Protection Well Construction Section 6. Well Location With Respect to Pollutants and Contaminants, and Structures. A. Separation. Cathodic protection wells shall be located an adequate distance from known or potential sources of pollution or contamination,where site constraints and corrosion control considerations allow. Potential sources of pollution and contamination include those listed in Section 8 of the Water Well Standards. As specified in Section 7 below, the length of the annular seal for a cathodic protection well shall be increased if the well is located in a congested urban area,or is located within 100 feet of any potential source of pollution or contamination. B. Flooding and Drainage. Cathodic protection wells should be located in areas protected from flooding, if possible. Wells located in areas of flooding shall be protected from flood waters and drainage, including protective measures outlined in Section 8, below. Ground surface surrounding a cathodic protection well shall slope away from the well. Drainage from areas surrounding a cathodic protection well shall be directed away from the well. C. Accessibility. All cathodic protection wells shall be located an adequate distance from buildings and other structures to allow access for well maintenance,modification,repair,and destruction, unless otherwise approved by the enforcing agency. Section 7. Sealing the Upper Annular Space. The space between the cathodic protection well casing and the wall of the well boring,often referred to as the "annular space,"shall be effectively sealed to prevent it from being a preferential pathway for the movement of poor-quality water,pollutants,or contaminants. In some cases,secondary purposes of the annular seal are to stabilize the borehole wall,protect casing from degradation or corrosion,and ensure the structural integrity of the casing. General discussion of sealing requirements and methods is contained in Section 9,Section 13,and Appendix B of the Water Well Standards. Special requirements for sealing cathodic protection wells are: A. Minimum Depth of Annular Seal. 1. Minimum Depth. The annular space shall be filled with appropriate sealing material from ground surface to a depth of at least 20 feet below land surface. The annular space shall be sealed to a depth of at least 50 feet below land surface in congested urban areas, or where a cathodic protection well is within 100 feet of any potential source of pollution or contamination. Additional annular sealing material shall be installed to greater depths where adverse conditions exist that increase the risk of pollution or contamination of ground water. 2. Fill. Any annular space existing between the base of the annular surface seal and the top of the anode and conductive fill interval shall be filled with appropriate fill or sealing material. Fill material should consist of washed granular material such as sand, pea gravel,or sealing material. Fill material shall not be subject to decomposition or -66-