Laserfiche WebLink
Vicki McCartney [EH] <br /> From: Amy Terrell [aterrell@waterboards.ca.gov] <br /> Sent: Friday, May 16, 2008 3:06 PM <br /> To: Kristene Tidwell <br /> Cc: SGuthmiller@herumcrabtree.com; Jeff Hawkins; Rob Gailey;Vicki McCartney[EH]; <br /> paulsheldonlaw@yahoo.com <br /> Subject: Re: Scope of Work Letter for Ripon Farm Service Site <br /> Attachments: citymwplan05O8figs.pdf; citymwplan05O8text.pdf <br /> LJ <br /> citymwplan0508figs citymwplan0508tex <br /> .pdf(1 MB) t.pdf(210 KB... <br /> Kristene, <br /> Thank you for sharing the 15 May 2008 Scope of Work for the monitoring wells you intend to <br /> install on Ripon Farm Service property and on adjacent property near City Well 12. For <br /> convenience, a copy of the Scope of Work and accompanying figures is attached. The three <br /> shallow wells slated to be installed on the Ripon Farm Service facility as proposed in a 5 <br /> December 2007 Work Plan previously received Central Valley Regional Water Quality Control <br /> Board (Regional Water Board) concurrence in a 21 December 2007 email. This concurrence <br /> requested that access agreements be secured before installation, and that the work is <br /> overseen by San Joaquin County Environmental Health Department. I understand that the <br /> access agreements are presently in place for all of the well locations. <br /> This email addresses the shallow/deep well pair proposed along North Frontage Road just <br /> west of Ripon Farm Service, and the shallow/deep well pair proposed along the South <br /> Frontage Road just east of City Well 12 . <br /> In a 16 May 2008 telephone discussion with Mr. Matt Sutton of the Source Group, he <br /> clarified that the two-inch diameter deep wells are proposed to be installed through an 8 <br /> inch diameter temporary conductor casing extending to 150 feet below ground surface. The <br /> monitoring well casing will be pressure grouted as the temporary casing is removed, <br /> allowing the grout to fill the annular space and into the formation. The Source Group <br /> shall make an estimate of the volume of grout needed and the amount used during the <br /> withdrawal of the temporary casing to provide some assurance of the competeness of the <br /> sealing. <br /> Pursuant to your 16 May 2008 telephone message, the deep wells (to depths of about 200 <br /> feet) will be installed with 20 foot screens in order to correlate the data more closely <br /> with the existing monitoring wells installed to similar depths. <br /> Thank you for offering to obtain soil samples and analyze them for grain size distribution <br /> and nitrate. This will be particularly valuable information for the on-site shallow <br /> wells, and for completeness, soil samples analyzed for nitrate should also be analyzed for <br /> ammonium. Ammonium is also a primary constituent of concern and can be converted to <br /> nitrate under some environmental conditions. <br /> Regional Water Board staff concur with the proposed installation of the shallow wells as <br /> proposed. <br /> In summary, Regional Water Board staff conditionally concur with the Scope of Work with <br /> the following conditions: <br /> 1. The deep monitoring wells shall be constructed within a conductor casing extending to <br /> about 150 feet below ground surface. The casing may be withdrawn provided grout <br /> completely seals the annular space surrounding the monitoring well casing between the <br /> bentonite chip seal above the screen filter pack and the ground surface. <br /> 2. The deep monitoring well screens should be 20 feet long. <br /> 3. Soil samples analyzed for nitrate should also be analyzed for ammonium. <br /> 4. San Joaquin County Environmental Health Department shall oversee the well <br /> 1 <br />