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Andrew Keller - 2 - 9 April 2007 <br />0 <br />During construction, the Discharger would use BATF Field Screen test results to <br />evaluate placement of cap material and need for re -work. The Discharger stated <br />that any cap area that failed the test, whether field test or lab test, would be <br />removed, re -compacted, and re -tested. ASTM D 5084 would be performed at a <br />frequency of one test for every 1,000 cubic yards of placed material. The <br />Discharger would use ASTM D 5084 as the confirmation test method to evaluate <br />installed cap material. <br />b. Staff Comments: Staff concurs with the Discharger's proposed use of the BATF <br />test method as a field screen technique. <br />3. Request to Increase PI Range to 37-43. <br />a. Discharger. Based on current test results of their suppliers' clay, the Discharger <br />requested that the PI range be increased to 37-43. The Discharger requested <br />that no further processing or mixing be performed to bring the clay into <br />compliance with the current requirement of <30 Pl. <br />b. Staff Comments. Staff does not concur with Dischargers requests and the PI <br />should not exceed 30. A PI greater than 30 will cause excessive cracking and <br />desiccation that could lead to preferential flow paths into the waste. In addition, <br />recent studies (performed by ACAP) have shown that cracked and desiccated <br />soils do not regain their original hydraulic conductivity properties after re -wetting. <br />Instead, preferential paths and root intrusions are formed. Moreover, after the <br />cap is installed and if preferential paths and root intrusion are formed, then the <br />Discharger would be required to remove, repair, and replace damaged areas of <br />the cap. <br />If you have questions, please contact me via email (mboyd waterboards.ca.gov) or telephone <br />at (916) 464-4676. <br />/f <br />ary L. Boyd <br />Water Resource Control Engineer <br />San Joaquin River Waste Discharge to Land Unit <br />cc: Dave Otsubo, CIWMB, Sacramento <br />Jeff Bennett, Miller Brooks, Huntington Beach <br />Robert McClellan, San Joaquin County Environmental Health Division, Stockton <br />MLBIMCove\Cove_RvwM2007_GWRprt.doc <br />