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John Schroeter • • <br /> - 2 - 14 November 2006 <br /> 6. With regard to the infiltration rate discussed in the RWD, please address the <br /> following: <br /> a. The RWD describes performance of double-ring infiltrometer tests to determine <br /> the percolation rate in the bottom of the proposed pond. Section 7.2 of the RWD <br /> states the Camanche lnflltration Rate Study— Summary Report is attached; it <br /> was not attached to the documents that were forwarded to me. Please submit <br /> the document. At a minimum the document should include the following: a <br /> description of the tests including: a statement of procedure, the impact that <br /> excavating the pits may have had on natural soil conditions, the source of the <br /> water used in the tests, the field data sheets, and the report conclusions. <br /> b. The infiltration rate, although presented as conservative in the RWD, may be <br /> significantly reduced by groundwater mounding below the pond. Please address <br /> the possibility that mounding may occur and how it might affect the infiltration <br /> rate. <br /> 7. With regard to the groundwater data presented in the RWD, please address the <br /> following: <br /> a. The groundwater information in the RWD is not site specific and refers to a <br /> groundwater study performed in San Joaquin and Contra Costa County. That <br /> data was collected miles away from the project location and therefore is not <br /> relevant. Groundwater at the site is likely to be much better quality than what is <br /> presented in the RWD. <br /> b. No site-specific groundwater information is provided in the RWD. At a minimum, <br /> please discuss the following: groundwater depth, flow direction, quality, and <br /> seasonal changes that might occur. On-site wells will be required to determine <br /> groundwater conditions. Determination of groundwater quality should be based <br /> on the anticipated constituents of concern. <br /> c. Please address the potential for dissolved solids in the wastewater to be <br /> evapoconcentrated in the pond and subsequently infiltrate and degrade <br /> groundwater quality. <br /> d. If groundwater monitoring wells do not exist at the facility, please use the <br /> attached guidance to prepare a groundwater monitoring well workplan. The <br /> workplan should be submitted for approval prior to implementation. Please note <br /> that all groundwater samples for metals analysis in this investigation should be <br /> filtered prior to digestion and analysis. <br /> 8. With regard to the water balance presented on Table 4 (water balance) please <br /> address the following: <br /> a. Describe the source of the pan evaporation data used in the calculations, the <br /> pan coefficient value used, and how the pond evaporation values were <br /> calculated. <br /> W\SW ObdenTSm Jwquin\Cmmche Dm &r mer 8 Nov M dm <br />