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Mr. Mike Desso . - 2 - • 3 October 2006 ,J agricultural water quality goals for the contaminants of concern. This statement is not relevant to the water quality of the aquifers in which the former facility plumes are migrating within. The determination of impact is based upon the beneficial uses of the groundwater. The beneficial uses of groundwater beneath Ripon and surrounding areas include supply for human consumption.. Determination of impact to each well used for purposes other than human consumption must be made on a case-by-case basis, and should be made after consideration of such factors as the affects that pumping would have on plume spread or aquifer cleanup. The Draft Plan should be revised to include definitions for threatened and impacted agricultural wells. The Draft Plan indicates that the wells covered under the plan are the domestic, agricultural, and municipal supply wells currently included in the MRP. The Draft Plan should be revised to include all supply wells ounemtly included in the MRP, and all supply wells not currently included in the MRP that are later determined to have been impacted by contaminants of concern (COC) emanating from the former facility. Comments on Definitions Regional Water Board staff feels that definitions are only necessary for threatened and impacted wells. However, all of the definitions above are acceptable, with some revisions to the definitions, and inclusion of another definition: impacted agricultural well (and potentially impacted agricultural well if Nestl6 so desires). Nestle should revise the Draft Plan to incorporate the following comments from Regional Water Board staff: 1. Potentially threatened domestic or municipal supply well. The Draft Plan should be revised to indicate that this definition and definitions 2 through 4 below include all water supply wells utilized for human consumption. Also, change the reporting limit (RL) to the quantitation limit (QL) specified in the former facility Monitoring and Reporting Program No. R5-2005-0829 (MRP) issued by the Regional Water Board on 21 July 2005. 2. Threatened domestic or municipal supply well. The Draft Plan should be revised to indicate that a threatened well will be defined as one in which the confirmation sample COC concentration is between the QL and the California Public Health Goal (PHG), or if a PHG has not been established for the constituent, the California Maximum Contaminant Level (MCL). 3. Potentially impacted domestic or municipal supply well. The Draft Plan should be revised to indicate that a potentially impacted well will be defined as one in which the initial sample COC concentration is above the PHG, or if a PHG has not been established for the constituent, the MCL. 4. Impacted domestic or municipal supply well. The Draft Plan should be revised to indicate that an impacted well will be defined as one in which the confirmation sample COC concentration is above the PHG, or if a PHG has not been established for the constituent, the MCL. 5. Potentially threatened agricultural well. The Draft Plan should be revised by changing the RL to the QL specified in the MRP. Also, this definition and definitions 6 through 8 below should include irrigation wells and other types of wells not utilized for human consumption.