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I v California Re¢ional Water Qualityntrol Board Central Valley Region Terry Tamminen Robert Schneider,Chair Arnold Schwarzenegger Secretaryfar 3443 Routier Road,Suite A,Sacramento,California 95827-3003 Governor Environmental (916)255-3000•Fax(916)255-3015 � Protection http:// .seb.ca.gov/mqcbS u UECE I ) ll U FEB 0 5lJ 12/V004 tJ ENVIRONMENT HEALTH 4 February 2004 PERMIT/SERVICES Ted Johnston,Director of Public Works City of Ripon 259 N. Wilma Ave. Ripon, CA 95366 REQUEST FOR WORKPLAN, CITY OF RIPON WASTEWATER TREATMENT FACILITY, SANJOAQUIN COUNTY Regional Board staff recently reviewed the first through third civarter 2003 groundwater monitoring reports submitted by the City of Ripon (City) as required by Revised Monitoring and Reporting Program(MRP)No. 94-263. Those monitoring reports concluded that the groundwater data collected to date is too limited and variable to determine groundwater flow direction and to determine whether the wastewater treatment facility(WWTF) complies with the Groundwater Limitations contained in Waste Discharge Requirements (WDRs) Order No. 94-263. The reports recommended the collection of additional information to the north and east of the site by coordinating the City's groundwater monitoring events with monitoring performed at the Fox River Paper Products facility, the Nestle facility, and the Stanislaus River stage. Staff concur with that recommendation. However, it does not appear that coordinated monitoring alone will be adequate to provide the data needed to assess compliance. Several of the on-site monitoring wells are in close proximity to ponds and the groundwater elevations in those wells may be influenced by groundwater mounding caused by the ponds. This may result in incorrect interpretations of groundwater flow direction and chemical concentration trends. Therefore, additional monitoring wells must be installed further from the ponds in order to provide an adequate groundwater monitoring network. Because of the above concerns, the City of Ripon is required to improve its groundwater monitoring well network and groundwater monitoring program in compliance with the schedule outlined below. The schedule we have imposed is tight,however,we feel it is achievable and necessary in order to install additional wells before the next rainy season. All required technical plans and reports must be prepared by or under the direction of a California Registered Engineer or Registered Geologist, and shall contain a statement of qualifications of the responsible licensed professional(s) as well as the professional's signature and/or stamp of the seal. `1 California Environmental Protection Agency 0 Recycled Paper