SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

MONITORING AND REPOIAG PROGRAM NO. R5-2010-0810 • - 2 - NESTL� USA, INC. - RIPON SAN JOAQUIN COUNTY 4. In 1986 the Discharger discovered TCE in two Site water production wells. Subsequently, the Discharger determined that TCE has impacted or is threatening to impact some of the City of Ripon's municipal supply and non-potable water supply wells. This pollution has impaired the beneficial use of groundwater resources at the Site. Between 1986 and the present time, the Discharger implemented several interim remedial actions including operation of groundwater and soil vapor extraction and treatment systems, and removal of wells with screens that have allowed for migration of TCE to deeper groundwater bearing materials. 5. Currently, the Discharger operates water treatment systems at 230 Industrial Avenue and 519 Stockton Avenue as interim measures to restrict the TCE migration and remove it from groundwater. The systems discharge treated groundwater to the City of Ripon industrial sewer lines and non-potable water supply lines in Industrial and Stockton Avenues. The industrial sewer lines discharge water to the City's sewage treatment plant which is operated under Waste Discharge Requirements Order No. 94-263, adopted by the Central Valley Water Board on 16 September 1994..-The non-potable-lines-supplywaterto the Ripon Cogeneration Facility at 944 Stockton Avenue and to City parks within Ripon. 6. In April 2005 the Discharger discovered TCE and the related breakdown products vinyl chloride (VC), 1,1-dicholoethene (DCE), cis-1,2-DCE, and trans-1,2-DCE, in two private drinking water supply wells south of the Stanislaus River. The Discharger immediately began providing bottled water to the users of both impacted private drinking water supply wells south of the Stanislaus River and installed GAC treatment systems on both wells to remove TCE and its breakdown products. Also, the Discharger sampled additional private wells and installed groundwater monitoring wells on the south side of the Stanislaus River to determine if other wells were contaminated. 7. The Central Valley Water Board issued Cleanup and Abatement Order No. R5-2006-0720 (CAO) on 24 July 2006 to the Discharger. One of the requirements of the CAO was to submit a water supply contingency plan. The Discharger submitted a draft plan on 7 September 2006, a final plan on 20 November 2006, and a revised final plan on 15 May 2007. 8. The Discharger has conducted extensive soil, soil vapor, and groundwater investigations throughout the central part of Ripon and the area south of Ripon adjacent to the Stanislaus River in Stanislaus County. 9. The Discharger's monitoring program can be generally described as including four (4) Discharger extraction wells, 67 Upper Aquifer monitoring wells, 40 Intermediate Aquifer monitoring wells, 20 Lower Aquifer monitoring wells, twelve (12) City of Ripon municipal supply wells, 14 private domestic drinking water supply wells, one (1) private irrigation well, one (1) school drinking-water supply well—, two (2) school irrigation wells, two (2) Neenah industrial supply wells, and one (1) California Department of Transportation irrigation well. The Monitoring Program for these wells and any wells installed subsequent to the issuance of this Order shall comply with the schedule below. The well locations are presented on attached Figure 1.