SITE HISTORY - Laserfiche WebLink

Home Browse Search

radius search for wells around the Delta Disposal site. The search used the available information from the Department of Water Resources files and City of Tracy files to document domestic, agricultural and industrial wells. The information is compiled into a summary table together with a map showing the well locations (see Figure 1 and Well Search Table 1). The well locations are approximate on Figure 1 and based upon the information on the individual well log; in some cases the well location, logging and well construction information may not be precise or incomplete from the well search information on the Well Completion Reports. Also in most cases the current use status of individual wells is not known or confirmed. Groundwater monitoring wells installed for regulatory compliance issues are not plotted on this search. The well search revealed City of Tracy-owned wells, and domestic wells occur in the area in and around the search radius. Several domestic wells are beyond the 2000-foot radius search radius and two domestic wells have been destroyed. Two Tracy Unified School District wells were destroyed in 2000. One irrigation well noted numerous screened intervals but no seal is reported. Based on the available well screen information, the wells appear to be screened below the uppermost aquifer sampled for this study. Well annular seals on the available State reports appear to extend at least 50 feet or greater below the ground surface (except the irrigation well). Some City of Tracy wells did not have a seal depth noted on the reports, however it is assumed these wells were sealed. In our opinion based upon the well information available there does not appear to be a threat to sensitive receptor wells since the contaminant plume appears relatively small and at shallow depth and well seals extend through the shallow aquifer and, screened intervals are below the shallow aquifer. 2.5 Site Maps with Borings, Groundwater Contours,Excavation Areas,Utilities Site maps showing exploratory boring and groundwater well locations, and general site geography are presented in Appendix A. 2.6 Exploratory Boring Logs and Geologic Cross Sections The exploratory boring logs and monitoring well construction details and geologic cross section are presented in attached in Appendix A. 2.7 Volume of Soil Excavated and Groundwater Pumped from the Site The City of Tracy did not have information regarding any soil excavation or any groundwater removal from work performed by the tank removal contractor in 1985. No other soil or groundwater removal work has been performed at this site. 2.8 Fate of On-site Existing Monitoring Wells Three groundwater monitoring wells currently exist at the site adjacent to Sixth Street. Upon the receipt by the City of the approved Closure Summary/NFAR, it is Wright's understanding that the three existing monitoring wells will be properly destroyed by the Page 5 of 17