COMPLIANCE INFO_FILE 8 - Laserfiche WebLink

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Csz Supplemental Information '1 The subject tank system was registered with the State Water Resources Control Board in May 1986 as 805-41D and has subsequently been renamed underground storage tank 805-D 1 U l (UST 805-D lU 1). Figure 1 (see Appendix B) shows the location of UST 805-D 1 U 1 tank system at Lawrence Livermore National Laboratory Site 300(LLNL). Figure 2 (see Appendix B)shows the utilities and tank piping in the immediate vicinity of the tank which were located by anunderground locator. Figure 3(see Appendix B)shows a plan view of UST 805-DIU1 tank system. UST 805-D 1 U 1 tank system was installed in 1978. A 300 gallon underground tank is shown at this location on a 1975 as-built drawing. UST 805-D 1 U 1 supplies diesel fuel to the Building 805 emergency generator which is immediately southeast of the tank(see Appendix B, Figure 3). The tank system consists of a single-walled 300 gallon carbon-steel tank and associated fill pipe, vent pipe,and supply and return piping. The area to be excavated is covered with gravel. A 9-inch-thick,reinforced concrete anchor pad may be present beneath the tank as suggested by the 1975 as-built drawing. If an anchor pad is present it will be removed as part of this tank closure. If minor soil contamination is found when the tank is removed,LLNL will remove up to 10 cubic yards of suspected contaminated soil.The underlying soil will then be sampled to determine if any contamination is remaining in the soil. Soil contamination that appears to be more than minor,or indication of contaminated groundwater,will result in further investigation and cleanup activities as agreed upon with San Joaquin County. Any contaminated soil removed from the excavation will be stored,sampled and disposed of properly. The emergency generator for Building 805 and UST 805-D 1 U 1 are currently in use. UST 805-D I 1 will be replaced with a new za4�Jallon aboveground storage tank,which will be f placed near the emergency generator. " UST 805-DIUI has never been suspected(if leaking. LLNL had contracted with the Gary Peters Enterprises to perform precision tank tests using the Tank Audit LEAK COMPUTER on this underground diesel fuel storage system for the past 4 years. The most recent test results (conducted by Clayton Environmental Consultants)are included as Appendix C and show the tank and piping to be product tight. The groundwater monitoring well locations shown on Figure 4 of Appendix B are not currently analyzed for the diesel constituents. The nearest existing monitoring well(W-806-06A)is approximately 850 feet south of UST 805-D 1 U 1. Groundwater contamination is not expected due to the tank integrity and the depth to the regional groundwater aquifer is estimated to be greater than 200 feet. Perched groundwater and a water table aquifer have been identified above the regional aquifer in the southeastern part of the High Explosives Process Area. The absence of perched zones near Monitoring Wells W-806-06A and W-810-01 suggest that water-bearing zones above the regional aquifer are not,present beneath Building 805. A State Water Resources Control Board Underground Storage Tank Permit Application Form B will be completed and sent to San Joaquin County Department of Environmental Health once UST 805-DIU1 has been removed. A-1