ARCHIVED REPORTS_XR0004254 - Laserfiche WebLink

Home Browse Search

d� KEZ-P91-0202 .R7 March 18, 1993 Page 2 whether ground water is threatened, and to what extent, by a given source of contamination. SESOIL is also capable of simulating contaminant transport in washload at the soil surface and volatili- zation rates to the atmosphere. The SESOIL model output is time- varying and is produced for each month of simulation. The SESOIL model is one module of a larger software package called PCGEMS. PCGEMS was developed by the General Sciences Corporation for the Environmental Protection Agency (EPA) . This software was developed to provide an information management tool for use in exposure assessment studies. The State of California Water Resources Control Board (CWRCB) Leaking Underground Fuel Tank (LUFT) Field Manual also references the SESOIL model. Appendix E of the California LUFT manual describes in detail how the SESOIL model was used for general risk appraisal. SESOIL VADOSE ZONE COMPUTER MODEL KEI generated SESOIL models to appraise the risk of hydrocarbon soil contamination impacting the local ground water as a result of activities associated with the above referenced Unocal service station facility. Three different simulations were performed, each of which is described in greater detail below: 1. Simulation #1 The first simulation was conducted with a number of extremely conservative "worst case" assumptions as a first attempt to assess the likelihood and degree of impact of contamination to the local ground water . The input data were divided into four general categories which included climate, soil, pollutant characteristics, and application parameters . The climate data that was used for Simulation #1 was chosen from the SESOIL climate data base. The climate data used was from the Sacramento area, which from the available data was closest both in proximity and characteristics to the Lodi area.