The analysis and interpretations by three disciplines - geology, hydrology, and chemistry - have been integrated to form a model of brine reservoir genesis, and to assess the current and future status of brine reservoirs as they relate to the WIPP site. In summary, the brine reservoirs appear to be local, isolated features that have reached equilibrium with their environment. Evidence for long-term hydraulic and chemical isolation includes: Hydraulic heads that are substantially different from reservoir to reservoir and higher than the heads of local ground waters. The containment of gas by the reservoirs. Brine and associated gas chamistries that differ from reservoir to reservoir. Geographic separation and nonuniform distribution of reservoirs, i.e., extensive drilling has taken place in this area, but only a few wells have intercepted pressurized brines. There is no evidence for a continuous, extensive aquifer in the Castile. Bulk chemical equilibrium between the brine, gas, and reservoir rock in the ERDA-6 and WIPP-12 reservoirs.