- The Texas Natural Resource Conservation Commission, its partner agencies, and contractors are conducting a statewide Water Availability Modeling (WAM) Project pursuant to Senate Bill 1 enacted by the Texas Legislature in 1997. The Water Rights Analysis Package (WRAP) is the river basin water management simulation model used in the WAM Project. WRAP provides flexible capabilities for analyzing water availability and reliability under a priority-based water allocation system. The water management and use requirements modeled may be quite complex, involving numerous water users governed by various institutional arrangements and configurations of water control facilities. WRAP may be applied to essentially any river basin whether in Texas or elsewhere. This paper describes both the generalized WRAP model and the Texas WAM Project.