The United States Bureau of Reclamation (Reclamation) and the Utah Division of Water Resources (UDWRe) have partnered to conduct the Great Salt Lake Basin Study (GSLBS) under Reclamation's WaterSMART Basin Study Program which has supported many successful Basin Studies on vulnerable river basins across the West since 2009. The GSLBS will provide the technical basis and tools necessary for execution of the Great Salt Lake Basin Integrated Plan (GSLBIP). The GSLBIP is a high-profile and highly collaborative basin-wide effort to address the vulnerabilities due to a changing climate and increased demand in the Great Salt Lake Basin. At the heart of the GSLBS is a suite of four linked computer models that simulate the origin, movement, and use of water in the GSL Basin. The four models in this suite are:

1. Downscaled regional climate models
2. Hydrology models
3. Water demand models
4. River Planning Model (RPM)

The final model in the succession of the four, the RPM, is a RiverWare© model which simulates the complex dynamics of the waters of the GSL Basin from headwaters down to the GSL. These dynamics include both natural physical processes as well as human management processes within the basin. The RPM will include representations of the five major subbasins that comprise the GSL Basin.

1. Bear River Basin
2. Weber River Basin
3. Utah Lake Basin
4. Jordan River Basin
5. Great Salt Lake (local) Basin

In this presentation, the model's purpose and role within the GSLBS and GSLBIP will be described. The highly collaborative development process, which includes five RiverWare modelers from the Modeling Team, many scientists and engineers from both the UDWRe and Reclamation, as well as stakeholder groups from each subbasin will be outlined. Several unique modeling challenges that have been encountered and addressed will be presented including complex municipal use throughout the highly urbanized Wasatch Front and modeling the unique and complex Great Salt Lake. Finally, a preview of how the model will be used to develop strategies to raise the critically low water levels of the Great Salt Lake will be given.