Natural salt pollution in the upper watersheds of the Brazos River Basin and other neighboring river basins contribute large total dissolved solids (TDS) loads to the rivers. The objectives of the studies of the Brazos River Basin reported here are (1) to enhance understanding of the occurrence, transport, and impacts of salinity in the Brazos River and Lakes Possum Kingdom, Granbury, and Whitney and (2) to improve salinity simulation capabilities of the Water Rights Analysis Package (WRAP) modeling system. Water volume and TDS load budgets are presented for five river reaches covering about 500 miles of the upper Brazos River. WRAP is applied to model the river basin for alternative modeling premises and water management scenarios. The impacts of salinity and salinity control measures on water supply capabilities are assessed.