The Lower Frio Watershed (HUC 12110108) covers an area of approximately 1,450 square miles in southwest Texas. The primary hydrological feature of the watershed is the Frio River, which flows into the Nueces River. The region experiences a semi-arid climate with hot summers and mild winters. The watershed is not known for significant snowpack, and surface water is limited to the Frio River and its tributaries. There are several small reservoirs within the watershed, which are used for irrigation and recreation. The primary constituents of these reservoirs are sediment, nutrients, and dissolved solids. Climate trends in the region suggest increasing temperatures and decreased precipitation, which may exacerbate already stressed water resources. The Lower Frio Watershed is an important area for agriculture, ranching, and outdoor recreation, but managing water resources sustainably is a critical challenge for the region.