What is the primary source of most surface water in Texas?

The primary source of most surface water in Texas is precipitation that falls within the state. This is because the water cycle plays a crucial role in replenishing rivers, lakes, and reservoirs directly from rainfall. In Texas, the nature of the climate, with periods of significant rainfall followed by droughts, greatly influences the availability and distribution of surface water.

While river systems from neighboring states contribute to some extent, the majority of surface water is derived from local precipitation. Groundwater, while an important resource in Texas, is distinct from surface water, as it is sourced from aquifers beneath the ground rather than from direct atmospheric conditions. Desalination plants, although emerging as a water supply method, do not represent a primary source of surface water and are generally used for treating seawater or brackish water rather than sourcing fresh surface water. Thus, local precipitation is the most prominent contributor to surface water supplies in the state.