Water School

The Clear Fork is one of the longest tributaries of the Brazos River. It originates as a draw in Scurry County and runs for about 307 river miles through  Fisher, Jones, Shackelford, Haskell, Stephens, and Throckmorton counties before joining the river’s main stem in Young County north of Possum Kingdom Lake.For a full-sized map, click here.

The United States Geological Survey (USGS) is a federal scientific agency that works in biology, geography, geology and hydrology. USGS is the nation’s primary civilian mapping agency. The agency also monitors streams and other bodies of water across the country for flow and depth. Among its other activities, USGS also monitors earthquakes and volcanic activity.The USGS web site may be found by clicking here.

A river basin is the area drained by a river and its tributaries. A river basin is synonymous with the term “watershed.”  For example, the Brazos River basin refers to the same area as the Brazos River watershed.  photo courtesy Texas Parks and Wildlife

A 500-year flood is a high streamflow that overflows the natural or artificial banks of a waterway and has a two-tenths of 1% chance of occurring in any given year.

A 50-year flood is a high streamflow that overflows the natural or artificial banks of a waterway and has a two percent chance of occurring in any given year.

The height above mean sea level that water in a reservoir has reached. Brazos River Authority and U.S. Army Corps of Engineers lakes are actually reservoirs, or parts of the Brazos River basin impounded by dams. (A free-flowing river is measured in stages, that is, by depth from the river bed to the surface.)