Water School

The level of water in all lakes fluctuates, raising during years of higher amounts of rainfall and snowmelt and falling during periods of drought. The Environmental Protection Agency has been measuring the fluctuations of the Great Lakes, the largest natural lakes in the United States, since the 1860s. Similarly, water levels in reservoirs, human-made lakes, fluctuate because of evaporation, a lack of rainfall, water supply use, and water flow requirements. Levels tend to be relatively lower in ...

Constant level is a term given to the practice of maintaining a body of water at a specific elevation.  No natural body of water has a constant level.  While some fluctuate more than others, all-natural bodies of water change on a daily basis, some rapidly during floods.Few man-made reservoirs have the ability to be maintained at a constant level as evaporation, drought, water use and/or flooding affect elevation levels. 

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.)

Sedimentation in water treatment is a process in which water is cleaned by allowing solids to settle out of the water by gravity during treatment.

Releases are made for several reasons including water supply for users near the lake and downstream, to pass through water released from another system reservoir, or to refill storage in a downstream reservoir.  For a look at current lake levels, click here.

Periodically, officials conduct surveys of reservoirs within the Brazos River basin to determine each lake’s volume. As part of that work, survey crews determine each lake’s depth (in feet). Do not confuse this measurement with lake level, however.A reservoir’s depth is the distance from the bottom to the top of the conservation pool, the point where the lake is considered full. The lake level is the number of feet the surface is above mean sea level.Surveys use a combinat...