Water School

DeCordova Bend Dam and Lake Granbury were constructed by the Brazos River Authority and are maintained and operated by the BRA as a source of water supply.Construction of the project began in December 1966 and was completed in September 1969. The reservoir provides 129,011 acre-feet of storage capacity for conservation of flood and storm waters to meet requirements of municipalities, industries, agriculture and mining.  The reservoir has a permitted yield of 64,712 acre feet. ...

Lake Limestone, located on the upper Navasota River in Limestone, Robertson and Leon counties, is a water supply reservoir built by the Brazos River Authority in 1978. Construction of the reservoir was made possible through the sale of water to Texas Electric Utilities to be used by their lignite-burning electric plants in the area.  To view a copy of the Lake Limestone state permit, click here.Water from the reservoir is supplied for similar use at a NRG steam-electric plant just...

A variety of maps of the Brazos basin can be found on the BRA’s website by clicking here.

Floodgates are solid metal barriers in a dam that can be opened to release flood waters downstream.

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. 

Maps of BRA lakes may be found online by visiting each reservoirs' web page: Possum Kingdom, Granbury and Limestone.  Printed maps of each reservoir are available free of charge at each lake office or by calling the Public Information Office at (888) 922-6272.

The on-water facility fee to place a dock on a BRA reservoir basically allows the permit holder to build and maintain a permanent structure over BRA property (the lake bed). It also gives the BRA the ability to ensure that the docks that are constructed on the reservoir are safe. The permit fee is not a tax, but a one-time fee.  There are no longer annual fees to maintain a dock on a BRA reservoir.  For an on-water facility permit application, click here.

Lakeside property owners can build docks on a BRA-owned reservoir if they complete an On-Water Facility Permit application and pay the relevant fees for inspection of the facility plans and completed work.  Lake regulations set requirements property owners must meet when building a dock.  Details on these regulations may be found in Section 7 of the BRA regulations.Permit applications may be obtained at each reservoir's office or by going to the appropriate website: Possu...

Motorized boats, sailboats extending 14 feet or longer, and vessels documented by the U.S. Coast Guard all must show proof of state registration when operating on Texas public waters, which includes the Brazos River, according to Texas law. This law does not apply to non-motorized rubber rafts, kayaks, punts, rowboats, or other vessels under 14 feet in length that have the ability to be paddled, oared, windblown, or poled. To learn more about water vessel requirements of public Texas waters, cli...

Primary Amebic Meningoencephalitis, or PAM, is a disease caused by the ameba Naegleria fowleri. It infects humans when water containing this ameba enters the body through the nostrils, according to the Texas Department of State Health Services.  The infected water travels to the brain through the nose, destroying brain tissue. While rare, PAM affects 1 to 3 people in the U.S. every year, according to the Centers for Disease Control and Prevention. PAM is usually fatal. Early symptoms of PAM...

The US Army Corps of Engineers (Corps) operates eight flood control reservoirs within the Brazos River basin that, through a contract with the federal government, also serve as water supply impoundments for the Brazos River Authority system of reservoirs.Lakes Proctor, Whitney, Aquilla, Belton, Stillhouse Hollow, Georgetown, Granger, and Somerville store water for use by municipal, agricultural, industrial, and mining use.Similar to the Authority’s three water supply reservoirs, water cont...

Allens Creek Reservoir is a planned water storage lake permitted for construction on Allens Creek, a tributary of the Brazos River, in Austin County. The permit to build the lake was originally issued to Houston Lighting and Power (Reliant Energy) in 1974 by the Texas Natural Resource Conservation Commission, now known as the Texas Commission on Environmental Quality (TCEQ).The reservoir was originally to have served as a cooling lake for a nuclear power plant. When Reliant Energy abandoned plan...

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.)

Emergency use of water is an exemption to the state’s water rights permitting that allows counties and rural fire departments to draw water from surface water sources in the event it is needed for an emergency situation.

An off-channel reservoir is a water supply lake built next to or near a river.  Off-channel reservoirs are considered by some to be environmentally friendly, lessening the impact on fish and other wildlife by avoiding the need to place a large dam directly on the main stem of the river.An example of an off-channel reservoir is the Brazos River Authority’s planned and permitted Allens Creek Reservoir, near Houston. For more information about Allens Creek, click here.

As the name implies, water supply lakes are built primarily to provide a place to store water for Texas residents, communities, businesses, agriculture, industry and others who all depend on water to survive and thrive. Such lakes are especially vital during periods of drought, when other sources of water may be limited.  Many of Texas’ flood control lakes serve a secondary purpose as a water storage facility.  However, reservoirs designed for water supply, do not necessarily also provide flood...

A dam is a structure designed to hold back water in a lake, river, stream or other waterbody. Large dams typically include gates or other outlet devices that can be raised or lowered, opened or closed to allow variable amounts of water to pass downstream or leave the lake. The path the water takes to leave the reservoir through the gates is called a spillway.There are several styles of dams used for different purposes to meet specific conditions at the dam site.  The design of the dam is in...

A reservoir may be a pond, lake or basin, either natural or man-made, used for the storage, regulation and control of water.

Natural lakes have been a rare commodity in Texas. In fact, the state had only one natural lake, Caddo Lake in East Texas, that was formed by a log jam.  A permanent dam was installed at the lake in the early 20th century.A large number of the state’s remaining lakes were made in response to the occasional propensity of Texas’ usually tranquil rivers to flood during heavy rains.Texas’ early history is filled with accounts of devastating floods causing loss of human life an...

While the process may vary for each location, here’s a general outline of how a reservoir goes from idea to reality.Once a need for water in an area is established, a site for the reservoir must be chosen. Several factors go into this decision, including nearness to a source of demand, a feeder supply of water (such as a river or creek), the geological suitability of the area and engineering constraints. Other factors considered could include impact on the environment, the local population...

The great majority of our lakes (reservoirs) in Texas were built to help tame the state’s rivers and streams, which from time to time would swell beyond their banks and cause devastating floods. Such was the case with the Brazos River. History books record numerous destructive floods took place in the Brazos basin before a series of dams were built along its length to create reservoirs to hold periodic flood waters.

Mean sea level is the average height of the ocean’s surface, between high and low tide. It is used as a standard in reckoning land and other elevations such as lake levels. A lake’s conservation pool will be measured as a certain number of feet above mean sea level.

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...

Texas streams and rivers are in constant motion and the waters they pour into our reservoirs carry with them a continuous but varying amount of sediment.When the water is slowed or stopped as it runs into a reservoir or by a dam, the sediment drops to the bottom. This sediment builds up year after year and at some point, fills the reservoir to a point it can no longer continue to serve its purpose in flood control or water supply. Without expensive dredging, this would be the end of the res...

The conservation pool of a reservoir is a specified amount of water dedicated to water storage. This water is to be used to meet water needs, including municipal, domestic, agricultural, industrial, and recreational.