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Lake Granbury
Frequently Asked Questions
Lakeside Living


Water Quality

The water in the main body of the lake meets standards for contact recreation. However, no surface water is entirely safe for all people, as all surface water contains bacteria that can be hazardous depending on exposure level and the health of the individual. Additionally, there are areas (canals, coves) that are known to contain elevated levels of bacteria. For additional information on waterborne illnesses, click here.


Golden Algae

Unfortunately no, golden algae is present at Lake Granbury and most other rivers and reservoirs in northwest Texas year round; however, fish kills occur only when the algae blooms and becomes toxic. Thankfully, we have not had a significant bloom in several years.

At this time there is no way to treat golden algae without doing significant damage to the environment and endangering our water supply. However, a number of groups across the nation are doing research on this topic and hope to find a treatment sometime in the future.


Water Sales

The State of Texas owns all surface water in the state and the Texas Commission on Environmental Quality is the agency responsible for regulating (permitting) the use of this surface water. The TCEQ issues the water rights for reservoirs in Texas.

The water rights issued to the Brazos River Authority grant the ability to store and use water for beneficial purposes, including the sale of water for municipal, steam-electric cooling and other uses. BRA owns the water right for Lake Granbury (and 10 other lakes) and provides water to our customers by contract under the terms of that water right. To view the permit granting the Authority water rights at Lake Granbury, click here.

Lake Granbury was built without the use of any tax dollars; having been financed entirely with revenues from the sale of water. The principal revenues used to finance the project were and continue to be provided under a contract with TXU Electric Company (now Luminant) for purchase of water for steam-electric cooling for a natural gas-fired power plant on the lake and the Comanche Peak nuclear power plant.

Current water use from Granbury can be broken down as follows:

  • 50,000 acre-feet per year for steam-electric cooling
  • 7,000 acre-feet per year for municipal use
  • 6,000 acre-feet per year for irrigation
  • 500 acre-feet per year for mining (additional mining use of approximately 2,500 acre-feet per year is supplied downstream of Lake Granbury with releases from Possum Kingdom that are passed through Lake Granbury.)

Lake Levels

Lake Granbury was built without the use of any tax dollars; having been financed entirely with revenues from the sale of water. The principal revenues used to finance the project were and continue to be provided under a contract with TXU Electric Company (now Luminant) for purchase of water for steam-electric cooling for a natural gas-fired power plant on the lake and the Comanche Peak nuclear power plant.

The lake was completed in 1969. The top of the conservation pool is at elevation 693-ft. Since completion:

  • 31 percent of the time the elevation has been below 692-ft
  • 16 percent of the time the elevation has been below 691-ft
  • 11 percent of the time the elevation has been below 690-ft
  • The lowest recorded elevation is 681.46-ft

For a chart of historic lake levels, click here.

The lake dropped to a historic low of 681 feet mean sea level or just below the 5- percent capacity of the reservoir. Since the lake’s creation, it has experienced only six other occasions where the level dropped below 688.3 msl (75 percent full) occurring in 1971, 1974, 1978, 1984, 2011 and 2014.

Lake Granbury was completed in September 1969 and filled to capacity before the end of that year. Since that time, the lowest the lake has dropped was in 2014 when the level hit 681.47 msl; just over 11 feet below the top of the conservation pool. For a chart of historic lake levels, here.

The lake level dropped to its historic low level in 2014 for a number of reasons; some naturally occurring, some man-made. However, the reservoir would have been lower without the benefit of the water released from storage in Possum Kingdom Lake as a result of the Possum Kingdom-Granbury Water Management Study. These fluctuations in lake levels are typical for water supply lakes, as those levels respond to use, evaporation, inflows and rainfall.

Lake Granbury is permitted by the State of Texas and is an integral component for water supply in the State Water Plan. Like all water supply lakes, it was built to accumulate and store water during times of abundance for use when rainfall and river flows are inadequate to meet water needs.

The BRA is permitted by the state to annually withdraw up to 100,000 acre feet for water sales from Lake Granbury. Though this may seem like a lot of water, during years with normal rainfall, streamflow and runoff keep the lake relatively full. Over the last 25 years, annual inflow to Lake Granbury has averaged about 470,000 acre feet per year.

As a water supply lake, Granbury is part of a system of lakes operated by the Brazos River Authority. Releases are made for several reasons, including:

  • water supply by users near the lake and downstream,
  • to pass through water released from the lake above Lake Granbury, and
  • to refill storage in the lake below Granbury.

The BRA maintains a small daily release to help provide a viable habitat for the environment of the Brazos River below Lake Granbury. However, the BRA also maintains a continuous release from Possum Kingdom Lake that was initially regulated by that reservoir's Federal Energy Regulatory Commission (FERC) license. These minimum releases were integrated into an agreement with FERC when the hydroelectric plant was decommissioned.

The releases made from Lake Granbury do not supply water to the nuclear power plant. The nuclear power plant supply is taken directly from Lake Granbury.

The current lake level is measured by a USGS gage situated at the dam. You may find that level by clicking here, or you may view current lake levels posted in the BRA home page here.

The BRA does not provide dredging of the lake bed. Our hydrologists have advised that with time a natural process of heavy rain will tend to clear the main channel of the river in the upper part of the lake. Additionally, the cost to dredge would be in the millions and therefore prohibitive.


Water Supply

On average, 43,000 acre-feet per year is pumped from Lake Granbury to Squaw Creek Reservoir for use at the current Comanche Peak plant.

Water released from Squaw Creek Reservoir is currently not returned to Lake Granbury. The water released from the plant flows down Squaw Creek and joins the Brazos River downstream of Lake Granbury.

Current water use from Granbury can be broken down as follows:

  • 50,000 acre-feet per year for steam-electric cooling
  • 7,000 acre-feet per year for municipal use
  • 6,000 acre-feet per year for irrigation
  • 500 acre-feet per year for mining (additional mining use of approximately 2,500 acre-feet per year is supplied downstream of Lake Granbury with releases from Possum Kingdom that are passed through Lake Granbury.)

The Allens Creek Reservoir near Houston is a separate project that is already permitted by TCEQ and is a good example of how BRA is working to develop new water supplies throughout the river basin.

For example, because Possum Kingdom Reservoir is our largest lake with the greatest amount of storage, it is partially dedicated to meeting demands as far downstream as the Houston area. The new water supplies provided either by the new Allens Creek Reservoir or approval of our System Operations Permit will allow the BRA to meet some of these downstream needs (such as the Houston area) with water from other storage reservoirs resulting in PK retaining water that may have otherwise been released.


Canal Development

Since the construction of Lake Granbury in 1969, the reservoir became increasingly developed with numerous canals constructed by developers to maximize lake front property. Canals were constructed without coordination with the Brazos Authority and without consideration for the potential negative impacts on water quality. The BRA began comprehensive water quality monitoring of many of the canal systems in 2002 and documented many areas with poor water quality that were attributable to canal designs that resulted in stagnant backwater conditions. In October, 2002, the BRA’s General Manager placed a moratorium on canal construction to assess the impact of such canals on water quality and the BRA’s water resource. Additionally, the Lake Granbury Watershed Protection Plan project was initiated with the objective of assessing and managing potential pollutant sources in the many canals and coves.

Yes, the moratorium on canal cut-throughs was instituted to ensure responsible management, development and protection of the lake. The moratorium allowed the Authority to assess the impact to the reservoir of future canal development including environmental/water quality issues, construction and design and administrative impacts.

Properties within the county are still subject to the canal moratorium. Hood County representatives have stated support for canal design standards but, at this time, do not intend to amend their sub-division rules to regulate canal construction. They are satisfied with leaving the moratorium in place for areas of Lake Granbury outside the city's jurisdiction. If Hood County eventually adopts the regulatory standards, the Brazos River Authority's Board would consider lifting the moratorium within the county as it did for the city.

The moratorium was initiated by the general manager/chief operating officer in October 2002.

Yes, the City of Granbury has adopted these standards for future canals to be developed within the city's jurisdictional areas. As a result, the moratorium on new canals has been lifted in the city. However, at this time, Hood County has not adopted these standards, so the moratorium remains in place within the county jurisdiction.