Anyone who has seen the placid waters of the Brazos as they gently roll across Texas to the Gulf of Mexico would likely find it hard to believe that years ago the river periodically became a roaring giant that would leave destroyed lives and property in its wake.

Fortunately, the devastating problem spurred state and federal officials to build a system of reservoirs to help contain the Brazos’ fury. Indeed, the Brazos River Authority was born from a need to put an end to the flooding.

Today, those reservoirs continue to help stave off disaster through the combined efforts of the Authority and the U.S. Army Corps of Engineers (Corps).

The Brazos watershed stretches more than 1,050 miles from New Mexico to the Gulf, covering about 42,000 square miles in Texas. Large portions of the upper basin are frequently arid. However, even early settlers learned Texas weather can be wild in its extremes, and heavy storms out west can cause runoff that can flood land downriver.

The Brazos basin has experienced numerous massive floods during recorded history, such as ones in 1833 and 1842. During those events the Brazos covered a swath six-miles-wide in some places, submerging the ground between Washington and present-day Navasota in the lower basin.

In his book “The Waters of the Brazos,” writer Kenneth E. Hendrickson Jr. described the desperate conditions after one of these floods as farmers “gathered corn from boats and watched great trees, debris, and the bodies of livestock float by from some unknown upstream location. Rich farmland was loosened from the banks and washed away by the ton…”

Another flood in 1913 caused the river to permanently change course, killed at least 177 people and caused more than $3.5 million in damage. Many of the deaths occurred in sparsely populated areas. It’s hard to imagine what the scale of the disaster would be today in these now-developed communities.

These and later floods prompted state and federal leaders to begin planning a means to slow and store river waters during major rains. The floods led the Texas Legislature in 1929 to create the Brazos River Conservation and Reclamation District, which was renamed the Brazos River Authority in 1955. About the same time, disasters prompted the federal government to task the Corps to respond to floods and develop plans to control them.

Over the next 50 years, the Brazos River basin has seen the construction of numerous water supply lakes including nine major reservoirs designed to provide flood control benefits. 

The Authority worked with the Corps to help build and maintain these flood-control lakes. In return, the Corps has allowed the Authority to store and move water in its reservoirs. Each of these Corps flood control reservoirs has a “conservation pool,” for water supply. Each also has a “flood pool,” additional space that can contain flood waters. The Corps determines when and how much of these flood waters to release from their reservoirs.

While the Authority’s three reservoirs, Possum Kingdom, Granbury and Limestone do not have flood pools, they are part of the larger flood control system. For instance, during heavy rains and runoff in the upper basin, Authority staff release water from the dams at Possum Kingdom and Granbury to make room for the water coming into the lakes. This water travels to the Corps’ Lake Whitney, which has a massive flood pool that can hold about 1.3 million acre-feet of water, said Brad Brunett, Authority water services manager. Lake Whitney has enough room to hold about two times the capacity of Possum Kingdom and Granbury combined, he said.

The water is stored in Lake Whitney until it can be gradually released into the Brazos downstream in a safe manner. The Corps’ other reservoirs in the system play a similar role by retaining water on Brazos tributaries. This keeps them from flooding the larger river as it snakes to the Gulf.

“When we have high inflows to either of our reservoirs upstream of Lake Whitney (Granbury and Possum Kingdom), we communicate with the Corps on a real-time basis each time we make a change to the release rate,” Brunett said. “We also communicate this information to the National Weather Service West Gulf River Forecast Center, which provides forecasts of flow conditions downstream.“This allows the Corps to know how much water is headed for Lake Whitney so it can manage that reservoir and its releases in conjunction with the other Corps’ reservoirs in the basin.”

An essential part of this system is the series of gages installed and maintained by the United States Geological Survey (USGS). These measure the depth and flow rate of the Brazos and its tributaries. Engineers and hydrologists monitor the gages to determine the timing and number of gates to open at the various lakes to balance water moving through the system. The Authority posts regular readings from many of these gages on our Web site, here.

Together, working with other federal, state and local agencies, the Authority and Corps help manage and prevent potentially catastrophic floods by operating the reservoir system. Through hard lessons learned by early Texans, officials have set up a system to keep the mighty Brazos tame.