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EVEN IN DROUGHT WATER PLANNING IS A FLUID OPERATION

What a difference a rain can make. Not long ago the drought was causing a continuous drain on Brazos basin water supplies, leading to steadily falling lake levels. Then came the heavy rains in early October that dumped more than 8 inches of water in parts of the basin followed by numerous days of misty, intermittant rain events. As a result, the Brazos River Authority closed reservoir gates that had been expected to remain open through the fall and winter.

However, Texas State Climatologist John Nielsen- Gammon continues to predict the drought could last into next year and beyond. In the midst of such severe dry conditions even infrequent rains can have a big impact on water planning.

Before the beginning of October, a gate at Lake Granbury was opened indefinitely to meet continuing needs downstream. At the time, plans were also set for a long term release from Possum Kingdom Lake. Authority hydrologists had predicted that due to those water demands, if the drought conditions continued, the entire reservoir system would be down to 57 percent capacity by Oct. 31. By then Stillhouse Hollow Lake was expected to join lakes Limestone, Georgetown and Procter at Stage 2 – Drought Warning Status.

But then it rained. It wasn’t enough to break the drought but it caused a drop in water demand downstream and led Authority hydrologists to reevaluate their water management plans. Lake levels rose in some places, and the Authority ended the indefinite release at Granbury instituting instead periodic releases lasting 4-5 days. The PK release was pushed further into the future, currently scheduled for mid-December.

So how did the rain affect the system overall? Instead of reaching the projected 57 percent capacity around Oct. 31, water levels now are not expected to drop to that level until mid-February. In other words, the system gained more than 3 months of water supply through just a few rain events.

Water planning is based on conditions at the time it is undertaken. Hydrologists constantly reevaluate the plan as each change occurs, such as rain in the midst of this record drought. With the state receiving rain in past few weeks, you can rest assured the plan will change again.

To learn more about the Authority’s drought status, including current and projected reservoir levels, click here. Current gate operations at Lakes PK, Granbury and Limestone are listed at the bottom of the Authority home page, here. Gate releases and other Authority news can be found on our Facebook page, here.