Posted: Tue, 29 Jul 2025 04:23 PM - 38 Readers

By: KXAN - Nick Bannin

Recent heavy rainfall and flooding have significantly raised water levels in Lake Travis and Lake Buchanan, the primary water supply reservoirs for Central Texas. Lake Buchanan is already at full capacity, with excess water being released downstream into Lake Travis, which is currently at 91% capacity, approximately 6.5 feet below its full level of 681 feet above sea level. The Lower Colorado River Authority (LCRA) manages water releases from Mansfield Dam based on Lake Travis water levels to balance water supply, ecological needs, and flood control.

When Lake Travis reaches its "full" mark at 681 feet, it enters the "flood pool" phase, where additional water can still be stored. The LCRA has specific protocols for releasing water based on forecasted lake levels to prevent flooding downstream and protect the dams integrity. These protocols include controlled releases ranging from 7,500 cubic feet per second (cfs) for levels between 681-683 feet, up to 90,000 cfs for levels between 714-722 feet, and unlimited releases if levels exceed 722 feet to ensure dam safety. Unlike Lake Travis, Lake Buchanan lacks a flood pool, so excess water is released immediately when it reaches its full capacity of 1,020 feet.

Projections from July 1, before the recent flooding, suggested that under median conditions, Lake Travis could reach full capacity by December due to reduced irrigation demand and seasonal rainfall. Wetter-than-average conditions could accelerate this timeline. The flood pool in Lake Travis is critical for slowing water releases to protect downstream communities like Austin from uncontrolled flooding along the Colorado River, ensuring both safety and water management.