Lake Conroe level: Dam release increased; officials warn of flooding along San Jacinto River

Montgomery County officials are urging those who live near the San Jacinto River south of the Lake Conroe Dam to take immediate action and be prepared for potential significant flooding along the river on Thursday.

"Rainfall totals in Walker County and northern Montgomery County were as high as 16 inches overnight. The amount of rainfall in conjunction with already saturated grounds is causing a tremendous amount of watershed towards Lake Conroe," the Montgomery County Office of Homeland Security and Emergency Management said in an urgent message.

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San Jacinto River Authority states Lake Conroe is one of several tributaries and creeks that contribute to water in the West Fork of the San Jacinto River. We do not contribute to the East Fork of the river. Watersheds north of Lake Conroe took on as much as 17 inches of rain over the last week; that runoff and the new bands of stormwater flow into Lake Conroe.

<div>Map of San Jacinto River forks. (Courtesy of San Jacinto River Authority)</div>
Map of San Jacinto River forks. (Courtesy of San Jacinto River Authority)

Due to the structure of the dam and the gates in place, Lake Conroe is managed to a level of 201 means sea level and releases begin once the level of water rises above 201, SJRA said.

Lake Conroe Dam release

Around 5:40 a.m., MCOHSEM said the San Jacinto River Authority was releasing 13,400 CFS and expected that amount to increase. At 8:30 a.m., the SJRA said the gate release was at 38,000 CFS. At 9:30 a.m., the release was at 49,585 CFS. At 10:15 a.m., the release was at 60,455 cfs. At noon, the lake release was at 66,100 cfs.

Lake Conroe water level

As of 3 p.m., the current level of Lake Conroe is 205.03 feet mean sea level (msl) and continuing to rise with a current gate release of 69,545 cubic feet per second (cfs).

According to SJRA, water releases occur when the lake level exceeds 201 msl. The level as of 8:30 a.m. was 203.68 msl. At 9:30 a.m., the lake's level was at 204.02 msl. At 10:15 a.m., the level was at 204.26 msl. At 11:30 a.m., the level was at 204.61. At 1 p.m., the level was at 204.8.

Montgomery County officials warn of flood risk

According to MCOHSEM, this is expected to cause significant flooding in areas south of Lake Conroe. They say they are working with the San Jacinto River Authority to understand the effects of the releases downstream.

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"MCOHSEM is closely monitoring the situation and will continue to provide updates as they materialize," the agency said.