Lake Conroe (San Jacinto River Basin)

Lake Conroe and Dam with Spillway in operation (Photo by owner)Lake Conroe is located approximately seven miles northwest of Conroe, on the West Fork of the San Jacinto River in Walker and Montgomery Counties. The water rights to Lake Conroe are owned by the San Jacinto River Authority and the City of Houston. The lake and dam facility are maintained by the San Jacinto River Authority. Certificate of Adjudication 10-4964 was granted to the City of Houston, the San Jacinto River Authority and the Texas Water Development Board to maintain and use the lake. Lake Conroe was built as an alternate water supply for the city of Houston. Freese, Nichols and Endress Engineering Inc. designed the project and H. B. Zachery Company was the general contractor.

The lake was completed January 1973 and was filled on October 31, 1973. Conroe Dam is an earthfill embankment, 11,300 feet in length including the levees. The crest elevation of the dam is 212.0 feet above mean sea level and has a height of 82 feet above the old riverbed. A controlled emergence spillway is located near the center of the embankment. The spillway is a concrete ogee crest, 200 feet in length with a crest elevation of 173.0 feet above mean sea level. Control for the spillway consists of five tainter gates, 40 feet in width by 30 feet in height with the top elevation of 202.5 feet. Low flow releases are made through a separate multi-gated inlet tower. Two of the gates are four feet by six feet, the third gate is five feet by five feet. The invert for the lowest outlet in the control tower is 144.5. Discharges are through a 10 foot diameter concrete conduit through the dam. Maximum design water surface may reach to 207 feet above mean sea level. Recorded highest water level in the lake history was 205.58 on October 19, 1994.

According to TWDB 2010 volumetric survey, at the conservation capacity pool elevation of 201 feet above mean sea level, the lake has approximately 19,640 acres of water surface and a storage volume of 411,022 acre feet. Inflows to the lake originate from a drainage area of about 445 square miles.

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