Lewis Creek Reservoir Update
THE WOODLANDS, May 22, 2015 - Entergy Texas, Inc. notified local authorities this afternoon of the potential for dam failure at the Lewis Creek Reservoir near Conroe. The persistent rainfall experienced in the surrounding area has caused extensive saturation of the soils that make up the reservoir dam.
Crews are working around the clock to make necessary repairs to the dam, but efforts are being hampered by the continuing rainfall. A preventative water release to lower the reservoir level is in progress in an effort to reduce the stress being applied to the dam. Thus far, the dam has not failed, and the nearby Lewis Creek power plant is fully operational.
A number of steps are being implemented to prevent further dam deterioration, including the installation of berms to minimize further slide movement, the installation of more than eight acres of protective covering to protect areas of concern from additional rainfall, and 24/7 monitoring of the soil by geotechnical engineers.
Entergy is working closely with local emergency management officials to ensure the safety of nearby residents and businesses.
Lewis Creek Reservoir is located about three miles west of Willis in Montgomery County, on Lewis Creek, a tributary of west Fork San Jacinto River which is a tributary of the San Jacinto River. The reservoir is owned and operated by the Entergy (formerly Gulf States Utilities Company) mainly for condenser cooling in the steam electricity generation plant and for recreational use. Permit (No. 2433) was issued on September 21, 1967 to the company by the State Board of Water Engineers for construction of the dam. Construction of the earth-fill dam started on November 11, 1967 and completed on August 25, 1969.
Deliberate impoundment of water began on February 12, 1969 and power generation began in October, 1970. Brown and Root, Inc designed the dam and acted as General Contractor of the construction. The dam measures 12,836 feet in length with a maximum height of 54 feet from the river bed and a width of 18 feet. At the normal elevation, 267 feet above mean sea level, the reservoir will stores 16,400 acre feet of water with a surface area of about 1,010 acres. The drainage area is 4.4 square miles. Water will be purchased by contract from Lake Conroe and pumped as required to maintain desirable water level.