Addicks Reservoir

About

The Addicks Reservoir and Addicks Dam in conjunction with the Barker Reservoir prevent downstream flooding of Buffalo Bayou in the city of Houston, Texas. Both reservoirs were authorized under the Rivers and Harbors Act of June 20, 1938, which was modified by the Flood Control Acts of 1938, 1954, and 1965. The US Army Corps of Engineers (USACE) completed construction of Addicks Dam and the outlet facility in 1948.

Addicks Reservoir is situated on the north side of Interstate 10. It extends slightly north of Clay Road and between Barker-Cypress Road to the west and Beltway 8/Sam Houston Tollway to the east. State Highway 6 (SH 6) bisects the reservoir north to south. In addition to the Reservoir's flood damage reduction mission, recreation and nature observation opportunities abound through the approximately 26,000 acres (11,000 ha) of land that makes up Addicks and Barker reservoirs, which are often dry wooded areas in normal times. The West Houston Airport is located within the western edge of the Addicks Reservoir, between Barker-Cypress Road and SH 6. The Addicks Reservoir spillway is located at 29°47′26″N 95°37′24″W and releases the remainder of Bear Creek just north of Buffalo Bayou. Addicks Reservoir and Dam get their name from the former town of Addicks, Texas, named after its original postmaster, Henry Addicks.

Addicks Reservoir is formed by a rolled earthen dam 61,666 feet (18,796 m) long and above the streambed. A 12-foot-wide (3.7 m) gravel road extends along the top of the dam. The top of the dam has a maximum elevation of 121 feet (37 m) above the North American Vertical Datum of 1988 (NAVD 1988) and is almost 50 feet (15 m) high in points. The maximum storage capacity of the reservoir is 201,000 acre-feet (248 GL), The record high water level for the reservoir prior to Hurricane Harvey was 123,100 acre-feet (151.8 GL), set on April 24, 2016. During Hurricane Harvey, the level peaked at 109.1 feet (33.3 m) on August 30, 2017, becoming the highest recorded level for Addicks Reservoir. Water retention at this level was 217,500 acre-feet (268.3 GL). Combined with the adjacent Barker Reservoir to the southwest, the total storage capacity is about 410,000 acre-feet (510 GL). From 2008 to 2014, the USACE Galveston District implemented $4.4 million (equivalent to $5.73 million in 2024) in interim risk reduction measures (at Addicks and Barker dams) to address deficiencies until long-term solutions could be identified and executed. In 2014, staff completed a Dam Safety Modification Study to evaluate long-term repairs and address issues associated with the dams. Staff presented this information during a public meeting on October 29 at Bear Creek Community Center in Houston to discuss these plans and gather feedback. Construction is scheduled to begin in May 2015 with an estimated completion date of 2019. The northern and western ends of the dam consist of roller-compacted concrete spillways. The existing ground at either end of Addicks Dam is lower than the top of the dam elevation. The existing ground at the north end of Addicks Dam is at an elevation of 108 feet (33 m) and ties into the concrete spillway crest at 112.5 feet (34.3 m). The existing ground at the western end is at an elevation of 111.0 feet (33.8 m) and ties into the concrete spillway which has a crest of 115.5 feet (35.2 m). (All elevations are NAVD 1988.)

On August 28, 2017, during flooding from Hurricane Harvey, USACE began controlled water releases at both the Addicks and Barker reservoirs, in an attempt to manage flood levels in the immediate area. The waters continued to rise, and on August 29, after reaching pool elevation over 108 feet (33 m) above NAVD 1988, the Addicks Reservoir began around the end of the dam near Tanner Road. Flows less than 100 cubic feet per second (2,800 L/s) were detected at the spillway. In the afternoon of August 29, 2017, USACE decided to raise the controlled release rates to 16,000 cubic feet per second (450,000 L/s). As of August 30, 2017, combined controlled discharge rates of Barker and Addicks were 13,700 cubic feet per second (390,000 L/s), and subdivisions surrounding the outlets and downstream past Beltway 8/Sam Houston Tollway experienced significantly increased flooding as Buffalo Bayou further overtopped its banks.

Adapted from Wikipedia (CC BY-SA). Photography via Wikimedia Commons.