San Antonio River Walk Flood Control System Preserves Downtown

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Tony Maples Photography


Despite flash floods that occur occasionally in the Texas Hill Country, San Antonio’s River Walk generally has remained safe from the river overflowing. The San Antonio River flood control system is an engineering marvel; one which other cities could consider for the protection of their own commercial centers. With a hidden secret at its heart, the River Walk flood control system protects the lives and businesses of thousands in downtown San Antonio.

Prior to the River Walk Flood Control System

San Antonio in 1886 long before the River Walk flood control system was installed

Photo: Wikimedia Commons

Long before downtown San Antonio centered around the River Walk, floods regularly devastated the area. This commonly occurs in the Hill Country where tropical and non-tropical weather systems can dump inches of water in a short amount of time. Between 1845 and 1921, seven catastrophic floods overflowed the San Antonio River (1845, 1865, 1880, 1899, two in 1913, and 1921). In 1920, prior to the last of these floods, civil engineers conducted a study of the river to determine the best ways to prevent future floods. This would form the basis of the planning for the River Walk flood control system, which would allow San Antonio’s downtown to flourish.

Creation of the River Walk

The River Walk flood control system protects businesses like Casa Rio

Photo: Wikimedia Commons

Development of the San Antonio River Walk always revolved around flood control options. Since its planning in 1929 by Robert Hughman, the River Walk would become a feat of engineering and commercialism. Hughman proposed several ideas to keep the river from inundating local businesses. He felt so confident in his plans for a bypass channel and dams that he had his architecture firm constructed along the river, in an area previously renowned to overflow. Thanks to funding procured from the Works Progress Administration in 1939, the River Walk’s initial bridges and walkways were built, and the signature cypress trees along the river were planted. The River Walk flood control system worked, and the tourist area could expand to its current multi-mile distance.

The River Walk Flood Control System Works

Dams and gates control the water levels along the San Antonio River especially along the River Walk

Photo: Facebook/Paul Delacruz

Along the length of the San Antonio River, 41 dams help to maintain water levels. These are critical components of river maintenance. Many of these dams were part of Hughman’s proposal for the River Walk. Though the San Antonio River Walk flood control system still uses these dams and gates, civil engineers realized that it wouldn’t be enough. In 1997, work finished on a tunnel that would further help divert water, and this happened just in time for massive flooding rains in 1998. Thanks to the new tunnel, downtown was spared flooding. This tunnel forces water to drain toward the south, to the Mission Branch of the river, away from downtown. By preserving downtown San Antonio from floodwaters in 1998, 2002, and 2017, the river tunnel has more than compensated the city that funded it by saving money and lives.