By NACD Southeast Region Representative Candice Abinanti
Strolling along San Antonio, Texas,’ Historic Downtown River Walk, it can be easy to overlook the infrastructure that keeps the water in the San Antonio River level. After all, San Antonio has a history with flooding. During the 73rd NACD Annual Meeting, the Association of Texas Soil and Water Conservation Districts (ATSWCD) partnered with the San Antonio River Authority to provide a tour that showed over 40 participants how both gray and green infrastructure along the San Antonio River help protect the city from floods and provide additional benefits.
The San Antonio River Flood Control Tunnel and other engineered flood protection projects such as dams, pumps and gates help maintain the Historic Downtown River Walk’s water levels, protecting businesses and residents from flooding. Finished in 1997, the Flood Control Tunnel paid for itself in damages prevented after just one flood event in 1998. Built to handle two one-percent annual chance floods (100-year floods) in a row, floodwaters entering the Tunnel Inlet are piped 150 feet below the city for three miles south to the Tunnel Outlet. Just beyond that outlet is the beginning of the Mission Reach section of the River Walk.
A green complement to the gray infrastructure of the Tunnel, Mission Reach is an eight-mile urban ecosystem restoration and recreation area along the river south of downtown San Antonio. Operated and maintained by the San Antonio River Authority, its natural, native landscape is a contrast to the paved historic section of the River Walk. With 13 acres of restored wetlands and 334 acres of riparian woodland habitat, this area holds, filters and directs floodwaters while providing habitat to diverse native species adapted to the Texas climate and recreation opportunities for residents and visitors. The project has restored habitat diversity to an area that once lacked it, providing a variety of habitat types: prairie, savanna, woodland and forest for hundreds of different species of native grasses, wildflowers, shrubs, trees, birds and other wildlife. Since December 2015, the Mission Reach Avian Study has recorded 196 bird species using the restored habitat.
At Confluence Park, one of many parks along the river, these restoration efforts and their benefits are on display. Newly opened in March 2018, the park uses low impact development features like swales vegetated with native plants to slow and direct water, and sand to filter water to underground storage used to irrigate the park’s native landscaping and to supply non-drinking water to the park’s restrooms. The park is energy-neutral, designed over a year to put energy back into the grid. It is a popular site for conservation education programs, hosting over 14,000 students since its opening.
Standing under an expansive concrete canopy shaped like petals that provide shade and channel and filter water, Frates Seeligson, the Director of Confluence Park with the San Antonio River Foundation, remarks that as school-aged children spend less time outside, this is a “park to exercise your brain,” helping students develop an appreciation for conserving natural resources through hands-on learning. Looking out at the river, as cormorants fly above and cyclists cruise along the river trail, Seeligson talks about how these improvements to the San Antonio River have connected neighborhoods and communities in San Antonio, becoming “tools for health and wellness and community and economic development.”
The tour highlighted the many benefits of the Mission Reach urban ecosystem restoration: flood management, outdoor recreation, wildlife habitat, conservation education and beyond. It is an example of how both gray and green infrastructure can play important roles in flood management while creating vibrant communities and healthy, diverse ecosystems.