SAN ANTONIO - As a result of the detailed analysis of flood conveyance of the Mission Reach project, the San Antonio River Authority (River Authority) announced today that it will target the removal of certain trees along the river as part of the adaptive management approach in maintaining proper flood conveyance throughout the eight-mile stretch of ecosystem restoration project. Over the seven years since the project’s completion, nature has provided additional vegetation along the banks of the river adding to the density of the trees and potentially impacting the river’s ability to safely convey future floods. With advanced modeling technology, the River Authority has identified where the additional tree density is not desirable and removal is required. This two-week effort will be conducted by the River Authority’s Watershed Park and Operations department beginning October 5, 2020.
The Mission Reach is part of the San Antonio River Improvements Project (SARIP) a $384.1 million investment by the City of San Antonio, Bexar County, San Antonio River Authority, the U.S. Army Corps of Engineers (USACE) and the San Antonio River Foundation in flood control, amenities, ecosystem restoration and recreational improvements along 13 miles of the San Antonio River from Hildebrand Avenue south to Loop 410 South.
The River Authority served as project manager for all sections of the SARIP and as local sponsor with USACE specifically for the Mission Reach. Since the Mission Reach’s opening in 2013, the River Authority’s Watershed and Parks Operations department has performed ongoing maintenance as part of an adaptive management process to sustain the integrity of its flood control function, provide proactive protection for surrounding infrastructure, and to maintain the viewshed of the river.
“As a part of our maintenance efforts, we aim to preserve the trees originally planted as part of the ecosystem restoration project and will focus on removing vegetation that arrived since the opening of the project,” said River Authority Watershed & Park Operations Manager Kristen Hansen. “Guided by the most updated floodplain models, we are able to determine the maximum number of stems allowed for any given area. The intent is to maintain high priority areas and allow as many trees to grow as possible without causing increased risk in the floodplain.”
The River Authority’s Watershed Engineering department conducted a study of the Mission Reach using the most current Federal Emergency Management Agency (FEMA) floodplain maps to identify high priority areas necessary for stem density removal. The study was completed with the goal of maximizing preservation of originally-planted, native trees while maintaining the flood conveyance requirements set forth by FEMA. The River Authority also coordinated with an avian expert to determine the ideal time from an avian perspective to perform the vegetation management. The effort will conclude by adding grassland vegetation to areas to assist with bank stabilization which also supports avian migration.
For more information about the Mission Reach Ecosystem Restoration and Recreation Project and to learn more about the River Authority’s flood mitigation efforts, visit sariverauthority.org.
