The San Antonio River Authority began a project to remove trees and grasses along the Mission Reach this week, work that will continue through early spring.
The tree removal helps to manage flooding by promoting effective stormwater channeling and helping provide proactive protection for surrounding infrastructure, the river authority stated in a flyer it mailed out earlier this month to more than 7,000 residents within a half-mile radius of the project.
Tommy Mitchell, watershed and park operations manager for the river authority, said the authority will identify which trees will remain this week and then will begin the removal process.
While the river authority planted roughly 20,000 trees and shrubs as part of the Mission Reach Ecosystem Restoration Project starting in 2008, many more have popped up since then. These “volunteer” trees and shrubs — so named because they simply show up — can slow floodwaters, backing these waters up instead of allowing them to flow freely downstream, Mitchell explained. Removing the extra trees and shrubs allows the water to move more smoothly away from nearby infrastructure, he said.
“It’ll be a two-pronged effort,” Mitchell said. “We will be doing some of the removals mechanically, but then also through [manual] efforts as well.”
Mechanical removal will include the use of forestry mulchers attached to skid-steer loaders, he said. River authority personnel and partners will be using chainsaws, wood chippers and axes to remove other vegetation.
The river authority will clean up about 25 to 30 acres, Mitchell said. The authority will be leaving most of the trees and shrubs’ root systems intact for now to prevent soil erosion while the land recovers, Mitchell added.
Before beginning the cleanup, the river authority increased its outreach efforts to area residents through neighborhood associations and homeowner groups after some were shocked in January 2022 to see trees being removed along the Mission Reach.
The authority tries to do this work during the winter so it doesn’t affect nesting birds, Mitchell said, since San Antonio is along the Central Flyway, a major bird migration route.
During a public meeting in August hosted by the river authority, U.S. Army Corps of Engineers Wildlife Biologist Danny Allen reminded the roughly 50 to 75 attendees that flood mitigation was the first priority of the project, followed by ecosystem restoration and recreation. That is because public safety must come first, Allen said, and the project must be in compliance with the floodplain requirements set forth by the Federal Emergency Management Agency.
“The project must comply with the zero-rise flood maps, as well as the … modeling of the hydraulics and hydrology of the project area,” Allen said.
Removing trees and shrubs and mulching the stems can help restore the land, allowing natural grasses to move in and quickly take root, Mitchell said.
Another benefit of the tree removal is to prevent a monoculture of trees from taking root on the river’s edges, he said. Ecosystems are healthiest when there is a good balance of variety among natural plant species, he said.
