Wildflower is published quarterly by the Wildflower Center. Its content is national in scope with articles about the conservation and use of native plants as well as news from the Wildflower Center. A subscription is provided to Wildflower Center members as a benefit of membership.
Letter from the Director - Winter 2009Restoration Nation
Imagine a river that outdated methods of flood control had turned into a ditch, its barren banks overrun with invasive Bermuda and Johnson grass. Not a tree in sight. And imagine that this river connects treasures of our national heritage—the four historic Spanish missions in South San Antonio that are a national historical park.
And then imagine that this river could be restored to something approaching its historic serpentine path, providing wildlife habitat and an inviting trail for hikers and cyclists.
This in fact is the Mission Reach project now underway on the San Antonio River. The Wildflower Center is working with the engineering firm Jacobs (previously Carter Burgess) and the U.S. Army Corps of Engineers and the San Antonio River Authority to restore much of the river while retaining the necessary flood control features. Funding comes from the Corps of Engineers, the City of San Antonio and the river authority.
It is a classic example of our innovative approach to landscape restoration. When we are hired to provide expertise on a landscape restoration project, our scientists apply the knowledge gained from our research at the Wildflower Center and also test new hypotheses as we work.
Mission Reach posed some unique challenges. It was a completely degraded river system. To prevent flooding in San Antonio, the river had been lowered 35 feet and channelized, straightening its natural bends and removing all vegetation. The goal of the project was to restore the river’s more natural serpentine path, recreate habitat and provide recreation and more attractive vistas. It took eight years to design and create a healthy system, one that restores native plants and riparian conditions, and still provides flood protection. This involved extensive earth-moving, erosion control measures, and eradication of harmful invasive plants.
At the Wildflower Center’s recommendation, more than 20 species of native prairie grasses were established on the banks. Techniques such as compost blankets and erosion mats were used to keep the banks stable until the grasses could root. To make this work, six inches of topsoil were removed to eliminate invasive plants without using herbicides that could contaminate the river.
Center staff also identified forest areas where native trees could be planted without impeding the flow of the river. When the project is completed, these areas along the eight-mile stretch of river will feature more than 30 species of native trees, growing in densities ranging from 70 to 300 trees per acre.
Mission Reach applies lessons we learned from our previous study of roadside vegetation. That three-year-long experiment showed that selecting the right native plants can produce rapid rates of revegetation and erosion control—much faster than the Texas Department of Transportation’s standard roadside mix which includes non-native species. Mission Reach will teach us how native grasses, trees and shrubs can be compatible with efficient flood control, and provide other amenities to the thousands of visitors to the San Antonio mission area.
Each project we take on provides a unique opportunity for demonstrating how native plants used in scientifically-based design can help address environmental problems Our list of blue-ribbon projects is growing, and includes large developments like Mueller in Austin; corporate campuses like AMD (Advanced Micro Devices) and L’Oreal; government agencies like NASA’s Johnson Space Center, the City of Austin and Williamson County, and non-profits like the Denver Botanic Gardens at Chatfield.
Each project also provides a valuable research opportunity. At Mueller, for example, we re-created a blackland prairie on what had been an airport parking lot in downtown Austin. At AMD, we worked with architects and contractors to create a corporate headquarters that minimized its impact on the Edwards Aquifer below.
A new project underway in Williamson County, just north of Austin, will apply what we discovered about sustainable, low-maintenance vegetation to roadways in one of the nation’s fastest-growing counties. Much of this research has been published in scientific journals.
Demand is growing rapidly for the Center’s expertise in landscape restoration. Besides producing important revenue for us, projects like Mission Reach give us an opportunity to demonstrate on a large scale new techniques and approaches to living sustainably on our planet. It’s a model that works for conservation and for business. – Susan K. Rieff