Why is revegetation important?
Revegetation is critical to the success of restoration and enhancement efforts in the Las Vegas Wash. At its peak, wetland vegetation covered more than 2,000 acres along the Wash. When revegetation activities began in 1999, only 200 acres of wetlands remained due to increasing flows in the Wash, which have subsequently altered surface and subsurface hydrology and accelerated erosional processes.
When land is cleared for channel stabilization, opportunities are created for revegetation. Most often the adjacent land is cleared of non-native invasive species, which also helps with long-term invasive management strategies in the Wash. These cleared areas are then planted with native wetland, riparian and upland plants, further protecting the channel against erosion and enhancing wildlife habitat. So far, 337 acres of land has been revegetated along the Wash.
The revegetation program benefits stabilization and enhancement efforts at the Wash in several ways:
- Plant roots hold on to soil particles that would otherwise erode downstream, causing the ground to become more stable. Plants also can serve as physical barriers slowing soil and water movement downstream.
- Revegetation creates habitat for fish and wildlife. Nearly 700 species of fish and wildlife have been found using the Wash, many of which are birds that are breeding in the Wash or periodically stopping over on their migration route. Approximately 80 percent of the U.S. breeding bird population and more than 50 percent of the protected migratory bird species in the U.S. rely on wetland and riparian habitats.
- Some plants can "polish" the water, removing nutrients and other compounds. Wetlands in the Wash act as a biological filter for all of the water draining from the Las Vegas Valley.
In addition to the environmental benefits of enhancing native vegetation in the Wash, much of the revegetation effort qualifies as mitigation under the U.S. Army Corps of Engineers 404 permit. The permit is required for the construction of grade control structures on the Wash and states that we must mitigate one acre for every acre of open water habitat that is impacted by weir construction activities. So far, 77 of the 337 acres we have planted qualify as mitigation.