The United States Environmental Protection Agency has identified the consequences of invasive species
. The projected damages are estimated to be as high as $138 billion annually. Those damages impact rangeland, food supplies, homes, yards, outdoor recreation, human and animal health, fishing, boating, rivers, forests, agriculture and water quality. It has also been reported that 42% of endangered or threatened species are at risk because of invasives.
"We're losing some of our historical native plants that were here 100 years ago," Johns said. "These native plants were great at supporting the ecosystem, but now they're being replaced by more competitive invasive plants."
Given the consequences, officials in Greenville County, South Carolina want to reduce the presence of non-native invasive plants. The county is starting by targeting invasive species along its streams during stream stabilization projects.
Decreasing the Impact in Greenville County
By removing invasive plants around its streams, Greenville County hopes to regain essential resources to improve water quality.
"Communities are beginning to recognize streams as assets to be protected instead of a nuisance,” said Crystal Muller, project manager and engineer at Woolpert. "Streams are a primary form of conveyance for stormwater runoff, and if you allow them to degrade over time, banks fail and streams widen, leading to higher amounts of sediment in streams and property loss. This sediment and associated pollutants contribute to many of the impairments we see today."
The Reedy River, a 65-mile-long tributary of Saluda River, runs through Greenville County and has been the subject of regulatory and stakeholder attention since an algal bloom occurred in Lake Greenwood in 1999. Today, it is one of only three watersheds in all of South Carolina impaired for nutrients like nitrogen and phosphorous.
“The pervasive nature of invasive vegetation and its qualities are in opposition to the county’s long-term water quality goals for the Reedy River,” said Judy Wortkoetter, PE, county engineer for Greenville County. “Many of the most pervasive invasive vegetations spread extremely fast, have shallow root systems, and do not uptake as many nutrients, making the areas where they are established less resilient to change and more likely to degrade over time.”
“Instead of allowing streams to contribute to these challenges, Greenville County is trying to re-establish native plants to get streams back to their original function,” Muller said.
This approach will ensure streams aren’t contributing to poor water quality
but rather helping fix the issue. With a healthy establishment of native vegetation along streams, streams can act as filters by removing nutrients and contaminants from the water.
“Stream restoration has proven to be an effective and aesthetic tool in reducing pollutant loading in watersheds around the country,” Wortkoetter said. “It repairs and prevents future bank failures, lowers erosive forces by increasing access to flood plains and benches and establishes a resilient native vegetation community that can play a significant role in nutrient reduction.”
With Greenville County taking steps to restore its streams, the intended result is decreased pollution in the Reedy River making it usable and safe to enjoy.
Reducing the Presence of Invasive Plants