PA Environment Digest

Share this:

Scientists Monitor New Wetland Designed For Flood Control, Improved Stream Habitat In Chester County

By Diane Huskinson, Stroud Water Research Center

A newly constructed wetland designed to reduce flooding downstream of White Clay Creek is showing promise.

“We had our first flooding event since the project was finished, and the data look good. It clearly helped hold some of the water from that flood,” says Melinda Daniels, Ph.D. “Of course, we will need to collect more data to conclusively quantify the wetland’s impact.”

Because of flooding caused by Hurricane Sandy, the National Fish and Wildlife Foundation provided Stroud Water Research Center with a $3 million grant to reduce flooding across the 1,800-acre White Clay Creek watershed by 40 percent.

The new wetland was constructed downstream of Spencer Road in Avondale, Chester County, an area that floods regularly, contributing to hazardous road conditions, as well as bridge and other infrastructure damage.

Daniels, the principal investigator for the project, says, “This is typical of the entire Brandywine-Christina watershed. For example, the local school district will cancel school during big floods because the buses have to cross these bridges; they just wouldn’t be safe to cross. It’s more than an inconvenience: There is a public safety and economic impact from flooding. It’s a real problem, and it’s because of land cover changes.”

Historically, this heavily farmed region would have been a mosaic of mostly bottomland hardwood forests with some open wetlands and beaver meadows. “Of course, we don’t want to get rid of our farms because we need to eat, and they provide economic and cultural value,” says Daniels.

“This project seeks to reduce flooding and secondarily improve the health of aquatic ecosystems by restoring the hydrology of the watershed without changing the land cover all that much.”

Princeton Hydro designed the wetland and brought in subcontractor RiverLogic Solutions to undertake its installation last fall.

The area designated for the wetland was narrow, so the team excavated some of the buildup of sediments within the floodplain, as well as part of the hill slope to widen the floodplain and lower its surface to make room for as much storage as possible.

During a storm when White Clay Creek rises, the wetland fills first before the stream spills over its banks and floods the actual floodplain surface. Then, after peak flood conditions have passed, the wetland slowly releases the water, which it has naturally purified by absorbing nutrients such as nitrogen and phosphorus.

Daniel says, by reducing nutrients and contributing organic matter, wetlands enhance freshwater ecosystems. “Rivers and streams that are connected to wetlands are highly productive — in other words, healthy — ecosystems with lots of fish and biodiversity.”

As part of the Hurricane Sandy project, the Stroud Center also expanded the riparian buffer and put in level-lip spreaders to control stormwater runoff.

Monitoring of the wetlands effectiveness will continue for two more years with funding provided by the Department of Environmental Protection’s Growing Greener program.

For more information on programs, initiatives and special events, visit the Stroud Water Research Center website, Click Here to subscribe to UpStream. Click Here to subscribe to Stroud’s Educator newsletter. Click Here to become a Friend Of Stroud Research, Like them on Facebook, Follow on Twitter, include them in your Circle on Google+ and visit their YouTube Channel.

(Photo: The project will help address this kind of flooding in the White Clay Creek Watershed.)

NewsClips:

Pittsburgh Bioswale Project Helps Reduce Stormwater And Is Beautiful

Letter: Go Green, Not Gray With Sewer Infrastructure

Compliance With Stormwater Requirements To Top $6.2M Over 5 Years In Blair

Easton Facing $7-8M Cost To Help Clean Up Impaired Lehigh River

North Lebanon Twp Supervisors Set Stormwater Management Fee

Allentown Airport To Sue City Over Stormwater Fee

Elementary School Students Work To Protect Stream That Runs By School

Greater Philadelphia Sustainable Business Network Recognizes Green Infrastructure Projects To Reduce Stormwater Pollution

Communities Look For Dig Once Opportunities To Integrate Green Infrastructure To Reduce Stormwater

Joint Senate-House Budget & Finance Committee To Release Water Use Fee Report June 6