Wetlands: Frogs and fish and snakes love 'em at Umstead State Park |
|
After constructing a beautiful, updated visitor’s center, William B. Umstead State Park officials noticed erosion and water-quality problems on the newly developed land.
Clearing the land for the new center, parking lot and access road replaced vegetation with impermeable surfaces that no longer absorbed stormwater, creating runoff that carved grooves in the supporting hill, carrying sediment, chemicals and metals from the parking lot and roof directly to the park’s streams and creeks. These drain to the Neuse, already one of North Carolina’s more polluted rivers. “Our goal at the state parks is to preserve nature for future generations to enjoy,” said Martha Woods, Umstead Park’s superintendent. “When we noticed the negative impact our park improvements were causing on the environment, we wanted to stop and reverse the damage as soon as possible.” Park officials turned to NC State University’s Biological and Agricultural Engineering Department and the NC Cooperative Extension Service Center in Wake County for advice.
“Wetlands are nature’s filters,” said water specialist and Neuse Education Team member Dr. Bill Hunt of NC State’s BAE Department. “We build stormwater wetlands to demonstrate a simple, natural way to filter pollutants from stormwater runoff.” The designers considered many factors when deciding which bio-retention option to implement. Because of clay soils and a large treatment area, BAE decided on a grassy swale and wetland to stall and treat the runoff. The swale stabilized the eroded area, channeling the water to the wetland. Because of the runoff’s fast flow, the swale employed a special turf reinforcement mat to stabilize the erosion, helping grass grow despite the fast-moving runoff.
Two connected deep pools that always hold at least four feet of water offer fish a home and frogs a place to lay eggs. The wetland also forces stormwater to curve around an upland peninsula, causing the water to remain in the wetland longer. This is an important feature, because the longer the water stays in the wetland, the longer it can be treated. Umstead State Park now uses the wetland as an outdoor classroom and an example for engineers and local officials. North Carolina State Parks provided the operator and equipment to create the wetland and continues to maintain it. An internal Cooperative Extension grant funded the vegetation. -- Kathleen Powers |
||||||
|
