The “First Flush”
Ever wonder what exactly enters your storm drains and makes its way into the waterways? Next time there is a significant rainfall, take a look at the nearest forebay–pollutants including trash, chemicals, and oils are swept through the storm drain and directly into the waterway via the forebay. This rush of pollutants during a rain event is known as the “First Flush.”
Take a look at the stormwater entering the forebay of the Crawford Farms Park Stormwater Treatment Wetland, a project funded by a 319 grant from the Ohio EPA with support from the City of Columbus Department of Public Utilities and Recreation and Parks Department, implemented by Franklin Soil and Water Conservation District.
Published: August 3rd, 2015
Crawford Farms and the Story Behind It
Dysart Run is a 5 mile long stream that enters the Blacklick mainstream in Reynoldsburg. Dysart drains a watershed of 4.2 sq. mi. Over the past 25 years, construction of subdivisions, apartment complexes, condominiums, shopping centers, commercial facilities and parking lots has resulted in a large area of hard surfaces in the watershed. Much of the rain that falls onto these surfaces drains into the creek without passing through any stormwater control features.As a result of the runoff from these hard surfaces, Dysart Run does not meet the water quality standards established by the Ohio EPA. In addition, the creek becomes a raging torrent during larger rain storms, eroding its banks and threatening homes along it.
The runoff near Dysart Run has to be intercepted at multiple locations. The recently created stormwater treatment wetland in Crawford Farms Park is one of those places. Crawford Farms is a subdivision off of Waggoner Road on Columbus’ east side, constructed from 1997 to 2003. The stormwater basin receiving runoff from 32 acres of the subdivision was excavated in Crawford Farms Park, which is owned by the City of Columbus. Of those 32 acres, approximately 11 acres is hard surface (roads, driveways, roofs etc.).
The Crawford Farms Park basin was designed to reduce flooding during rare, very large rain storms. Before, runoff from most rain events passed through the basin with almost no water quality treatment and extremely limited volume control. In other words, most of the water simply ran straight into Dysart Run via a system of pipes and a small tributary stream. In an average year, nearly 12 million gallons of stormwater runoff and the pollution it carried ran off of the Crawford Farms subdivision through the stormwater basin in Crawford Farms Park to Dysart Run.
In 2012, Franklin Soil and Water Conservation District submitted a grant proposal to the Ohio Environmental Protection Agency to turn the existing stormwater basin into a stormwater treatment wetland, which would both treat stormwater runoff and reduce the runoff entering Dysart Run. The City of Columbus Department of Public Utilities offered matching funds as a part of the proposal, and Columbus’ Recreation and Parks Department committed its support as well.The proposal was funded in 2013, and the design process began later that same year. The plan, developed by Cardno, was approved by the City of Columbus in the spring of 2015. Most of the project was implemented from May 18, 2015 to June 4. Facemyer Landscaping completed the excavation of the project, and MAD Scientist and Associates was responsible for planting the site.
Franklin Soil and Water has been monitoring the stormwater flow from the basin for over a year prior to construction of the project and will continue to monitor flow rates now that it has been completed. The data will help us determine how much runoff was intercepted by the wetland, never entering Dysart Run.
We are grateful to the Ohio EPA for providing the grant money and the City of Columbus Department of Public Utilities for contributing the matching funds that made this project. Columbus Recreation and Parks has also been a key partner in the implementation of the Crawford Farms Park Stormwater Treatment Wetland.
Published: July 2nd, 2015