Stormwater
Why is Stormwater Runoff so Important to Our Community?
As stormwater runoff flows over various surfaces such as streets, parking lots, rooftops and construction sites, it picks up debris, chemicals, sediment and other pollutants and carries them into local streams and rivers by way of the storm sewer system. These pollutants adversely affect the water quality of our streams. Increased peak stormwater flows due to development can cause erosion and further degrade the health of the stream.
Typically for municipalities and urbanized areas, the most common pollutants associated with stormwater include oils and greases, salts, heavy metals, pesticides, fertilizers, sediment, suspended solids, litter and other debris.
What is a Municipal Separate Storm Sewer System (MS4)?
The City of Winchester was designated by the State of Virginia as an “urbanized area” and was therefore required to obtain NPDES (National Pollutant Discharge Elimination System) Phase II stormwater permit. The City has a separate storm sewer system that conveys only stormwater and is made up of streets with drainage systems, including curbs, gutters, catch basins, ditches, man-made channels, and storm sewers. The stormwater enters directly into receiving surface waters. With increases in impervious surfaces due to development and redevelopment, the quantity of stormwater typically increases and transports with it a typical spectrum of pollutants.
The separate storm sewer system is different from a combined system which collects both stormwater and sanitary sewer waste and conveys the combination to a wastewater treatment facility prior to discharge. Communities with combined sewer systems are typically challenged with undersized infrastructure and treatment facilities due to high peak flows associated with storm events.
As of March 2003, the City of Winchester is covered by a Virginia Pollutant Discharge Elimination System (VPDES) Permit for municipalities with separate storm sewer systems. This permit requires the development and implementation of a stormwater management program consisting of six key elements including:
- Public Education and Outreach on Stormwater Impacts
- Public Involvement/Participation
- Illicit Discharge Detection and Elimination
- Construction Site Stormwater Runoff Control
- Post-construction Stormwater Management in New Development and Redevelopment
- Pollution Prevention/Good Housekeeping for Municipal Operations
- View Summary of Stormwater Program Activies (as of November 2007).
What is a Watershed?
A watershed is an area of land where the majority of the stormwater drains into the nearby streams, rivers or creeks. Since all water runs downhill by the force of gravity, watershed boundaries are typically comprised of ridge tops or high elevation areas. A watershed can be very large and can cover several states, such as the Chesapeake Bay Watershed, which encompasses areas of New York, Pennsylvania, Maryland, West Virginia and Virginia. Watersheds can also be very small, though, consisting of just a few small streams or wetlands area, much like the Opequon Creek watershed.
The City of Winchester is located within the broad Chesapeake Bay Watershed. This means that all of the stormwater present in Winchester could eventually make its way to the Chesapeake Bay. However, the smaller watersheds within the City include the watersheds for Town Run, Abrams Creek, Hogue Run, Buffalo Lick Run and Redbud Run. All of these smaller watersheds eventually contribute to the Opequon Creek watershed.