Below you will find answers to some of Dover Township’s most Frequently Asked Questions:
MS4 is short for, “Municipal Separate Storm Sewer System”, where the word “Municipal” refers to a unit of local government like a borough or a township but may also refer to an organization responsible for the administration of a developed area. And the number 4 refers to the four words that start with the letter “S”; “Separate,” “Storm,” “Sewer,” “System.”
A separate storm sewer system is a collection of structures, including retention basins, ditches, roadside inlets, and underground pipes, designed to gather stormwater from built-up areas and discharge it, without treatment, into local streams and rivers. It’s called a separate system because it’s not connected to the sanitary sewer system which drains wastewater from inside a home to a sewage treatment facility or a private septic system.
Many rural developments have stormwater management structures, but only communities that the United States Census Bureau classifies as “Urbanized Areas,” or UAs, based on population density, are required to become part of the MS4 program. UAs contain plenty of commercial and residential development which produces large amounts of stormwater runoff. Large institutions, like college campuses and hospital complexes, are also part of the MS4 program because they also contain the type of dense development that produces concentrated stormwater flows. Finally, PennDOT and the Pennsylvania Turnpike Commission are in the MS4 program because of the many separate storm sewer systems they maintain along roads and highways.
The MS4 program is managed by the Pennsylvania Department of Environmental Protection or DEP, which fulfills this role to comply with federal mandates under the Clean Water Act. The Environmental Protection Agency (EPA) has an oversight role because they are the federal agency charged with implementing the Clean Water Act.
The authorization that MS4 communities get from the DEP to legally discharge stormwater into local stream and rivers is called an “NPDES” permit which stands for National Pollution Discharge Elimination System. The word “National” references the connection with the Federal Clean Water Act, and the word “Discharge” refers to the fact that separate storm sewer systems eventually release stormwater into local creeks, rivers, and lakes, untreated. These particular NPDES permits are also commonly called, “MS4 Permits” or “Stormwater Permits.” To meet the terms of their NPDES Permit, communities need to develop what’s called a “Stormwater Management Program” (SWMP). Communities like Dover Township, that discharge stormwater into the Chesapeake Bay Watershed, or into any other waterway that the DEP identifies as “impaired,” are also required to develop a “Pollutant Reduction Plan” (PRP).
Because every MS4 faces unique stormwater challenges each management plan is unique. But every SWMP includes the same six focus areas that the Environmental Protection Agency considers essential for success, called Minimum Control Measures or “MCMs”:
- Public Education and Outreach
- Construction Site Erosion Control
- Public Participation and Involvement
- Post Construction Stormwater Management
- Illicit Discharge Detection and Elimination
- Pollution Prevention and Good Housekeeping
A Watercourse is a stream, river, brook, creek, channel, ditch or swale where water flows on a continuous, seasonal, or intermittent basis. A watercourse can be natural or manmade.
As the property owner, you are responsible to maintain the Watercourse. This means keeping it free of trash, debris, excessive vegetation, and obstacles that could block the flow of water. You also have the responsibility to prevent pollution and contamination of the water flowing through the Watercourse.
A Stormwater Management (SWM) Permit Application must be completed for any improvements that will result in 100 square feet or more of new impervious (water cannot get through) surface. Examples would include sheds, home additions, patios and driveways. A copy of our Stormwater Management Permit Application can be obtained by clicking the following link:
The SWM application is typically completed at the time a building permit application is completed. Following the completion of a SWM application, Township Staff will utilize the following criteria in reviewing the application and information provided as part of the building permit application.
- Will the project result in 1000 square feet or more of new impervious surface?
- Yes, the applicant will be required to provide a SWM Site Plan which will require the services of a qualified professional. The completed SWM Site Plan will then need to be reviewed and approved by the Township Engineer before Township Staff can issue a SWM Permit.
- No, Township Staff will review the SWM Application and will work with the Property Owner and/or Contractor to determine the Best Management Practice (BMP) to be used for managing rainwater runoff from the new impervious surface.
- Does the project site qualify as a Disconnected Impervious Area (DIA)?
- Yes, there are adequate on-site conditions to ensure that runoff from the new impervious surface will infiltrate into the soil and not leave the property. A slope of less than 5%, no more than 500 SF of roof drainage discharged to any one point, and a flow path greater than 75 feet would constitute adequate on-site conditions. If the site is approved for a DIA, the completion of an SWM Permit will not be required.
- No, some form of Structural BMP will be required such as infiltration beds, infiltration trenches, and/or Rain Gardens. The completion of a SWM Permit will be required.
A copy of our SWM Small Project Guide can be obtained by clicking on the following link:
Our SWM Small Project Guide describes the on-site conditions necessary to qualify for a Disconnected Impervious Area (DIA) along with specifications and diagrams of the structural BMPs (beds, trenches, and Rain Gardens) that Township Staff can approve and permit.
The Property Owner and his/her Contractor are responsible to see that the structural BMP is constructed according to Township specifications and requirements. Dover Township will require a construction phase inspection to verify that these are being met.
The Small Project Stormwater Management Permit will also list the Property Owner’s responsibilities to Maintain and Inspect Structural BMPs.