What's an MS4?

What's an MS4?

MS4 stands for Municipal Separate Storm Sewer System. An MS4 community owns or operates a system for collecting and conveying storm water. Regulated conveyance systems include roads with drains, municipal streets, catch basins, curbs, gutters, storm drains, piping, channels, ditches, tunnels, and conduits. It does not include combined sewer overflows and publicly owned treatment works.

MS4 is an unfunded, federally mandated program that requires municipalities to take measures to reduce pollutants in storm water runoff to improve water quality. The state requires the Town of Cumberland to comply with this rule (327 IAC 15-13).

The MS4 is permitted under the National Pollutant Discharge Elimination System (NPDES) program through the Indiana Department of Environmental Management (IDEM). MS4 permits are granted in five-year cycles at the end of which the permit must be renewed.

What is a Storm Water Quality Management Plan (SWQMP)?

The SWQMP is divided into three distinct components. The first part of the SWQMP is Part A or the initial application. Part A includes a general budget sheet used to indicate to the State that a budget allocation has been made to the MS4 Program.

Part B is the Baseline Characterization. The MS4 Operator provides in the Part B information on the characterization of known water quality of all waters that receive storm water outfall discharges within the MS4 area.

The third component is the Implementation Plan and is designated as Part C. Part C is the working document that outlines the priorities, goals, and implementation strategies that the MS4 will utilize to improve water quality. It is expected that this document will change as issues are solved, best management practices are utilized, and technology improvements are developed.

The MS4 Program

Storm water discharges are regulated through the municipal separate storm sewer system (MS4) program, which is administered in Indiana by the Indiana Department of Environmental Management (IDEM). As part of the MS4 program, communities are required to implement six minimum control measures (MCMs) related to storm water discharges. These MCMs are described below:

Public Education and Outreach: Educate residents, visitors, public service employees and others about the impacts storm water runoff can have on water quality and ways they can minimize their impact on storm water quality. An understanding of storm water issues will help gain public support for the MS4 program.

Public Involvement and Participation: Encourages citizens within the MS4 area to participate and provide input in the development and implementation of the MS4 program. A community that is active and involved will be critical to the success of the program.

Illicit Discharge Detection and Elimination: Illicit discharge is defined as any discharge to an MS4 conveyance that is not composed entirely of storm water, except naturally occurring floatables, such as leaves or tree limbs. Sources of illicit discharges include sanitary wastewater, septic tank effluent, car wash wastewater, oil disposal, radiator flushing disposal, laundry wastewater, roadway accident spillage, and household hazardous wastes. An MS4 operator is required to develop and implement a strategy to detect and eliminate illicit discharges into MS4 conveyances.

Construction Site Storm water Runoff Control: This control is intended to reduce pollutants, principally sediment that is associated with construction activities. Requirements include the use of erosion and sediment control measures, as well as measures to properly manage and control other pollutants that may be associated with construction activities.

Post-Construction Storm water Management: Addresses storm water discharges from new development and redeveloped areas, often through the use of storm water BMPs. Post-construction storm water quality measures are long-term control systems that must be managed and maintained to ensure performance. The program will ensure that adequate maintenance will be performed on these storm water quality measures.

Pollution Prevention and Good Housekeeping for Municipal Operations: Requires the MS4 to evaluate and alter operations internally to ensure a reduction in the pollutants that are generated from municipal operations. Including maintenance and cleaning of roads, parking lots, and MS4 conveyances, as well as proper disposal of wastes removed from these areas. Municipal personnel must also receive relevant storm water training.