MS4

MS4: "The Municipal Separate Storm Sewer Systems"

The Municipal Separate Storm Sewer Systems (MS4s) are designed to collect stormwater runoff and discharge it into local water bodies, untreated. Stormwater is water originating from precipitation that does not immerse into the ground, but rather runs off into waterways. It comes from a variety of surfaces such as rooftops, paved areas, and bare soil which travels through sloped lawns while collecting several materials on its way. When adding up the countless residential, commercial, and industrial runoff, the concentrations of contaminants threaten our local waterbodies.  

An MS4 needs to be owned or operated by a municipality, designed and used for collecting stormwater, not part of a combined sewer, and is not part of a Publicly Owned Treatment Works (POTW). In order to prevent any harmful pollutants from entering an MS4, it is required to obtain a permit from National Pollutant Discharge Elimination System (NPDES) as well as develop a stormwater management program. There are six minimum control measures that need to be addressed in the stormwater management plan.

The six control measures are:

•    Public Education and Outreach
•    Public Participation/Involvement
•    Illicit Discharge Detection and Elimination
•    Construction Site Runoff Control
•    Post-Construction Runoff Control
•    Pollution Prevention/Good Housekeeping

In 1999, the Stormwater Phase II Rule became in effect, which required regulated small MS4s in and outside of urbanized areas, such as Utica. Since then, it has been a continuous effort to reduce the amount of pollutants carried by stormwater during storm events to the “maximum extent practicable” (MEP), protect water quality, and satisfy the appropriate water quality requirements of the Clean Water Act; as required by the U.S. Environmental Protection Agency (EPA). There are several pollutants that affect the well being of the waterbodies. For example, nutrients such as phosphorus and nitrogen can promote algae growth and reduce oxygen content in the waterway, causing harm to aquatic life. A common pollutant resulting from various forms of transportation are oil and grease. This causes an odor and shine to the water, also making it difficult for aquatic animals to retrieve oxygen. Sediment from construction activities and litter interferes with the habitat of living things that depend on the water as well as diminish the natural beauty of the waterways. Bacteria from animal waste can make recreational uses unsafe and the fish inedible.

MS4 Annual Report - 2011 (PDF)