Municipal Separate Storm Sewer System Permit

After rain falls, it flows over the land and into ditches, pipes or basins before it eventually discharges into the Huron River. The various stormwater management practices that the city owns and maintains is called a Municipal Storm Sewer System or MS4.

The Huron River is considered Waters of the State, meaning it is under state and federal jurisdiction. To prevent harmful pollutants from entering waters of the state, municipalities within state defined Urbanized Areas are required to obtain permits and develop stormwater management programs. This permit is called a National Pollutant Discharge Elimination System, or NPDES Permit. Permits in this program dedicated to stormwater pollutants are called MS4 Permits. 

The City is permitted by the Michigan Department of Environment, Great Lakes, and Energy to discharge stormwater through NPDES, MS4 Permit No. MI0053856. 

 

Permit Requirements

As part of the MS4 Permit, the city is required to establish a stormwater management program that contains the following minimum measures: 

The Public Participation and Involvement Program, or PPP, is facilitated by the Huron River Watershed Council and shared across several partners within the Middle Huron. The goal of the PPP is to encourage public involvement in stormwater activities. 

The Public Education Program, or PEP, establishes requirements for educating the public on issues surrounding stormwater. The City primarily does this through calendar distribution, water newsletters, educational social media content  and stormwater related events a throughout the year.

 

The Illicit Discharge Elimination Program, or IDEP, is focused on finding, preventing and stopping illicit discharges. An illicit discharge is any discharge, or seepage into the MS4 that is not composed of entirely stormwater or uncontaminated groundwater. The goals of the IDEP are primarily met through regular screening, water sampling and education throughout the city. The City collaborates with both the Huron River Watershed Council and the Office of the Washtenaw County Water Resources Commissioner to meet IDEP goals. 

The Construction Stormwater Program works to prevent sediment and other pollutants generated by construction projects from entering the river. The City has a regulatory program in place to control stormwater run-off from construction sites per Chapter 63 of Code of the City of Ann Arbor. 

The Post Construction Stormwater Program aims to mitigate the effects of development, by establishing requirements for permanent stormwater controls. These controls include detention, retention and sediment separation devices. 

The Pollution Prevention and Good Housekeeping Program, or P2GH Program, establishes requirements for how the City manages the effects of stormwater from municipal activities. This includes the stormwater generated on sites with increased pollution risks and from municipal activities that may have impacts on stormwater activities such as road deicing and pesticide application. 

 

The Michigan Department of Environment, Great Lakes and Energy, or EGLE, establishes Water Quality Standards for all waterbodies throughout the state based on their designated use. When waterbodies to not meet the standards for their designated use, Total Maximum Daily Loads, or TMDLs, are set to establish the maximum amount of a pollutant that can be discharged into them. 

The City of Ann Arbor currently has the following TMDLs in effect: 

  1. Phosphorus in Ford Lake and Belleville Lake
  2. E. Coli in Huron River from Argo Pond to Geddes Pond
  3. Biota in Swift Run and Malletts Creek

The city actively pursues projects in accordance with the Middle Huron Partners TMDL Implementation Plan to reduce the effects of the TMDL defined pollutants. 

MS4 Permit Implementation Plan MS4 Permit

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301 East Huron Street

Ann Arbor, MI 48104

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