During the 1990’s, the United States Environmental Protection Agency (EPA) amended the Clean Water Act (CWA) and created a two-phased national program to address water pollution emanating from stormwater runoff.
Phase I of the program was designed to address stormwater discharges from the nations’ largest cities. Phase II of the program was designed to address stormwater discharges from smaller Municipal Separate Storm Sewer Systems (MS4s) (or those that are located in urbanized areas with a population less than 100,000). Under both phases of the program, operators of these systems are required to obtain National Pollution Discharge Elimination System (NPDES) permit coverage for their stormwater discharges.
Through delegation by the federal government, New York State is administering these program requirements through the NYS Department of Environmental Conservation (DEC). The NYS DEC is using two different General Permits as the framework for managing stormwater across the state. The State’s program requires operators of construction sites to obtain coverage under the “SPDES General Permit for Stormwater Discharges from Construction Activities”. Operators of regulated Municipal Separate Storm Sewer Systems (MS4s) must obtain coverage under the “SPDES General Permit for Stormwater Discharges from Municipal Separate Storm Sewer Systems.
This municipality (or a portion of this municipality) is considered to be a small MS4 and is, therefore, required to comply with the Phase II Stormwater regulations. The Phase II regulations require that a regulated MS4 must “develop, implement and enforce a Stormwater Management Program (SWMP) designed to reduce the discharge of pollutants from the MS4 to the Maximum Extent Practicable (MEP) in order to protect water quality and to satisfy the requirements of the Clean Water Act”.
A regulated MS4’s Stormwater Management Program must satisfy the requirements for each of six required program components, known as Minimum Control Measures (MCMs). These control measures are:
- Public Education and Outreach
- Public Involvement and Participation
- Illicit Discharge Detection and Elimination
- Construction Site Stormwater Runoff Control
- Post-construction Stormwater Management
- Pollution Prevention/Good Housekeeping for Municipal Operations
The State’s stormwater program may also require additional provisions if certain conditions are met. For example, if a small MS4 discharges a particular pollutant of concern (e.g. phosphorous, nitrogen, pathogens, etc) to a waterbody identified as being impaired, the MS4 must ensure that there is no net increase in its discharge of that particular pollutant to that waterbody. To accomplish this, the small MS4s must assess pollutant loadings using a NYS DEC supported pollutant loading model. If modeling indicates increased in loading of the pollutant of concern, the stormwater program must be modified to reduce the loading to meet the no net increase requirement
Further, small MS4s located in watersheds with approved TMDL (Total Maximum Daily Load) allocations are required to implement additional permit criteria to achieve compliance with specific TMDL provisions. In these cases, the MS4 must ensure that discharges of the pollutants of concern are reduced so that the waste load allocation is met for that particular waterbody or watershed. To accomplish this, the small MS4s must assess pollutant loadings using a NYS DEC supported pollutant loading model. If modeling indicates there is no reduction in loading of the pollutant of concern, their stormwater program must be modified to reduce the loading to meet the waste load allocation
A Notice of Intent (NOI) for this municipality to obtain coverage under the MS4 General Permit has been filed with the NYS DEC and summarizes the best management practices (BMPs) and activities that were selected to meet the six minimum measures. A copy of the NOI is provided below. Activities undertaken to address each minimum control measure are further detailed in the corresponding web-pages.