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The MS4 Stormwater Management Program & Plan: Introduction to the Stormwater Management Program/Plan

Updated: May 17, 2021

The Stormwater Management Program:

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.

Notice of Intent:

Village of Oriskany Notice of Intent
Download PDF • 1.96MB

The Stormwater Management Plan: The General Permit for Stormwater Discharges from MS4s requires the development of a Stormwater Management Program Plan (SWMPP) to document developed, planned and implemented stormwater program elements. In an effort to comply with this requirement, our MS4 has developed this website to serve as that Stormwater Management Program Plan. In accordance with the NYS Department of Environmental Conservation's (NYS DEC) guidance, this SWMP plan generally describes how pollutants in stormwater runoff will be controlled within our community and/or designated MS4 area. This SWMP plan includes a detailed written explanation of all management practices, activities and other techniques that the MS4 has developed, planned and implemented to meet the federal and state requirements. Information included in the Notice of Intent (NOI) is reflected in this SWMP plan but, it should be recognized that the SWMP plan is considered a separate and more inclusive document. Our stormwater management program and plan includes measurable goals for each of the management practices and activities we have selected to reduce pollutants in stormwater to the maximum extent practicable. These measurable goals are identified to help the MS4 assess the status and progress of its program. Other elements of the stormwater management program and plan include: the identification and inclusion of time lines, schedules and milestones for development and implementation; copies of local laws and ordinances; inter-municipal agreements and other legal authorities; staffing and staff development programs and organization charts; program budgets; policy, procedures, and materials for each minimum measure; outfall and stormwater system maps; operation and maintenance schedules; documentation of public outreach efforts and public comments; a summary of construction site Stormwater Pollution Prevention Plans and review letters, and construction site inspection reports. This web-based format will allow the MS4 to easily record, assess and modify program and plan elements as needed. This SWMP plan will be revised regularly to incorporate any new or modified BMPs or measurable goals. The plan will be made readily available to the MS4's staff, to the public, and to regulators, such as NYS DEC and US EPA staff. This web-based format was developed through a partnership with the Digital Towpath Cooperative and the Herkimer-Oneida Counties Comprehensive Planning Program. Funding was provided by the Finger Lakes-Lake Ontario Watershed Protection Alliance (FL-LOWPA).

Glossary of Terms:

BMP / Best Management Practice: Activities or structural improvements that help reduce the quantity and improve the quality of stormwater runoff. BMPs include public education and outreach, treatment requirements, operating procedures, and practices to control runoff, spillage or leaks, sludge or waste disposal, or drainage from raw material storage.

Combined Sewer System: A sewer system designed to convey both sanitary wastewater and stormwater.

CWA / Clean Water Act: Amendments made to the Federal Water Pollution Control Act in 1972 to establish water quality standards and to create the National Pollutant Discharge Elimination System to protect the waters of the U. S. by regulating the discharge of pollutants from point source discharges and municipal separate storm sewer systems.

Detention Pond: Pond that stores a volume of water for a given period of time and then discharges the water downstream.

Discharge: An outflow of water from a stream, pipe, ground water system or watershed.

Erosion: the overall process of the transport of material on the earth’s surface including the movement of soil and rock by agents such as water, wind, or gravity.

Groundwater: all of the water contained in void space beneath the earth’s surface.

Heavy Metals: Metals such as zinc, copper, lead, mercury, chromium, cadmium, iron, manganese, nickel, molybdenum and silver that, even in low concentrations can be toxic or lethal to humans, animals and aquatic life.

Illicit Discharge: The term refers to any discharge to an MS4 that is not composed entirely of stormwater unless authorized via an NPDES permit or otherwise excluded from regulation. Thus, not all illicit discharges are illegal or prohibited.

Industrial Waste: Unwanted materials from an industrial operation. It may be liquid, sludge, solid, or hazardous waste.

MEP / Maximum Extent Practicable: a water quality standard that applies to all MS4 operators under NPDES permits. The standard has no exact definition, as it was intended to be flexible to allow operators to tailor their stormwater programs to their particular site.

MS4 / Municipal Separate Storm Sewer Systems: Areas with a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, and storm drains) that are not a combined sewer or part of a publicly owned treatment system and are owned or operated and regulated by a municipality or authorized agency. MS4s may be small, medium or large with the medium or large MS4s being principally determined by population size.

NOI / Notice of Intent: An application to notify the permitting authority of a facility’s intention to be covered by a general permit. This exempts a facility from having to submit an individual or group application.

NPDES / National Pollutant Discharge Elimination System: the EPA’s regulatory program to control the discharge of pollutants to waters of the United States.

NPS / Non-Point Source Pollutants: pollution coming from many diffuse sources whose origin is often difficult to identify. This pollution occurs as rain or snowmelt travels over the land surface and picks up pollutants such as fertilizer, pesticides, and chemicals from cars. This pollution is difficult to regulate due to its origin from many different sources. These pollutants enter waterways untreated and are a major threat to aquatic organisms and people who fish or use waterways for recreational purposes.

Nutrients: The term typically refers to nitrogen and phosphorus or compounds containing free amounts of the two elements. These elements are essential for the growth of plant life, but can create problems in the form of algal blooms, depletion of dissolved oxygen and pH changes in streams and other water bodies when higher concentrations are allowed to enter drainage systems and lakes.

Ordinance: A law based on state statutory authority developed and approved by a governmental agency to allow them to regulate the enforcement of criteria contained within the specific law and to invoke sanctions and other enforcement measures to ensure facilities comply with the criteria.

Outfall: the point where a sewer or drainage discharges into a receiving waterway.

Point Source Pollution: pollution coming from a single, definable source, such as a factory.

PWL / Priority Waterbodies List: A statewide inventory (database) of NYS waterbodies which characterizes water quality, the degree to which water uses are supported, progress toward the identification of water quality problems and sources, and activities to restore and protect each individual waterbody.

Retention Pond: Pond that stores a volume of water without allowing it to discharge downstream.

Runoff: any drainage that leaves an area as surface flow.

Sanitary Sewer: an underground pipe system that carries sanitary waste and other wastewater to a treatment plant.

Sediment: material derived from the weathering of rock such as sand and soil. This material can be detrimental to aquatic life and habitats if too much is allowed to wash into rivers and ponds.

Site Plan: a geographic representation of the layout of buildings and other important features on a tract of land.

SPDES / State Pollutant Discharge Elimination System: the state’s regulatory program to control the discharge of pollutants to waters of the Unites States.

Storm Drain: any drain which drains directly into the storm sewer system, usually found along roadways or in parking lots.

Storm Sewer: an underground pipe system that carries runoff from streets and other surfaces.

Stormwater: stormwater or snow melt runoff, and surface runoff and drainage.

Stormwater Management: any measure associated with the planning, maintenance, and regulation of facilities which collect, store, or convey stormwater.

Surface Runoff: the flow of water across the land surface that occurs when the rainfall rate exceeds the ability of the soil to absorb the water. Also occurs on impervious surfaces, such as parking lots, where water cannot infiltrate at all.

Surface Water: any water that remains on the earth’s surface, such as ponds, rivers, streams, impoundments, wetlands, oceans, etc.

SWPPP / Stormwater Pollution Prevention Plan: A plan developed by a facility or entity that thoroughly evaluates potential pollutant sources at a construction site and selects and implements appropriate best management practice measures designed to prevent or control the discharge of pollutants in stormwater runoff.

TMDL / Total Maximum Daily Load: a regulatory limit of the maximum amount of a pollutant type that can be released into a body of water in a twenty-four hour period without adversely affecting water quality.

Tributary: a stream which drains into another larger stream or body of water.

UA / Urbanized Area: Is a land area consisting of one or more central places and the adjacent densely settled surrounding area (urban fringe) that together have a residential population of at least 50,000 and a minimum average population density of at least 1,000 people per square mile.

Waters of the US: These are surface waters defined as wetlands, lakes (including dry lakes), rivers, streams (including intermittent streams, ephemeral washes and arroyos), mudflats, sandflats, sloughs, wet meadows, playa lakes, natural ponds, and man-made impoundments.

Watershed: a geographic area in which water flowing across the surface will drain into a certain stream or river and flow out of the area via that stream or river. All of the land that drains to a particular body of water. Also known as a catchment or drainage basin.

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