MS4 APPENDIX B
DEFINITIONS AND ABBREVIATIONS
The definitions in this Part are for purposes of this permit only.
- “Active Karst” means geographic areas underlain by carbonate bedrock (or other forms of bedrock that can erode or dissolve) with less than 50 feet of sediment cover.
- "Agency” means the Minnesota Pollution Control Agency or MPCA. (Minn. Stat. § 116.36, subd. 2.)
- “Alum or Ferric Chloride Phosphorus Treatment System” means the diversion of flowing stormwater from a MS4, removal of phosphorus through the use a continuous feed of alum or ferric chloride additive, flocculation, and the return of the treated stormwater back into a MS4 or receiving water.
- “Applicable WLA” – means a Waste Load Allocation assigned to the permittee and approved by the USEPA.
- “Best Management Practices” or “BMPs” means practices to prevent or reduce the pollution of the waters of the state, including schedules of activities, prohibitions of practices, and other management practices, and also includes treatment requirements, operating procedures and practices to control plant site runoff, spillage or leaks, sludge, or waste disposal or drainage from raw material storage. (Minn. R. 7001.1020, subp.5.)
- “Commissioner” means the Commissioner of the Minnesota Pollution Control Agency or the Commissioner’s designee. (Minn. Stat. § 116.36, subd. 3.)
- “Common Plan of Development or Sale” means a contiguous area where multiple separate and distinct land disturbing activities may be taking place at different times, on different schedules, but under one proposed plan. One plan is broadly defined to include design, permit application, advertisement or physical demarcation indicating that land-disturbing activities may occur.
- "Construction Activity" includes construction activity as defined in 40 CFR § 122.26(b)(14)(x) and small construction activity as defined in 40 CFR § 122.26(b)(15). This includes a disturbance to the land that results in a change in the topography, existing soil cover (both vegetative and non-vegetative), or the existing soil topography that may result in accelerated stormwater runoff, leading to soil erosion and movement of sediment into surface waters or drainage systems. Examples of construction activity may include clearing, grading, filling, and excavating. Construction activity includes the disturbance of less than one acre of total land area that is a part of a larger common plan of development or sale if the larger common plan will ultimately disturb one (1) acre or more.
- “DNR Catchment Area” means the Hydrologic Unit 08 areas delineated and digitized by the Minnesota DNR. The catchment areas are available for download at the Minnesota DNR Data Deli website. DNR catchment areas may be locally corrected, in which case the local corrections may be used.
- “Effective Date” means the date, located on the front cover of this permit, on which this permit shall become effective.
- “Existing Permittee” means an Owner/Operator of a small MS4 that has been authorized to discharge stormwater under a previously issued general permit for small MS4s in the state of Minnesota.
- “General permit” means a permit issued under Minn. R. 7001.0210 to a category of permittees whose operations, emissions, activities, discharges, or facilities are the same or substantially similar. (Minn. R. 7001.0010, subp.4.)
- “Geographic Coordinate” means the point location of a stormwater feature expressed by X, Y coordinates of a standard Cartesian coordinate system (i.e. latitude/longitude) that can be readily converted to Universal Transverse Mercator (UTM), Zone 15N in the NAD83 datum. For polygon features, the geographic coordinate will typically define the approximate center of a stormwater feature.
- “Green Infrastructure” means a wide array of practices at multiple scales that manage wet weather and that maintains or restores natural hydrology by infiltrating, evapotranspiring, or harvesting and using stormwater. On a regional scale, green infrastructure is the preservation or restoration of natural landscape features, such as forests, floodplains and wetlands, coupled with policies such as infill and redevelopment that reduce overall imperviousness in a watershed. On the local scale, green infrastructure consists of site and neighborhood-specific practices, such as bioretention, trees, green roofs, permeable pavements and cisterns.
- “High Flow Bypass” means a function of an inlet device that allows a certain flow of water through, but diverts any higher flows away. High flow bypasses are generally used for BMPs that can only treat a designed amount of flow and that would be negatively affected by higher flows.
- “Illicit Discharge” means any discharge to a municipal separate storm sewer that is not composed entirely of stormwater except discharges pursuant to a NPDES permit (other than the NPDES permit for discharges from the municipal separate storm sewer) and discharges resulting from firefighting activities. (40 CFR § 122.26(b)(2))
- “Impaired Water” means waters identified as impaired by the Agency, and approved by the USEPA, pursuant to section 303(d) of the Clean Water Act (33 U.S.C. § 303(d)).
- “Maximum Extent Practicable” or “MEP” means the statutory standard (33 U.S.C. § 1342(p)(3)(B)(iii)) that establishes the level of pollutant reductions that an Owner or Operator of Regulated MS4s must achieve. The USEPA has intentionally not provided a precise definition of MEP to allow maximum flexibility in MS4 permitting. The pollutant reductions that represent MEP may be different for each small MS4, given the unique local hydrologic and geologic concerns that may exist and the differing possible pollutant control strategies. Therefore, each permittee will determine appropriate BMPs to satisfy each of the six Minimum Control Measures (MCMs) through an evaluative process. The USEPA envisions application of the MEP standard as an iterative process.
- “Municipal separate storm sewer system” or “MS4” means a conveyance or system of conveyances including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains:
a. owned or operated by a state, city, town, county, district, association, or other public body, created by or pursuant to state law, having jurisdiction over disposal of sewage, industrial wastes, stormwater, or other wastes, including special districts under state law such as a sewer district, flood control district, or drainage district or similar entity, or an Indian tribe or an authorized Indian tribe organization, or a designated and approved management Agency under section 208 of the federal Clean Water Act, United States Code, title 33, section 1288, that discharges into waters of the state
b. designed or used for collecting or conveying stormwater
c. that is not a combined sewer; and
d. that is not part of a publicly owned treatment works as defined in 40 CFR § 122.2
Municipal separate storm sewer systems do not include separate storm sewers in very discrete areas, such as individual buildings. (Minn. R. 7090.0080, subp. 8).
- “New development” means all construction activity that is not defined as redevelopment.
- “New Permittee” means an Owner/Operator of a small MS4 that has not been authorized to discharge stormwater under a previously issued General Stormwater Permit for small MS4s in the state of Minnesota and that applies for, and obtains coverage under this permit.
- “Non-Stormwater Discharge” means any discharge not composed entirely of stormwater.
- “Operator” means the person with primary operational control and legal responsibility for the municipal separate storm sewer system. (Minn. R. 7090.0080, subp.10.)
- “Outfall” means the point source where a municipal separate storm sewer system discharges to a receiving water, or the stormwater discharge permanently leaves the permittee’s MS4. It does not include diffuse runoff or conveyances that connect segments of the same stream or water systems (e.g., when a conveyance temporarily leaves an MS4 at a road crossing).
- “Owner” means the person that owns the municipal separate storm sewer system. (Minn. R. 7090.0080, subp.11.)
- “Permittee” means a person or persons, that signs the permit application submitted to the Agency and is responsible for compliance with the terms and conditions of this permit.
- “Person” means the state or any Agency or institution thereof, any municipality, governmental subdivision, public or private corporation, individual, partnership, or other entity, including, but not limited to, association, commission or any interstate body, and includes any officer or governing or managing body of any municipality, governmental subdivision, or public or private corporation, or other entity.(Minn. Stat. § 115.01, subd. 10.)
- “Pipe” means a closed manmade conveyance device used to transport stormwater from location to location. The definition of pipe does not include foundation drain pipes, irrigation pipes, land drain tile pipes, culverts, and road sub-grade drain pipes.
- “Pollutant of Concern” means a pollutant specifically identified in a USEPA-approved TMDL report as causing a water quality impairment.
- “Receiving Water” means any lake, river, stream or wetland that receives stormwater discharges from an MS4.
- “Redevelopment” means any construction activity where, prior to the start of construction, the areas to be disturbed have 15 percent or more of impervious surface(s).
- “Reduce” means reduce to the Maximum Extent Practicable (MEP) unless otherwise defined in the context in which it is used.
- “Saturated Soil” means the highest seasonal elevation in the soil that is in a reduced chemical state because of soil voids being filled with water. Saturated soil is evidenced by the presence of redoximorphic features or other information.
- “Significant Materials” includes, but is not limited to: raw materials, fuels, materials such as solvents, detergents, and plastic pellets; finished materials such as metallic products; raw materials used in food processing or production; hazardous substances designated under Section 101(14) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA); any chemical the facility is required to report pursuant to Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA); fertilizers, pesticides, and waste products such as ashes, slag, and sludge that have the potential to be released with stormwater discharges. When determining whether a material is significant, the physical and chemical characteristics of the material should be considered (e.g. the material’s solubility, transportability, and toxicity characteristics) to determine the material’s pollution potential. (40 CFR § 122.26(b)(12).
- “Small Municipal Separate Storm Sewer System” or “small MS4”, means all separate storm sewers that are:
- Owned or operated by the United States, a state, city, town, borough, county, parish, district, association, or other public body (created by or pursuant to state law) having jurisdiction over disposal of sewage, industrial wastes, stormwater, or other wastes, including special districts under state law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management Agency under section 208 of the CWA that discharges to waters of the United States.
- Not defined as “large” or “medium” Municipal Separate Storm Sewer Systems pursuant to 40 CFR § 122.26 paragraphs (b)(4) and (b)(7) or designated under paragraph (a)(1)(v).
- This term includes systems similar to separate storm sewer systems in municipalities, such as systems at military bases, large hospital or prison complexes, and highways and other thoroughfares. The term does not include separate storm sewers in very discrete areas, such as individual buildings.
- “Stormwater” means stormwater runoff, snow melt runoff, and surface runoff and drainage. (Minn. R. 7090.0080, subp.12.)
- “Stormwater flow direction” means the direction of predominant flow within a pipe. Flow direction can be discerned if pipe elevations can be displayed on the storm sewer system map.
- “Stormwater Pollution Prevention Program” or “SWPPP” means a comprehensive program developed by the permittee to manage and reduce the discharge of pollutants in stormwater to and from the small MS4.
- “Structural Stormwater BMP” means a stationary and permanent BMP that is designed, constructed and operated to prevent or reduce the discharge of pollutants in stormwater.
- “Total Maximum Daily Load” or “TMDL” means the sum of the individual Waste Load Allocations for point sources and load allocations for nonpoint sources and natural background, as more fully defined in 40 CFR § 130.2, paragraph (i). A TMDL sets and allocates the maximum amount of a pollutant that may be introduced into a water of the state and still assure attainment and maintenance of water quality standards. (Minn. R. 7052.0010 subp. 42)
- “Waste Load Allocation” or “WLA” means the portion of a receiving water's loading capacity that is allocated to one of its existing or future point sources of pollution, as more fully defined in Code of Federal Regulations, http://www.gpo.gov/fdsys/pkg/CFR-2002-title40-vol18/pdf/CFR-2002-title40-vol18-sec130-2.pdf title 40, section 130.2], paragraph (h). In the absence of a TMDL approved by USEPA under CFR § 130.7, or an assessment and remediation plan developed and approved according to part 7052.0200, subpart 1, item C, a WLA is the allocation for an individual point source that ensures that the level of water quality to be achieved by the point source is derived from and complies with all applicable water quality standards and criteria. (Minn. R. 7052.0010 subp. 45)
- “Water pollution” means (a) the discharge of any pollutant into any waters of the state or the contamination of any waters of the state so as to create a nuisance or render such waters unclean, or noxious, or impure so as to be actually or potentially harmful or detrimental or injurious to public health, safety or welfare, to domestic, agricultural, commercial, industrial, recreational or other legitimate uses, or to livestock, animals, birds, fish or other aquatic life; or (b) the alteration made or induced by human activity of the chemical, physical, biological, or radiological integrity of waters of the state. (Minn. Stat. § 115.01, subd. 13)
- “Water Quality Standards” means those provisions contained in Minn. R. 7050 and 7052.
- “Waters of the State” means all streams, lakes, ponds, marshes, watercourses, waterways, wells, springs, reservoirs, aquifers, irrigation systems, drainage systems and all other bodies or accumulations of water, surface or underground, natural or artificial, public or private, which are contained within, flow through, or border upon the state or any portion thereof. (Minn. Stat. § 115.01, subd. 22.)
- “Wetlands” are those areas that are inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. Constructed wetlands designed for wastewater treatment are not waters of the state. Wetlands must have the following attributes:
- A predominance of hydric soils
- Inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support a prevalence of hydrophytic vegetation typically adapted for life in a saturated soil condition and
- Under normal circumstances support a prevalence of such vegetation. (Minn. R. 7050.0186, subp. 1a.B.)
ABBREVIATIONS AND ACRONYMS
- BMP - Best Management Practice
- CFR – Code of Federal Regulations
- CWA – Clean Water Act or the Federal Water Pollution Control Act, 33 U.S.C. §1251 et seq)
- DNR – Department of Natural Resources
- DWSMA – Drinking Water Supply Management Area
- ERPs– Enforcement Response Procedures
- IDDE - Illicit Discharge Detection and Elimination
- MCM – Minimum Control Measure
- MDH – Minnesota Department of Health
- MEP – Maximum Extent Practicable
- MS4 - Municipal Separate Storm Sewer System
- NPDES - National Pollutant Discharge Elimination System
- ORVW - Outstanding Resource Value Water
- SDS – State Disposal System
- TMDL - Total Maximum Daily Load
- TP – Total Phosphorus
- TSS - Total Suspended Solids
- USEPA - United States Environmental Protection Agency
- WLA – Waste Load Allocation