Definitions

MINNEHAHA CREEK WATERSHED DISTRICT BOARD OF MANAGERS

REVISIONS PURSUANT TO MINNESOTA STATUTES §103D.341

Adopted April 24, 2014
Effective June 6, 2014

Key definitions

• Abstraction means permanent retention of runoff on a site through structures and practices such as infiltration, evapotranspiration and capture and reuse. See also the Abstraction Credit Schedule in Appendix A of the Stormwater Management Rule.
• Access Corridor means a corridor equal to 30 percent of the total shoreline length to a maximum of 30 feet.
• Agricultural activity means the use of land for the production of agronomic, horticultural or silvicultural crops, including nursery stock, sod, fruits, vegetables, flowers, forages, cover crops, grains, and Christmas trees. Agricultural activity also includes grazing.
• Alteration or alter means any activity that will change or diminish the course, current, or cross-section of public waters and wetlands.
• BMPs (best management practices) are actions taken to prevent or reduce detrimental impacts to the environment while maintaining the natural characteristics of the environment.
• Beds of a waterbody means all portions of a waterbody located below the ordinary high-water level.
• Bioengineering Stabilization means the strategic installation of natural, vegetative, biologically active materials in conjunction with toe stabilization, riprap or other hard-armoring materials to stabilize shoreline or streambank areas and associated slopes and prevent erosion.
• Biological Stabilization means the strategic placement of natural, vegetation, biologically active materials – such as but not limited to brush mattresses, live stakes/plantings, brush layering, fiber rolls, root wads and willow wattles – to stabilize shoreline or streambank areas and prevent erosion.
• Design Storm refers to a storm magnitude with a return period (T) which has the probability (1/T) of being equaled or exceeded in any given year. For example, a “100-year” event at a given location has a chance of 1/100 or 0.01 or 1% of being equaled or exceeded in any given year. For MCWD regulatory purposes, the rainfall depths to be used are as follows:
  •  1-year event = 2.4″ in 24 hours
  • 10-year event = 4.1″ in 24 hours
  • 100-year event = 5.9″ in 24 hours

All rainfall depths shall use the NRCS Type II rainfall distribution.

• Development means any land-disturbing activity that creates impervious surface, with the exception of Linear Transportation Projects.
• Dredge means the removal of the sediment or other materials from the beds, banks or shores of, a waterbody by means of hydraulic suction, mechanical excavation or any other means.
• Excavation means the displacement or removal of sediment or other material.
• Fast Track Permit means a permit issued by staff for standard rip rap, sandblankets or maintenance fill projects which are installed according to technical specifications provided by District engineers, or an erosion control permit issued by staff in accordance with the criteria in the Erosion Control Rule.
• Fill means any material placed or intended to be placed on the bed or bank of any protected water or wetland. Fill must be clean, inorganic material that is free of pollutants.
• Floodplain means the areas adjoining a watercourse or water basin which have been or hereafter may be covered by a 100-year regional flood.
• Impervious refers to surfaces that are compacted or covered with a layer of material such that it is highly resistant to infiltration of runoff including but not limited to gravel, rock, asphalt, concrete and non-pervious paver systems.
• Land-disturbing activity or land disturbance means any disturbance to the ground surface that exposes soil and, through the action of wind or water, may result in soil erosion or the movement of sediment into waters, wetlands or storm sewers or onto adjacent property. Land-disturbing activity includes but is not limited to the demolition of a structure or surface, soil stripping, clearing, grubbing, grading, excavating, filling and the storage of soil or earth materials, but does not include agricultural activity.
• Linear Reconstruction Project means rebuilding a road, sidewalk or trail within existing right-of-way, and may include an increase in the area of impervious surface. Rehabilitation, including mill and overlay, of a road, sidewalk or trail within existing right-of-way in a manner that disturbs and/or replaces only the existing pavement and does not involve the addition of impervious surface area or the exposure of underlying soils is not considered a Linear Reconstruction Project.
• Linear Transportation Project means construction of a new road, trail, or sidewalk or reconstruction of an existing road, trail, or sidewalk (see Linear Reconstruction Project).
• Meadow Condition shall be modeled using an event mean concentration of 0.04 mg/L of Total Phosphorus in runoff in accordance with the Minnesota Pollution Control Agency’s Minnesota Stormwater Manual and the MCWD Hydrologic, Hydraulic, and Pollutant Loading Study (HHPLS). For runoff rates, meadow condition shall be modeled using curve numbers corresponding to soil and cover types “meadow,” “brush,” or “woods,” as appropriate, provided in Table 2-2c of the Natural Resources Conservation Service’s (NRCS) Technical Release 55 (TR-55).
• Native Vegetation means plant species that are indigenous to Minnesota or that expand the range into Minnesota without being intentionally or unintentionally introduced by human activity and that are classified as native in the Minnesota Plant Database, Minnesota Department of Natural Resources, St. Paul, 2002.
• Natural State refers toa segment of shoreline or streambank displaying essentially no evidence of constructed stabilization or from which constructed stabilization measures have been removed by degradation or deconstruction. 
• New Principal Residential Structure means a single-family residential building constructed on undeveloped property zoned for residential use or on a property zoned for residential use from which the principal building has been removed for purposes of constructing a new single-family residential building.
• NPDES refers to Clean Water Act National Pollutant Discharge Elimination System.
• NURP means Nationwide Urban Runoff Program developed by the Environmental Protection Agency (EPA) to study stormwater runoff from urban development.
• 100-year high water elevation means the highest water elevation associated with a waterbody reached during a 24-hour precipitation event with a recurrence interval of 100 years, as specified by the District in a written guidance document or, if not so specified, as determined by the District in order to act on a permit application.
• Ordinary high water level (OHW) means the boundary of a waterbody and shall be an elevation delineating the highest water level which has been maintained for a sufficient period of time to leave evidence upon the landscape, commonly that point where the natural vegetation changes from predominantly aquatic to predominantly terrestrial. For watercourses, the ordinary high water level shall be the elevation of the top of the bank of the channel. For reservoirs and flowages, the ordinary high water level is the operating elevation of the normal summer pool.
• Parcel or Site means a contiguous area of land under common ownership, designated and described in official public records and separated from other lands.  “Parcel” and “site” generally have equivalent meanings for purposes of these rules, and are used interchangeably in rule text.
• Person means any natural person, partnership, unincorporated association, corporation, municipal corporation or political subdivision of the State of Minnesota.
• Pervious refers to surfaces that are readily penetrated or permeated by rainfall or runoff resulting in infiltration and reduced runoff.
• PID means Property Tax Identification Number and is an abbreviated method to substitute for the legal description for a parcel of property (ex. 03-117-24 33 0004 is Section 3 of Township 117; Range 24; Quarter 33 and Parcel 4).
• Preserve Wetland is the highest of four management classifications assigned through use of either the District’s Functional Assessment of Wetlands (FAW) or the current version of the Minnesota Routine Assessment Method (MnRAM).
• Public waters means all waters identified as public waters under Minn Stat.103G.005, Subd. 15.
• Public waters wetlands means all wetlands identified as public waters wetlands under Minn. Stat. 103G.005, Subd. 18.
• Redevelopment means land-disturbing activity that creates or replaces impervious surface on a parcel that is fully or partially occupied by buildings and/or impervious surface with the exception of Linear Transportation Projects.
• Regional flood means a flood which is representative of large floods known to have occurred generally in Minnesota and reasonably characteristic of what can be expected to occur on an average frequency in the magnitude of the 100-year recurrence interval.
• Shoreline means the ordinary high water level of a water basin and the area waterward thereof.
• Site – see Parcel
• Stabilization Zone means the area of land paralleling the shoreline or streambank and extending 20 feet inland from all points along the ordinary high-water mark of the shoreline.
• Structural Stabilization is the use of engineered systems – such as riprap, retaining walls, headwalls, groins, revetments, gabions – to stabilize shoreline or streambank areas and associated slope and prevent erosion.
• Subwatershed means one of the fifteen major subwatershed planning units within the Minnehaha Creek Watershed District.
• Top of bank means the ordinary high water level for a water basin or wetland, and the break in slope for a watercourse.
• Waterbasin means an enclosed natural depression with definable banks capable of containing water which may be partly filled with waters.
• Waterbody means all waterbasins, watercourses and wetlands as defined in these rules.
• Watercourse means any channel having definable beds and banks capable of conducting generally confined runoff from adjacent lands, or any channel included in the District’s inventory of first order streams. During floods water may leave the confining beds and banks but under low and normal flows water is confined within the channel. A watercourse may be perennial or intermittent. Watercourse does not include roadside ditches created by excavation or other human construction activity.
• Wetland buffer zone means an area of vegetated groundcover abutting or surrounding a wetland.
• Wetlands means all wetlands identified as wetlands under Minnesota Stat. 103G.005, Subd 19. The term does not include “public waters wetlands” as defined under Minnesota Statutes 103G.005, subdivision 15a.