(10) “Connected imperviousness” means an impervious surface connected to the waters of the state via a separate storm sewer, an impervious flow path, or a minimally pervious flow path.
(11) “Design storm” means a hypothetical discrete rainstorm characterized by a specific duration, temporal distribution, rainfall intensity, return frequency, and total depth of rainfall.
(12) “Development” means residential, commercial, industrial, or institutional land uses and associated roads.
(13) “Direct conduits to groundwater” means wells, sinkholes, swallets, fractured bedrock at the surface, mine shafts, non-metallic mines, tile inlets discharging to groundwater, quarries, or depressional groundwater recharge areas over shallow fractured bedrock.
(14)* “Division of land” means the creation from one parcel of [number] or more parcels or building sites of [number] or fewer acres each in area when such creation occurs at one time or through the successive partition within a 5-year period.
Note to Users: This definition is only needed depending on the type of jurisdiction selected under S. 04 (2) above.
(15) “Effective infiltration area” means the area of the infiltration system that is used to infiltrate runoff and does not include the area used for site access, berms, or pretreatment.
(16) “Erosion” means the process by which the land’s surface is worn away by the action of wind, water, ice, or gravity.
(17) “Exceptional resource waters” means waters listed in s. NR 102.11, Wis. Adm. Code. (18)* “Extraterritorial” means the unincorporated area within three miles of the corporate limits of a first, second, or third class city, or within one and a half miles of a fourth class city or village.
Note to Users: This definition is only needed depending on the type of jurisdiction selected under S. 04 (2) above.
(19) “Filtering layer” means soil that has at least a 3-foot deep layer with at least 20 percent fines; or at least a 5-foot deep layer with at least 10 percent fines; or an engineered soil with an equivalent level of protection as determined by the regulatory authority for the site.
(20) “Final stabilization” means that all land disturbing construction activities at the construction site have been completed and that a uniform perennial vegetative cover has been established with a density of at least 70 percent of the cover for the unpaved areas and areas not covered by permanent structures or that employ equivalent permanent stabilization measures.
(21) “Financial guarantee” means a performance bond, maintenance bond, surety bond, irrevocable letter of credit, or similar guarantees submitted to the [administering authority] by the responsible party to assure that requirements of the ordinance are carried out in compliance with the storm water management plan.
(22) “Impervious surface” means an area that releases as runoff all or a large portion of the precipitation that falls on it, except for frozen soil. Rooftops, sidewalks, driveways, gravel or paved parking lots and streets are examples of areas that typically are impervious.
(23) “In-fill” means an undeveloped area of land located within an existing urban sewer service area, surrounded by development or development and natural or man-made features where development cannot occur.
(24) “Infiltration” means the entry of precipitation or runoff into or through the soil.
(25) “Infiltration system” means a device or practice such as a basin, trench, rain garden, or swale designed specifically to encourage infiltration, but does not include natural infiltration in pervious surfaces such as lawns, redirecting of rooftop downspouts onto lawns, or minimal infiltration from practices, such as swales or road side channels designed for conveyance and pollutant removal only.
(26) “Land disturbing construction activity” means any man-made alteration of the land surface resulting in a change in the topography or existing vegetative or non-vegetative soil cover that may result in runoff and lead to an increase in soil erosion and movement of sediment into waters of the state. “Land disturbing construction activity” includes clearing and grubbing, demolition, excavating, pit trench dewatering, filling, and grading activities.
(27) “Landowner” means any person holding fee title, an easement, or another interest in property that allows the person to undertake cropping, livestock management, land disturbing construction activity, or maintenance of storm water BMPs on the property.
(28) “Maintenance agreement” means a legal document that provides for long-term maintenance of storm water management practices.
(29) “Maximum extent practicable” means the highest level of performance that is achievable but is not equivalent to a performance standard identified in this ordinance as determined in accordance with S. 055 of this ordinance.
(30) “New development” means development resulting from the conversion of previously undeveloped land or agricultural land uses.
(31) “NRCS MSE3 or MSE4 distribution” means a specific precipitation distribution developed by the United States Department of Agriculture, Natural Resources Conservation Service, using precipitation data from Atlas 14.
(32) “Off-site” means located outside the property boundary described in the permit application.
(33) “On-site” means located within the property boundary described in the permit application.
(34) “Ordinary high-water mark” has the meaning given in s. NR 115.03 (6), Wis. Adm. Code. (35) “Outstanding resource waters” means waters listed in s. NR 102.10, Wis. Adm. Code. (36) “Percent fines” means the percentage of a given sample of soil that passes through a # 200 sieve.
(37) “Performance standard” means a narrative or measurable number specifying the minimum acceptable outcome for a facility or practice.
(38) “Permit” means a written authorization made by the [administering authority] to the applicant to conduct land disturbing construction activity or to discharge post-construction runoff to waters of the state.
(39) “Permit administration fee” means a sum of money paid to the [administering authority] by the permit applicant for the purpose of recouping the expenses incurred by the authority in administering the permit.
(40) “Pervious surface” means an area that releases as runoff a small portion of the precipitation that falls on it. Lawns, gardens, parks, forests, or other similar vegetated areas are examples of surfaces that typically are pervious.
(41) “Pollutant” has the meaning given in s. 283.01 (13), Wis. Stats. (42) “Pollution” has the meaning given in s. 281.01 (10), Wis. Stats. (43) “Post-construction site” means a construction site following the completion of land disturbing construction activity and final site stabilization.
(44) “Pre-development condition” means the extent and distribution of land cover types present before the initiation of land disturbing construction activity, assuming that all land uses prior to development activity are managed in an environmentally sound manner.
(45) “Preventive action limit” has the meaning given in s. NR 140.05 (17), Wis. Adm. Code. (46) “Protective area” means an area of land that commences at the top of the channel of lakes, streams, and rivers, or at the delineated boundary of wetlands, and that is the greatest of the following widths, as measured horizontally from the top of the channel or delineated wetland boundary to the closest impervious surface.
(47) “Redevelopment” means areas where development is replacing older development.
(48) “Responsible party” means the landowner or any other entity performing services to meet the requirements of this ordinance through a contract or other agreement.
(49) “Runoff” means storm water or precipitation including rain, snow or ice melt or similar water that moves on the land surface via sheet or channelized flow.
(50) “Separate storm sewer” means a conveyance or system of conveyances including roads with drainage systems, streets, catch basins, curbs, gutters, ditches, constructed channels, or storm drains that meets all of the following criteria:
(a) Is designed or used for collecting water or conveying runoff.
(b) Is not part of a combined sewer system.
(c) Is not part of a publicly owned wastewater treatment works that provides secondary or more stringent treatment.
(d) Discharges directly or indirectly to waters of the state.
(51) “Silviculture activity” means activities including tree nursery operations, tree harvesting operations, reforestation, tree thinning, prescribed burning, and pest and fire control. Clearing and grubbing of an area of a construction site is not a “silviculture activity.”
(52) “Site” means the entire area included in the legal description of the land on which the land disturbing construction activity occurred.
(53) “Stop work order” means an order issued by the [administering authority] that requires that all construction activity on the site be stopped.
(54) “Storm water management plan” means a comprehensive plan designed to reduce the discharge of pollutants from storm water, after the site has under gone final stabilization, following completion of the construction activity.
(55) “Storm water management system plan” means a comprehensive plan designed to reduce the discharge of runoff and pollutants from hydrologic units on a regional or municipal scale.
(56) “Technical standard” means a document that specifies design, predicted performance and operation and maintenance specifications for a material, device, or method.
(57) “Top of the channel” means an edge, or point on the landscape landward from the ordinary high-water mark of a surface water of the state, where the slope of the land begins to be less than 12 percent continually for at least 50 feet. If the slope of the land is 12 percent or less continually for the initial 50 feet landward from the ordinary high-water mark, the “top of the channel” is the ordinary high-water mark.
(58) “Total maximum daily load” or “TMDL” means the amount of pollutants specified as a function of one or more water quality parameters, that can be discharged per day into a water quality limited segment and still ensure attainment of the applicable water quality standard.
(59) “TP-40” means Technical Paper No. 40, Rainfall Frequency Atlas of the United States, published in 1961.
(60) “TR-55” means the United States Department of Agriculture, Natural Resources Conservation Service (previously soil conservation service), Urban Hydrology for Small Watersheds, Second Edition, Technical Release 55, June 1986, that is incorporated by reference for this chapter.
(61) “Transportation facility” means a highway, a railroad, a public mass transit facility, a public-use airport, a public trail, or any other public work for transportation purposes such as harbor improvements under s. 85.095 (1) (b), Wis. Stats. “Transportation facility” does not include building sites for the construction of public buildings and buildings that are places of employment that are regulated by the Wisconsin Department of Natural Resources pursuant to s. 281.33, Wis. Stats. (62) “TSS” means total suspended solids.
(63) “Type II distribution” means a rainfall type curve as established in the “United States Department of Agriculture, Soil Conservation Service, Technical Paper 149, published in 1973.”
(64) “Waters of the state” includes those portions of Lake Michigan and Lake Superior within the boundaries of this state, and all lakes, bays, rivers, streams, springs, ponds, wells, impounding reservoirs, marshes, watercourses, drainage systems, and other surface water or groundwater, natural or artificial, public or private, within this state or its jurisdiction.
(65) “Wis. Adm. Code” means the Wisconsin Administrative Code, published under s. 35.93, Wis. Stats. (66) “Wis. Stats.” means the Wisconsin Statutes published under s. 35.18 of the Wisconsin Statutes. S. 055 APPLICABILITY OF MAXIMUM EXTENT PRACTICABLE.
Maximum extent practicable applies when a person who is subject to a performance standard of this ordinance demonstrates to the [administering authority]’s satisfaction that a performance standard is not achievable and that a lower level of performance is appropriate. In making the assertion that a performance standard is not achievable and that a level of performance different from the performance standard is the maximum extent practicable, the responsible party shall take into account the best available technology, cost effectiveness, geographic features, and other competing interests such as protection of public safety and welfare, protection of endangered and threatened resources, and preservation of historic properties.
S. 06 TECHNICAL STANDARDS.
The following methods shall be used in designing the water quality, peak discharge, and infiltration components of storm water practices needed to meet the water quality standards of this ordinance:
(1) The use of the standards are consistent with the technical standards identified, developed, or disseminated by the Wisconsin Department of Natural Resources under subch. V of ch. NR 151, Wis. Adm. Code. (2) When technical standards have not been identified or developed by the Wisconsin Department of Natural Resources, other technical standards may be used provided that the methods have been approved by the [administering authority].
Note to Users: Pollutant loading models such as DETPOND, WinSLAMM, P8, or equivalent methodology may be used to evaluate the efficiency of the design in reducing total suspended solids. Use the most recent version of the model, rainfall files, and other parameter files identified for Wisconsin users unless directed otherwise by the regulatory authority.
S. 07 PERFORMANCE STANDARDS.
(1) RESPONSIBLE PARTY. The responsible party shall comply with this section.
(2) STORM WATER MANAGEMENT PLAN. A written storm water management plan in accordance with S. 09 shall be developed and implemented for each post-construction site.
(3) MAINTENANCE OF EFFORT. For redevelopment sites where the redevelopment will be replacing older development that was subject to post-construction performance standards of ch. NR 151, Wis. Adm. Code, in effect on or after October 1, 2004, the responsible party shall meet the total suspended solids reduction, peak flow control, infiltration, and protective areas standards applicable to the older development or meet the redevelopment standards of this ordinance, whichever is more stringent. (4) REQUIREMENTS. The storm water management plan required under sub. (2) shall include all of the following:
(a) TOTAL SUSPENDED SOLIDS. BMPs shall be designed, installed, and maintained to control total suspended solids carried in runoff from the post-construction site as follows:
Note to Users: Under s. 281.33 (6) (a) 2., Wis. Stats., the municipality may enact and enforce provisions of an ordinance that are stricter than the TSS performance standards in ch. NR 151, Wis. Adm. Code, if the stricter provisions are necessary to comply with federally-approved total maximum daily load requirements. 1. Best Management Practice Design. BMPs shall be designed in accordance with Table 1. or to the maximum extent practicable as provided in subd. 2. The design shall be based on an average annual rainfall, as compared to no runoff management controls.
2. Maximum Extent Practicable. If the design cannot meet a total suspended solids reduction performance standard of Table 1., the storm water management plan shall include a written, site-specific explanation of why the total suspended solids reduction performance standard cannot be met and why the total suspended solids load will be reduced only to the maximum extent practicable.
Note to Users: Pollutant loading models such as DETPOND, WinSLAMM, P8 or equivalent methodology may be used to evaluate the efficiency of the design in reducing total suspended solids. Use the most recent version of the model, rainfall files, and other parameter files identified for Wisconsin users unless directed otherwise by the regulatory authority.
3. Off-Site Drainage. When designing BMPs, runoff draining to the BMP from off-site shall be taken into account in determining the treatment efficiency of the practice. Any impact on the efficiency shall be compensated for by increasing the size of the BMP accordingly.
(b) PEAK DISCHARGE.
1. By design, BMPs shall be employed to maintain or reduce the 1-year, 24-hour; the 2-year, 24-hour post-construction peak runoff discharge rates to the 1-year, 24-hour; and the 2-year, 24-hour pre-development peak runoff discharge rates respectively, or to the maximum extent practicable. The runoff curve numbers in Table 2. shall be used to represent the actual pre-development conditions. Peak discharges shall be calculated using TR-55 runoff curve number methodology, Atlas 14 precipitation depths, and the appropriate NRCS Wisconsin MSE3 or MSE4 precipitation distribution. On a case-by-case basis, the [administering authority] may allow the use of TP-40 precipitation depths and the Type II distribution.
Note to Users: For determining compliance with the peak flow requirement, the Wisconsin Department of Natural Resources recommends use of the National Oceanic and Atmospheric Administration (NOAA) Atlas 14 Precipitation Frequency Estimates for precipitation depth. The Natural Resources Conservation Service (NRCS) – Wisconsin has calculated county-specific Atlas 14 precipitation depths and they are to be used in combination with the appropriate NRCS MSE3 or MSE4 precipitation distribution. The NRCS calculated county-specific Atlas 14 precipitation depths and MSE3 and MSE4 precipitation distributions are available at: http://www.nrcs.usda.gov/wps/portal/nrcs/detail/wi/technical/engineering/?cid=nrcs142p2_025417. Note to Users: When the pre-development condition is a combination of woodland, grassland, or cropland, the runoff curve number should be pro-rated by area.
2. This subsection of the ordinance does not apply to any of the following:
a. A post-construction site where the discharge is directly into a lake over 5,000 acres or a stream or river segment draining more than 500 square miles.
b. Except as provided under S. 07 (3), a redevelopment post-construction site.
