[HISTORY: Adopted by the Common Council of the City of Mayville as indicated in article histories. Amendments noted where applicable.]
[Adopted 6-8-2020 by Ord. No. 1114-2020]
This article is adopted by the Common Council under the authority granted by § 62.234, Wis. Stats. This article supersedes all provisions of an ordinance previously enacted under § 62.23, Wis. Stats., that relate to stormwater management regulations. Except as otherwise specified in § 62.234, Wis. Stats., § 62.23, Wis. Stats., applies to this article and to any amendments to this article.
Note to Users: There may be instances where this article does not supersede other ordinances relating to construction erosion control previously adopted by the governing body.
The provisions of this article are deemed not to limit any other lawful regulatory powers of the same governing body.
The Common Council hereby designates the Building Inspector to administer and enforce the provisions of this article.
The requirements of this article do not preempt more stringent stormwater management requirements that may be imposed by any of the following:
Wisconsin Department of Natural Resources administrative rules, permits or approvals including those authorized under §§ 281.16 and 283.33, Wis. Stats.
Targeted nonagricultural performance standards promulgated in rules by the Wisconsin Department of Natural Resources under § NR 151.004, Wis. Adm. Code.
The Common Council acknowledges that uncontrolled, post-construction runoff has a significant impact upon water resources and the health, safety and general welfare of the community and diminishes the public enjoyment and use of natural resources. Specifically, uncontrolled post-construction runoff can:
Degrade physical stream habitat by increasing stream bank erosion, increasing streambed scour, diminishing groundwater recharge, diminishing stream base flows and increasing stream temperature.
Diminish the capacity of lakes and streams to support fish, aquatic life, recreational and water supply uses by increasing pollutant loading of sediment, suspended solids, nutrients, heavy metals, bacteria, pathogens and other urban pollutants.
Alter wetland communities by changing wetland hydrology and by increasing pollutant loads.
Reduce the quality of groundwater by increasing pollutant loading.
Threaten public health, safety, property and general welfare by overtaxing storm sewers, drainageways, and other minor drainage facilities.
Purpose. The general purpose of this article is to establish long-term, post-construction runoff management requirements that will diminish the threats to public health, safety, welfare and the aquatic environment. Specific purposes are to:
Further the maintenance of safe and healthful conditions.
Prevent and control the adverse effects of stormwater; prevent and control soil erosion; prevent and control water pollution; protect spawning grounds, fish and aquatic life; control building sites, placement of structures and land uses; preserve ground cover and scenic beauty; and promote sound economic growth.
Control exceedance of the safe capacity of existing drainage facilities and receiving water bodies; prevent undue channel erosion; and control increases in the scouring and transportation of particulate matter.
Minimize the amount of pollutants discharged from the separate storm sewer to protect the waters of the state.
Intent. It is the intent of the Common Council that this article regulates post-construction stormwater discharges to waters of the state. This article may be applied on a site-by-site basis. The Common Council recognizes, however, that the preferred method of achieving the stormwater performance standards set forth in this article is through the preparation and implementation of comprehensive, systems-level stormwater management plans that cover hydrologic units, such as watersheds, on a municipal and regional scale. Such plans may prescribe regional stormwater devices, practices or systems, any of which may be designed to treat runoff from more than one site prior to discharge to waters of the state. Where such plans are in conformance with the performance standards developed under § 281.16, Wis. Stats., for regional stormwater management measures and have been approved by the Common Council, it is the intent of this article that the approved stormwater management plan be used to identify post-construction management measures acceptable for the community.
Except as provided under Subsection A(2), this article applies to a post-construction site whereupon one acre or more of land-disturbing construction activity occurs during construction.
Note to Users: The one-acre land disturbance threshold is consistent with state and federal laws regarding applicability of construction site erosion control permits. The municipality may apply its ordinance to sites of less than one acre.
A site that meets any of the criteria in this paragraph is exempt from the requirements of this article:
A post-construction site with less than 10% connected imperviousness, based on the area of land disturbance, provided the cumulative area of all impervious surfaces is less than one acre. However, the exemption of this paragraph does not include exemption from the protective area standard of this article.
Agricultural facilities and practices.
Underground utility construction, but not including the construction of any aboveground structures associated with utility construction.
Notwithstanding the applicability requirements in Subsection A(1), this article applies to post-construction sites of any size that, as determined by the Building Inspector, are likely to result in runoff that exceeds the safe capacity of the existing drainage facilities or receiving body of water, causes undue channel erosion, or increases water pollution by scouring or the transportation of particulate matter.
Jurisdiction. This article applies to post-construction sites within the boundaries and jurisdiction of the City of Mayville, as well as the extraterritorial division of land subject to an ordinance enacted pursuant to § 236.45(2) and (3), Wis. Stats.
Note to Users: These options differ in the amount of land area covered by this article and may have ramifications for enforcement authority. For counties, the first option will be the only option since counties do not have extraterritorial authority. Under § 59.693(10), Wis. Stats., if a county stormwater management ordinance exists at the time of annexation, then the municipal ordinance must be at least as restrictive as the county ordinance.
Exclusions. This article is not applicable to activities conducted by a state agency, as defined under § 227.01(1), Wis. Stats.
As used in this article, the following terms shall have the meanings indicated:
- ADEQUATE SOD OR SELF-SUSTAINING VEGETATIVE COVER
- Maintenance of sufficient vegetation types and densities such that the physical integrity of the streambank or lakeshore is preserved. Self-sustaining vegetative cover includes grasses, forbs, sedges and duff layers of fallen leaves and woody debris.
- ADMINISTERING AUTHORITY
- A governmental employee, or a regional planning commission empowered under § 62.234, Wis. Stats., that is designated by the Common Council to administer this article.
- AGRICULTURAL FACILITIES AND PRACTICES
- Has the meaning given in § 281.16(1), Wis. Stats.
- ATLAS 14
- The National Oceanic and Atmospheric Administration (NOAA) Atlas 14 Precipitation-Frequency Atlas of the United States, Volume 8 (Midwestern States), published in 2013.
- AVERAGE ANNUAL RAINFALL
- A typical calendar year of precipitation as determined by the Wisconsin Department of Natural Resources for users of models such as WinSLAMM, P8 or equivalent methodology. The average annual rainfall is chosen from a department publication for the location closest to the municipality.
- BEST MANAGEMENT PRACTICE or BMP
- Structural or nonstructural measures, practices, techniques or devices employed to avoid or minimize sediment or pollutants carried in runoff to waters of the state.
- BUSINESS DAY
- A day the office of the Building Inspector is routinely and customarily open for business.
- CEASE-AND-DESIST ORDER
- A court-issued order to halt land-disturbing construction activity that is being conducted without the required permit or in violation of a permit issued by the Building Inspector.
- COMBINED SEWER SYSTEM
- A system for conveying both sanitary sewage and stormwater runoff.
- CONNECTED IMPERVIOUSNESS
- 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.
- DESIGN STORM
- A hypothetical discrete rainstorm characterized by a specific duration, temporal distribution, rainfall intensity, return frequency and total depth of rainfall.
- Residential, commercial, industrial or institutional land uses and associated roads.
- DIRECT CONDUITS TO GROUNDWATER
- Wells, sinkholes, swallets, fractured bedrock at the surface, mine shafts, nonmetallic mines, tile inlets discharging to groundwater, quarries, or depressional groundwater recharge areas over shallow fractured bedrock.
- DIVISION OF LAND
- The creation from one parcel of [number] or more parcels or building sites of [number] or fewer acres each in area where such creation occurs at one time or through the successive partition within a five-year period.
- EFFECTIVE INFILTRATION AREA
- 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.
- The process by which the land's surface is worn away by the action of wind, water, ice or gravity.
- EXCEPTIONAL RESOURCE WATERS
- Waters listed in § NR 102.11, Wis. Adm. Code.
- The unincorporated area within three miles of the corporate limits of a first, second, or third class city, or within 1 1/2 miles of a fourth class city or village.
- FILTERING LAYER
- Soil that has at least a three-foot-deep layer with at least 20% fines; or at least a five-foot-deep layer with at least 10% fines; or an engineered soil with an equivalent level of protection as determined by the regulatory authority for the site.
- FINAL STABILIZATION
- 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% of the cover for the unpaved areas and areas not covered by permanent structures or that employ equivalent permanent stabilization measures.
- FINANCIAL GUARANTEE
- A performance bond, maintenance bond, surety bond, irrevocable letter of credit, or similar guarantees submitted to the Building Inspector by the responsible party to assure that requirements of the article are carried out in compliance with the stormwater management plan.
- GOVERNING BODY
- Town board of supervisors, county board of supervisors, city council, village board of trustees or village council.
- IMPERVIOUS SURFACE
- 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.
- 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.
- The entry of precipitation or runoff into or through the soil.
- INFILTRATION SYSTEM
- 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.
- LAND-DISTURBING CONSTRUCTION ACTIVITY
- Any man-made alteration of the land surface resulting in a change in the topography or existing vegetative or nonvegetative 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.
- Any person holding fee title, an easement or other interest in property, which allows the person to undertake cropping, livestock management, land-disturbing construction activity or maintenance of stormwater BMPs on the property.
- MAINTENANCE AGREEMENT
- A legal document that provides for long-term maintenance of stormwater management practices.
- MAXIMUM EXTENT PRACTICABLE
- The highest level of performance that is achievable but is not equivalent to a performance standard identified in this article as determined in accordance with § 365-6 of this article.
- NEW DEVELOPMENT
- Development resulting from the conversion of previously undeveloped land or agricultural land uses.
- NRCS MSE3 OR MSE4 DISTRIBUTION
- A specific precipitation distribution developed by the United States Department of Agriculture, Natural Resources Conservation Service, using precipitation data from Atlas 14.
- Located outside the property boundary described in the permit application.
- Located within the property boundary described in the permit application.
- ORDINARY HIGH-WATER MARK
- Has the meaning given in § NR 115.03(6), Wis. Adm. Code.
- OUTSTANDING RESOURCE WATERS
- Waters listed in § NR 102.10, Wis. Adm. Code.
- PERCENT FINES
- The percentage of a given sample of soil, which passes through a #200 sieve.
- PERFORMANCE STANDARD
- A narrative or measurable number specifying the minimum acceptable outcome for a facility or practice.
- A written authorization made by the Building Inspector to the applicant to conduct land-disturbing construction activity or to discharge post-construction runoff to waters of the state.
- PERMIT ADMINISTRATION FEE
- A sum of money paid to the Building Inspector by the permit applicant for the purpose of recouping the expenses incurred by the authority in administering the permit.
- PERVIOUS SURFACE
- 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.
- Has the meaning given in § 283.01(13), Wis. Stats.
- Has the meaning given in § 281.01(10), Wis. Stats.
- POST-CONSTRUCTION SITE
- A construction site following the completion of land-disturbing construction activity and final site stabilization.
- PREDEVELOPMENT CONDITION
- 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.
- PREVENTIVE ACTION LIMIT
- Has the meaning given in § NR 140.05(17), Wis. Adm. Code.
- PROTECTIVE AREA
- 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.
- Areas where development is replacing older development.
- RESPONSIBLE PARTY
- The landowner or any other entity performing services to meet the requirements of this article through a contract or other agreement.
- Stormwater or precipitation including rain, snow or ice melt or similar water that moves on the land surface via sheet or channelized flow.
- SEPARATE STORM SEWER
- A conveyance or system of conveyances including roads with drainage systems, streets, catch basins, curbs, gutters, ditches, constructed channels or storm drains, which meets all of the following criteria:
- SILVICULTURE ACTIVITY
- 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.
- The entire area included in the legal description of the land on which the land-disturbing construction activity occurred.
- STOP-WORK ORDER
- An order issued by the Building Inspector which requires that all construction activity on the site be stopped.
- STORMWATER MANAGEMENT PLAN
- A comprehensive plan designed to reduce the discharge of pollutants from stormwater, after the site has undergone final stabilization, following completion of the construction activity.
- STORMWATER MANAGEMENT SYSTEM PLAN
- A comprehensive plan designed to reduce the discharge of runoff and pollutants from hydrologic units on a regional or municipal scale.
- TECHNICAL STANDARD
- A document that specifies design, predicted performance and operation and maintenance specifications for a material, device or method.
- TOP OF THE CHANNEL
- 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% continually for at least 50 feet. If the slope of the land is 12% 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.
- TOTAL MAXIMUM DAILY LOAD or TMDL
- 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.
- Technical Paper No. 40, Rainfall Frequency Atlas of the United States, published in 1961.
- 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, which is incorporated by reference for this chapter.
- TRANSPORTATION FACILITY
- 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 § 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 Department pursuant to § 281.33, Wis. Stats.
- Total suspended solids.
- TYPE II DISTRIBUTION
- A rainfall type curve as established in the United States Department of Agriculture, Soil Conservation Service, Technical Paper 149, published in 1973.
- 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.
Maximum extent practicable applies when a person who is subject to a performance standard of this article demonstrates to the Building Inspector'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.
The following methods shall be used in designing the water quality, peak discharge, and infiltration components of stormwater practices needed to meet the water quality standards of this article:
Consistent with the technical standards identified, developed or disseminated by the Wisconsin Department of Natural Resources under Subchapter V of Ch. NR 151, Wis. Adm. Code.
Where 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 Building Inspector.
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 and the rainfall files and other parameter files identified for Wisconsin users unless directed otherwise by the regulatory authority.
Responsible party. The responsible party shall comply with this section.
Stormwater management plan. A written stormwater management plan in accordance with § 365-10 shall be developed and implemented for each post-construction site.
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 article, whichever is more stringent.
Requirements. The stormwater management plan required under Subsection B shall include the following:
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 § 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.
BMPs shall be designed in accordance with Table 1, or to the maximum extent practicable as provided in Subsection D(1)(b). The design shall be based on an average annual rainfall, as compared to no runoff management controls.
Maximum extent practicable. If the design cannot meet a total suspended solids reduction performance standard of Table 1, the stormwater 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 and the rainfall files and other parameter files identified for Wisconsin users unless directed otherwise by the regulatory authority.
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.
Note to Users: Under § 281.33(6)(a)1, Wis. Stats., the municipality may enact and enforce provisions of an ordinance that are stricter than the peak discharge performance standards in Ch. NR 151, Wis. Adm. Code, if the stricter provisions are necessary to control stormwater quantity or control flooding.
By design, BMPs shall be employed to maintain or reduce the one-year, twenty-four-hour, and the two-year, twenty-four-hour post-construction peak runoff discharge rates to the one-year, twenty-four-hour, and the two-year, twenty-four-hour predevelopment 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 predevelopment 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 Building Inspector 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 Department 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=nrc s142p2_025417.
This subsection of the article does not apply to any of the following:
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.
An in-fill development area less than five acres.
Note to Users: The intent of the peak discharge standard is to minimize stream bank erosion, under bank-full conditions. For water quantity concerns, the post-development peak flow rate for the ten-, twenty-five-, fifty- and one-hundred-year-twenty-four-hour storm events should also be controlled either at or below predevelopment discharge rates. This has not been addressed in this model ordinance but may need to be included in the local ordinance to address local flood control issues.
Best management practices. BMPs shall be designed, installed, and maintained to infiltrate runoff in accordance with the following or to the maximum extent practicable:
Low imperviousness. For development up to 40% connected imperviousness, such as parks, cemeteries, and low-density residential development, infiltrate sufficient runoff volume so that the post-development infiltration volume shall be at least 90% of the predevelopment infiltration volume, based on an average annual rainfall. However, when designing appropriate infiltration systems to meet this requirement, no more than 1% of the post-construction site is required as an effective infiltration area.
Moderate imperviousness. For development with more than 40% and up to 80% connected imperviousness, such as medium- and high-density residential, multifamily development, industrial and institutional development, and office parks, infiltrate sufficient runoff volume so that the post-development infiltration volume shall be at least 75% of the predevelopment infiltration volume, based on an average annual rainfall. However, when designing appropriate infiltration systems to meet this requirement, no more than 2% of the post-construction site is required as an effective infiltration area.
High imperviousness. For development with more than 80% connected imperviousness, such as commercial strip malls, shopping centers, and commercial downtowns, infiltrate sufficient runoff volume so that the post-development infiltration volume shall be at least 60% of the predevelopment infiltration volume, based on an average annual rainfall. However, when designing appropriate infiltration systems to meet this requirement, no more than 2% of the post-construction site is required as an effective infiltration area.
Predevelopment. The predevelopment condition shall be the same as specified in Table 2 of the peak discharge section of this article.
Prohibitions. Runoff from the following areas may not be infiltrated and may not qualify as contributing to meeting the requirements of this section unless demonstrated to meet the conditions identified in Subsection D(3)(f):
Areas associated with a Tier 1 industrial facility identified in § NR 216.21(2)(a), Wis. Adm. Code, including storage, loading and parking. Rooftops may be infiltrated with the concurrence of the regulatory authority.
Storage and loading areas of a Tier 2 industrial facility identified in § NR 216.21(2)(b), Wis. Adm. Code.
Note to Users: Runoff from the employee and guest parking and rooftop areas of a Tier 2 facility may be infiltrated but runoff from the parking area may require pretreatment.
Fueling and vehicle maintenance areas. Runoff from rooftops of fueling and vehicle maintenance areas may be infiltrated with the concurrence of the regulatory authority.
Exemptions. Runoff from the following areas may be credited toward meeting the requirement when infiltrated, but the decision to infiltrate runoff from these source areas is optional:
Parking areas and access roads less than 5,000 square feet for commercial development.
Parking areas and access roads less than 5,000 square feet for industrial development not subject to the prohibitions under Subsection D(3)(c).
In-fill development areas less than five acres.
Roads on commercial, industrial and institutional land uses, and arterial residential roads.
Location of practices.
Prohibitions. Infiltration practices may not be located in the following areas:
Areas within 1,000 feet upgradient or within 100 feet downgradient of direct conduits to groundwater.
Areas within 400 feet of a community water system well as specified in § NR 811.16(4), Wis. Adm. Code, or within the separation distances listed in § NR 812.08, Wis. Adm. Code, for any private well or noncommunity well for runoff infiltrated from commercial, including multifamily residential, industrial and institutional land uses or regional devices for one- and two-family residential development.
Areas where contaminants of concern, as defined in § NR 720.03(2), Wis. Adm. Code, are present in the soil through which infiltration will occur.
Infiltration practices shall be located so that the characteristics of the soil and the separation distance between the bottom of the infiltration system and the elevation of seasonal high groundwater or the top of bedrock are in accordance with Table 3:
Infiltration rate exemptions. Infiltration practices located in the following areas may be credited toward meeting the requirements under the following conditions, but the decision to infiltrate under these conditions is optional:
Where the infiltration rate of the soil measured at the proposed bottom of the infiltration system is less than 0.6 inch per hour using a scientifically credible field test method.
Where the least permeable soil horizon to five feet below the proposed bottom of the infiltration system using the U.S. Department of Agriculture method of soils analysis is one of the following: sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay, or clay.
Alternate use. Where alternate uses of runoff are employed, such as for toilet flushing, laundry, or irrigation or storage on green roofs where an equivalent portion of the runoff is captured permanently by rooftop vegetation, such alternate use shall be given equal credit toward the infiltration volume required by this section.
Infiltration systems designed in accordance with this section shall, to the extent technically and economically feasible, minimize the level of pollutants infiltrating to groundwater and shall maintain compliance with the preventive action limit at a point of standards application in accordance with Ch. NR 140, Wis. Adm. Code,. However, if site-specific information indicates that compliance with a preventive action limit is not achievable, the infiltration BMP may not be installed or shall be modified to prevent infiltration to the maximum extent practicable.
Pretreatment. Before infiltrating runoff, pretreatment shall be required for parking lot runoff and for runoff from new road construction in commercial, industrial and institutional areas that will enter an infiltration system. The pretreatment shall be designed to protect the infiltration system from clogging prior to scheduled maintenance and to protect groundwater quality in accordance with Subsection D(3)(f). Pretreatment options may include, but are not limited to, oil and grease separation, sedimentation, biofiltration, filtration, swales or filter strips.
Definition. In this section, "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. However, in this section, "protective area" does not include any area of land adjacent to any stream enclosed within a pipe or culvert, so that runoff cannot enter the enclosure at this location.
For outstanding resource waters and exceptional resource waters: 75 feet.
For perennial and intermittent streams identified on a U.S. Geological Survey 7.5-minute series topographic map, or a county soil survey map, whichever is more current: 50 feet.
For lakes: 50 feet.
For highly susceptible wetlands: 75 feet. Highly susceptible wetlands include the following types: calcareous fens, sedge meadows, open and coniferous bogs, low prairies, coniferous swamps, lowland hardwood swamps, and ephemeral ponds.
For less susceptible wetlands: 10% of the average wetland width, but no less than 10 feet nor more than 30 feet. Less susceptible wetlands include degraded wetland dominated by invasive species such as reed canary grass; cultivated hydric soils; and any gravel pits, or dredged material or fill material disposal sites that take on the attributes of a wetland.
Wetland boundary delineation shall be made in accordance with § NR 103.08(1m), Wis. Adm. Code. This paragraph does not apply to wetlands that have been completely filled in compliance with all applicable state and federal regulations. The protective area for wetlands that have been partially filled in compliance with all applicable state and federal regulations shall be measured from the wetland boundary delineation after a fill has been placed. Where there is a legally authorized wetland fill, the protective area standard need not be met in that location.
For concentrated flow channels with drainage areas greater than 130 acres: 10 feet.
Applicability. This section applies to post-construction sites located within a protective area, except those areas exempted pursuant to Subsection D(4)(d).
Requirements. The following requirements shall be met:
Impervious surfaces shall be kept out of the protective area entirely or to the maximum extent practicable. If there is no practical alternative to locating an impervious surface in the protective area, the stormwater management plan shall contain a written, site-specific explanation.
Where land-disturbing construction activity occurs within a protective area, adequate sod or self-sustaining vegetative cover of 70% or greater shall be established and maintained where no impervious surface is present. The adequate sod or self-sustaining vegetative cover shall be sufficient to provide for bank stability, maintenance of fish habitat, and filtering of pollutants from upslope overland flow areas under sheet flow conditions. Nonvegetative materials, such as rock riprap, may be employed on the bank as necessary to prevent erosion such as on steep slopes or where high-velocity flows occur.
Note to Users: It is recommended that seeding of noninvasive vegetative cover be used in the protective areas. Some invasive plants that should not be used are listed in Ch. NR 40, Wis. Adm. Code. Flood- and drought-tolerant vegetation that can provide long-term bank stability because of an extensive root system is preferable. Vegetative cover may be measured using the line transect method described in the University of Wisconsin extension publication number A3533, titled "Estimating Residue Using the Line Transect Method."
BMPs such as filter strips, swales, or wet detention ponds, that are designed to control pollutants from nonpoint sources, may be located in the protective area.
Note to Users: Other laws, such as Ch. 30, Wis. Stats., and Chs. NR 103, 115, 116 and 117, Wis. Adm. Code, and their associated review and approval processes may apply in the protective area.
Exemptions. This section does not apply to any of the following:
In-fill development areas less than five acres.
Structures that cross or access surface water such as boat landings, bridges, and culverts.
Structures constructed in accordance with § 59.692(1v), Wis. Stats.
Areas of post-construction sites from which the runoff does not enter the surface water, including wetlands, without first being treated by a BMP to meet the local ordinance requirements for total suspended solids and peak flow reduction, except to the extent that vegetative ground cover is necessary to maintain bank stability.
Note to Users: A vegetated protective area to filter runoff pollutants from post-construction sites described in Subsection D(4)(d) is not necessary since the runoff at that location is treated prior to entering the surface water. Other practices necessary to meet the requirements of this section, such as a swale or pond, will need to be designed and implemented to reduce runoff pollutants prior to runoff entering a surface water of the state.
Fueling and maintenance areas. Fueling and vehicle maintenance areas shall have BMPs designed, installed, and maintained to reduce petroleum within runoff, so that the runoff that enters waters of the state contains no visible petroleum sheen, or to the maximum extent practicable.
Note to Users: A combination of the following BMPs may be used: oil and grease separators, canopies, petroleum spill cleanup materials, or any other structural or nonstructural method of preventing or treating petroleum in runoff.
Swale treatment for transportation facilities.
Requirement. Except as provided in Subsection D(6)(b), transportation facilities that use swales for runoff conveyance and pollutant removal are exempt from the requirements of local ordinance requirements for peak flow control, total suspended solids control, and infiltration, if the swales are designed to do all of the following or to the maximum extent practicable:
Swales shall be vegetated. However, where appropriate, nonvegetative measures may be employed to prevent erosion or provide for runoff treatment, such as rock riprap stabilization or check dams.
Note to Users: It is preferred that tall and dense vegetation be maintained within the swale due to its greater effectiveness at enhancing runoff pollutant removal.
Swales shall comply with Sections V.F. (Velocity and Depth) and V.G. (Sale Geometry Criteria) with a swale treatment length as long as that specified in Section V.C. (Pre-Treatment) of the Wisconsin Department of Natural Resources technical standard 1005, "Vegetated Infiltration Swales," dated May 2007, or a superseding document. Transportation facility swale treatment does not have to comply with other sections of technical standard 1005.
Notwithstanding Subsection D(6)(a), the Building Inspector may, consistent with water quality standards, require that other requirements, in addition to swale treatment, be met on a transportation facility with an average daily traffic rate greater than 2,500 and where the initial surface water of the state that the runoff directly enters is one of the following:
An outstanding resource water.
An exceptional resource water.
Waters listed in Section 303(d) of the Federal Clean Water Act that are identified as impaired in whole or in part, due to nonpoint source impacts.
Water where targeted performance standards are developed pursuant to § NR 151.004, Wis. Adm. Code.
The transportation facility authority shall contact the Building Inspector to determine if additional BMPs beyond a water quality swale are needed under this subsection.
General considerations for stormwater management measures. The following considerations shall be observed in on-site and off-site runoff management:
Natural topography and land cover features such as natural swales, natural depressions, native soil infiltrating capacity, and natural groundwater recharge areas shall be preserved and used, to the extent possible, to meet the requirements of this section.
Emergency overland flow for all stormwater facilities shall be provided to prevent exceeding the safe capacity of downstream drainage facilities and prevent endangerment of downstream property or public safety.
To comply with the performance standards required under § 365-8 of this article, BMPs may be located on-site or off-site as part of a regional stormwater device, practice or system, but shall be installed in accordance with § NR 151.003, Wis. Adm. Code.
Note to Users: This section does not supersede any other applicable federal, state or local regulation such as Ch. NR 103, Wis. Adm. Code, and Ch. 30, Wis. Stats.
The Building Inspector may approve off-site management measures, provided that all of the following conditions are met:
The [administrating authority] determines that the post-construction runoff is covered by a stormwater management system plan that is approved by the City of Mayville and that contains management requirements consistent with the purpose and intent of this article.
The off-site facility meets all of the following conditions:
The facility is in place.
The facility is designed and adequately sized to provide a level of stormwater control equal to or greater than that which would be afforded by on-site practices meeting the performance standards of this article.
The facility has a legally obligated entity responsible for its long-term operation and maintenance.
Where a regional treatment option exists such that the Building Inspector exempts the applicant from all or part of the minimum on-site stormwater management requirements, the applicant shall be required to pay a fee in an amount determined in negotiation with the Building Inspector. In determining the fee for post-construction runoff, the Building Inspector shall consider an equitable distribution of the cost for land, engineering design, construction, and maintenance of the regional treatment option.
Additional requirements. The Building Inspector may establish stormwater management requirements more stringent than those set forth in this article if the Building Inspector determines that the requirements are needed to control stormwater quantity or control flooding, comply with federally approved total maximum daily load requirements, or control pollutants associated with existing development or redevelopment.
Permit required. No responsible party may undertake a land-disturbing construction activity without receiving a post-construction runoff permit from the Building Inspector prior to commencing the proposed activity.
Permit application and fees. Unless specifically excluded by this article, any responsible party desiring a permit shall submit to the Building Inspector a permit application on a form provided by the Building Inspector for that purpose.
Unless otherwise excluded by this article, a permit application must be accompanied by a stormwater management plan, a maintenance agreement and a nonrefundable permit administration fee.
The stormwater management plan shall be prepared to meet the requirements of §§ 365-8 and 365-10; the maintenance agreement shall be prepared to meet the requirements of § 365-11; the financial guarantee shall meet the requirements of § 365-12; and fees shall be those established by the Common Council as set forth in § 365-13.
Permit application review and approval. The Building Inspector shall review any permit application that is submitted with a stormwater management plan, maintenance agreement, and the required fee. The following approval procedure shall be used:
Within [number] business days of the receipt of a complete permit application, including all items as required by Subsection B, the Building Inspector shall inform the applicant whether the application, stormwater management plan and maintenance agreement are approved or disapproved based on the requirements of this article.
If the stormwater permit application, stormwater management plan and maintenance agreement are approved, or if an agreed-upon payment of fees in lieu of stormwater management practices is made, the Building Inspector shall issue the permit.
If the stormwater permit application, stormwater management plan or maintenance agreement is disapproved, the Building Inspector shall detail in writing the reasons for disapproval.
The Building Inspector may request additional information from the applicant. If additional information is submitted, the Building Inspector shall have [number] business days from the date the additional information is received to inform the applicant that the stormwater management plan and maintenance agreement are either approved or disapproved.
Failure by the Building Inspector to inform the permit applicant of a decision within [number] business days of a required submittal shall be deemed to mean approval of the submittal and the applicant may proceed as if a permit had been issued.
Permit requirements. All permits issued under this article shall be subject to the following conditions, and holders of permits issued under this article shall be deemed to have accepted these conditions. The Building Inspector may suspend or revoke a permit for violation of a permit condition, following written notification of the responsible party. An action by the Building Inspector to suspend or revoke this permit may be appealed in accordance with § 365-15.
Compliance with this permit does not relieve the responsible party of the responsibility to comply with other applicable federal, state, and local laws and regulations.
The responsible party shall design and install all structural and nonstructural stormwater management measures in accordance with the approved stormwater management plan and this permit.
The responsible party shall notify the Building Inspector at least 10 business days before commencing any work in conjunction with the stormwater management plan, and within 10 business days upon completion of the stormwater management practices. If required as a special condition under Subsection E, the responsible party shall make additional notification according to a schedule set forth by the Building Inspector so that practice installations can be inspected during construction.
Practice installations required as part of this article shall be certified "as built" or "record" drawings by a licensed professional engineer. Completed stormwater management practices must pass a final inspection by the Building Inspector or its designee to determine if they are in accordance with the approved stormwater management plan and ordinance. The Building Inspector or its designee shall notify the responsible party in writing of any changes required in such practices to bring them into compliance with the conditions of this permit.
The responsible party shall notify the Building Inspector of any significant modifications it intends to make to an approved stormwater management plan. The Building Inspector may require that the proposed modifications be submitted to it for approval prior to incorporation into the stormwater management plan and execution by the responsible party.
The responsible party shall maintain all stormwater management practices in accordance with the stormwater management plan until the practices either become the responsibility of the Common Council or are transferred to subsequent private owners as specified in the approved maintenance agreement.
The responsible party authorizes the Building Inspector to perform any work or operations necessary to bring stormwater management measures into conformance with the approved stormwater management plan, and consents to a special assessment or charge against the property as authorized under Subchapter VII of Ch. 66, Wis. Stats., or to charging such costs against the financial guarantee posted under § 365-12.
If so directed by the Building Inspector, the responsible party shall repair at the responsible party's own expense all damage to adjoining municipal facilities and drainageways caused by runoff, where such damage is caused by activities that are not in compliance with the approved stormwater management plan.
The responsible party shall permit property access to the Building Inspector or its designee for the purpose of inspecting the property for compliance with the approved stormwater management plan and this permit.
Where site development or redevelopment involves changes in direction, increases in peak rate and/or total volume of runoff from a site, the Building Inspector may require the responsible party to make appropriate legal arrangements with affected property owners concerning the prevention of endangerment to property or public safety.
Stormwater management plan requirements. The stormwater management plan required under § 365-8B shall contain at a minimum the following information:
Name, address, and telephone number for the following or their designees: landowner; developer; project engineer for practice design and certification; person(s) responsible for installation of stormwater management practices; and person(s) responsible for maintenance of stormwater management practices prior to the transfer, if any, of maintenance responsibility to another party.
A proper legal description of the property proposed to be developed, referenced to the U.S. Public Land Survey system or to block and lot numbers within a recorded land subdivision plat.
Predevelopment site conditions, including:
One or more site maps at a scale of not less than one inch equals [number] feet. The site maps shall show the following: site location and legal property description; predominant soil types and hydrologic soil groups; existing cover type and condition; topographic contours of the site at a scale not to exceed [number] feet; topography and drainage network including enough of the contiguous properties to show runoff patterns onto, through, and from the site; watercourses that may affect or be affected by runoff from the site; flow path and direction for all stormwater conveyance sections; watershed boundaries used in hydrology determinations to show compliance with performance standards; lakes, streams, wetlands, channels, ditches, and other watercourses on and immediately adjacent to the site; limits of the 100-year floodplain; location of wells and wellhead protection areas covering the project area and delineated pursuant to § NR 811.16, Wis. Adm. Code.
Hydrology and pollutant loading computations as needed to show compliance with performance standards. All major assumptions used in developing input parameters shall be clearly stated. The geographic areas used in making the calculations shall be clearly cross-referenced to the required map(s).
Post-development site conditions, including:
Explanation of the provisions to preserve and use natural topography and land cover features to minimize changes in peak flow runoff rates and volumes to surface waters and wetlands.
Explanation of any restrictions on stormwater management measures in the development area imposed by wellhead protection plans and ordinances.
One or more site maps at a scale of not less than one inch equals [number] feet showing the following: post-construction pervious areas including vegetative cover type and condition; impervious surfaces including all buildings, structures, and pavement; post-construction topographic contours of the site at a scale not to exceed [number] feet; post-construction drainage network including enough of the contiguous properties to show runoff patterns onto, through, and from the site; locations and dimensions of drainage easements; locations of maintenance easements specified in the maintenance agreement; flow path and direction for all stormwater conveyance sections; location and type of all stormwater management conveyance and treatment practices, including the on-site and off-site tributary drainage area; location and type of conveyance system that will carry runoff from the drainage and treatment practices to the nearest adequate outlet such as a curbed street, storm drain, or natural drainageway; watershed boundaries used in hydrology and pollutant loading calculations and any changes to lakes, streams, wetlands, channels, ditches, and other watercourses on and immediately adjacent to the site.
Hydrology and pollutant loading computations as needed to show compliance with performance standards. The computations shall be made for each discharge point in the development, and the geographic areas used in making the calculations shall be clearly cross-referenced to the required map(s).
Results of investigations of soils and groundwater required for the placement and design of stormwater management measures. Detailed drawings including cross-sections and profiles of all permanent stormwater conveyance and treatment practices.
A description and installation schedule for the stormwater management practices needed to meet the performance standards in § 365-8.
A maintenance plan developed for the life of each stormwater management practice including the required maintenance activities and maintenance activity schedule.
Cost estimates for the construction, operation, and maintenance of each stormwater management practice.
Other information requested in writing by the Building Inspector to determine compliance of the proposed stormwater management measures with the provisions of this article.
All site investigations, plans, designs, computations, and drawings shall be certified by a [licensed professional engineer] to be prepared in accordance with accepted engineering practice and requirements of this article.
Maintenance agreement required. The maintenance agreement required under § 365-9B for stormwater management practices shall be an agreement between the Building Inspector and the responsible party to provide for maintenance of stormwater practices beyond the duration period of this permit. The maintenance agreement shall be filed with the County Register of Deeds as a property deed restriction so that it is binding upon all subsequent owners of the land served by the stormwater management practices.
Agreement provisions. The maintenance agreement shall contain the following information and provisions and be consistent with the maintenance plan required by § 365-10A(6):
Identification of the stormwater facilities and designation of the drainage area served by the facilities.
A schedule for regular maintenance of each aspect of the stormwater management system consistent with the stormwater management plan required under § 365-9B.
Identification of the responsible party(s), organization or city, county, town or village responsible for long-term maintenance of the stormwater management practices identified in the stormwater management plan required under § 365-9B.
Requirement that the responsible party(s), organization, or city, county, town or village shall maintain stormwater management practices in accordance with the schedule included in Subsection B(2).
Authorization for the Building Inspector to access the property to conduct inspections of stormwater management practices as necessary to ascertain that the practices are being maintained and operated in accordance with the agreement.
A requirement on the Building Inspector to maintain public records of the results of the site inspections, to inform the responsible party responsible for maintenance of the inspection results, and to specifically indicate any corrective actions required to bring the stormwater management practice into proper working condition.
Agreement that the party designated under Subsection B(3), as responsible for long-term maintenance of the stormwater management practices, shall be notified by the Building Inspector of maintenance problems which require correction. The specified corrective actions shall be undertaken within a reasonable time frame as set by the Building Inspector.
Authorization of the Building Inspector to perform the corrected actions identified in the inspection report if the responsible party designated under Subsection B(3) does not make the required corrections in the specified time period. The Building Inspector shall enter the amount due on the tax rolls and collect the money as a special charge against the property pursuant to Subchapter VII of Ch. 66, Wis. Stats.
Establishment of the guarantee. The Building Inspector may require the submittal of a financial guarantee, the form and type of which shall be acceptable to the Building Inspector. The financial guarantee shall be in an amount determined by the Building Inspector to be the estimated cost of construction and the estimated cost of maintenance of the stormwater management practices during the period which the designated party in the maintenance agreement has maintenance responsibility. The financial guarantee shall give the Building Inspector the authorization to use the funds to complete the stormwater management practices if the responsible party defaults or does not properly implement the approved stormwater management plan, upon written notice to the responsible party by the Building Inspector that the requirements of this article have not been met.
Conditions for release. Conditions for the release of the financial guarantee are as follows:
The Building Inspector shall release the portion of the financial guarantee established under this section, less any costs incurred by the Building Inspector to complete installation of practices, upon submission of "as built plans" or "record" drawings by a licensed professional engineer. The Building Inspector may make provisions for a partial pro-rata release of the financial guarantee based on the completion of various development stages.
The Building Inspector shall release the portion of the financial guarantee established under this section to assure maintenance of stormwater practices, less any costs incurred by the Building Inspector, at such time that the responsibility for practice maintenance is passed on to another entity via an approved maintenance agreement.
The fees referred to in other sections of this article shall be established by the Building Inspector and may from time to time be modified by resolution. A schedule of the fees established by the Building Inspector shall be available for review in [location].
Any land-disturbing construction activity or post-construction runoff initiated after the effective date of this article by any person, firm, association, or corporation subject to the article provisions shall be deemed a violation unless conducted in accordance with the requirements of this article.
Upon receipt of a complaint from any person affected by a responsible party's land-disturbing construction activity or post-construction runoff, or at such other times as the Building Inspector may become aware of noncompliance by a responsible party with the requirements of this article, the Building Inspector may notify the responsible party by certified mail of any noncomplying land-disturbing construction activity or post-construction runoff. The notice shall describe the nature of the violation, remedial actions needed, a schedule for remedial action, and additional enforcement action which may be taken.
Upon receipt of written notification from the Building Inspector under Subsection B, the responsible party shall correct work that does not comply with the stormwater management plan or other provisions of this permit. The responsible party shall make corrections as necessary to meet the specifications and schedule set forth by the Building Inspector in the notice.
If the violations to a permit issued pursuant to this article are likely to result in damage to properties, public facilities, or waters of the state, the Building Inspector may enter the land and take emergency actions necessary to prevent such damage. The costs incurred by the Building Inspector plus interest and legal costs shall be billed to the responsible party.
The Building Inspector is authorized to post a stop-work order on all land-disturbing construction activity that is in violation of this article, or to request the [municipal attorney, corporation counsel] to obtain a cease-and-desist order in any court with jurisdiction.
The Building Inspector may revoke a permit issued under this article for noncompliance with article provisions.
Any permit revocation, stop-work order, or cease-and-desist order shall remain in effect unless retracted by the Building Inspector or by a court with jurisdiction.
The Building Inspector is authorized to refer any violation of this article, or a stop-work order or cease-and-desist order issued pursuant to this article, to the City Attorney for the commencement of further legal proceedings in any court with jurisdiction.
Any person, firm, association, or corporation who does not comply with the provisions of this article shall be subject to a forfeiture of not less than $50 or more than $500 per offense, together with the costs of prosecution. Each day that the violation exists shall constitute a separate offense.
Compliance with the provisions of this article may also be enforced by injunction in any court with jurisdiction. It shall not be necessary to prosecute for forfeiture or a cease-and-desist order before resorting to injunction proceedings.
Note to Users: Injunction orders are authorized pursuant to § 59.69(11), 61.35, or 62.23(8), Wis. Stats., for counties, villages and towns with village powers, and cities, respectively.
When the Building Inspector determines that the holder of a permit issued pursuant to this article has failed to follow practices set forth in the stormwater management plan, or has failed to comply with schedules set forth in said stormwater management plan, the Building Inspector or a party designated by the Building Inspector may enter upon the land and perform the work or other operations necessary to bring the condition of said lands into conformance with requirements of the approved stormwater management plan. The Building Inspector shall keep a detailed accounting of the costs and expenses of performing this work. These costs and expenses shall be deducted from any financial security posted pursuant to § 365-12 of this article. Where such a security has not been established, or where such a security is insufficient to cover these costs, the costs and expenses shall be entered on the tax roll as a special charge against the property and collected with any other taxes levied thereon for the year in which the work is completed.
Board of [appeals or adjustment]. The Board of [appeals or adjustment], created pursuant to section [number] of the City of Mayville ordinances pursuant to § [59.694, 60.65, 61.354(4)(b), or 62.23(7)(e)], Wis. Stats., shall hear and decide appeals where it is alleged that there is error in any order, decision or determination made by the Building Inspector in administering this article. The Board shall also use the rules, procedures, duties, and powers authorized by statute in hearing and deciding appeals. Upon appeal, the Board may authorize variances from the provisions of this article that are not contrary to the public interest, and where owing to special conditions a literal enforcement of the article will result in unnecessary hardship.
Who may appeal. Appeals to the Board of [appeals or adjustments] may be taken by any aggrieved person or by an officer, department, board, or bureau of the City of Mayville affected by any decision of the Building Inspector.
If any section, clause, provision or portion of this article is judged unconstitutional or invalid by a court of competent jurisdiction, the remainder of the article shall remain in force and not be affected by such judgment.
This article shall be in force and effect from and after its adoption and publication. The above and foregoing article was duly adopted by the Common Council of the City of Mayville on the [number] day of [month], [year].