City of Muskego, WI
Waukesha County
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Table of Contents
Table of Contents
[HISTORY: Adopted by the Common Council of the City of Muskego at time of adoption of Code (see Ch. 1, General Provisions, Art. II). Amendments noted where applicable.]
GENERAL REFERENCES
Construction site erosion and sediment control — See Ch. 162.
Construction standards — See Ch. 164.
Sewers — See Ch. 290.
Floodplain zoning — See Ch. 386.
Land division — See Ch. 392.
Zoning — See Ch. 400.
A. 
This chapter is adopted by the City of Muskego under the authority granted by § 62.234, Wis. Stats. This chapter 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 chapter and to any amendments to this chapter.
B. 
The provisions of this chapter are deemed not to limit any other lawful regulatory powers of the same governing body.
C. 
The City of Muskego hereby designates the City Engineer or his designee to administer and enforce the provisions of this chapter.
D. 
The requirements of this chapter do not preempt more stringent stormwater management requirements that may be imposed by any of the following:
(1) 
Wisconsin Department of Natural Resources administrative rules, permits or approvals, including those authorized under §§ 281.16 and 283.33, Wis. Stats.
(2) 
Targeted nonagricultural performance standards promulgated in rules by the Wisconsin Department of Natural Resources under § NR 151.004, Wis. Adm. Code.
(3) 
Milwaukee Metropolitan Sewerage District.
The City of Muskego 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:
A. 
Degrade physical stream habitat by increasing stream bank erosion, increasing streambed scour, diminishing groundwater recharge, diminishing stream base flows and increasing stream temperature.
B. 
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.
C. 
Alter wetland communities by changing wetland hydrology and by increasing pollutant loads.
D. 
Reduce the quality of groundwater by increasing pollutant loading.
E. 
Threaten public health, safety, property and general welfare by overtaxing storm sewers, drainageways, and other minor drainage facilities.
F. 
Threaten public health, safety, property, and general welfare by increasing major flood peaks and volumes.
G. 
Undermine floodplain management efforts by increasing the incidence and levels of flooding.
H. 
Aggravate excessive infiltration and inflow of water into sanitary sewer connections during peak storm events causing the conveyance system to surcharge, overflow, or back up into basements.
A. 
Purpose. The general purpose of this chapter 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:
(1) 
Further the maintenance of safe and healthful conditions.
(2) 
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.
(3) 
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.
(4) 
Minimize the amount of pollutants discharged from the separate storm sewer to protect the waters of the state.
B. 
Intent. It is the intent of the City of Muskego that this chapter regulates post-construction stormwater discharges to waters of the state. This chapter may be applied on a site-by-site basis. The City of Muskego recognizes, however, that the preferred method of achieving the stormwater performance standards set forth in this chapter 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 City of Muskego, it is the intent of this chapter that the approved stormwater management plan be used to identify post-construction management measures acceptable for the community.
A. 
Applicability.
(1) 
Except as provided under Subsection A(2) or (3), the water quality management duties apply to a post-construction site whereupon one acre or more of land disturbing construction activity occurs during construction and the water quantity management duties apply to a post-construction site that increases impervious surface by 1/2 acre or more.
(2) 
A site that meets any of the criteria in this subsection is exempt from the water quality requirements of this chapter:
(a) 
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 subsection does not include exemption from the protective area standard of this chapter.
(b) 
Agricultural facilities and practices.
(c) 
Underground utility construction, but not including the construction of any aboveground structures associated with utility construction.
(3) 
Water quantity management duties do not apply to:
(a) 
Residential infill on a site five acres or less; site is exclusively residential; net increase in the area of impervious surface is less than 20% of the area of the site; and each boundary of the site is contiguous to sites that contain earlier development served by sanitary sewers, streets, or public water supply when the governmental unit receives the plans for the new development or parkland, other public land, a utility right-of-way, or a watercourse.
(b) 
Sites where area of impervious surface after development or redevelopment will be 5% or less of the total area of the site.
(c) 
Recreation trails if the trail is less than or equal to 10 feet in width and has a continuous pervious buffer at least five feet wide on each side disregarding interruption by streets, driveways, or other impervious surfaces crossing the trail.
(4) 
Notwithstanding the applicability requirements in Subsection A(1), this chapter applies to post-construction sites of any size that, as determined by the City Engineer or his designee, 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.
B. 
Jurisdiction. This chapter applies to post-construction sites within the boundaries and jurisdiction of the City of Muskego.
C. 
Exclusions. This chapter is not applicable to activities conducted by a state agency, as defined under § 227.01(1), Wis. Stats.
As used in this chapter, 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 stream bank or lake shore is preserved. "Self-sustaining vegetative cover" includes grasses, forbs, sedges and duff layers of fallen leaves and woody debris.
ADMINISTERING AUTHORITY
A governmental employee empowered under § 62.234, Wis. Stats., that is designated by the Council to administer this chapter.
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 and/or manage the rate or volume of runoff.
BUSINESS DAY
A day the offices of the City of Muskego are 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 City of Muskego.
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.
CRITICAL TIME
The period starting at the time of peak rainfall intensity with a duration equal to the time of concentration of the watershed.
DESIGN STORM
A hypothetical discrete rainstorm characterized by a specific duration, temporal distribution, rainfall intensity, return frequency and total depth of rainfall.
DEVELOPMENT
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 two or more parcels or building sites of 20 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.
EROSION
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.
EXTRATERRITORIAL
The unincorporated area within three miles of the corporate limits of a first-, second-, or third-class city or within 1.5 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
All land disturbing construction activities at the construction site have been completed and 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 employment of equivalent permanent stabilization measures.
FINANCIAL GUARANTEE
A performance bond, maintenance bond, surety bond, irrevocable letter of credit, or similar guarantees submitted to the City of Muskego by the responsible party to assure that requirements of this chapter are carried out in compliance with the stormwater management plan.
GOVERNING BODY
City of Muskego Common Council.
ILLICIT CONNECTION
Any drain or conveyance, whether on the surface or subsurface, which allows an illegal discharge to enter the storm drain system, including but not limited to any conveyances which allow any nonstormwater discharge, including sewage, process wastewater, and wash water, to enter the storm drain system and any connections to the storm drain system from indoor drains and sinks, regardless of whether said drain or connection had been allowed, permitted, or approved by a government agency prior to the adoption of this chapter.
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.
INFILL
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.
INFILTRATION
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 roadside 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.
LANDOWNER
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 chapter as determined in accordance with § 309-6 of this chapter.
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. MSE3 is applicable for Waukesha County.
OFF SITE
Located outside the property boundary described in the permit application.
ON SITE
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 No. 200 sieve.
PERFORMANCE STANDARD
A narrative or measurable number specifying the minimum acceptable outcome for a facility or practice.
PERMIT
A written authorization made by the City of Muskego 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 City of Muskego 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.
POLLUTANT
Has the meaning given in § 283.01(13), Wis. Stats.
POLLUTION
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.
PRE-DEVELOPMENT 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.
PRETREATMENT
The practice of reducing pollutants in stormwater before discharging the stormwater to a wetland or another pollution control structure.
PREVENTIVE ACTION LIMIT
Has the meaning given in § NR 140.05(17), Wis. Adm. Code.
PROTECTIVE AREA
As defined in § 309-8D(4)(a).
PUBLIC RIGHT-OF-WAY
Any road, alley, street, parking lot, sidewalk, plaza, mall, or pathway owned by or dedicated to a governmental unit.
RECREATION TRAIL
A path that is:
A. 
Distinctly set apart from a roadway, street, or sidewalk;
B. 
Designed for activities such as jogging, walking, hiking, bird watching, bicycle riding, roller-skating, or other recreation not involving the use of motorized vehicles; and
C. 
Not a sidewalk according to § 340.01(58), Wis. Stats.
REDEVELOPMENT
Areas where development is replacing older development.
REGIONAL FLOOD
The peak flow and peak elevations of water with a one-percent probability of occurring during any one year, considering rainfall time and intensity patterns, rainfall duration, area distribution, antecedent moisture, and snow melt.
REGIONAL FLOODPLAIN
The area of land covered by water during the regional flood.
RESPONSIBLE PARTY
The landowner or any other entity performing services to meet the requirements of this chapter through a contract or other agreement.
RUNOFF
Stormwater or precipitation including rain, snow or ice melt or similar water that moves on the land surface via sheet or channelized flow.
RUNOFF MANAGEMENT SYSTEM
The complete combination of structural and nonstructural means used to reduce the rate or volume of runoff from a particular area, including but not limited to facilities constructed for conveyance and storage, management practices, and the protection, creation, or restoration of natural areas or systems such as vegetated swales, prairies, and wetlands for storage, conveyance, or infiltration.
RUNOFF RELEASE RATE
The volume of stormwater flowing off of development per unit of time and area.
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:
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.
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.
SITE
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 City of Muskego which requires that all construction activity on the site be stopped.
STORM DRAINAGE SYSTEM
Any publicly owned facilities by which stormwater is collected and/or conveyed, including but not limited to any roads with drainage systems, municipal streets, gutters, curbs, inlets, piped storm drains, pumping facilities, retention and detention basins, natural and human-made or altered drainage channels, reservoirs, and other drainage structures.
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.
TIME OF CONCENTRATION
The time required for the point furthest from the outlet of the watershed to contribute to flow at the outlet of the watershed.
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.
TP-40
Technical Paper No. 40, Rainfall Frequency Atlas of the United States, published in 1961.
TR-55
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 of Natural Resources pursuant to § 281.33, Wis. Stats.
TSS
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 chapter demonstrates to the City Engineer's or designee'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 and quantity standards of this chapter:
A. 
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.
B. 
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 City Engineer or his designee.
C. 
The most recent rainfall data identified by the Southeastern Wisconsin Regional Planning Commission shall be used for the analyses required by Chapter 13 of the Milwaukee Metropolitan Sewerage District rules as implemented and enforced by the City of Muskego.
A. 
Responsible party. The responsible party shall comply with this section.
B. 
Stormwater management plan. A written stormwater management plan in accordance with § 309-10 shall be developed and implemented for each post-construction site.
C. 
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 chapter, whichever is more stringent.
D. 
Requirements. The stormwater management plan required under Subsection B shall include the following:
(1) 
Total suspended solids. Best management practices shall be designed, installed and maintained to control total suspended solids carried in runoff from the post-construction site as follows:
(a) 
Best management practices 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.
Table 1: TSS Reduction Standards
Development Type
TSS Reduction
New development
80%
Infill development
80%
Redevelopment
40% of load from parking areas and roads
(b) 
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.
(c) 
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.
(2) 
Water quantity and management of peak runoff.
(a) 
Best management practices shall manage the volume, timing, and peak flow rate of runoff to prevent increases in the regional flood and stream bank erosion rates.
(b) 
These BMPs may be implemented either on site or off site as part of a regional stormwater device, practice or system. The BMP shall manage runoff from the post-construction site prior to discharge to waters of the state.
(c) 
When implemented on a regional basis, the BMPs implemented at a particular site shall comply with the findings of the relevant local or regional stormwater management plan, rather than Subsection D(2)(d) and (e).
(d) 
The following peak runoff reductions are required:
[1] 
By design, BMPs shall be employed to maintain or reduce the one-year, twenty-four-hour post-construction peak runoff discharge rates to the one-year, twenty-four-hour pre-development peak runoff discharge rates, or to the maximum extent practicable.
[2] 
For the 50%/two-year, twenty-four-hour design storm, BMPs shall be designed to either maintain or reduce the peak runoff discharge rates, to the maximum extent practicable, as compared to pre-development conditions, or achieve a maximum runoff release rate of 0.15 cubic foot per second per acre, whichever is more stringent.
[3] 
Development; redevelopment.
[a] 
For development, runoff management shall prevent increases in the regional flood and stream bank erosion rates.
[b] 
If demolition or construction during redevelopment will disturb an area larger than two acres, then the redevelopment shall reduce the runoff rate by the amount listed in Table 2 for the 1%/one-hundred-year and 50%/two-year storms, except as provided for in MMSD Chapter 13.11(5) rules.
Table 2: Runoff Rate Reduction
Area Disturbed by Demolition or Construction
Reduction of the Existing Runoff Release Rate as of October 25, 2010
Greater than 2 acres to 3.5 acres
10%
Greater than 3.5 acres to 5 acres
15%
Greater than 5 acres
20%
[c] 
If redevelopment will add 1/2 acre or more of impervious surface, then the requirements of Subsection D(2)(d)[3][a] apply rather than Subsection D(2)(d)[3][b].
[4] 
The runoff curve numbers in Table 3 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 NRCS Wisconsin MSE3 precipitation distribution, which is applicable for Waukesha County. On a case-by-case basis, the City Engineer or his designee may allow the use of TP-40 precipitation depths and the Type II distribution.
[5] 
Unless the project site is located in the area described in Subsection D(2)(d)[6], BMPs for the 1%/one-hundred-year, twenty-four-hour design storm shall be designed to achieve a runoff release rate that is less than or equal to either 0.5 cubic foot per second per acre or a rate determined for the individual site that distributes runoff over the critical time sufficient to comply with Subsection D(2)(a).
[6] 
The City of Muskego has identified areas (map is available from the City Engineer) that require greater runoff control. In the identified areas, BMPs for the 1%/one-hundred-year, twenty-four-hour design storm shall be designed to achieve a runoff release rate that is less than or equal to the 50%/two-year, twenty-four-hour peak release rate under pre-development conditions calculated as described in Subsection D(2)(d)[4].
Table 3: Maximum Pre-Development Runoff Curve Numbers
Hydrologic Soil Group
Runoff Curve Number
A
B
C
D
Woodland
30
55
70
77
Grassland
39
61
71
78
Cropland1
55
68
77
80
1
Maximum curve numbers from MMSD Chapter 13 Technical Guidance.
(e) 
This subsection does not apply to any of the following:
[1] 
Except as provided under Subsection C or D(2)(d)[3] for redevelopment post-construction site.
[2] 
Except as provided under Subsection D, a redevelopment post-construction site.
(3) 
Infiltration.
(a) 
Best management practices. Best management practices shall be designed, installed, and maintained to infiltrate runoff in accordance with the following or to the maximum extent practicable:
[1] 
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 pre-development 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.
[2] 
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 pre-development 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.
[3] 
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 pre-development 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.
(b) 
Pre-development. The pre-development condition shall be the same as specified in Table 3 of Subsection D(2).
(c) 
Source areas.
[1] 
Prohibitions. Runoff from the following areas may not be infiltrated and may not qualify as contributing to meeting the requirements of this subsection unless demonstrated to meet the conditions identified in Subsection D(3)(f):
[a] 
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.
[b] 
Storage and loading areas of a Tier 2 industrial facility identified in § NR 216.21(2)(b), Wis. Adm. Code.
[c] 
Fueling and vehicle maintenance areas. Runoff from rooftops of fueling and vehicle maintenance areas may be infiltrated with the concurrence of the regulatory authority.
[2] 
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:
[a] 
Parking areas and access roads less than 5,000 square feet for commercial development.
[b] 
Parking areas and access roads less than 5,000 square feet for industrial development not subject to the Prohibitions under Subsection D(3)(c)[1].
[c] 
Except as provided under Subsection C, redevelopment post-construction sites.
[d] 
Infill development areas less than five acres.
[e] 
Roads on commercial, industrial and institutional land uses and arterial residential roads.
(d) 
Location of practices.
[1] 
Prohibitions. Infiltration practices may not be located in the following areas:
[a] 
Areas within 1,000 feet upgradient or within 100 feet downgradient of direct conduits to groundwater.
[b] 
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.
[c] 
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.
[2] 
Separation distances.
[a] 
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 4:
Table 4" Separation Distances and Soil Characteristics
Source Area
Separation Distance
Soil Characteristics
Industrial, commercial, institutional parking lots and roads
5 feet or more
Filtering layer
Residential arterial roads
5 feet or more
Filtering layer
Roofs draining to subsurface infiltration practices
1 foot or more
Native or engineered soil with particles finer than coarse sand
Roofs draining to surface infiltration practices
Not applicable
Not applicable
All other impervious source areas
3 feet or more
Filtering layer
[b] 
Notwithstanding Subsection D(3)(d)[2], applicable requirements for injection wells classified under Ch. NR 815, Wis. Adm. Code, shall be followed.
[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:
[a] 
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.
[b] 
Where the least permeable soil horizon to five feet below the proposed bottom of the infiltration system using the United States 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.
(e) 
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 subsection.
(f) 
Groundwater standards.
[1] 
Infiltration systems designed in accordance with this subsection 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.
[2] 
Notwithstanding Subsection D(3)(f)[1], the discharge from BMPs shall remain below the enforcement standard at the point of standards application.
(g) 
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.
(h) 
Maximum extent practicable. Where the conditions of Subsection D(3)(c) and (d) limit or restrict the use of infiltration practices, the performance standard of Subsection D(3) shall be met to the maximum extent practicable.
(4) 
Protective areas.
(a) 
Definition. In this subsection, "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 subsection, "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.
[1] 
For outstanding resource waters and exceptional resource waters, 75 feet.
[2] 
For perennial and intermittent streams identified on a United States Geological Survey 7.5-minute series topographic map, or a county soil survey map, whichever is more current, 50 feet.
[3] 
For lakes, 50 feet.
[4] 
For wetlands not subject to Subsection D(4)(a)[5] or [6], 50 feet.
[5] 
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.
[6] 
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.
[7] 
In Subsection D(4)(a)[4] to [6], determinations of the extent of the protective area adjacent to wetlands shall be made on the basis of the sensitivity and runoff susceptibility of the wetland in accordance with the standards and criteria in § NR 103.03, Wis. Adm. Code.
[8] 
Wetland boundary delineation shall be made in accordance with § NR 103.08(1m), Wis. Adm. Code. This subsection 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.
[9] 
For concentrated flow channels with drainage areas greater than 130 acres, 10 feet.
[10] 
Notwithstanding Subsection D(4)(a)[1] to [9], the greatest protective area width shall apply where rivers, streams, lakes and wetlands are contiguous.
(b) 
Applicability. This subsection applies to post-construction sites located within a protective area, except those areas exempted pursuant to Subsection D(4)(d).
(c) 
Requirements. The following requirements shall be met:
[1] 
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.
[2] 
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.
[3] 
Best management practices, 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.
(d) 
Exemptions. This subsection does not apply to any of the following:
[1] 
Except as provided under Subsection C, redevelopment post-construction sites.
[2] 
Infill development areas less than five acres.
[3] 
Structures that cross or access surface water such as boat landings, bridges, and culverts.
[4] 
Structures constructed in accordance with § 59.692(1v), Wis. Stats.
[5] 
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.
(5) 
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.
(6) 
Swale treatment for transportation facilities.
(a) 
Requirement. Except as provided in Subsection D(6)(b), transportation facilities that use swales for runoff conveyance and pollutant removal are exempt from 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:
[1] 
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.
[2] 
Swales shall comply with Sections VF (Velocity and Depth) and VG (Sale Geometry Criteria) with a swale treatment length as long as that specified in Section VC (Pretreatment) 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.
(b) 
Other requirements.
[1] 
Notwithstanding Subsection D(6)(a), the City of Muskego 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:
[a] 
An outstanding resource water.
[b] 
An exceptional resource water.
[c] 
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.
[d] 
Water where targeted performance standards are developed pursuant to § NR 151.004, Wis. Adm. Code.
[2] 
The transportation facility authority shall contact the City Engineer to determine if additional BMPs beyond a water quality swale are needed under this subsection.
E. 
General considerations for stormwater management measures. The following considerations shall be observed in on-site and off-site runoff management:
(1) 
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.
(2) 
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.
(3) 
All stormwater conveyance systems within the proposed development shall be designed to completely contain the peak storm flows as described in Subsection D(2)(d)[5] and [6]. Calculations for determining peak flows for conveyance system sizing shall use runoff curve numbers based on the existing or future proposed land use for off-site areas (whichever results in the highest peak flows), and the proposed land use for the on-site areas. Appropriate runoff curve numbers are described in Urban Hydrology for Small Watersheds, TR-55 (Technical Release 55) published by the United States Department of Agriculture, Natural Resources Conservation Service (previously Soil Conservation Service), June 1986. Peak discharges shall be calculated using TR-55 runoff curve number methodology, Atlas 14 precipitation depths, and the NRCS Wisconsin MSE3 precipitation distribution, which is applicable for Waukesha County. On a case-by-case basis, the City Engineer may allow the use of TP-40 precipitation depths and the Type II distribution. An alternative method that may be used is the Rational Method as described in Chapter 13 of the Wisconsin Department of Transportation Facilities Development Manual.
(a) 
For open channel conveyance systems, the peak flow from the 2%/fifty-year, twenty-four-hour storm shall be completely contained within the channel bottom and banks.
(b) 
For storm sewer pipes, the peak flow from the 4%/twenty-five-year, twenty-four-hour storm shall be completely contained within the pipes with no surcharging.
(c) 
For storms greater than the 4%/twenty-five-year, twenty-four-hour event and up to the 1%/one-hundred-year, twenty-four-hour event, ponding shall not exceed existing or proposed street right-of-way, whichever is less. In no case shall the depth of water exceed 12 inches at the outer edge of pavement.
(4) 
Increases or decreases in the hydrology of natural wetlands shall be minimized. Existing wetlands shall not be incorporated in the proposed stormwater management practice for peak flow control. Peak flow shall be managed prior to discharge to an existing wetland. Should any changes to natural wetlands be proposed, the impact of the proposal on wetland functional values shall be assessed. Significant changes to wetland functional values shall be avoided (as defined by Ch. NR 103, Wis. Adm. Code).
F. 
Best management practices location.
(1) 
To comply with the performance standards required under this section, 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.
(2) 
The City of Muskego may approve off-site management measures provided that all of the following conditions are met:
(a) 
The City Engineer or his designee determines that the post-construction runoff is covered by a stormwater management system plan that is approved by the City of Muskego and that contains management requirements consistent with the purpose and intent of this chapter.
(b) 
The off-site facility meets all of the following conditions:
[1] 
The facility is in place.
[2] 
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 chapter.
[3] 
The facility has a legally obligated entity responsible for its long-term operation and maintenance.
(3) 
Where a regional treatment option exists such that the City of Muskego 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 City of Muskego. In determining the fee for post-construction runoff, the City of Muskego shall consider an equitable distribution of the cost for land, engineering design, construction, and maintenance of the regional treatment option.
G. 
Additional requirements. The City of Muskego may establish stormwater management requirements more stringent than those set forth in this chapter if the City of Muskego 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.
H. 
Credit for removal of impervious surfaces.
(1) 
Same site credit. The City of Muskego may use the removal of pavement, covered structures, or other impervious surfaces at the same property to calculate the net post-construction impervious acreage and corresponding water quantity management duties to meet MMSD 13.11 requirements. The credit does not change the water quantity management requirements under Subsection D(2)(d)[1] and [2]. Credit may equal but not be larger than the acreage of impervious surfaces removed when runoff release rates and detention are the best management practices utilized at the site. When best management practices with a higher order of preference are utilized in lieu of detention, equivalent credit may be granted as determined by the City Engineer or his designee with the concurrence of the MMSD. Credit for reducing impervious surfaces at a site, not utilized by the development on the site, belongs to the City of Muskego and may be banked for allocation to other development within the watershed under Subsection H(2).
(2) 
Dispersed site in same watershed credit. The City of Muskego may bank the removal of impervious surface, which individually must be 1/2 acre or more, within the same watershed, where the volume, timing and peak flow runoff will be distributed over the critical time sufficient to assure the level of protection provided by MMSD flood abatement projects will not be reduced. The City of Muskego may allocate banked credit to promote a policy of smart growth. The total acreage banked or allocated, or both, shall be reported, by watershed or subwatershed, annually to the MMSD for concurrence. The credit does not change the water quantity management requirements under Subsection D(2)(d)[1] and [2].
A. 
Permit required. No responsible party may undertake a land disturbing construction activity without receiving a land disturbing permit from the City of Muskego prior to commencing the proposed activity.
B. 
Permit application and fees. Unless specifically excluded by this chapter, any responsible party desiring a permit shall submit to the City of Muskego a permit application on a form provided by the City of Muskego for that purpose.
(1) 
Unless otherwise excluded by this chapter, a permit application must be accompanied by a stormwater management plan, grading plan, and maintenance agreement.
(2) 
The stormwater management plan shall be prepared to meet the requirements of §§ 309-8 and 309-10, the maintenance agreement shall be prepared to meet the requirements of § 309-11, the financial guarantee shall meet the requirements of § 309-12, and fees shall be those established by the City of Muskego as set forth in § 309-13.
C. 
Permit application review and approval. The City Engineer or his designee 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:
(1) 
Within 60 business days of the receipt of a complete permit application, including all items as required by Subsection B, the City Engineer or his designee shall inform the applicant whether the application, stormwater management plan and maintenance agreement are approved or disapproved based on the requirements of this chapter.
(2) 
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 City Engineer or his designee shall issue the permit.
(3) 
If the stormwater permit application, stormwater management plan or maintenance agreement is disapproved, the City Engineer or his designee shall detail in writing the reasons for disapproval.
(4) 
The City Engineer or his designee may request additional information from the applicant. If additional information is submitted, the City Engineer or his designee shall have 15 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.
D. 
Permit requirements. All permits issued under this chapter shall be subject to the following conditions, and holders of permits issued under this chapter shall be deemed to have accepted these conditions. The City of Muskego may suspend or revoke a permit for violation of a permit condition, following written notification of the responsible party. An action by the City of Muskego to suspend or revoke this permit may be appealed in accordance with § 309-15.
(1) 
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.
(2) 
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.
(3) 
The responsible party shall notify the City of Muskego at least three business days before commencing any work in conjunction with the stormwater management plan and within five 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 City of Muskego so that practice installations can be inspected during construction.
(4) 
Practice installations required as part of this chapter shall be certified "as built" or "record" drawings by a licensed professional engineer. Completed stormwater management practices must pass a final inspection by the City Engineer or his designee to determine if they are in accordance with the approved stormwater management plan and this chapter. The City Engineer or his 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.
(5) 
The responsible party shall notify the City Engineer or his designee of any significant modifications it intends to make to an approved stormwater management plan, grading plan or maintenance agreement. The City Engineer or his designee 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.
(6) 
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 City of Muskego or are transferred to subsequent private owners as specified in the approved maintenance agreement.
(7) 
The responsible party authorizes the City of Muskego 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 § 309-12.
(8) 
If so directed by the City of Muskego, 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.
(9) 
The responsible party shall permit property access to the City Engineer or his designee for the purpose of inspecting the property for compliance with the approved stormwater management plan and this permit.
(10) 
Where site development or redevelopment involves changes in direction or increases in peak rate and/or total volume of runoff from a site, the City Engineer or his designee may require the responsible party to make appropriate legal arrangements with affected property owners concerning the prevention of endangerment to property or public safety.
(11) 
The responsible party is subject to the enforcement actions and penalties detailed in § 309-14, if the responsible party fails to comply with the terms of this permit.
E. 
Permit conditions. Permits issued under this section may include conditions established by City Engineer or his designee in addition to the requirements needed to meet the performance standards in § 309-8 or a financial guarantee as provided for in § 309-12.
F. 
Permit duration. Permits issued under this section shall be valid from the date of issuance through the date the City of Muskego notifies the responsible party that all stormwater management practices have passed the final inspection required under Subsection D(4) or one year from the date of issuance, whichever is shorter.
A. 
Stormwater management plan requirements. The stormwater management plan required under § 309-8B shall contain at a minimum the following information:
(1) 
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.
(2) 
A proper legal description of the property proposed to be developed, referenced to the United States Public Land Survey system or to block and lot numbers within a recorded land subdivision plat.
(3) 
Pre-development site conditions, including:
(a) 
One or more site maps at a scale of not less than one inch equals 100 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 two 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 1%/one-hundred-year floodplain; and location of wells and wellhead protection areas covering the project area and delineated pursuant to § NR 811.16, Wis. Adm. Code.
(b) 
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).
(4) 
Post-development site conditions, including:
(a) 
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.
(b) 
Explanation of any restrictions on stormwater management measures in the development area imposed by wellhead protection plans and ordinances.
(c) 
One or more site maps at a scale of not less than one inch equals 100 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 two 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.
(d) 
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).
(e) 
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.
(5) 
A description and installation schedule for the stormwater management practices needed to meet the performance standards in § 309-8.
(6) 
A maintenance plan developed for the life of each stormwater management practice, including the required maintenance activities and maintenance activity schedule.
(7) 
Cost estimates for the construction, operation, and maintenance of each stormwater management practice.
(8) 
Other information requested in writing by the City Engineer or his designee to determine compliance of the proposed stormwater management measures with the provisions of this chapter.
(9) 
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 chapter.
B. 
Alternate requirements. The City of Muskego may prescribe alternative submittal requirements for applicants seeking an exemption to on-site stormwater management performance standards under § 309-8E.
A. 
Maintenance agreement required. The maintenance agreement required under § 309-9B for stormwater management practices shall be an agreement between the City of Muskego 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.
B. 
Agreement provisions. The maintenance agreement shall contain the following information and provisions and be consistent with the maintenance plan required by § 309-10A(6):
(1) 
Identification of the stormwater facilities and designation of the drainage area served by the facilities.
(2) 
A schedule for regular maintenance of each aspect of the stormwater management system consistent with the stormwater management plan required under 309-9B.
(3) 
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 § 309-9B.
(4) 
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).
(5) 
Authorization for the City of Muskego, its designee and the Milwaukee Metropolitan Sewerage District 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.
(6) 
A requirement on the City of Muskego 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.
(7) 
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 City of Muskego of maintenance problems which require correction. The specified corrective actions shall be undertaken within a reasonable time frame as set by the City of Muskego.
(8) 
Authorization of the City of Muskego to perform the corrective 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 City of Muskego 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.
A. 
Establishment of the guarantee. The City of Muskego may require the submittal of a financial guarantee, the form and type of which shall be acceptable to the City of Muskego. The financial guarantee shall be in an amount determined by the City Engineer or his designee 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 City of Muskego 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 City Engineer that the requirements of this chapter have not been met.
B. 
Conditions for release. Conditions for the release of the financial guarantee are as follows:
(1) 
The City of Muskego shall release the portion of the financial guarantee established under this section, less any costs incurred by the City of Muskego to complete installation of practices, upon submission of "as built" plans or "record" drawings by a licensed professional engineer. The City of Muskego may make provisions for a partial pro rata release of the financial guarantee based on the completion of various development stages.
(2) 
The City of Muskego shall release the portion of the financial guarantee established under this section to assure maintenance of stormwater practices, less any costs incurred by the City of Muskego, 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 chapter shall be established by City of Muskego and may from time to time be modified by resolution. A schedule of the fees established by the City of Muskego shall be available for review in the City Hall, W182 S8200 Racine Avenue, Muskego, Wisconsin, 53150.
A. 
Any land disturbing construction activity or post-construction runoff initiated after the effective date of this chapter by any person, firm, association, or corporation subject to the provisions of this chapter shall be deemed a violation unless conducted in accordance with the requirements of this chapter.
B. 
The City of Muskego shall notify the responsible party 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.
C. 
Upon receipt of notification from the City of Muskego 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 City of Muskego in the notice.
D. 
If the violations of a permit issued pursuant to this chapter are likely to result in damage to properties, public facilities, or waters of the state, the City of Muskego may enter the land and take emergency actions necessary to prevent such damage. The costs incurred by the City of Muskego plus interest and legal costs shall be billed to the responsible party.
E. 
The City of Muskego is authorized to post a stop-work order on all land disturbing construction activity that is in violation of this chapter, or to request the City of Muskego Attorney to obtain a cease-and-desist order in any court with jurisdiction.
F. 
The City of Muskego may revoke a permit issued under this chapter for noncompliance with ordinance provisions.
G. 
Any permit revocation, stop-work order, or cease-and-desist order shall remain in effect unless retracted by the City of Muskego or by a court with jurisdiction.
H. 
The City of Muskego is authorized to refer any violation of this chapter, or a stop-work order or cease-and-desist order issued pursuant to this chapter, to the City of Muskego Attorney for the commencement of further legal proceedings in any court with jurisdiction.
I. 
Any person, firm, association, or corporation who or which does not comply with the provisions of this chapter shall be subject to the general penalty provision of § 1-4 of the Muskego Municipal Code.
J. 
Every violation of this chapter is a public nuisance. Compliance with the provisions of this chapter may also be enforced by injunction in any court with jurisdiction pursuant to § 62.23(8), Wis. Stats. It shall not be necessary to prosecute for forfeiture or a cease-and-desist order before resorting to injunctional proceedings.
K. 
When the City of Muskego determines that the holder of a permit issued pursuant to this chapter 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 City of Muskego or a party designated by the City of Muskego 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 City of Muskego 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 § 309-12 of this chapter. 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.
A. 
Zoning Board of Appeals. The Zoning Board of Appeals, created pursuant to Chapter 400, Zoning, of the City of Muskego Municipal Code pursuant to § 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 City Engineer or his designee in administering this chapter. 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 chapter that are not contrary to the public interest and where owing to special conditions a literal enforcement of this chapter will result in unnecessary hardship.
B. 
Who may appeal. Appeals to the Zoning Board of Appeals may be taken by any aggrieved person or by an officer, department, board, or bureau of the City of Muskego affected by any decision of the City of Muskego.
A. 
Discharges. Except for stormwater and other discharges specifically exempted under Subsection C below, no discharge, spilling or dumping of substances or materials shall be allowed into receiving water bodies or onto driveways, sidewalks, parking lots or other areas that drain into the storm drainage system.
B. 
Connections. The construction, use, maintenance or continued existence of illicit connections to the storm drainage system is prohibited. This prohibition expressly includes, without limitation, illicit connections made prior to the adoption of this chapter, regardless of whether the connection was permissible under law or practice applicable or prevailing at the time of connection.
C. 
Exemptions. The following activities are exempt from the provisions of this section unless found to have an adverse impact on the stormwater:
(1) 
Discharges authorized by permit issued by the Wisconsin Department of Natural Resources.
(2) 
Discharges resulting from firefighting activities.
(3) 
Discharges from uncontaminated groundwater, potable water source, roof drains, foundation drain and sump pump, air-conditioning condensation, springs, lawn watering, individual residential car washing, water main and hydrant flushing, and swimming pools if the water has been dechlorinated.
D. 
Notice of violation. Whenever the City of Muskego finds a violation of this section, the City of Muskego may order compliance by written notice of violation to the responsible party.
(1) 
Such notice may require without limitation:
(a) 
The elimination of illicit connections or discharges.
(b) 
That violating discharges, practices, or operation shall cease and desist.
(c) 
The abatement or remediation of stormwater pollution or contaminated hazards and the restoration of any affected property.
(2) 
Any responsible party that fails to comply with a notice of violation under this section shall be subject to further enforcement action under the provisions of § 309-14.