City of Amery, WI Plan Requirements for Stormwater Management

§ 367-23 General stormwater management plan requirements.

A stormwater management plan shall describe how the permit holder and other responsible party will meet the stormwater management requirements of this article and other related requirements in this chapter. All stormwater management plans and associated BMPs shall comply with the planning, design, implementation and maintenance requirements described in this chapter to achieve a no net increase in runoff from the disturbed site.

§ 367-24 Guiding principles for stormwater management.

A stormwater management plan shall, to the maximum extent practicable, adhere to the following principles:

Preserve natural watershed boundaries and drainage patterns;

Reserve adequately sized areas for stormwater infiltration, detention and treatment early in the site planning process;

Locate stormwater BMPs prior to runoff leaving the site or entering waters of the state, wetlands, floodplains, primary or secondary environmental corridors or isolated natural areas;

Minimize soil compaction and maintain predevelopment groundwater recharge areas;

Minimize impervious surfaces and have them drain to vegetated areas for pollutant filtering and infiltration;

Emphasize vegetated swales, warm season and wetland plantings, and low-flow velocities for stormwater conveyance, treatment and infiltration, especially for transportation-related projects;

Note: Tall, dense, deep-rooted vegetation and low-flow velocities in open channels encourage infiltration and increase their effectiveness for runoff pollutant removal. Check dams may also be included in the swale design to slow runoff flows and improve pollutant removal. Soil amendments such as compost can help reduce soil compaction and increase infiltration.

Allow for different stormwater management strategies for cleaner runoff (i.e., roofs) versus more polluted runoff (i.e., heavily used streets and parking lots);

Provide for emergency overflow in all stormwater BMP designs;

Distribute stormwater bioretention and infiltration BMPs throughout the site plan for large land developments.

§ 367-25 Site plan map requirements.

A site plan map and supporting data of site conditions at a scale of one inch equals no more than 100 feet (unless otherwise noted) shall delineate or display all the following applicable items:

(1)

Development title, graphic scale and North arrow;

(2)

Property location description by public land survey system (1/4 section, section, township, range, county);

(3)

Location map (smaller scale) showing the site location within a public land survey section or subdivision, oriented the same as Subsection A(4) below;

(4)

Ownership boundaries, bearings, lengths and other survey references that will accurately identify the site's location, in accordance with Ch. 236, Wis. Stats., and county and/or City mapping standards for all land divisions;

(5)

Lot numbers and dimensions, including outlots for all land divisions;

(6)

Name and complete contact information for the applicant, landowner, developer and project engineer;

(7)

Surveyor's certificate, signed, dated and sealed for all land divisions;

(8)

Sheet numbers and revision dates on every page;

(9)

Existing site topography at a contour interval not to exceed two feet, including spot elevations for physical features such as culvert (invert elevations), retaining walls, road and ditch center lines and topographic high and low points;

(10)

Location and name, if applicable, of all lakes, streams, channels, ditches, and other water bodies or areas of channelized flow on or adjacent to the site;

(11)

Location and name, if applicable, of all wetlands and identification of source of delineation. For final land divisions, these boundaries shall be field-verified;

(12)

Boundaries of shoreland zones and the ordinary high-water mark (OHWM) for any navigable water body as defined by the Polk County Shoreland Protection Zoning Ordinance. For final land divisions, the OHWM boundaries shall be field-verified;

[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II)]

(13)

Boundaries and elevation of the 100-year floodplains, flood fringes and floodways, as defined by the Polk County Shoreland Protection Zoning Ordinance. For final land divisions, these boundaries and elevations shall be field-verified;

[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II)]

(14)

Boundaries and soil symbol for each soil mapping unit and the identification of all hydric soils as defined by the USDA Natural Resources Conservation Service;

(15)

Locations of all available soil borings or soil profile evaluations with unique references to supplemental data report forms;

(16)

Location of primary and secondary environmental corridors, as defined by the Northwestern Wisconsin Regional Planning Commission. For final land divisions, these boundaries shall be field-verified;

(17)

Location and description of isolated natural area boundaries as defined by the Northwestern Wisconsin Regional Planning Commission, woodland areas and other vegetative cover types;

(18)

Location and descriptive notes for existing and proposed structures within 50 feet of the property boundaries and their proposed use, including but not limited to buildings and foundations, roads, parking areas, fence lines, access lanes, culverts (include size and type), aboveground utilities and retaining walls;

(19)

Location and descriptive notes for other known existing site features, including but not limited to rock outcrops or other karst features, tile drains, buried utilities, dumps, landfills, and manure or other waste storage facilities;

(20)

Boundaries and descriptive notes for all applicable setbacks and for protective areas, as specified in § 367-26D of this chapter;

(21)

Location and descriptive notes for any existing or proposed easements, rights-of-way, vision corners or other known site restrictions. Road rights-of way and building setbacks shall be in compliance with all applicable administrative codes, adopted plans and ordinances;

(22)

Location and descriptive notes for existing and proposed public dedications of parcels or rights-of-way;

(23)

Location and descriptive notes for preplanned building or waste disposal sites, when limited by site features;

(24)

Location and documentation of any existing well and delineation of any applicable regulatory setbacks, in accordance with Ch. NR 811 and Ch. NR 812, Wis. Adm. Code;

(25)

Notes describing source documents, date and measure of accuracy for all applicable mapping features noted above;

(26)

Other site information that the Designated City Representative determines is necessary to administer this chapter.

Note: The Designated City Representative will provide the applicant with a written checklist of the above items, including guidance on which items are applicable to the proposed project. Items may need to be displayed on more than one map for purposes of clarity.

§ 367-26 Specific stormwater management plan requirements and performance standards.

All stormwater management plans and associated BMPs shall meet the following minimum requirements to the maximum extent practicable. It is highly recommended that the applicant meet with the Designated City Representative prior to preparing a stormwater management plan to determine the applicability of these requirements early in the site planning process.

Peak discharge.

(1)

Minimum requirement. To minimize erosion and the failure of conveyance systems, the calculated post-development peak stormwater discharge rate shall not exceed the calculated predevelopment discharge rates for the two-year, ten-year, and one-hundred-year, twenty-four-hour design storms. Modeling requirements for this provision are further described in Article VI.

(2)

Release rate per acre. The Designated City Representative may establish a maximum allowable release rate on a per acre basis that would supersede the requirements of Subsection A(1) above for certain watersheds after the necessary hydrologic modeling is completed and the maximum release rate is established.

Note: A detailed watershed-based hydrologic analysis can generate a more accurate peak discharge rate for the protection of downstream properties from increased flooding due to the addition of impervious surfaces.

(3)

Peak discharge exemptions. Certain sites or portions of sites may be exempted from the peak discharge requirements of this subsection in accordance with § 367-27 below.

Total suspended solids. By design, each stormwater management plan shall meet the following post-development total suspended solids reduction targets, based on average annual rainfalls, as compared to no runoff management controls:

(1)

For new land development, 80% reduction in total suspended solids load;

(2)

For redevelopment, 40% reduction of total suspended solids load;

(3)

For infill development that occurs prior to October 1, 2012, 40% reduction total suspended solids load;

(4)

For in-fill development that occurs after October 1, 2012, 80% reduction of total suspended solids load.

Note: The first flush of stormwater runoff from an urban landscape contains the vast majority of pollutants, which tend to be associated with suspended solids. Pollutant loading models such as SLAMM, P8 or equivalent methodology may be used to evaluate the efficiency of the design in reducing total suspended solids under Subsection B(1) above.

Infiltration. BMPs shall be designed, installed, and maintained to infiltrate runoff in accordance with the following requirements, except as provided in Subsection C(5) through (8) below.

(1)

Residential. For residential developments, one of the following shall be met:

(a)

Infiltrate sufficient runoff volume so that the post-development infiltration volume shall be at least 100% 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 project site is required as an effective infiltration area.

(b)

Infiltrate 25% of the post-development runoff volume from the two-year, twenty-four-hour design storm with a Type II distribution. Separate runoff curve numbers for pervious and impervious surfaces shall be used to calculate runoff volumes, not composite curve numbers, as prescribed in Article VI. However, when designing appropriate infiltration systems to meet this requirement, no more than 1% of the project site is required as an effective infiltration area.

(2)

Nonresidential. For nonresidential development, including commercial, industrial and institutional development, one of the following shall be met:

(a)

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 project site is required as an effective infiltration area.

(b)

Infiltrate 10% of the post-development runoff volume from the two-year, twenty-four-hour design storm. Separate curve numbers for pervious and impervious surfaces shall be used to calculate runoff volumes, not composite curve numbers, as defined in TR-55. However, when designing appropriate infiltration systems to meet this requirement, no more than 2% of the project site is required as an effective infiltration area.

(3)

Modeling. Refer to § 367-30 for details on calculating runoff volumes and predevelopment conditions.

(4)

Pretreatment. Pretreatment shall be required before infiltrating parking lot and road runoff from commercial, industrial and institutional areas. 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 C(8) below. Pretreatment options may include, but are not limited to, oil/grease separators, sedimentation or bioretention basins, filtration swales or filter strips. All designs shall comply with the technical standards in § 367-31.

Note: To achieve the infiltration requirement for the parking lots or roads, "maximum extent practicable" should not be interpreted to require significant topography changes that create an excessive financial burden. To minimize potential groundwater impacts, it is desirable to infiltrate the cleanest runoff. To achieve this, a design may propose greater infiltration of runoff from low pollutant sources such as roofs, and less from higher pollutant source areas such as parking lots.

(5)

Infiltration exclusions. Infiltration of runoff shall not be credited toward meeting the requirements of this subsection, and is prohibited to minimize the potential for groundwater contamination for the following:

(a)

Runoff from outdoor material storage and loading docks for tier 1 and tier 2 industrial facilities, as identified in § NR 216.21(2), Wis. Adm. Code.

(b)

Runoff from fueling and vehicle maintenance areas, not including rooftops and canopies.

(c)

Infiltration of runoff within 1,000 feet upgradient or within 100 feet downgradient of karst features.

(d)

Infiltration of runoff from any area except rooftops with less than three feet separation distance from the top of the filtering layer to the elevation of seasonal high groundwater or the top of bedrock.

(e)

Infiltration of runoff from industrial, commercial and institutional parking lots and roads and residential arterial roads with less than five feet separation distance from top of the filtering layer to the elevation of seasonal high groundwater or the top of bedrock.

(f)

Areas within 400 feet of a community water system well as specified in § NR 811.12(5), Wis. Adm. Code, or as required by applicable wellhead protection ordinances, or within 100 feet of a private well as specified in § NR 812.08(4), Wis. Adm. Code, for runoff infiltrated from commercial, industrial and institutional land uses or regional devices for residential development, not including rooftop runoff.

(g)

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.

(h)

Areas associated with Tier 1 industrial facilities identified in § NR 216.21(2)(a), Wis. Adm. Code, including storage, loading, rooftop and parking.

(i)

Any area where the soil does not exhibit one of the following characteristics between the bottom of the infiltration system and the seasonal high groundwater and top of bedrock: at least a three-foot soil layer with 20% fines or greater or at least a five-foot soil layer with 10% fines or greater.

Note: This subsection does not apply where the soil medium within the infiltration system provides an equivalent level of protection and does not prohibit infiltration of roof runoff.

(6)

Infiltration exemptions. The infiltration requirements of this subsection do not apply to frozen soil conditions and may be exempted if soils have a measured infiltration rate of less than 0.6 inch per hour and the Designated City Representative determines it would be impracticable to modify existing soil conditions. Other sites may be exempted in accordance with § 367-27 below.

(7)

Alternate runoff uses. Where storage and reuse of runoff are employed, such as to support green roofs, landscape watering, toilet flushing, laundry or irrigation, such alternate uses shall be given equal credit toward the infiltration volume required by this section.

(8)

Groundwater protection.

(a)

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.

(b)

The discharge from BMPs shall remain below the enforcement standard at the point of standards application.

(c)

No stormwater BMP shall be installed that meets the definition of an injection well under Ch. NR 812, Wis. Adm. Code.

(d)

All stormwater BMPs shall comply with the provisions of any applicable wellhead protection plan for a community water supply under Ch. NR 811, Wis. Adm. Code.

Protective areas.

(1)

"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, such that runoff cannot enter the enclosure at this location (minimums listed below).

(a)

For perennial and intermittent streams, 75 feet.

(b)

For lakes, 75 feet.

(c)

For highly susceptible wetlands, as determined by the Designated City Representative, 50 feet. Highly susceptible wetlands include the following types: fens, sedge meadows, bogs, low prairies, conifer swamps, shrub swamps, other forested wetlands, fresh wet meadows, shallow marshes, deep marshes and seasonally flooded basins.

(d)

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 wetlands dominated by invasive species such as reed canary grass.

(e)

In Subsection D(1)(a), (c) and (d), 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 Ch. NR 103, Wis. Adm. Code.

(f)

For concentrated flow channels with drainage areas greater than 130 acres, 10 feet.

(2)

Requirements. The following requirements shall be met for all land development activity located within a protective area:

(a)

Impervious surfaces shall be kept out of the protective area, except for boathouses and walkways authorized under Ch. NR 115, Wis. Adm. Code, and applicable shoreland and/or floodplain zoning. The erosion control plan shall contain a written site-specific explanation for any parts of the protective area that are disturbed during construction.

(b)

Where land disturbing activity occurs within a protective area, and where no impervious surface is present, adequate sod or self-sustaining vegetative cover of 70% or greater shall be established and maintained. 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: It is recommended that seeding of nonaggressive native vegetative cover be used in the protective areas. Vegetation that is flood and drought tolerant and can provide long-term bank stability because of an extensive root system is preferable. Vegetative cover can 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."

(c)

Best management practices such as filter strips, swales, or wet detention basins, which are designed to control pollutants from nonpoint sources, may be located in the protective area as reviewed and approved by Designated City Representative on a site-by-site basis, but shall not encroach into wetlands, floodplains or primary or secondary environmental corridors.

Note: Other regulations, such as Ch. 30, Wis. Stats., and Chs. NR 103, NR 115, NR 116 and NR 117, Wis. Adm. Code, and their associated review and approval process may apply in the protective area.

(3)

Protective area exemptions. The protective area requirements of this subsection may be exempted in accordance with § 367-27 below and do not apply to the following:

(a)

Structures that cross or access surface waters such as boat landings, bridges and culverts;

(b)

Structures constructed in accordance with § 59.692(1v), Wis. Stats.; and

(c)

Sites where runoff does not enter the surface water, except to the extent that vegetative ground cover is necessary to maintain bank stability.

Note: A vegetated protective area to filter runoff pollutants from post-construction sites described in Subsection D(3) above is not necessary since runoff is not entering the surface water at that location. Other practices, necessary to meet the requirements of this section, such as a swale or basin, will need to be designed and implemented to reduce runoff pollutants before the runoff enters a surface water of the state.

Fueling and vehicle maintenance areas. Fueling and vehicle maintenance areas shall have BMPs designed, installed and maintained to reduce petroleum within runoff, such that the runoff that enters waters of the state contains no visible petroleum sheen.

Note: 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.

Site drainage. Measures shall be implemented to ensure proper site drainage, prevent property damage and protect public health and safety, including the following minimum requirements:

(1)

Drainage easement. Perpetual drainage easements or other deed restrictions shall be recorded on the property to preserve stormwater flow paths and permanent stormwater BMP locations. Recorded covenants in these areas shall not allow buildings or other structures and shall prevent any grading, filling or other activities that interrupt or obstruct flows in any way. Recorded covenants shall also specify maintenance responsibilities and authorities in accordance with Article VII.

(2)

Site grading. Site grading shall ensure positive flows away from all buildings, roads, driveways and septic systems, be coordinated with the general stormwater drainage patterns for the area, and minimize adverse impacts on adjacent properties.

(3)

Street drainage. All street drainage shall be designed to prevent concentrated flows from crossing the traffic lanes to the maximum extent practicable. Design flow depths at the road center line for on-street drainage shall not exceed six inches during the peak flows generated by the one-hundred-year, twenty-four-hour design storm, using planned land use conditions for the entire contributing watershed area.

(4)

Bridges and cross-culverts. All new or modified bridges and cross-culverts shall comply with applicable design standards and regulations, facilitate fish passage and prevent increased flooding or channel erosion upstream or downstream from the structure. Design flow depths at the road center line for all crossings shall not exceed six inches during the peak flows generated by the one-hundred-year, twenty-four-hour design storm, using planned land use conditions for the entire contributing watershed area. All predevelopment runoff storage areas within the flow path upstream of bridges and cross-culverts shall be preserved and designated as drainage easements, unless compensatory storage is provided and accounted for in modeling. As-built documentation shall be submitted in accordance with Article III for all new or modified structures that are located within a mapped floodplain or that the Designated City Representative determines to be necessary to maintain floodplain modeling for the applicable watershed.

(5)

Subsurface drainage. Basement floor surfaces shall be built one foot above the seasonal high water table elevation, as documented in the submitted soil evaluations, and shall avoid hydric soils as much as possible. The Designated City Representative shall be notified of any drain tiles that are uncovered during construction, which the Designated City Representative may require to be restored or connected to other drainage systems. No discharge of groundwater from tile lines, sump pumps or other means shall be allowed onto another person's land or any public space without the written approval of the owner or unit of government.

(6)

Open channels. All open channel drainage systems shall at a minimum be designed to carry the peak flows from a ten-year, twenty-four-hour design storm using planned land use for the entire contributing watershed area. Side slopes shall be no steeper than 3h:1v unless otherwise approved by the Designated City Representative for unique site conditions. Open channels that carry runoff from more than 130 acres shall, at a minimum, be designed to carry the peak flows from a twenty-five-year, twenty-four-hour design storm.

(7)

Storm sewers. All storm sewers shall be designed in accordance with applicable City technical standards and specifications.

(8)

Structure protection and safety. Flows generated by the one-hundred-year, twenty-four-hour design storm under planned land use conditions may exceed the design capacity of conveyance systems but shall not come in contact with any buildings. For buildings designed for human occupation on a regular basis, the following additional requirements shall apply:

(a)

The lowest elevation of the structure that is exposed to the ground surface shall be a minimum of two feet above the maximum water elevation produced by the one-hundred-year, twenty-four-hour design storm, including flows through any stormwater BMP that may temporarily or permanently store water at a depth of greater than one foot; and

(b)

The structure shall be set back at least 50 feet horizontally from any stormwater BMP that may temporarily or permanently store water at a depth of greater than one foot. Setback distance shall be measured from the closest edge of water at the elevation produced by the one-hundred-year, twenty-four-hour design storm.

Additional requirements. The Designated City Representative may establish more stringent requirements than the minimums set forth in this section, such as addressing thermal impacts of stormwater or chronic wetness conditions, if the Designated City Representative determines that an added level of protection is needed to protect:

(1)

Low-impact development for all new development or additional impervious areas. The first one inch of runoff from impervious areas shall be treated from drainage areas no larger than one acre. Treatment options include and may be limited to bioinfiltration, infiltration, rain gardens, stormwater reuse and buffers. Small practices shall be employed in large sites to the greatest extent possible.

(2)

An environmentally sensitive area.

(3)

A downstream property.

(4)

Public health or safety.

§ 367-27 Technical exemptions.

Exemption criteria. Following the provisions of this subsection, the Stormwater Committee may recommend to exempt a site or a portion of a site from meeting certain technical requirements of this article to the City Council for review and action, if the Designated City Representative determines that one or more of the following applies:

[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II)]

(1)

Off-site BMP(s). The requirement has been satisfied through the use of off-site BMP(s). Off-site BMPs may be installed beyond the boundaries of the property covered by the application. However, to be eligible for this exemption, the off-site BMP(s) must treat runoff from the site covered by the application and have approval to use the off-site BMP(s) or lands to construct BMP(s);

(2)

Internally drained sites. The site is internally drained and will not discharge runoff from the site after development occurs and has no potential impacts to groundwater; or

(3)

Site conditions. It is impracticable to meet the requirement due to site conditions such as slopes, soils, proximity to structures or desirable trees, limited site dimensions, surrounding land uses, the potential for groundwater contamination, public health or safety problems, or other factors beyond the control of the applicant. No site shall be entitled to an exemption under this subsection due solely to the size of the proposed land development activity in relation to the parcel size. Special consideration may be considered in granting exemptions under this subsection for the following sites:

(a)

Roadway projects where limited public right-of-way land is available for the installation of stormwater BMPs.

Application for exemption. An exemption under Subsection A above may only be granted by the City Council upon the applicant submitting the following items to the Designated City Representative and review by the Stormwater Committee, which shall constitute a completed application:

[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II)]

(1)

A written request describing the provisions of this subsection for which an exception is being requested and an explanation of why;

(2)

A site plan in accordance with § 367-25 above, including the delineation of the area and size (in acres) to which the exemption would apply and any other stormwater BMPs required to meet this chapter or as recommended in a regional stormwater management plan;

(3)

The necessary technical documentation to demonstrate that the site meets one or more of the criteria for which an exemption is being applied, including documentation of the applicable provisions of any regional stormwater management plan that may be involved;

(4)

For off-site BMP(s) under Subsection A(1) above:

(a)

Documentation that the necessary BMP(s) have been properly installed, including as-built plans, construction certification and design summaries in accordance with § 367-16.

(b)

A copy of the recorded maintenance agreement in accordance with Article VII, and any other easements or legal arrangement that may be involved to ensure the long-term maintenance of the off-site BMP(s).

(c)

Documentation of payment of any applicable fees that may be required by a unit of government charged with implementing a regional stormwater management plan.

Note: Fees may be through a stormwater utility district or other unit of government and would usually be based on an equitable distribution of costs for land acquisition, engineering design, construction, certification and maintenance of stormwater BMPs implemented through the regional stormwater management plan.

(5)

Other materials that the Designated City Representative determines to be necessary to make a determination under this subsection or to comply with this chapter.

Review procedure. The Designated City Representative shall review all exemption application materials submitted under Subsection B above, determine compliance and notify the applicant of a decision within 20 working days of the submittal date, in accordance with the procedures under § 367-12 above. The Stormwater Committee shall approve all exemptions under Subsection A(3) above. The Designated City Representative shall review the submittal and provide a written review of the exemption request. In consideration of all exemption requests, the Designated City Representative shall ensure that the applicant meets the requirements to the maximum extent practicable.

Exemption fee. For those sites that are exempted under this section, the applicant shall pay a fee to the Designated City Representative to be used exclusively for stormwater BMP implementation or stream restoration expenses within the same watershed. Same watershed is considered same subwatershed as designated in the City of Amery Stormwater Management Plan. Consideration may be given for same basin or adjacent subwatershed if overall intent of ordinance is maintained for water quality and water quantity purposes. The fee amount shall be based on the average costs for the typical BMP(s) that would have been required on site to comply with the requirements of this article if exemption was not granted. The Designated City Representative shall publish a fee schedule for this purpose, to be periodically updated to reflect current BMP costs.

Appeal. If the applicant does not agree with any determination of the Designated City Representative under this section, the applicant may appeal the decision pursuant to the procedures in § 367-46.

§ 367-28 Preliminary stormwater management plan requirements.

Preliminary stormwater management plans shall contain the following applicable items:

Drafting date and contact information for the project engineer with all other mapping elements and scale consistent with the site plan map.

Delineation of existing and proposed watersheds, subwatersheds and major flow paths within the site and draining into the site from adjacent properties.

Location, type and preliminary design of proposed stormwater BMPs needed to comply with this chapter.

Location and type of major stormwater conveyance systems proposed for the site.

Existing and proposed stormwater discharge points.

Location and preliminary dimensions of proposed drainage easements.

Location of soil borings and soil profile evaluations with surface elevations and unique references to supplemental data sheets, as needed to determine feasibility of any proposed stormwater BMP and to comply with applicable BMP technical standards.

Note: The required location, depth and type of soil evaluations will depend on the stormwater BMPs proposed for the site. In general, soil profile evaluations usually need to extend to a depth of three to 10 feet below the proposed bottom elevation of stormwater BMPs. Refer to BMP technical standards for details.

Preliminary location of access lanes for maintenance of stormwater BMPs. (Exemptions may be made by Designated City Representative. Access lanes for maintenance intended for larger BMPs.)

Support documentation, including:

(1)

A preliminary plan narrative describing site drainage, ultimate receiving water body for off-site discharges, major site restrictions, and how the preliminary stormwater management plan will meet the requirements of this chapter and other objectives identified by the project engineer.

(2)

Summary of watershed, subwatershed and land use data in acres and the preliminary results of any hydrology calculations.

(3)

Soil profile evaluation data in accordance with BMP technical standards.

(4)

Proposed ownership and maintenance responsibilities for all proposed stormwater BMPs.

Note: Mapping elements may be included in the site plan map.

§ 367-29 Final stormwater management plan requirements.

Final stormwater management plans shall contain the following applicable items:

Drafting date and contact information for the project engineer, with all other mapping elements and scale consistent with the site plan map;

Location of existing and proposed stormwater discharge points;

Delineation and labeling of all proposed impervious areas and accompanying area computations;

Final design drawings of all proposed stormwater BMPs with unique references to support documentation, prepared in accordance with minimum Designated City Representative standards and of sufficient clarity for those responsible for site grading, including:

(1)

Plan views showing the location of proposed BMPs in combination with the site plan map at a scale of one inch equals no more than 100 feet;

(2)

Additional detail plan view drawings at a scale of one inch equals no more than 40 linear feet, showing proposed two-foot contours and all critical design features and elevations;

(3)

Detailed cross-sections and profiles of each BMP showing all critical design features, side slopes, structures, soil profiles and applicable elevations, including seasonal high water table; and

(4)

Detailed drawings or material specifications for inlets or outlets.

Type, size, location and cross-sections of all pipes, open channels, grade stabilization structures and other proposed stormwater conveyance systems, with references to support documentation;

Location and dimensions of proposed drainage easements;

Location, dimensions and surfacing material or soils data of proposed access lanes and delineation of easements needed to allow future maintenance of all stormwater BMPs in accordance with § 367-38 below. The minimum width of any access easement shall be 15 feet; (Exemptions may be made by Designated City Representative for access lanes and easements or outlot designations. Access lanes and easements for maintenance intended for larger BMPs.)

Location of soil borings and soil profile evaluations with surface elevations and references, as needed to determine feasibility of any proposed stormwater BMP and to comply with technical standards;

Detailed construction notes explaining all procedures to implement the plan, including planting and landscaping specifications, timing and sequencing of construction and any temporary measures needed to protect BMPs during the construction phase;

Note: Some BMPs, such as infiltration and bioretention practices, are susceptible to sedimentation and may need to be protected during construction or planned for construction later in the project sequence.

A detailed construction inspection plan, outlining the critical elements in the plan that need to be surveyed or inspected by a representative of the project engineer, and the Designated City Representative, and the timing and notification requirements involved.

Note: Examples of critical elements for a construction inspection plan include, but are not limited to: checking subgrade elevations or the placement of footings, pipes or other structures prior to covering, soil testing, material inspections and final grade checks before seeding. Any inspection conducted by the Designated City Representative(s) or the City does not waive the permit holder's responsibility for construction oversight and verification.

A final stormwater BMP maintenance agreement in accordance with Article VII;

Support documentation summarized in accordance with Designated City Representative standards, including but not limited to:

(1)

A narrative summary of the stormwater management plan, briefly explaining any unique information that led to the selection of BMPs, how the proposed plan meets the guiding principles under § 367-24 above, and the specific stormwater planning requirements under § 367-26 above;

Note: The narrative can be combined with the narrative for erosion control planning under Article IV above. Some provisions may also be included in the construction notes under Subsection I above.

(2)

Maps of existing and proposed watersheds, subwatersheds, Tc/Tt flow paths, soil types, hydrologic soil groups, land uses/cover type and accompanying runoff curve numbers within the site and draining into the site from adjacent properties, with unique references to hydrology data summaries and a description of the ultimate receiving water body(ies) for off-site discharges;

(3)

Predevelopment and post-development hydrology and pollutant loading (if applicable) data for each watershed, such as peak flows and runoff volumes, as needed to meet the requirements of this chapter. All major assumptions used in developing input parameters shall be clearly stated and cross-referenced to the maps under Subsection L(2) above;

(4)

Impervious surface maps and calculations of runoff volumes and effective infiltration areas, in accordance with § 367-26C above;

(5)

Hydraulic and hydrologic data summaries for all existing and proposed pipes, open channels, grade stabilization structures and other stormwater conveyance systems, and the necessary documentation to demonstrate compliance with the site drainage requirements under § 367-26F above;

(6)

BMP design data for each proposed BMP, showing how it complies with applicable technical standards and the requirements of this chapter;

(7)

Soil evaluation reports, following the standards in § 367-34, with matching references to map features showing their location and elevations;

(8)

A cover sheet stamped and signed by a professional engineer registered in the State of Wisconsin indicating that all plans and supporting documentation have been reviewed and approved by the engineer and certifying that they have read the requirements of this chapter and that, to the best of their knowledge, the submitted plans comply with the requirements;

(9)

Cost estimates for the installation of proposed stormwater BMPs, which shall serve as a basis for the financial assurance under § 367-15 above. The applicant may use average costs for BMP installations in the City rather than specific estimates, upon approval by the Designated City Representative; and

(10)

For sites where changes are proposed in stormwater flow paths, or where proposed stormwater discharges may otherwise have a significant negative impact on downstream property owner(s), the Designated City Representative may require the applicant to submit written authorization or complete other legal arrangements with the affected property owner(s); and

Other items deemed necessary by the Designated City Representative to ensure compliance with the requirements of this chapter.