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Any applicant for a stormwater management permit as defined in § 161.02 must meet all of the following performance goals:
(A) New development volume control. For new, nonlinear developments on sites without restrictions, stormwater runoff volumes will be controlled and the post-construction runoff volume shall be retained on site for 1.1 inches of runoff from all impervious surfaces on the site.
(B) Redevelopment volume control. Nonlinear redevelopment projects on sites without restrictions that create or fully reconstruct impervious surfaces shall capture and retain on site 1.1 inches of runoff from the new and/or fully reconstructed impervious surfaces.
(C) Linear development volume control. Linear projects on sites without restrictions that create new and/or fully reconstructed impervious surfaces, shall capture and retain the larger of the following:
(1) 0.55 inches of runoff from the new and fully reconstructed impervious surfaces on the site; or
(2) 1.1 inches of runoff from the net increase in impervious area on the site. Mill and overlay and other resurfacing activities are not considered fully reconstructed.
(D) Flexible treatment alternatives for sites with restrictions. Applicant shall attempt to comply fully with the appropriate performance standards described above. Alternatives considered and presented shall examine the merits of relocating project elements to address varying soil conditions and other constraints across the site. If full compliance is not possible due to any of the factors listed below, the applicant must document the reason. If site constraints or restrictions limit the full treatment goal, the following flexible treatment alternatives shall be used:
(1) Applicant shall document the flexible treatment alternatives sequence starting with Alternative #1. If Alternative #1 cannot be met, then Alternative #2 shall be analyzed. Applicants must document the specific reasons why Alternative #1 cannot be met based on the factors listed below. If Alternative #2 cannot be met then Alternative #3 shall be met. Applicants must document the specific reasons why Alternative #2 cannot be met based on the factors listed below. When all of the conditions are fulfilled within an alternative, this sequence is completed.
(2) Volume reduction techniques considered shall include infiltration, reuse and rainwater harvesting, and canopy interception and evapotranspiration and/or additional techniques included in the MIDS calculator and the Minnesota Stormwater Manual.
(3) Higher priority shall be given to BMPs that include volume reduction. Secondary preference is to employ filtration techniques, followed by rate control BMPs. Factors to be considered for each alternative will include:
(a) Karst geology;
(b) Shallow bedrock;
(c) High groundwater;
(d) Hotspots or contaminated soils;
(e) Drinking water source management areas or within 200 feet of drinking water well;
(f) Zoning, setbacks or other land use requirements; and
(g) Poor soils (infiltration rates that are too low or too high, problematic urban soils).
(4) Alternative #1. Applicant attempts to comply with the following conditions:
(a) Achieve at least 0.55-inch volume reduction from all impervious surfaces if the site is new development or from the new and/or fully reconstructed impervious surfaces for a redevelopment or linear development site;
(b) Remove 75% of the annual TP load from all impervious surfaces if the site is new development or from the new and/or fully reconstructed impervious surfaces for a redevelopment site; and
(c) Options considered and presented shall examine the merits of relocating project elements to address varying soil conditions and other constraints across the site.
(5) Alternative #2. Applicant attempts to comply with the following conditions:
(a) Achieve volume reduction to the maximum extent practicable;
(b) Remove 60% of the annual TP load from all impervious surfaces if the site is new development or from the new and/or fully reconstructed impervious surfaces for a redevelopment site; and
(c) Options considered and presented shall examine the merits of relocating project elements to address varying soil conditions and other constraints across the site.
(6) Alternative #3. Off-site treatment. Mitigation equivalent to the performance of 1.1 inches of volume reduction for new development, linear development or redevelopment as described above in this section, (including banking or cash) can be performed off-site to protect the receiving water body. Off-site treatment shall be achieved in areas selected in the following order of preference:
(a) Locations that yield benefits to the same receiving water that receives runoff from the original construction activity;
(b) Locations within the same Department of Natural Resource (DNR) catchment area (Hydrologic Unit 08) as the original construction activity;
(c) Locations within the next adjacent DNR catchment area upstream; and
(d) Locations anywhere within the city's jurisdiction. The MIDS design sequence flowchart can be found in the Minnesota Stormwater Manual: (http://stormwater.pca.state.mn.us/index.php/Flexible_treatment_options.)
(Ord. 7553, passed 3-15-2016)
For new development, redevelopment and linear development sites the site design shall provide on-site treatment during construction and post-construction to ensure no increase from existing conditions in offsite peak discharge for the 1-year, 2-year, 10-year, and 100-year, 24-hour storm events based on the standards defined by the MSCWMO or VBWD. For single family residential building lots not part of a common plan of development site, rate control requirements do not apply.
(Ord. 7553, passed 3-15-2016)
(A) Minnesota Stormwater Manual. All volume control for water quality and quantity and site design specifications shall conform to the current version of the Minnesota Stormwater Manual.
(B) NPDES/SDS construction stormwater general permit. All volume control and water quality and quantity best management practice design specifications shall conform to the current version of the NPDES/SDS construction stormwater general permit.
(C) Site erosion and sediment control requirements. All erosion and sediment control requirements shall conform to the current requirements of NPDES/SDS construction stormwater general permit.
(D) Watershed district/WMO requirements. All stormwater management and erosion and sediment control activities shall comply with all applicable requirements of the watershed districts or watershed management organizations in which the project is located. In case provisions in this chapter and requirements of the watershed district or watershed management organizations overlap or conflict, the strictest provisions shall apply to the activities.
(E) Where applicable, a minimum of 20-feet shall be provided on all sides of all publicly owned stormwater facilities for facility maintenance.
(Ord. 7553, passed 3-15-2016)
(A) Inspections and record keeping.
(1) Applicant responsibilities. The applicant is responsible for inspections and record keeping during and after construction for all privately-owned stormwater treatment practices on the site.
(2) City inspections. The city reserves the right to conduct inspections on a regular basis to ensure that both temporary and permanent stormwater management and erosion and sediment control measures are properly installed and maintained prior to construction, during construction, and at the completion of the project.
(B) Right of entry and inspection; powers. The issuance of a permit constitutes a right-of-entry for the city or its authorized representative to enter upon the construction site. The applicant shall allow the city and its authorized representatives, upon presentation of credentials, to:
(1) Enter upon the permitted site for the purpose of obtaining information, examining records, and conducting investigations or surveys;
(2) Bring such equipment upon the permitted development as is necessary to conduct such surveys and investigations;
(3) Examine and copy any books, papers, records, or memoranda pertaining to activities or records required to be kept under the terms and conditions of the permit;
(4) Inspect the stormwater pollution control measures;
(5) Sample and monitor any items or activities pertaining to stormwater pollution control measures; and
(6) Correct deficiencies in stormwater and erosion and sediment control measures.
(C) Fees. Fees will be applied per city fee schedule.
(D) Enforcement tools/stop work orders. The city reserves the right to issue construction stop work orders when cooperation with inspections is withheld or when a violation has been identified that needs immediate attention to protect human health and/or the environment.
(1) Construction stop work order. The city may issue construction stop work orders until stormwater management measures meet specifications and the applicant repairs any damage caused by stormwater runoff. An inspection by the city must follow before the construction project work can resume.
(2) Other actions to ensure compliance. The city can take any combination of the following actions in the event of a failure by an applicant to meet the terms of this chapter:
(a) Withhold inspections or issuance of certificates or approvals;
(b) Revoke any permit issued by the city to the applicant;
(c) Conduct remedial or corrective action on the development site or adjacent site affected by the failure;
(d) Charge applicant for all costs associated with correcting the failure or remediating damage from the failure; if payment is not made within 30 days, payment will be made from the applicant's financial securities;
(e) Bring other actions against the applicant to recover costs of remediation or meeting the terms of this chapter; and
(f) Any person, firm or corporation failing to comply with or violating any of these regulations, shall be deemed guilty of a misdemeanor and be subject to a fine or imprisonment or both. Each day that a separate violation exists shall constitute a separate offense.
(E) Long term inspection and maintenance of stormwater facilities.
(1) Private stormwater facilities.
(a) Maintenance plan required. No private stormwater facilities may be approved unless a maintenance agreement is provided that defines who will conduct the maintenance, the type of maintenance necessary to ensure effective performance, and the maintenance intervals. All private stormwater facilities shall be inspected by the property owner and maintained in proper condition by the owner consistent with the performance goals for which they were originally designed.
(b) Facility access. The applicant shall obtain all necessary easements or other property interests to allow access to the facilities for inspection or maintenance for both the responsible party and the city or authorized representative.
(c) Removal of settled materials. All settled materials including settled solids, shall be removed from ponds, sumps, grit chambers, and other devices as necessary and disposed of properly.
(d) Inspections. All stormwater facilities within the city shall be inspected by the property owner at a frequency consistent with the maintenance plan. Inspection reports shall be provided to the city upon request.
(2) Public stormwater facilities.
(a) Acceptance of publicly owned facilities. Before work under the permit is deemed complete; the permittee must submit as-builts and a maintenance plan demonstrating at the time of final stabilization that the stormwater facilities conform to design specifications. A final inspection shall be required before the city accepts ownership of the stormwater facilities.
(b) Maintenance. The city shall perform maintenance of publicly owned stormwater facilities in accordance with their comprehensive stormwater management plan and other regulatory requirements.
(Ord. 7553, passed 3-15-2016)
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