§ 52.04. Stormwater pollution control plan.  


Latest version.
  • Any person, firm, sole proprietorship, partnership, corporation, state agency, or political subdivision proposing a construction activity of one (1) acre or more within the city shall submit a stormwater pollution control plan to the city for approval. No land shall be disturbed until the plan, conforming to the standards set forth herein, is approved by the city. At a minimum these pollution abatement control practices must conform to those in the current version of the MPCA's publication, "Protecting Water Quality in Urban Areas" or other sources as defined in section 52.03(2).

    (a)

    Minimum requirements of the stormwater pollution control plan:

    (1)

    The name, address and telephone number of the following individuals:

    a.

    Owner,

    b.

    Applicant,

    c.

    Person responsible for the preparation of the stormwater pollution control plan,

    d.

    On-site person responsible for implementation, inspection and maintenance of the requirements of the stormwater pollution control plan,

    e.

    Person responsible for the long term operation and maintenance of the permanent stormwater management system.

    (2)

    A project description that includes the nature and purpose of the construction activity, the amount of grading, utilities, and building construction involved and the location of the project.

    (3)

    Construction phasing that includes time frames and schedules for the project's various aspects including erosion and sediment control practices.

    (4)

    A map of the existing site conditions that includes existing topography, property information, steep slopes, existing drainage systems/patterns, type of soils, waterways, wetlands, vegetative cover and one hundred-year flood plain boundaries.

    (5)

    A site construction plan that includes the location of the proposed construction activity and the plan for the maintenance and inspection of the stormwater pollution control measures, including the plan for disposal of collected sediment and floating debris.

    (6)

    Location of temporary and permanent stormwater pollution control measures.

    (7)

    Standard plates and/or specifications for all stormwater pollution control measures.

    (8)

    Location of streams, lakes or wetlands which may be impacted by the construction activity.

    (9)

    Provisions for preventing sediment damage to adjacent properties and other designated areas such as streams, wetlands and lakes.

    (10)

    A plan to stabilize utility construction areas as soon as possible.

    (11)

    A plan for permanent stabilization including how the site will be stabilized after construction is completed, including specifications and schedules.

    (12)

    A plan for removal of temporary erosion and sediment control measures at the end of the project.

    (13)

    Calculations that were made for the design of such items as rate control, sediment basins, wet detention basins, diversions, waterways, infiltration zones and other applicable practices.

    (b)

    Minimum stormwater pollution control measures. These minimum control measures are required where bare soil is exposed. Where additional control measures are needed, they will be specified at the discretion of the city.

    (1)

    All stormwater pollution control plans must be reviewed by the city for the effectiveness of erosion control measures in the context of site topography and drainage.

    (2)

    Sediment control measures must be properly installed by the builder before the construction activity begins. Such structures may be adjusted during dry weather to accommodate short term activities, such as those that require the passage of very large vehicles. As soon as this activity is finished or before rainfall, the erosion and sediment control structures must be returned to the original configuration.

    (3)

    Divert channeled runoff around disturbed areas and protect the channel.

    (4)

    If a stormwater management plan involves directing some or all of the site's runoff to adjacent property, the applicant or his designated representative shall obtain from adjacent property owners any necessary easements or other property interests concerning the flowing of such water.

    (5)

    Scheduling the site's activities to lessen their impact on erosion and sediment creation, so as to minimize the amount of exposed soil.

    (6)

    Control stormwater runoff as follows:

    a.

    All exposed soil areas with a continuous positive slope within two hundred (200) lineal feet of a surface water, must have temporary erosion protection or permanent cover for the exposed soil areas, according to the following table of slopes and time frames:

    Type of Slope Time*
    Steeper than 3:1 7 days
    10:1 to 3:1 14 days
    Flatter than 10:1 21 days

     

    *

    Maximum time an area can remain open when the area is not actively being worked.

    These areas include pond side slopes, and any exposed soil areas with a positive slope to a stormwater conveyance system, such as a curb and gutter system, storm sewer inlet, temporary or permanent drainage ditch or other natural or man made systems that discharge to a surface water.

    b.

    Install erosion and sediment controls at locations specified in the stormwater management plan. Minimum requirements include silt fences, rock check dams, or other equivalent control measures along slopes. Silt fences are required along channel edges to reduce sediment reaching channel. Silt fences, rock check dams, etc. must be regularly inspected and maintained.

    c.

    The work shall conform to the current version of the MPCA's publication, "Protecting Water Quality in Urban Areas," and the current requirements found in the same agency's NPDES/SDS permits for stormwater associated with construction activities.

    (7)

    Silt fence shall be required to hold all sheet flow runoff generated at an individual site, until it can either infiltrate or seep through silt fence's pores.

    (8)

    Temporary soil stockpiles must have silt fence or other effective sediment controls, and cannot be placed in surface waters, including stormwater conveyances such as curb and gutter systems, or conduits and ditches.

    (9)

    Temporary rock construction entrances are required wherever vehicles enter and exit a site.

    (10)

    Streets must be cleaned and swept whenever tracking of sediments occurs and before sites are left idle for weekends and holidays. A regular sweeping schedule shall be established.

    (11)

    Water (impacted by the construction activity) removed from the site by pumping must be treated by temporary sedimentation basins, geotextile filters, grit chambers, sand filters, up-flow chambers, hydro-cyclones, swirl concentrators or other appropriate controls. Such water shall not be discharged in a manner that causes erosion or flooding of the site, receiving channels, adjacent property or a wetland.

    (12)

    All storm drain inlets must be protected during construction until control measures are in place with either silt fence or an equivalent.

    (c)

    Stormwater Runoff Rate Control Stormwater runoff rate control is required for sites larger than one-quarter (¼) of an acre which go through the city's site plan review process. Stormwater discharge into public storm sewers shall be controlled, in accordance with the department of public works policy. Required information to be submitted as part of the stormwater pollution control plan is available in a handout from the department of public works. Peak stormwater discharge rates from the site for all storms up to and including the critical 100-year frequency will not exceed:

    Q = 1.64 × A

    where Q = the maximum acceptable discharge rate in cubic feet per second and A = the site area in acres.

    Discharge of all stormwater runoff and surface water shall be in a fashion so as to preclude drainage onto adjacent property or toward buildings.

    (d)

    Flood control for buildings The low floor elevation for new construction must be a minimum of one (1) foot above the critical one hundred-year flood elevation and at least four (4) feet above normal groundwater elevation.

    (e)

    Temporary Sediment Basins For common drainage locations that serve an area with ten (10) or more acres disturbed at one (1) time, a temporary (or permanent) sediment basin must be provided prior to the runoff leaving the construction site or entering surface waters. In addition to this requirement, the applicant is encouraged to install temporary sediment basins where appropriate in areas with steep slopes or highly erodible soils even if less than ten (10) acres drains to one (1) area. The basins must be designed and constructed in accordance with the current version of the MPCA's general permit to discharge stormwater associated with construction activity under the NPDES.

    (f)

    Permanent stormwater pollution controls.

    (1)

    Where a project's ultimate development replaces vegetation and/or other pervious surfaces with one (1) or more acres of cumulative impervious surface, a water quality volume of one-half (½) inch of runoff from the new impervious surfaces created by the project must be treated in one (1) of the following ways prior to the runoff leaving the site or entering surface waters (excluding drainage systems that convey stormwater to a constructed permanent stormwater management facility designed to treat the water quality volume from the project): wet sedimentation basin, infiltration/filtration, regional ponds, a combination of practices, or alternate methods in accordance with the current version of the MPCA's general permit to discharge stormwater associated with construction activity under the NPDES.

    (2)

    At a minimum these facilities must conform to the most current technology as reflected in the current version of the MPCA's publication "Protecting Water Quality in Urban Areas" or other sources as defined in section 52.03 and the current requirements found in the same agency's NPDES permits for stormwater associated with construction activities.

    (3)

    Permanent stormwater pollution controls to be designed by a professional engineer licensed in the state. Constructed controls must be certified by a professional engineer as required in section 52.04(g)(3).

    (g)

    Models/methodologies/computations. Hydrologic models and design methodologies used for the determining runoff characteristics and analyzing stormwater management structures must be approved by the city. Plans, specifications and computations for stormwater management facilities submitted for review must be sealed and signed by a licensed professional engineer. All computations must appear in the plans submitted for review, unless otherwise approved by the city.

    (h)

    Inspection and maintenance of the stormwater pollution control plan's measures.

    (1)

    The applicant must routinely inspect the construction site once every seven (7) days during active construction and within twenty-four (24) hours after a storm event greater than one-quarter (0.25) inches in twenty-four (24) hours.

    (2)

    The city's inspection staff is authorized to perform inspection and enforce provisions of this article as may be required, to ensure that erosion and sediment control measures are properly installed and maintained. If the applicant fails to maintain proper erosion control measures on site and/or perform necessary remedial action, as directed by the inspector, the inspector may take such enforcement action as may be required to achieve compliance. Enforcement may be, but is not limited to, stopping all construction work at the site, until necessary remedial actions have been completed and erosion and sediment controls are in compliance with the approved plans.

    (3)

    For sites that require permanent stormwater pollution controls, a certification letter shall be submitted after the facilities have been installed to affirm that construction has been completed in accordance with the approved stormwater pollution control plan. At a minimum, certification shall include a set of as-built drawings comparing the approved stormwater management plan with what was constructed. Other information shall be submitted as required by the approving agency.

    (4)

    It shall be the responsibility of the applicant to obtain any necessary easements or other property interests to allow access to the stormwater management facilities for inspection and maintenance purposes.

    (5)

    All stormwater pollution control management facilities must be designed to minimize the need of maintenance, to provide easy vehicle and personnel access for maintenance purposes and be structurally sound. These facilities must have a plan of operation and maintenance that ensures continued effective removal of the pollutants carried in stormwater runoff.

(C.F. No. 04-267, § 1, 4-7-04)