(A) Compliance. No stormwater management plan that fails to meet the standards in this section shall be approved. At a minimum these pollution abatement control practices must conform to those in the current version of the State Pollution Control Agency’s publication, Protecting Water Quality in Urban Areas.
(B) Site dewatering. Water pumped from the site including temporary sedimentation basins, grit chambers, sand filters, up-flow chambers, hydro cyclones, swirl concentrators or other appropriate controls as appropriate. Water may not be discharged in a manner that causes erosion or flooding of the site or receiving channels of a wetland.
(C) Waste and material disposal. All waste and unused building materials, including garbage, debris, cleaning wastes, wastewater, toxic materials or hazardous materials, shall be properly disposed of off-site and not allowed to be carried by runoff into a receiving channel or storm sewer system.
(D) Tracking. Graveled roads, access drives, and parking areas must be of sufficient width and length to prevent sediment from being tracked onto public or private roadways. Any sediment reaching a public or private road shall be removed by street cleaning, not flushing, before the end of each workday.
(E) Drain inlet protection. All storm drain inlets must be protected during construction until control measures are in place with a straw bale, silt fence, or equivalent barrier meeting accepted design criteria, standards and specifications contained in the MPCA publication, Protecting Water Quality in Urban Areas.
(F) Soil erosion control. The following criteria apply only to construction activities that result in runoff leaving the site.
(1) Channelized runoff from adjacent areas passing through the site must be diverted around disturbed areas, if practical. Otherwise, the channel must be protected as follows: sheet-flow runoff from adjacent areas greater than 10,000 square feet in area shall be diverted around disturbed areas unless shown to have resultant runoff of less than 1/2-foot per 3 seconds across the disturbed area for a 1-year storm event. Diverted runoff must be conveyed in a manner that will not erode the conveyance and receiving channels.
(2) All activities on the site must be conducted in a logical sequence to minimize the area of bare soil at any one time.
(3) Runoff from the entire disturbed area on the site must be controlled by meeting either divisions 1 and 2 or divisions 1 and 3.
(a) All disturbed ground left inactive for 14 or more days must be stabilized by seeding or sodding or by mulching or covering or other equivalent control measures.
(b) For sites with more than ten acres disturbed at one time, or if a channel originates in the disturbed area, 1 or more temporary or permanent sedimentation basins must be constructed. Each sedimentation basin must have a surface area of at least 1% of the area draining to the basin and at least 3 feet of depth and constructed in accordance with accepted design specifications. Sediment must be removed to maintain a depth of three feet. The basin discharge rate must also be sufficiently low as to not cause erosion along the discharge channel or the receiving water.
(c) For sites with less than 10 acres disturbed at one time, silt fences, straw bales or equivalent control measures must be placed along all side-slope and down-slope sides of the site. If a channel or area of concentrated runoff passes through the site, silt fences must be placed along the channel edges to reduce sediment reaching the channel. The use of silt fences, straw bales or equivalent control measures must include a maintenance and inspection schedule.
(d) Any soil or dirt storage piles containing more than 10 cubic yards of material should not be located with a down-slope drainage length of less than 25 feet from the toe of the storage pile to a roadway or drainage channel. If remaining for more than 7 days, it must be stabilized by mulching, vegetative cover, tarps or other means. Soil deposit piles that will be in existence for less than 7 days must be controlled by placing straw bales or silt barriers around the storage pile. In-street utility repair or construction soil or dirt storage piles located closer than 25 feet of a roadway or drainage channel must be covered with tarps or suitable alternative control, if exposed for more than 7 days the storm drain inlets must be protected with straw bales or other appropriate filtering barriers.
(Ord. 2011-06-07A, passed 6-7-2011)