§ 205.09 EROSION AND DRAINAGE.
   (A)   Permit applicants. No person or political subdivision shall commence a land disturbing activity or create new impervious surface without first obtaining a permit from the city that incorporates and approves a storm water pollution prevention plan (SWPPP) for the activity, development or redevelopment. For sites disturbing less than one acre, an erosion and sediment control plan may be submitted as part of the building permit application.
   (B)   Development not permitted. No land shall be developed and no use shall be permitted that will result in water runoff causing flooding, erosion, or deposit of sediment on adjacent properties. Such runoff shall be properly channeled into a storm drain, watercourse, ponding area, or other public facilities subject to the review and approval of the City Engineer.
   (C)   Standards. Erosion and sediment controls shall meet the standards for the general permit authorization to discharge stormwater associated with construction activity under the national pollutant discharge elimination system/state disposal system permit program permit MN R100001 (NPDES general construction permit) issued by the Minnesota Pollution Control Agency, as amended. Final stabilization of the site must be completed in accordance with NPDES general construction permit requirements.
   (D)   Engineer approval. In the case of all single-family lots, multiple-family lots, business, industrial, and institutional developments, the drainage and erosion control plans shall satisfy the provisions of the subdivision ordinance in regard to storm water management and be subject to the City Engineer’s written approval. No modification in grade and drainage flow through fill, cuts, erection of retaining walls, or other such actions shall be permitted until such plans have been reviewed and received written approval from the City Engineer.
   (E)   Approval of erosion control measures. Proposed erosion control measures may be approved by the City Engineer as part of grading plan review. Erosion control may be specified by the City Engineer as part of a site survey for individual building permits. Erosion and sediment control measures shall be consistent with best management practices (BMP’s) for erosion and sedimentation control as specified in the “Minnesota Stormwater Manual” (MPCA, 2005), as amended, and shall be sufficient to retain sediment on-site. Erosion control measures may also be specified by the City Engineer as needed and deemed appropriate during the construction and post-construction periods separate from the above.
   (F)   Sediment control practices. All temporary erosion and sediment controls shall be installed on all down gradient perimeters before commencing the land disturbing activity, and left in place and maintained as needed until removed per city approval after the site had been stabilized. Property and streets adjacent to the site of a land disturbance shall be protected from sediment deposition. All permanent erosion control measures shall be installed, maintained, repaired if needed and operational per the design and as required by the city to assure the continued performance of their intended function.
   (G)   Storm sewer inlets. All storm sewer inlets which are functioning during construction shall be protected so that sediment laden water does not enter the conveyance system without first being filtered or otherwise treated to remove sediment.
   (H)   Stormwater channels. All on-site stormwater conveyance channels shall be designed and constructed to withstand the expected velocity of flow from a 10-year frequency storm without erosion. Erosion controls must be provided at the outlets of all storm sewer pipes.
   (I)   Site dewatering. Water pumped from the site shall be treated by temporary sedimentation basins, grit chambers, sand filters, upflow chambers, hydrocyclones, 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. All dewatering shall be in accordance with all applicable county, state, and federal rules and regulations. Minnesota Department of Natural Resources regulations regarding appropriate permits shall also be strictly adhered to.
   (J)   Sites more than 1 acre not graded. If the activity creates more than 1 acre of disturbed area, and the activity is taking place on a site where soils are currently disturbed (e.g., a tilled agricultural site that is being developed), areas that will not be graded as part of the development and areas that will not be stabilized according to the time frames specified in the NPDES general construction permit part IV.B.S, shall be seeded with a temporary or permanent cover before commencing the proposed land disturbing activity.
   (K)   Seeding. All disturbed ground left inactive for 7 or more days shall be stabilized by seeding or sodding or by mulching or covering or other equivalent control measure.
   (L)   Removal. All temporary erosion and sediment control devices including silt fence, gravel, hay bales, or other measures shall be removed from the construction site and properly disposed of or recycled. This removal and disposal must occur within 30 days of the establishment of permanent vegetative cover or final site stabilization is achieved on the disturbed area.
   (M)   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.
   (N)   Tracking. Each site shall have rock construction entrance, access drives, and parking areas 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 or more often if necessary to maintain the road in safe driving condition.
   (O)   Foundation, garage floor. Unless approved by the City Engineer, the top of the foundation and garage floor of all structures shall be at least 18 inches above the grade of the crown of the street.
   (P)   Stop work order. The Zoning Administrator, City’s Building Official, or City Engineer may issue stop work orders for any violation of this title.
(Ord. 2011-06-07A, passed 6-7-2011)