(A) Requirements. The standards contained in this chapter must be met to the degree required by the City Council.
(B) Site dewatering. Water pumped from the site shall be treated by temporary sedimentation basins, grit chambers, sand filters, upflow chambers, hydro-calcines, swirl concentrators, or other controls as appropriate. Water may not be discharged in a manner that causes erosion or flooding of the site or receiving channels, or a wetland.
(C) Waste and material disposal. All waste and unused building materials (including garbage, rubbish, debris, cleaning wastes, waste water, 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. Each site shall have graveled roads, 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.
(E) Drain inlet protection. All storm drain inlets shall 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 state’s Pollution Control Agency publication Protecting Water Quality in Urban Areas.
(F) Site erosion control. The requirements of this division (F) apply only to construction activities that result in runoff leaving the site.
(1) Channelized runoff from adjacent areas passing through the site shall be diverted around disturbed areas, if practical. Otherwise, the channel shall be protected as described below. Sheetflow runoff from adjacent areas greater than 10,000 square feet in area shall also be diverted around disturbed areas, unless shown to have resultant runoff velocity of less than one-half foot per second across the disturbed area for the one-year storm. Diverted runoff shall be conveyed in a manner that will not erode the conveyance and receiving channels.
(2) All activities on the site shall be conducted in a logical sequence to minimize the area of bare soil exposed at any one time.
(3) Runoff from the entire disturbed area on the site shall be controlled by meeting either divisions (F)(3)(a) and (F)(3)(b) below or divisions (F)(3)(a) and (F)(3)(c) below.
(a) All disturbed ground left inactive for 14 or more days shall be stabilized by seeding or sodding (only available prior to September 15) or by mulching, or covering, or other equivalent control measure.
(b) For sites with more than three acres disturbed at one time, or if a channel originates in the disturbed area, one or more temporary or permanent sedimentation basins shall be constructed. Each sedimentation basin shall have a surface area of at least 1% of the area draining to the basin and at least three feet of depth and constructed in accordance with accepted design specifications. Sediment shall be removed to maintain a depth of three feet. The basin discharge rate shall also be sufficiently low as to not cause erosion along the discharge channel or the receiving water.
(c) For sites with less than ten acres disturbed at one time, silt fences, straw bales, or equivalent control measure shall be placed along all side slope and downslope sides of the site. If a channel or area of concentrated runoff passes through the site, silt fences shall be placed along the channel edges to reduce sediment reaching the channel. The use of silt fences, straw bales, or equivalent control measure must include a maintenance and inspection schedule.
(4) If remaining for more than seven days, they shall be stabilized by mulching, vegetative cover, tarps, or other means. Erosion from piles which will be in existence for less than seven days shall be controlled by placing straw bales or silt fence barriers around the 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 seven days, and the storm drain inlets must be protected with straw bale or other appropriate filtering barriers.
(G) Storm water management criteria for permanent facilities. Storm water management criteria for permanent facilities shall be in conformance with the city’s current Comprehensive Water Resource Management Plan.
(H) Design standards. Storm water detention facilities constructed in the city shall be designed in conformance with the city’s current Comprehensive Water Resource Management Plan.
(I) Wetlands. Wetlands shall be maintained and protected in conformance with the city’s current Comprehensive Storm Water Management Plan,
(J) Steep slopes. No land disturbing or development activities shall be allowed on slopes of 18% or more.
(K) Catch basins. When deemed necessary by the Public Works Director or designee, all newly installed and rehabilitated catch basins shall be provided with a sump area for the collection of coarse-grained material. The basins shall be cleaned when they are half filled with material.
(L) Drain leaders. When deemed necessary by the Public Works Director or designee, all newly constructed and reconstructed buildings will route drain leaders to pervious areas wherein the runoff can be allowed to infiltrate. The flow rate of water exiting the leaders shall be controlled so no erosion occurs in the previous areas.
(M) Inspection and maintenance. All storm water management facilities shall be designed to minimize the need of maintenance, to provide access for maintenance purposes and to be structurally sound. All storm water management facilities be inspected and maintained in accordance with the city’s Comprehensive Storm Water Management Plan. It shall be the responsibility of the applicant to obtain any necessary easements or other property interests allow access to the storm water management facilities for inspection maintenance purposes.
(N) Models/methodologies/computations. Hydrologic models and design methodologies used for the determination of runoff and analysis of storm water management structures shall be approved by the Public Works Director or designee. Plans, specifications, and computations for storm water management facilities submitted for review shall be sealed and signed by a registered professional engineer. All computations shall appear on the plans submitted for review, unless otherwise approved by the Public Works Director or designee.
(O) Watershed management plans/ground water management plans. Plans shall be consistent with adopted watershed management plans and ground water management plans prepared in accordance with M.S. §§ 103B.231 and 103B.255, as they may be amended from time to time, respectively, and as approved by the State Board of Water and Soil Resources in accordance with the state law.
(P) Easements. If a plan involves direction of some or all runoff off of the site, it shall be the responsibility of the applicant to obtain from adjacent property owners any necessary easements or other property interests concerning flowage of water.
(Q) Lawn maintenance education. The city shall participate in on-going educational opportunities to inform the residents of the harmful impacts.
(Prior Code, § 153.08)