(A) Purpose. The purpose of this section is to require preparation and implementation of grading and erosion control plans for land-disturbing activity to:
(1) Prevent sediment deposits on roadways;
(2) Retain sediment on site;
(3) Prevent disruption or damage to water resources and public stormwater systems;
(4) Prevent adverse impacts to neighboring property;
(5) Reduce soil compaction and enhance infiltration and the establishment of vegetation;
(6) Prevent damage to natural resources, such as trees, that are intended to be preserved; and
(7) Maintain stable slopes.
(B) Where the provisions of state law or other city regulation or ordinance set higher standards than those of this chapter, the provisions of the laws, regulations or ordinances shall apply.
(C) General standards. The following management practices shall be applied to all development and earth moving activities:
(1) All development shall conform to the natural limitations presented by the topography and soil in order to create the best potential for preventing soil erosion.
(2) Best management practices for erosion control and sediment control shall be applied to each development/construction site.
(3) Slopes over 18% in grade shall not be developed.
(4) Development on slopes with a grade between 12% and 18% shall be carefully reviewed to ensure that adequate measures have been taken to prevent erosion, sedimentation and structural damage.
(5) Erosion and siltation control measures shall be coordinated with the different stages of development. Appropriate control measures shall be installed prior to development when necessary to control erosion.
(6) Land shall be developed in increments of workable size such that adequate erosion and siltation controls can be provided as construction progresses. The smallest practical area of lands shall be exposed at any one period of time and no exposure shall exceed 60 days unless extended by the Council.
(7) Where the topsoil is removed, sufficient arable soil shall be set aside for respreading over the developed area. The topsoil shall be restored to a depth of four inches and shall be of a quality at least equal to the soil quality prior to development.
(8) The natural drainage system shall be used, as far as feasible for storage and flow of runoff except that no stormwater drainage shall be discharged to marshlands, swamps or wetlands. Stormwater drainage shall be discharged to retention basins or other treatment facilities.
(9) Public and private properties adjacent to the development site shall be protected from the effects of sedimentation. Any violations of this provision must be corrected by the owner to the satisfaction of the city within five days of receiving notification of such. If the violation is not remedied within the time period specified, the city may correct the problem and assess the costs incurred to the property owner.
(D) Exposed slopes. The following control measures shall be taken to control erosion during construction.
(1) No exposed slopes should be steeper in grade than four feet horizontal to one foot vertical.
(2) At the foot of each exposed slope, a channel and berm should be constructed to control runoff. The channelized water should be diverted to a sedimentation basin (debris basin, silt basin or silt trap) before being allowed to enter the natural drainage system.
(3) Along the top of each exposed slope, a berm should be constructed to prevent runoff from flowing over the edge of the slope. Where runoff collecting behind the berm cannot be diverted elsewhere and must be directed down the slope, appropriate measures shall be taken to prevent erosion. The measures should consist of either an asphalt paved flow apron and drop chute laid down the slope or a flexible slope drain. At the base of the slope drain or flow apron a gravel energy dissipater should be installed to prevent erosion at the discharge end.
(4) Exposed slopes shall be protected by means which will effectively prevent erosion considering the degree of the slope, soils material and expected length of exposure.
(a) Slope protection shall consist of mulch, sheets of plastic, burlap or jute netting, sod blankets, fast growing grasses or temporary seedlings of annual grasses.
(b) Mulch consists of hay, straw, wood chips, corn stalks, bark or other protective material.
(c) Mulch should be anchored to slopes with liquid asphalt or stakes and netting or should be worked into soil to achieve additional slope stability.
(5) Control measures, other than those specifically stated above, may be used in place of the above measures if it can be demonstrated that they will as effectively protect exposed slopes.
(E) Grading permit:
(1) Except as provided below, a grading permit is required for the following activities:
(a) Excavating, grading, filling or other land-disturbing activity on a per project basis that exposes soil in an area or areas encompassing at least 5,000 square feet or results in the movement of at least 50 cubic yards of material;
(b) Excavating, grading, filling or any other land-disturbing activity that exposes soil in or on any steep slope, wetland or floodplain; or
(c) Excavating, grading, filling or any other land-disturbing activity that destabilizes the soil, involves the movement of contaminated soils, involves work in the right-of-way that is approved by the City Engineer, or creates the potential of erosion onto property not in common ownership with the location of the activity or creates the potential of erosion into a water resource.
(2) A separate grading permit is not required for land disturbing activity that is undertaken in compliance with a grading and erosion control plan approved in conjunction with a building permit if in conformance with this section.
(F) Grading and erosion control plan. A grading and erosion control plan is required to be submitted for city approval as part of an application for any grading permit, site plan review, and wetland/floodplain alteration permit and as part of an application for a building permit that involves any amount of land-disturbing activity.
(Ord. 879, passed 10-28-2020)