Effective stormwater pollution prevention on construction sites is dependent on a combination of preventing movement of soil from its original position (erosion control), intercepting displaced soil prior to entering a waterbody (sediment control) and proper on-site materials handling. The developer must submit to the city a SWPPP with detailed erosion and sediment control plans as well as a narrative describing materials handling and storage and construction sequencing. The following principles apply to all land-disturbing activities and should be considered in the preparation of a stormwater pollution prevention plan within the city area.
(A) Minimize the potential for soil erosion by designing a development that fits the topography and soils of the site. Deep cuts and fills in areas with steep slopes should be avoided wherever possible, and natural contours should be followed as closely as possible.
(B) Existing natural vegetation should be retained and protected wherever possible. Areas immediately adjacent (within 35 feet of top of bank) to watercourses and lakes also should be left undisturbed wherever possible. Unvegetated or vegetated areas with less than 70% cover that are scheduled or likely to be left inactive for 15 days or more must be temporarily or permanently stabilized with measures appropriate for the season to reduce erosion potential. Alternative measures to site stabilization may be acceptable if the project site owner or his or her representative can demonstrate he or she has implemented and maintained erosion and sediment control measures adequate to prevent sediment discharge from the inactive area.
(C) All activities on a site should be conducted in a logical sequence so that the smallest practical area of land will be exposed for the shortest practical period of time during development.
(D) The length and steepness of designed slopes should be minimized to reduce erosion potential. Drainage channels and swales must be designed and adequately protected so that their final gradients and resultant velocities will not cause erosion in the receiving channel or at the outlet. Methods for determining acceptable velocities are included (publication w/standards and forms).
(E) Sediment-laden water which otherwise would flow from the project site shall be treated by erosion and sediment control measures appropriate to minimize sedimentation. A stable construction site access shall be provided at all points of construction traffic ingress and egress to the project site.
(F) Appropriate measures shall be implemented to prevent wastes or unused building materials, including, garbage, debris, packaging material, fuels and petroleum products, hazardous materials or wastes, cleaning wastes, wastewater, concrete truck washout and other substances from being carried from a project site by run-off or wind. Identification of areas where concrete truck washout is permissible must be clearly posted at appropriate areas of the site. Wastes and unused building materials shall be managed and disposed of in accordance with all applicable state statutes and regulations. Proper storage and handling of materials such as fuels or hazardous wastes, and spill prevention and cleanup measures shall be implemented to minimize the potential for pollutants to contaminate surface or groundwater or degrade soil quality.
(G) Public or private roadways shall be kept cleared of accumulated sediment that is a result of run- off or tracking. Bulk clearing of accumulated sediment shall not include flushing the area with water. Cleared sediment shall be redistributed or disposed of in a manner that is in accordance with all applicable statutes and regulations.
(H) Collected run-off leaving a project site must be either discharged directly into a well-defined, stable receiving channel, or diffused and released to adjacent property with out causing an erosion or pollutant problem to the adjacent property owner.
(I) Natural features, including wetlands, shall be protected from pollutants associated with stormwater run-off.
(Ord. 06-15, passed 11-13-2006; Ord. 2015-01, passed 1-26-2015)