(a) Construction Site Runoff Control. The Owner/Developer shall use adequate measures to minimize erosion and other negative water quality impacts as a result of construction and development activity. The Planning Commission shall have the authority to require a Storm Water Pollution Prevention Plan in those cases where the scope and scale of the development warrants, as recommended by the City Engineer. The plan shall be prepared by a Professional Engineer or other certified professional and shall be developed utilizing current industry standards and effective Best Management Practices (BMPs). As part of the plan, the Owner/Developer shall install, inspect and keep records of inspection, and maintain BMPs throughout the duration of the permit. The City may inspect the construction site for compliance with the Storm Water Pollution Prevention Plan and, if found lacking, may issue a permit violation, stop work order, fine or other measure to ensure compliance.
(b) Post Construction Runoff Control. Post construction runoff control shall be addressed in the design phase of proposed subdivisions. Both structural and nonstructural post construction BMPs will be considered. Use of riparian setbacks, green space preservation, porous pavements, water quality swales and grass filter strips are a few methods to be considered. Specific sites within the proposed subdivision may be inspected for compliance and, if found lacking, an inspector may issue a permit violation, stop work order, or fine to ensure compliance. Fines as defined by separate ordinance may be levied by the City as soon as one (1) week after notification of violation.
(c) Storm Water Drainage.
(1) General. No subdivision plan or plat shall be approved that does not make adequate provision for storm water runoff and flood waters. The Planning Commission shall have the authority to deny subdivision approval for areas of extremely poor drainage, including subdivisions in areas dominated by hydric soils. In any subdivision, the storm drainage system shall be separate and independent of any sanitary sewer system.
(2) Preservation of Natural Drainage Courses. The flow of all existing drainage courses, including underground drainage systems, shall not be impeded. Such underground systems, including farm field tile systems, shall be identified and mapped as part of the preliminary plan.
No natural drainage course shall be altered and no fill, buildings or structures shall be located unless provision is made for the flow of storm runoff and/or surface water. An easement shall be provided on both sides of the existing surface drainage course adequate for the purpose of future widening, deepening, enclosing or otherwise improving said drainage course. If such drainage course crosses private property, easements must be obtained by the Owner/Developer for construction and future maintenance. These easements must be shown on the Construction Plans, including the volume and page number of the recorded easement.
(3) Outlets. No subdivision plan or plat shall be approved by the Planning Commission unless an adequate outlet for storm water, as shown on the plan or plat, is approved by the City Engineer. Generally it will be necessary to pipe storm water to an adequate watercourse, stream or existing storm system which has the capacity to accommodate the flow, or to utilize acceptable on-site water retention methods adequate to minimize excessive off-site storm water flows.
(4) Submittal Data. Culverts and other components of storm water conveyance systems that cross streets or roadways shall be designed so as to adequately address the ten (10) year storm under residential streets and the fifty (50) year storm under collector and arterial streets. The City Engineer may require the Owner/Developer to pay for an analysis of the existing storm water system to determine how best to connect the proposed development to the existing system or any required improvements downstream so as not to overload the system. The post development runoff rate may not exceed the predevelopment runoff rate as determined by the 100 year storm event.
(d) Culverts. All culverts utilized in subdivisions shall have the appropriate headwalls and/or other structures and improvements to protect the facility.
(e) Open Drainage Channels. The determination as to whether a specific drainage course shall be enclosed or open shall be made by the City Engineer. In those cases where an open channel is determined to be acceptable, the cross section and profile of the open channel and its banks shall be determined by the City Engineer.
(Ord. 2009-85. Passed 12-8-09.)