The following information and data provided by a state-licensed professional engineer or land surveyor engaged in stormwater drainage design, shall be submitted to the Board at the time of application for a building permit for any development, redevelopment, or new construction on real estate which lies within the regulated area.
(A) Topographic and soils maps. A soils map of the proposed development indicating soil names and their hydrologic classification must be provided when soil conservation service (SCS) hydrologic methods are used. In addition, a topographic map of the land to be subdivided, and such adjoining land whose topography may affect the layout or drainage of the development, must be provided. The contour intervals shall be one foot when slopes are less than 4%, and shall be two feet when the slope exceeds 4%. On this map, the following shall be shown:
(1) The location of streams and other floodwater runoff channels, the extent of the floodplains at the established 100-year flood elevation where available (regulatory floodway), and the limits of the floodway, all must be properly identified;
(2) The normal shoreline of lakes, ponds, swamps, and detention basins, their floodplains, and lines of inflow and outflow, if any;
(3) The location of regulated (legal) drains, farm drains, inlets, and outfalls, if any of record;
(4) Storm, sanitary, and combined sewers and outfalls, if any of record;
(5) Septic tank systems and outlets, if any of record; and
(6) Seeps, springs, flowing, and other wells that are visible, or of record.
(B) Preliminary drainage plan. A comprehensive plan in preliminary form (or in combined preliminary and final form), designed to handle safely the stormwater runoff and to detain the increased stormwater runoff must be provided. The plan shall provide or be accompanied by maps or other descriptive materials indicating the feasibility of the drainage plan and showing the following:
(1) The extent and area of such watershed affecting the design of detention facilities, as shown on USGS quadrangle maps or other more detailed maps, as required by the Board;
(2) The preliminary layout and design of proposed storm sewers, the outfall and outlet locations, and approximate elevations of the receiving stream or channel;
(3) The location and design of the proposed street system;
(4) The locations and profiles of existing streams and floodplains to be maintained, and new channels to be constructed;
(5) The materials, elevations, waterway openings, and the basis for design of proposed culverts and bridges;
(6) Existing detention ponds and basins to be maintained, enlarged, or otherwise altered and new ponds or basins to be built, and the basis of their design;
(7) The estimated depth and amount of storage required in the new ponds or basins; and
(8) The estimated location and percentage of impervious surfaces existing and expected to be constructed when the development is completed.
(C) Valley cross section. One or more typical cross sections must be provided showing all existing and proposed channels.
(D) Site plan. A plan drawn to scale showing dimensions of the site with existing and proposed storm drainage facilities must be provided.
(E) Final drainage plans. Upon approval of the preliminary drainage plans by the Board, final drainage plans shall be submitted to the Board. The final plans shall be provided or be accompanied by calculations, maps, and/or other descriptive material showing the following:
(1) The extent and area of each watershed tributary to the drainage channels in the development;
(2) The street storm sewers and other storm drains to be built, the basis of their design, outfall, and outlet locations and elevations, and the receiving stream or channel;
(3) The parts of the proposed street system where pavements are planned to be depressed sufficiently to convey or temporarily store overflow from storm sewers and over the curb runoff resulting from the heavier rainstorms, and the outlets for such overflow;
(4) Existing streams and floodplains to be maintained, and new channels to be constructed, their locations, cross sections, and profiles;
(5) Proposed culverts and bridges to be built, their materials, elevations, waterway openings, and basis of their design;
(6) Existing detention basins and ponds to be maintained, enlarged, or otherwise altered and new basins or ponds to be built, and the basis of their design;
(7) The estimated location and percentage of impervious surfaces existing and expected to be constructed when the development is completed;
(8) The slope, type, and size of all sewers and other waterways; and
(9) For all detention basins, a plot or tabulation of storage volumes with corresponding water surface elevations, and a plot or tabulation of the basin outflow rates for those water surface elevations.
(F) Submittal and consideration of plans. Preliminary and final drainage plans and/or construction plans shall be submitted to the Board 20 days prior to its regularly-scheduled meeting. A stormwater permit review fee shall also be submitted to the Board along with the preliminary drainage and/or construction plans. The amount of the permit review fee shall be established by the Board on an annual basis. The permit review fee will be used to cover the cost incurred by the Board in review of all stormwater drainage and/or construction plans, review of all hydraulic calculations, and review of computer models for compliance with this subchapter. All preliminary plans, final plans, and/or construction plans in compliance with the standards of this subchapter shall be approved by the Board. The Board shall stamp such approval on a copy of such plans and deliver the same to the applicant. The Board shall approve or disapprove any preliminary plans, final plans, and/or construction plans within 60 days of submission unless the applicant consents to a continuance or extension. All approvals and disapprovals with written reasons shall be incorporated into the Board minutes.
(Ord. 2007-10, passed - -)