(A) All of the following information and data, prepared and certified by a state licensed professional engineer or professional surveyor engaged in storm drainage design, shall be submitted to the Board for approval prior to application for an improvement location permit for any development, re-development or new construction on real estate which lies within the jurisdiction of the Board.
(B) The minimum sheet size of all maps and plats submitted in conjunction with the following shall be 8 1/2 inches by 11 inches; and the maximum sheet size shall be 24 inches by 36 inches.
(1) Topographic and soils map. A soils map of the proposed development and off-site contributing drainage areas, indicating soil names and their hydrologic classification, must be provided. In addition, a topographic map of the land to be developed and the 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:
(a) The location of streams and other flood water runoff channels, the extent of the floodplains at the established 100-year flood elevation where available (regulatory floodway), and limits of the floodway, all properly identified;
(b) The normal shoreline of lakes, ponds, swamps and storm water control facilities, their floodplains, and points of inflow and outflow if any;
(c) The location and elevation of regulated drains, farm drains, inlets and outfalls, if any of record;
(d) Storm, sanitary, and combined sewers and outfalls, if any of record;
(e) The location of domestic and commercial waste systems and outlets, if any of record, or as otherwise known to applicant; and
(f) Seeps, wetlands, springs and wells, that are visible or of record.
(2) Drainage plan. A comprehensive plan designed to safely handle the storm water runoff and to detain the increased storm water runoff must be provided. The plan shall provide or be accompanied by maps or other descriptive materials, illustrating pre-development and proposed development conditions, indicating the feasibility of the drainage plan and showing the following:
(a) The extent and area of each watershed affecting the design of detention facilities as shown on USGS Quadrangle Maps or other more detailed maps as required by the Board. Also, provide a vicinity map that geographically locates the project area within the county;
(b) The extent and area of each watershed tributary to the drainage channels in the development;
(c) The street storm sewers and other storm drains to be built, the basis of their design, outfall and outlet locations and elevations, the receiving stream or channel and its 100-year water elevation, and the functioning of the drains during high water conditions;
(d) 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 the overflow;
(e) Existing streams and floodplains to be maintained, and new channels to be constructed, their locations, cross sections and profiles;
(f) Proposed culverts and bridges to be built, their materials, elevations, waterway openings and basis of their design;
(g) Existing storm water control facilities to be maintained, enlarged or otherwise altered and new basins or ponds to be built and the basis of their design;
(h) The estimated location and percentage of impervious surfaces existing and expected to be constructed when the development is completed;
(i) The slope, type and size of all sewers and other waterways;
(j) For all detention and retention 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;
(k) Proof that a storm water pollution prevention plan for handling storm water runoff associated with construction activity, in accordance with 327 I.A.C. 15-5, has been filed with the County Soil and Water Conservation District;
(l) Any existing and proposed easements and rights of access; and
(m) Party responsible for the permanent ownership and maintenance of the drainage system and a description of all maintenance requirements.
(3) Valley cross section. One or more typical cross sections must be provided showing all existing and proposed channels or other open drainage facilities carried to a point above the 100-year high water elevation; showing the elevation of the existing land and the proposed changes thereto, together with the high water elevations expected from the 100-year storm under the controlled conditions called for by this chapter; and showing the relationship of structures, streets and other facilities.
(4) Site plan. A plan drawn to scale showing dimensions of the site with existing and proposed storm drainage facilities must be provided.
(Ord. 8-2014, passed 7-21-2014)