(A) The following information and data provided by an Indiana licensed professional engineer, architect or land surveyor engaged in storm drainage design shall be submitted to the city at the time of application for development plan review or subdivision plat review:
(1) The extent and area of each watershed affecting the design of detention facilities, as shown on United States Geological Survey (USGS) Quadrangle Maps or other more detailed maps as required by the Commission.
(2) A topographic map of the site to be developed and such adjoining land whose topography may affect the layout or drainage of the development. Contour interval shall be one foot when slopes are less than four percent, and shall be two feet when the slope exceeds four percent. Topographic map shall also include:
(a) Locations, cross sections and profiles of existing streams and floodplains, and new channels to be constructed.
(b) Locations of regulated drains, farm drains, inlets and outfalls, if any of record.
(c) Storm, sanitary, and combined sewers and outfalls, if any of record. Septic tank systems and outlets, if any of record.
(3) The preliminary layout and design of proposed storm sewers, the outfall and outlet locations and approximate elevations, the receiving stream or channel, and its 100-year return period water elevation.
(4) The location and design of the proposed street system, especially including depressed pavements used to convey or temporarily store overflow from the heavier rainstorms, and the outlets for such overflow.
(5) The materials, elevations, waterway openings, and the basis for the 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.
(8) The estimated location and percentage of impervious surfaces existing and expected to be constructed when the development is completed.
(9) All hydrologic and hydraulic computation should be included in the submittal. These calculations should include: runoff curve numbers or runoff coefficients; runoff calculations; stage-discharge relationships; times of concentration; and storage volume.
(10) Soil erosion and sediment control plan.
(B) 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.
(C) Five copies of the stormwater plan shall be submitted with the development plan or subdivision plat application.
(Ord. 16-C-98, passed 6-9-98; Am. Ord. 22-C-98, passed 8-11-98; Am. Ord. 22-C-04, passed 11-9-04)