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Rule C: Storm -Water Management Plans I Rice Creek Watershed District Page 3 of 4 • (b) Delineation of the subwatershed contributing runoff from off-site, proposed and existing subwatersheds on-site, emergency overflows, and drainageways. • (c) Proposed and existing stormwater facilities location, alignment and elevation. • (d) Delineation of existing on-site wetland, marshes, shoreland and/or floodplain areas. • (e) Identification of existing and proposed normal, and ordinary high and 100 -year water elevations on-site. • (f) Identification of existing and proposed site contour elevations related to NGVD, 1929 datum. • (g) Construction plans and specifications of all proposed stormwater management facilities, including design details for outlet control structures. • (h) Stormwater runoff volume and rate analyses for the one and 100 -year critical events, existing and proposed conditions. • (i) All hydrologic, water quality, and hydraulic computations completed to design the proposed stormwater management facilities. • 0) Narrative addressing incorporation of infiltration BMPs. • (k) Delineation of any ponding or flowage easements or other property interest dedicated to stormwater management purposes. 5. Platting Or Easement Documents. Applicant must provide platting or easement documents showing sufficient drainage and ponding/flowage easements over hydrologic features such as floodplains, storm sewers, ponds, ditches, swales, wetlands and waterways. Structures and facilities subject to flood damage built within the 100 -year flood will have two feet of freeboard between the lowest floor and the 100 -year flood profile. 6. Exceptions. • (a) Rule C and its requirements will not apply to development or redevelopment of individual sites less than 2.5 acres in size for industrial, commercial, and multi -unit residential, and less than five acres in size for single-family residential, unless such development or redevelopment: o (1) Is within the 100 -year floodplain. o (2) Is within 1,000 feet of a public water or protected wetland. o (3) Is within 300 feet of Rice Creek, Clearwater Creek, Hardwood Creek, or of a public ditch. • (b) Rule C and its requirements will not apply to construction of single-family detached dwelling on an isolated lot, unless such dwelling: o (1) Is within the 100 -year floodplain. o (2) Is within 1,000 feet of a public water or protected wetland. o (3) Is within 300 feet of Rice Creek, Clearwater Creek, Hardwood Creek, or of a public ditch. • (c) Rule C and its requirements will not apply to construction on individual lots within a residential subdivision approved by the District, unless the activity does not comply with the original development plan or has been superseded by state law. • (d) The requirements of paragraph (f) of Section 3 will be modified for redevelopment sites at which less than fifty -percent of the total site area (including any road right-of-way) will be disturbed, such that water quality ponding will be required only for the areas being disturbed. • (e) Subdivision of land which does not propose construction of impervious surfaces or structures will be exempt from the requirements of Section 3 and paragraphs (c), (g), (h), (i) of Section 4. However, a Rule C permit is required when such future development does occur. • (f) Rate control criteria discussed in Section 3 may be waived if the site discharges directly to a water body with large storage capacity (such as a public water) which has a time-to-peak elevation greater than that for an on-site pond and the volume discharged from the on-site pond is negligible, relative to the volume of runoff entering the waterbody. • (g) The requirements of paragraphs (e) and (f) of Section 3 may be waived for sites with total impervious area of less than one acre, if infiltration BMPs have been incorporated into the project to the maximum extent possible. • (h) The requirements of paragraph 0) of Section 3 may be waived for short -duration floods not associated with regulatory (FEMA -FIS) floodplain. Low floor elevations will not be allowed below the 100 -year water level, and the two -foot freeboard requirement would apply to the minimum building opening elevation. Additionally, applicant must submit calculations demonstrating the duration of the flood event was sufficiently brief to prevent saturation of the soil at the low floor. http://www.ricecreekwd.com/Hiles/rcwd/c 11/13/2006