11/28/2001 Env Bd Packet - Laserfiche WebLink

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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 water body. (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 BMP's have been incorporated into the project to the maximum extent possible. (h) The requirements of paragraph (j) 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. (i) In cases where structures are proposed below the runout elevation of land- locked basins, the low -floor elevation will be a minimum of two feet above the high water level as determined from an estimate of highwater levels determined from the highest of either the 100 -year, ten -day runoff event or back -to -back 100 -year, twenty- four -hour rainfalls. Aerial photos, vegetation, soils, and topography will be used to derive a "normal" water elevation for the basin for purposes of computing the 100 -year elevation. 16