10/14/1986 - Laserfiche WebLink

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1 BOOK 66 r 70 The Board reviewed the following memo dated 10/1/86: y TO: The Honorable Members of the DATE: October 1, 1986 FILE:. Board of County Commissioners THROUGH c Charles P. Balczun, County Administrator SUBJECT: Proposed Amendment to the StOnWater Management and Flood Protection Ordinance FROM: REFERENCn7e Henderson, Attorney 'James W. Davis, P.E., for Grand Harbor Dev. Public Works Director to Indian River Board of rntln±3z (`m mi cci C.Mg=1 "sr_ ated 9-17-86 11 %)6 ��l•� The County's Stormwater Management and Flood Protection Ordinance requires that along the Indian River Floodplain, a balance of cut and fill must be provided below elevation 4.0 to preserve the available storage capacity for flood waters until the inlet at Sebastian and Fort Pierce can discharge these flood waters to the Atlantic Ocean. There are many acres of land along the Indian River below elevation 4.0 that are not considered_ "wetlands" and that cannot be filled without the developer excavating an equal volume of material from the site to achieve a "balance of cut and fill". The Grand Harbor Development, the Shorelands Subdivision and 4 similar developments, both on the mainland side and barrier island side of the River, are such developments and are having difficulty meeting this requirement. As a result, the attorney for the Grand Harbor development is requesting that language be added to Section 21i -7(B)(1) of the County Code to allow the Board of County Cmimissioners to grant a waiver from "the cut and fill balance" requirement if an engineering study can show that the development project is: 1) Situated in an estuarine (tidal) envirorzent 2) Meets all other requirements of the Stormwater Management and Flood Protection Ordinance 3) Will not.create a material adverse impact on flood protection on other lands in the estuarine environment. This proposed waiver provision will provide an alternative to requesting a variance from. the Board of Adjustments, which is currently provided for in the existing ordinance. ALTERNATIVES AND ANALYSIS In analyzing this requested modification, the staff has researched the technical implications of the requirement. Basically, along such a wide floodplain as the tidal Indian River, many Engineers believe that filling of land that is not environmentally sensitive between the mean high water line and elevation 4.0 (NGVD), will not cause a significant increase in the water elevation along the River. Any increase in the water level would be infinitesimally small and would probably not be measurable. Staff has contacted the St. Johns River Water Management District Chief Engineer in Palatka, Florida, and requested an opinion on this issue. The District is not concerned with the cut and fill balance along the Indian River and does not require this action. The staff's only concern is that during high tide conditions, the Sebastian Inlet and Fort Pierce Inlet, which are 29 miles apart, have limited convey- ance capability and serve as the only channels that drain a large area (Brevard County to St. Lucie County). Filling of minor flood plain areas probably will have no measurable effect, however, a cumulative filling 70