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<br />I <br />I <br />il <br />~I <br />,I <br />'I <br />,I <br />!I <br />,I <br />II <br />il <br />,I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Between 1973 and 1979, the US Army Corps of Engineers re-visited the hydrologic <br />conditions of the South Boulder Creek drainage basin and increased the 100-year flood <br />discharge from its 1969 findings of 5,000 cubic feet per second to 6,200 cfs. This <br />revised 100-year discharge was used in studies that followed this reported change. <br /> <br />In 1979, prior to commencement of mining operations, Flatiron Companies contracted <br />with Leonard Rice Consulting Water Engineers (LRCWE) to prepare an "Application for <br />a Special Permit for Floodplain Construction - South Boulder Creek" in order to obtain a <br />Boulder County floodplain construction permit for the site perimeter berm which was to <br />be constructed on the southern and eastern edges of the Property. The LRCWE study, <br />using a 100-year flood discharge of 6,200 cfs, initially determined the I-foot rise <br />floodway and then set the site perimeter berm location so that the berm, in conjunction <br />with an excavated channel comprised of a 50-foot base width located adjacent to and <br />outside of the berm within the floodplain, would together not cause a rise in the <br />floodplain of more than I-foot. The purpose of this site perimeter berm was to protect <br />the gravel mine from flood damage should a flood occur during the time mining <br />operations were underway at the site, See Figure 3 for the LRCWE loo-year delineation <br />of the South Boulder Creek floodplain based upon the constructed site perimeter berm, <br />No request was made by the Flatiron Property owners or their consultants to modify the <br />regulatory floodplain based upon the LRCWE floodplain analysis nor to cause the berm <br />to meet FEMA's flood levee criteria, <br /> <br />The most recent flood study and the one currently being used by FEMA to regulate the <br />South Boulder Creek floodplain was a study completed in July, 1986 by Greenhorne & <br />O'Mara, Inc. (G&O) and published in a document entitled South Boulder Creek <br />Flood Hazard Area Delineation (FHAD). This study was undertaken through a <br />contract with Boulder County and the Urban Drainage & Flood Control District <br />(UD&FCD) and is based upon 1980 topographic mapping. The G&O loo-year <br />floodplain delineation is shown on Figure 4. The current FEMA Flood Insurance Study <br />(PIS) regulatory floodplain for South Boulder Creek is based upon the G&O study, <br />which utilized a 100-year discharge of 6,160 cfs at U.S. Highway 36. The G&O <br /> <br />-6- <br /> <br />", <br />