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1 <br /> ' The next floodplain study was generated in August 1978 by the Federal Insurance <br /> Administration (FIA) who published a Flood Insurance Study (FIS) for unincorporated <br /> areas within Boulder County. Hydrologic and hydraulic analyses for this study were <br /> ' performed by the U.S. Soil Conservation Service (SCS) utilizing the HEC-2 water surface <br /> profiles model and a 100-year flood discharge of 5,000 cfs. <br /> In 1979, Flatiron Companies contracted with Leonard Rice Consulting Water Engineers <br /> (LRCWE) to prepare an "Application for a Special Permit for Flood Plain Construction - <br /> South Boulder Creek" in order to obtain a Boulder County floodplain construction permit <br /> ' for the site perimeter berm around the proposed gravel mining operations within the <br /> Flatiron Property. The LRCWE study initially determined the 1-foot rise floodway and <br /> ' then set the site perimeter berm location so that the berm, in conjunction with an <br /> excavated channel comprised of a 50-foot base width located adjacent to the berm within <br /> ' the floodplain, would together not cause a rise in the floodplain of more than 1-foot. The <br /> purpose of this site perimeter berm was to protect the gravel mine from flood damage <br /> ' should a flood occur during the time mining operations were underway at the site. <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 of 1986 by Greenhome & <br /> O'Mara, Inc. (G&O) and published in a document entitled South Boulder Creek Flood <br /> ' Hazard Area Delineation (FHAD). This study was undertaken through a contract with <br /> Boulder County and the Urban Drainage & Flood Control District (UD&FCD) and is <br /> ' based upon 1980 topographic mapping. The FIS regulatory floodplain for South Boulder <br /> Creek is based upon this study, which utilized a 100-year discharge of 6,160 cfs. The FIS <br /> ' study defines a split flow condition for South Boulder Creek between U.S. Highway 36 <br /> and State Highway 93. A split flow condition is caused when physical constraints within <br /> the floodplain do not allow floodwaters to remain hydraulically connected and the water <br /> that normally would remain in the floodplain splits from the floodplain and flows away <br /> ' from the floodplain, sometimes returning to the floodplain and sometimes creating its own <br /> separate floodplain disconnected from the historic floodplain. On both US Highway 36 <br /> 9 <br />