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<br />2 m3/s) since the fire, which reflects channel instability. Lower tributaries reaches that agraded on July 12, <br /> <br /> <br />1996, generally have degraded by about a meter by the end of 1997, but hillslope erosion continues to <br /> <br /> <br />contribute sediment to channels. Sediment from the bumed area has filled most reaches of the NF and <br /> <br /> <br />South Platte Rivers to Strontia Springs Reservoir w~h about a meter of sediments. About 75 percent of <br /> <br /> <br />Denver's water comes through the reservoir, which has a capacity of about 9.74 hm3. From May 1996 to <br /> <br /> <br />October 1997, about 0.31 hm3 of sediment washed into the reservoir compared to about 0.14 hm3 in the <br /> <br /> <br />13 years since the reservoir was built (Denver Water Department, wr~ten commun., 1997). Snowmen <br /> <br /> <br />runoff in the NF and South Platte Rivers likely will continue to move large amounts of wildfire-produced <br /> <br /> <br />sediments towards the reservoir. <br /> <br />Geomorphic investigations of alluvial sediments in the burned and unburned (in 1996) areas indicate at <br /> <br /> <br />least 10 fireslflood sequences have occurred in the study area prior to 1996. At least one paleoflood was <br /> <br /> <br />larger than the July 12, 1996 flood, and runoff after several of the prehistoric fires produced much thicker <br /> <br /> <br />alluvial depos~s than following the 1996 wildfire. Radiocarbon dating of organic material in alluvial <br /> <br /> <br />sediments in a Buffalo Creek tributary indicated that these sequences span about the last 2,500 years <br /> <br /> <br />(John Elliott, USGS, written commun., 1997). Add~ional investigations will help determine the long-term <br /> <br /> <br />fire and flood history in the region, which could help forest managers develop policy for prescribed burns <br /> <br /> <br />and other management practices. <br /> <br />Study results can be used to develop and verify hydrologic- and sediment-budget models for burned <br /> <br /> <br />watersheds. In conjunction w~h the NWS, study resuns and rainfall-runoff modeling was conducted to <br /> <br /> <br />help determine threshold-rainfall amounts for flash-flood conditions. These results were used to refine <br /> <br /> <br />flash-flood warnings, particularly to minimize the number of false alarms that can cause complacency of <br /> <br /> <br />those at risk. The Colorado Water Conservation Board (1997) prepared an emergency response, hazard- <br /> <br /> <br />mitigation, and awareness plan for government officials, residents, and vis~ors in the Buffalo Creek area. <br /> <br />Studying only the Buffalo Creek area can not provide answers to all questions about wildfire hazards in <br /> <br />other forest ecosystems. Thus, add~ional paleoflood studies are needed for burned (wildfire and <br /> <br />13 <br />