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<br />The average channel slope below Cascad,~ Lake through Aspen- <br />glen Campground was again steep (5='0,0880), and this second surge <br />traveled at about 8.0 miles pe'r hour. <br /> <br />Below the National Park Bounilary, the slope of Fall River <br />gradually begins to flatten (S=0.0200), and the flood velocity <br />reduced to about 4.0 miles per hour. <br /> <br />At Estes Park, the estimated rate of flow was 5,500 cfs. <br />Maximum channel flood depths i.n Fall River were typically 10 to <br />12 feet or about 2.5 times the average 500-year flood depth esti- <br />mated in the Flood Insurance Study. In comparison, the 100-year <br />flood discharge for Fall Rivel: at Estes Park was computed to be <br />only 680 cfs and the 500-year disch;~rge was only 830 cfs. <br /> <br />After passing through the business distr ict, of the town of <br />Estes Park, the flood reached the confluence with the Big <br />Thompson River shortly after 8:30 a.m. The Big Thompson River at <br />this point serves a larger drainage basin, and the channel was <br />slightly better able to convey the flood. 'rhe boundaries of the <br />flood are shown in fig ure 2.3. <br /> <br />The 100- and 500-year diE'charges for the Bi.g Thompson river <br />at Estes Park were previously calculated to be 1,460 and 1,760 <br />cfs, respectively. <br /> <br />At about 8: 47 a.m the flood entered Lake Estes wh ich rose <br />approximately 2.0 feet by 11:00 a.m. but containE~ the flood. It <br />has been estimated the flood deposited approximately 51,000 tons <br />of debris in the town of EstE~S Pa,rk. Figure 2.4 is an aerial <br />photograph showing the lower r'~aches of the floodplain. <br /> <br />2.1.3 People at Risk <br /> <br />The number of people at risk in the upper reaches of the <br />Lawn Lake drainage was limited to about 25 to 30 people camped <br />either at Lawn Lake or at other National Park campsites located <br />along the banks of Roaring Riv'~r. <br /> <br />In Horseshoe Park above Cascade Lake there ~Iere probably <br />fewer than 20 people at risk. <br /> <br />Approximately 275 people were reported camped in Aspenglen <br />Campground in the early morni~J hours of July 15. <br /> <br />Downstream from the National Park boundary, however, a few <br />thousand people were at risk as a result of the failure of the <br />Lawn Lake dam and Cascade Lake dam. <br /> <br />-11- <br />