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Ritschard Dam Emergency Action Plan
<br />Appendix A-2 - Inundation Map
<br />
<br /> A-2-3 Appendix A-2
<br />
<br />RESULTS OF DAM-FAILURE INUNDATION MAPPING
<br />
<br />The results of the dam-failure inundation analyses are illustrated on the flood inundation
<br />mapping and summarized in Table A-2.3. The inundation boundaries were developed using the
<br />HEC-GeoRAS extension to locate the intersection of the topographic surface and the maximum
<br />water surface elevation. The dam-failure inundation information provided in this EAP should be
<br />used as a guideline of conservatively estimated dam-failure flooding conditions. Actual flooding
<br />conditions during an emergency at Ritschard Dam may vary significantly from this information
<br />based on the actual conditions at the time of the emergency.
<br />
<br />Flood wave travel times shown on the flood inundation maps and in Table A-2.3 are based on
<br />the assumption that Ritschard Dam-failure begins at time 0:00 (hours: minutes). The flood wave
<br />arrival time shown in the inundation summary below represents the approximate time after dam-
<br />failure when the water surface elevation at each cross-section has risen two feet as a result of
<br />the dam-failure flood. The peak flood stage time shown represents the estimated time after
<br />Ritschard Dam-failure that the maximum expected flood depths are reached at each
<br />downstream cross-section.
<br />
<br />TABLE A-2.3 – SUMMARY OF DOWNSTREAM ROUTING:
<br />IDF-PLUS-BREACH OF RITSCHARD DAM
<br />RITSCHARD DAM EAP
<br />
<br />
<br />
<br />Cross Section
<br />
<br />
<br />Miles
<br />Downstream
<br />of the dam
<br />
<br />
<br />Peak
<br />Flow
<br />(cfs)
<br />Peak
<br />Water
<br />Surface
<br />Elevation
<br />(feet)
<br />
<br />Peak
<br />River
<br />Stage
<br />(feet)
<br />Flood
<br />Wave
<br />Arrival
<br />Time
<br />(hrs:min)
<br />Time to
<br />Peak
<br />Flood
<br />Stage
<br />(hrs:min)
<br />Downstream of Ritschard Dam 0.0 903,230 7,487 83 0:00 0:15
<br />Muddy Creek Entering Kremmling, CO 5.7 597,807 7,365 21 0:26 1:05
<br />Downstream of Confluence with Colorado River 9.0 145,559 7,356 37 1:14 2:45
<br />Entering Gore Canyon 11.0 148,883 7,340 39 1:26 2:50
<br />Leaving Gore Canyon 15.5 148,849 6,993 27 1:41 3:00
<br />Radium 20.6 138,415 6,907 50 2:15 4:30
<br />Entering Red Gorge 22.6 138,048 6,901 48 2:23 4:35
<br />Leaving Red Gorge 23.6 137,657 6,877 40 2:35 4:40
<br />State Highway 131 Crossing 31.2 134,701 6,785 42 3:20 5:45
<br />Bond, CO 34.3 134,531 6,712 25 3:40 6:00
<br />Railroad Crossing 35.9 131,147 6,702 41 4:05 6:40
<br />Railroad Crossing 36.5 131,019 6,700 39 4:08 6:41
<br />McCoy, CO 38.5 126,921 6,665 45 4:28 7:35
<br />Railroad Crossing 47.8 123,902 6,548 38 5:43 8:45
<br />Railroad Crossing 50.8 123,271 6,532 37 6:21 9:00
<br />Burns, CO 51.6 123,098 6,516 30 6:32 9:05
<br />Railroad Crossing 56.9 122,383 6,446 37 7:26 9:40
<br />Railroad Crossing 59.7 122,241 6,381 27 7:50 9:55
<br />Railroad Crossing 61.1 121,197 6,354 31 8:01 10:20
<br />Railroad Crossing 61.7 121,339 6,353 30 8:10 10:25
<br />State Highway 301 Crossing 68.2 117,912 6,275 40 9:32 11:55
<br />Dotsero, CO/Interstate I-70 Crossing 76.8 86,568 6,172 38 10:56 16:30
<br />Garfield/Eagle County Boundary 80.6 89,814 6,164 31 11:54 16:45
<br />Interstate I-70 Crossing 85.1 89,362 6,134 33 12:41 17:20
<br />Shoshone Dam 85.9 89,355 6,120 20 12:56 17:25
<br />Shoshone Power Plant 88.6 89,348 5,942 30 13:06 17:30
<br />Entering Glenwood Springs, CO 95.7 89,232 5,756 25 14:09 18:05
<br />State Highway 82 Crossing 96.0 89,211 5,750 26 14:12 18:15
<br />Leaving Glenwood Springs, CO 96.6 96,843 5,742 27 14:22 18:25
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