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<br />64
<br />
<br />LAWN LAKE DAM AND CASCADE LAKE DAM FAILURES, COLORADO
<br />
<br /> DISCHARGE AT INDICATED TIME, 1982
<br /> {Its/s, cllbic feet pel' second]
<br />Tim, Discharge 'Nmo Discharge Tim, Discharge
<br /> (fts/s) (fts/s) tlts/s)
<br />July 15
<br />0845 '387 1000 2,046 2200 431
<br />0850 1,279 1015 1,699 2300 431
<br />0855 2,876 1030 1,792 2400 427
<br />0900 4,039 1045 1,545
<br />0905 4,768 BOO 1,458 July 16
<br />0910 5,066 1200 1,106 0100 389
<br />0915 5,364 1300 766 0200 383
<br />0920 3,628 1400 718 0300 387
<br />0925 4,356 1500 671 0400 421
<br />0930 3,632 1600 533 0500 431
<br />0935 3,782 1700 479 0600 429
<br />0940 3,495 1800 439 0700 427
<br />0945 2,625 1900 418 0800 416
<br />0950 3,351 2000 401 0900 412
<br />0955 2,192 2100 418 1000 385
<br /> BOO 385
<br /> 1200 363
<br /> Total Big Thompson River inflow volume 1,500 acre-ft
<br /> Big Thompson River inflow volume - 837 acre-ft
<br /> Lawn Lake flood volume 663 acre-ft
<br />lIBig Thompson River average inflow was approximately 371 ItSI! during time period.
<br />
<br />Datum of gage is 7,492.5 ft above mean sea level
<br />(levels by U.S. Bureau of Reclamation). Stage records
<br />unusable from 0835 MDT to 1200 MDT, July 15,
<br />1982, because gage intakes were plugged by sediment.
<br />Discharge record. - Stage-discharge relation defined by
<br />current-meter measurement below 1,500 ft'/s. Peak
<br />discharge for July 15, 1982, determined by flow
<br />through Parshall flume and flow over weir. '
<br />Maxima.-July 15, 1982: Discharge, 5,500 ft'/s (gage
<br />height not determined). 1949 to 1982: Discharge,
<br />1,660 ft'/s June 18, 1949 (gage height 3.16 ft, site
<br />and datum then in use).
<br />
<br />Site 7: Lake Estes at Estes Park, Colo. (Miscellaneous
<br />site)
<br />
<br />REFERENCES
<br />
<br />Barnes. H. H.t Jr., 1967, Roughness characteristics of natural chan.
<br />nels: U,S, Geological Survey Water-Supply Paper 1849, 213 p.
<br />Barnes, H. H.t Jr., and Davidian, Jacob, 1978. Indirect methods, in
<br />Herschey, R. W" ed., Hydrometry-Principles and Practices: New
<br />York, Wiley. p. 189-190.
<br />Chen, C-L, and Armbruster, J. T.. 1979, Field verification of
<br />reconstructed dam.break flood, Laurel Run, Pennsylvania: U .8.
<br />Geological Survey Open,File Report 79-1483, 37 p.
<br />Church, Michael, and Desloges, J. R., 1984, Debris torrents and natural
<br />hazards of steep mountain channels-east shore of Howe Sound:
<br />Canadian Association of Geographers Field Trip Guidebook #7,
<br />Department of Geography, University of British Columbia, Van~
<br />couver, 83 p.
<br />Clark, Champ, 1982, Floods, v, 3 of Planet Earth [Time-Life Book
<br />Series]: Alexandria, Va., Time-Life Books, Inc., 176 p.
<br />
<br />Location,-Lat 40022'32", long 105029'13", in NE\I.i
<br />sec. 29, T. 5 N., R. 72 W., Larimer County. Gage
<br />located at Olympus dam on the Big Thompson River,
<br />2.22 mi downstream from State Highway 66 bridge
<br />in Estes Park.
<br />Gage-height record.- Water-surface elevations obtained
<br />at selected time intervals by Bureau of Reclamation
<br />personnel as well as te1emetered reservoir levels at the
<br />dam. The lake level began rising at 0847 MDT.
<br />Discharge record. - Discharge based on change in
<br />storage and accounting of inflow and outflow. Values
<br />given are reconstructed Big Thompson River inflows.
<br />Maximum.-July 15, 1982: 5-minute average peak
<br />discharge, 5,364 ft'/s, which occurred from 0910 to
<br />0915 MDT.
<br />
<br />Colorado Water Conservation Board. 1983, Flood hazard mitigation
<br />plan for Colorado: Denver, Colo., Colorado Water Conservation
<br />Board. Department of Natural Resources, 135 P.
<br />Costs, J. E. 1984, The phyloicaI geomorphology of debris flows, in Coota,
<br />J. E., and Fleisher, P. J.. ada., Developments and Applications of
<br />Geomorphology: Springer-Verlag, New York, p. 268-317.
<br />Cunge, T. A., Holly, F. M., Jr., Verwey, Adr~ 1980, Practical Aspects
<br />of Computational River Hydraulics: Pitman Pub1iabing Lid., 420 p.
<br />Dalrymple, Tate, and Benson. M. A., 1987, Measurement of peak
<br />discharge by the alope-aree method: u.s. Geological Survey 'Thchni-
<br />ques of Water-Resources Investigations, Book 3, Chapter A-12,
<br />12 p.
<br />Fread. D. 4, 1977, The development and testing of a dam-break flood
<br />forecasting model, in Dam-Break Flood Routing Model Workshop
<br />Proceedings, Bethesda, Md,: U.s. Water Resources Council, Task
<br />Force on Dam,Break Flood Routing, p. 164-197,
<br />Greham, W. J" and Brown, C. A., 1983, Dam failure warnings
<br />evaluated: in Natural Hazards Observer, Boulder, University of
<br />
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