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<br />GAGING-STATION AND MISCELLANEOUS-SITE DATA PLA'lTE RIVER BASIN
<br />
<br />have reached Estes Park at the same time. For this
<br />hypothetical case, Cascade Lake dam still would have
<br />failed. For a breach width of 200 ft, peak discharge
<br />would have been 22,600 ft'ls greater downstream from
<br />Lawn Lake dam to 5,400 ft'ls greater at river mile
<br />12.5. Maximum flood depth averaged 2.7 ft higher, and
<br />the flood wave would have reached Estes Park 0.4 h
<br />earlier. The model indicated that outflow peak discharge
<br />from a worst-case failure of Lawn Lake dam could have
<br />been at least 56,000 ft'/s.
<br />If Cascade Lake dam had not failed (or had not been
<br />present), peak discharges would have been 11,300 ft'/s
<br />less immediately downstream from the dam, to
<br />500 ft'ls less just upstream from Lake Estes. Max-
<br />imum flood depths would have averaged 0.6 ft lower,
<br />and the flood wave would have reached Lake Estes 0.3
<br />hour later.
<br />
<br />GAGING-STATION AND
<br />MISCELLANEOUS-SITE DATA
<br />PLATTE RIVER BASIN
<br />
<br />Site 1: Fall River above Cascade Lake dam above Estes,
<br />Park, Colo. (Miscellaneous site)
<br />Location.-Lat 40024'05", long 105036'18", ill SWv.
<br />NWV. sec. 17, T. 5 N., R. 73 W., Rocky MountainNa-
<br />tional Park, Larimer County. Site located at down-
<br />stream end of Horseshoe Park, 6.50 mi downstream
<br />from Lawn Lake dam, 900 ft upstream from Cascade
<br />Lake dam, and 5.47 mi upstream from State Highway
<br />66 bridge in Estes Park.
<br />Discharge record. - Peak discharge determined by slope-
<br />area method.
<br />Maximum.-July 15, 1982: Discharge, 7,210 ft'/s.
<br />
<br />Site 2: Fall River at Cascade dam above Estes Park,
<br />Colo. (Miscellaneous site)
<br />Location.-Lat 40024'03", long 105036'08", in NEV.
<br />SWv. sec. 17, T. 5 N., R. 73 W., Rocky Mountain Na-
<br />tional Park, Larimer County. Site located 6.67 mi
<br />downstream from Lawn Lake dam and 5.30 mi
<br />upstream from State Highway 66 bridge in Estes
<br />Park.
<br />Discharge record. -Discharge, at time of dam failure,
<br />determined by critical-depth method.
<br />Value.-July 15, 1982: Discharge, 4,500 Wis.
<br />
<br />Site 3: Fall Rive.r below Cascade Lake dam above Estes
<br />Park, Colo. (Miscellaneous site)
<br />Location.-Lat 40023'59", long 105035'05", in NWV.
<br />SWv. sec. 16, T. 5 N., R. 73 W., Estes Park, Larimer
<br />County. Site located at 12-ft concrete drop structure,
<br />
<br />63
<br />
<br />7.68 mi downstream from Lawn Lake dam, 1.01 mi
<br />downstream from Cascade Lake dam, 500 ft down-
<br />stream from Estes Park powerplant, and 4.29 mi
<br />upstream from State Highway 66 bridge in Estes
<br />Park.
<br />Discharge record. - Peak discharge determined by
<br />critical-depth method.
<br />Maximum.-July 15, 1982: Discharge, 13,100 ft'/s.
<br />
<br />Site 4: Fall River above Estes Park, Colo. (Miscellane-
<br />ous site)
<br />Location.-Lat 40023'01 ", long 105032'58", in SWv.
<br />SWv. sec. 23, T. 5 N., R. 73 W., Larimer County. Site
<br />is located 1.17 mi upstream from gage (site 5) and 1.70
<br />mi upstream from State Highway 66 bridge in Estes
<br />Park.
<br />Discharge record. - Peak discharge determined by slope-
<br />area method.
<br />Maximum.-July 15, 1982: Discharge, 8,520 ft'/s.
<br />
<br />Site 5: 06732500 Fall River at Estes Park, Colo.
<br />Location.-Lat 40022'40", long 105031'56", in NWV.
<br />NWV. sec. 25, T. 5 N., R. 73 W., Larimer County on
<br />left bank 100 ft upstream from U.S. Highway 34
<br />bridge and 0.7 mi upstream from mouth.
<br />Drainage area.-39.5 mi'.
<br />Gage-height record.-1947 to 1953: Water-stage
<br />recorder approximately 2,000 ft downstream from
<br />present site. Datum of gage was 7,547.06 ft above
<br />mean sea level (levels by U.s. Bureau of Reclamation).
<br />1978 to present: Crest-stage gage. Arbitrary datum.
<br />Discharge record. -Stage discharge relationship defined
<br />by current meter measurement to 350 ft'/s. Peak
<br />discharge for July 15, 1982, determined by linear in-
<br />terpolation by stream distance of peak discharge at
<br />sites 4 and 6.
<br />Maxima.-July 15, 1982: Discharge 6,550 ft'/s (gage
<br />height, 11.10 ft). 1947 to 1953: Discharge, 476 ft'ls,
<br />June 14, 1953 (gage height, 2.69 ft, site and datum
<br />then in use). 1978 to 1981: Discharge, 565 ft'ls 1980
<br />(gage height, 8.56 ft).
<br />
<br />Site 6: 06733000 Big Thompson River at Estes Park,
<br />Colo.
<br />Location.-Lat 40022'42", long 105030'48", in NWV.
<br />NWV. sec. 30, T. 5 N., R. 72 W., Larimer County, on
<br />right bank in Estes Park, 600 ft downstream from
<br />bridge on State Highways 7 and 66, 900 ft down-
<br />stream from Black Canyon Creek, and 0.3 mi north-
<br />east of Estes Park powerplant. Station is upstream
<br />from Lake Estes.
<br />Drainage area.-137 mi',
<br />Gage-height record. -Water-stage recorder graph fur-
<br />nished by Colorado Division of Water Resources.
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