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<br />f1ISTO\l.Y OF FLOODING
<br />
<br />This section describes the flood histories and storm characteristics
<br />typicllloftheLovelandarea.. The main csuse of flooding of the Big
<br />Thompson River in the Loveland area is due to intense rainfall during the
<br />lat~ spring and summer season, and during some years the rainfall runoff is
<br />increased by snowmelt during May and June.
<br />
<br />Past recorda of floods in the Loveland area show that overbank flows
<br />can last from several hours to 1 or Z days. A cloudburst in the lower
<br />basin could result in flooding at Loveland in Z or 3 hours. A ato~ in the
<br />upper basin would produce high waters at Loveland for I or 2 days.
<br />
<br />A stream gage was operated in the vicinity of the Greeley and Loveland
<br />Canal diversion at the western side of Loveland from June 1947 to September
<br />1955. Flood events during the period of operation occurred on June 4,
<br />1949, and August 3, 1951, with respective discharges of 7,750 cfs and
<br />22,000 ds. Stream gaging stations located in the reach 4 to 6 miles east
<br />of Drake near the mouth of the canyon have been operated intermittently
<br />since 1887. These records indicated that floods occurred nbout once every
<br />6 years On the average. The drainage area upstream of the Drake gage
<br />(mouth of the c~nyon) iB only 60 percent of the drainage area upstream of
<br />Loveland. Flooding at Loveland may not hav~ alv~ys corresponded to flood-
<br />ing at the Drake gage. Various Bources indicate that approKimately 14
<br />floods occurred in the Loveland vicinity in 1864, 1894, 1906,1919,1921,
<br />ln3, 1938, 1941, 1942, 1945, 1949, 1951, 1976, and 1980. Tables 2and3
<br />s~arize the recorded flows for the gages near Drake and near LaSalle.
<br />
<br />,
<br />
<br />RE:\OURCE: CON\UlT~NT\ INC
<br />
<br />I.
<br />
<br />Table 2
<br />Peak FLood for the Big Thompson f~ver
<br />at Mouth of Ca~on near Drake-
<br />
<br />I
<br />1
<br />
<br />Date Discharge
<br /> (cia)
<br /> .
<br />July '. 1906 6,000
<br /> .
<br />Sept. '. 1938 5,600
<br />June 11, 1941 4,690
<br />June 7, 1942 3,730
<br />July 19, 1945 7,600
<br />June 21, 1947 2.320
<br />June 4, 1949 3,330
<br /> -
<br />Aug. J. 1951 3,530
<br />May 9, 1957 2,040
<br />June 16, 1965 2,220
<br />July 31, 1976 31,200 (eat,)
<br />
<br />,
<br />
<br />"
<br />- From USGS Gaging Station at mouth of canyon,
<br />500 feet upstream from Handy Ditch diversion
<br />dam and 6 ~iles east of Drake.
<br />
<br />.
<br />
<br />Not a continuous record.
<br />
<br />Table 3
<br />Feak Flood for the Big Thompson River
<br />near LaSallel)
<br />
<br />Date
<br />
<br />Dischatge
<br />(ets)
<br />
<br />.
<br />Aug. 4, H51
<br />May 9, 1957
<br />11ay16,1958
<br />June 4, 1961
<br />June 18, 1965
<br />May8,1969
<br />Apr. 27, 1971
<br />May 22, 1973
<br />A...g.1,1976
<br />May I, 1980
<br />
<br />0,100
<br />2,460
<br />1,760
<br />2,050
<br />1,480
<br />2,480
<br />1,130
<br />1,280
<br />2,500
<br />6,050
<br />
<br />"
<br />- Ftom USCS Caging Station on left bank 0.7 mile
<br />upstream from highway bridge, 1.6 milen upstream
<br />from mouth and 4 miles vest of LaSalle.
<br />
<br />.
<br />
<br />Not a continuous retard.
<br />
<br />"
<br />
<br />RE:\OURCE: CON\UlT~NT\ INC
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