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<br />The South Platte River flows through the county in shifting
<br />channels in a broad, shallow bed with low, flat overbanks. It is a
<br />continuous flowing stream, whereas all the tributaries except Clear
<br />Creek are intermittent flowing streams. The South PlaCte River and
<br />its tributaries have two major flooding characteristics, snow melt
<br />and summer weather fronts or thunderstorms. The tributary basins
<br />are narrow, hydraulically steep, and composed of highly erodible
<br />clay loam soils. In the undeveloped portions of the basins, the
<br />ground cover is predominantly short grass called buffalo grass and
<br />willow and cottonwood trees. Clear Creek and tributaries in the
<br />eastern two-thirds of the county flow in wide flat channels similar
<br />to the South Platte River.
<br />
<br />Development has occurred up to the channels on the tributaries.
<br />The floodplain on the South Platte River in the past was mostly
<br />agricultural, but today commercial, industrial, and residential
<br />development has encroached into the floodplain. In most of the
<br />segments of the floodplains, development pressures continue to
<br />exist. The county government is working to retain the open space
<br />of the floodplain areas.
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<br />2.3 Principal Flood Problems
<br />
<br />Major recorded floods have occurred on the South Platte River and
<br />its tributaries since 1844 in the Adams County area. During that
<br />period, eleven devastating floods have occurred on the South Platte
<br />River, three on Clear Creek, and three each on Box Elder, Comanche,
<br />and Bijou Creeks.
<br />
<br />In 1844 and 1864, reports stated that "bottomlands near Denver were
<br />covered with water bluff to bluff" (Reference 20). By 1876,
<br />encroachment into the floodplain had developed to such an extent
<br />that on May 23, 1876, the Rocky Mountain News reported that, "(The
<br />South Platte River) was higher to be sure.. .several feet higher
<br />perhaps in 1864.. .but it was not able to work such destruction at
<br />that time as now. There was not so much town here in 1864, as now,
<br />nor as many bridges." (Reference 17).
<br />
<br />The most significant floods of recent times on the South Platte
<br />River occurred in 1912, 1921, 1933, 1935, 1942, 1965, and 1973.
<br />The discharges for these floods were 13,000 cubic feet per second
<br />(cfs), 8,790 cfs, 22,000 cfs, 12,320 cfs, 10,200 cfs, 40,300 cfs,
<br />and 33,000 cfs, respectively, at the Denver gage. Clear Creek
<br />experienced flood discharges of 8,700 cfs, 5,390 cfs, and 5,250 cfs
<br />in 1888, 1933, and 1956, respectively recorded at the Golden Gage.
<br />ci tizens interviewed in Watkins, Strasburg, Byers, and Deer Trail
<br />recalled severe damage and lives lost in 1905, 1933, 1935, and 1965
<br />floods on Box Elder Creek, Comanche Creek, West Bijou Creek, and
<br />East Bijou Creek.
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