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<br />WATERSHED PROBLEMS
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<br />The principal problem is control of runoff, which under present
<br />conditions causes significant floodwater, sediment, and erosion
<br />dwuage. The topography of the area and generally low infiltration
<br />rates of the soils are conducive to high runoff, The locations of
<br />problem areas are shown on Figure 1 and estimates of annual dmuages
<br />are presented in Table 7.
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<br />Floodwater Damage
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<br />Records of severe flooding along Cherry Creek date back to 1864,
<br />Flood,s of major proportions occurred on: May 19-20, 1864; July 20,
<br />1875; May 22, 1876; May 22, 1878; July 26, 1885; July 14, 1912;
<br />July 28, 1922; August 3, 1933; and May 30, 1935, Major floods in the
<br />Franktown-Parker segment of the Cherry Creek drainage occur about once
<br />in every 8 years and minor floods may be expected at least once a year,
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<br />The flood of July 14, 1912, was caused by intensive rainfall in
<br />the Franktown-Parker area and produced an estimated peak flow of 25,000
<br />c,f,s. at the tOtvn of Parker. The flood of July 28, 1922, was caused
<br />by a local storm over the Bayou Gulch drainage with the main storm
<br />covering 19 square miles along Bayou Gulch. Reported rainfall ranged
<br />up to four inches. The estimated peak flow near the mouth of Bayou
<br />Gulch was 8,700 c.f.s. Downstream on Cherry Creek at a point three
<br />miles north of Parker, the peak flow was estimated at 17,000 c,f,s,
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<br />These and other storms have since enlarged the channel capacities
<br />of Bayou Gulch, Sulphur, Scott, Lemon, and other tributaries in the
<br />lower portion of the watershed. Consequently, overbank flooding is
<br />infrequent and floodwater damages insignificant, Stream reaches which
<br />have channel capacity equal to or greater than 10-year frequency flow
<br />are shown in Figure 1.
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<br />The storm of August 3, 1933, with a reported precipitation of 8
<br />inches, centered above the site of Castlewood Dam, an irrigation water
<br />storage structure south of Franktown. The resulting runoff overtopped
<br />the dam and caused structure failure,
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<br />The storm of May 30, 1935, caused dan~ge estimated at $1,700 in the
<br />town of Parker, Residential property, business establishments, and town
<br />streets were damaged. A flood in 1938 in the vicinity of Parker also
<br />caused severe damage in town, The most recent minor floods in the
<br />watershed occurred in 1954 and 1956. The 1954 flood caused county road
<br />and bridge damage in excess of $24,000,
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<br />Sediment Damage
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<br />The principal sediment damage results from the deposition of silt and
<br />sand on floodplain lands, thereby reducing their productive capability,
<br />Approximately 900 acres have been damaged or lo&through sediment deposition
<br />from past floods, Much of the land that has been lost or damaged was sub-
<br />irrigated meadow land of key importance to the economy of the area for the
<br />production of hay crops, Many of the stockwater ponds on tributary streams
<br />have been subjected to moderately high losses in storage capacity from
<br />sedimentation. Large amounts of sediment are produced in certain upstream
<br />tributaries where active channel headcuts are advancing through the
<br />upstream meadow lands,
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