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<br />MOUTH OF CANYON <br /> <br /> <br />This gage is located about 2 miles west of the junction of Colorado <br /> <br /> <br />Highway 14 and U.s. Highway 287 northwest of Fort Collins. The period <br /> <br />of discharge records available at this stream gage was from 1882 to 1976 <br /> <br /> <br />including an estimated discharge for the 1904 event. In the final dis- <br /> <br />charge-probability analysis of the gaged data, the period 1910 to 1976 <br /> <br /> <br />was selected as being the most representative of existing control condi- <br /> <br /> <br />tions in the basin. The years of record prior to 1910, except 1904, <br /> <br /> <br />were not used because Halligan Reservoir, built on the North Fork in <br /> <br /> <br />1910, provides significant attenuation effects downstream. The gage <br /> <br />was destroyed during the flood of 20 and 21 May 1904. Follansbee and <br /> <br /> <br />Sawyer in Floods in Colorado, USGS, 1948, quote J. A. Armstrong, an <br /> <br /> <br />irrigation engineer who investigated the flood, as saying that the <br /> <br /> <br />storm wa~ centered "about Stonewall Mountain at the head of Stonewall <br /> <br /> <br />Creek .. The volume of water passing Livermore has been estimated <br /> <br /> <br />at 20,000 cubic feet per second." Since most of the runoff generated <br /> <br /> <br />by the 1904 storm was below the Halligan Reservoir site, the flood with <br /> <br /> <br />an estimated peak discharge of 25,000 cubic feet per second was used in <br /> <br /> <br />the freqJency analysis as a historic event. The flood routings of <br /> <br /> <br />Seaman Reservoir indicated very little effect on downstream peak dis- <br /> <br /> <br />charges. Therefore, no adjustments of the annual peaks were required <br /> <br />for the peTiod of record before Seaman Reservoir became operational in <br /> <br /> <br />1947. The generalized skew coefficient of +1 obtained from the Corps <br /> <br /> <br />of Engineers regional study of similar streams was used to help shape <br /> <br /> <br />the distribution. The computed skew of +1.3 was weighted with the +1 <br /> <br /> <br />generalized skew coefficient, giving an adopted skew of +1.2. The <br /> <br /> <br />resulting curve, along with confidence limits and adjustments for <br /> <br />length of record, is shown in figure 2. <br /> <br />NEAR GREELEY <br /> <br /> <br />This gage was analyzed in the 1973 studies. The discharge-proba- <br /> <br /> <br />bility analysis of the Greeley stream, gage was based on 51 years of <br /> <br /> <br />record, from 1916 to 1970. The frequency curve was normally distributed <br /> <br />8 <br /> <br />. <br /> <br />. <br />