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<br /> <br />e. Ungaged Sites on the North Fork Gunnison and Gunnison Rivers. <br />Peak flow-frequency curves for the ungaged sites on the North Fork Gunnison <br />and Gunnison Rivers were based on regionalized peak flow-frequency statis- <br />tics (mean, standard deviation, and skew coefficient). The n~an peak dis- <br />charge for the curves was based on the relationships shown on Chart 4. The <br />standard deviation and skew coefficients for the curves were based primarily <br />on the values adopted for the linear Somerset, II lInear Grand Junction," and <br />"below Gunnison Tunnel" gages, and secondarily on the values adopted for <br />other gages in the area. Frequency curves for the ungaged sites are shown <br />on Charts 17-25. <br /> <br />Peak flow-frequency statistics for the index points on the North Fork <br />Gunnison and Gunnison Rivers are shown in Table 3 (on page 11). <br /> <br />11. Peak Flow-Frequency Analysis <br />flow-frequency curves for present <br />Gunnsion and Gunnison Rivers were <br /> <br />for Present (Regulated) Conditions. <br />(regulated) conditions on the North <br />developed as deseribed below. <br /> <br />Peak <br />Fork <br /> <br />a. North Fork Gunnison IUver near Somerset. The peak flow-frequency <br />curve for the North Fork Gunnison River near Somerset was based on the: <br /> <br />(1) Curve for natural conditions. <br /> <br />(2) Plotted peak and maximum I-day flows since regulation of Paonia <br />Reservoir (1961-1976). <br /> <br />(3) Curve for maximwfi I-day flows for project conditions and the hypo- <br />thetical routings of the May 1952 and June 1957 floods (in the report on <br />reservoir regulation of Paonia Reservoir). <br /> <br />(4) Maximum safe downstream channel capacity of 3,500 cfs. <br /> <br />The adopted curve, shown on Chart 14, satisfies the established criteria in <br />a "best fit" manner. It follows the curve for natural conditions to the <br />intercept with the computed curve, then generally follows the computed curve <br />until it approaches the curve for natural conditions at about the 200-year <br />exceedence interval. <br /> <br />b. Gunnison River below Gunnison Tunnel and near Grand Junction. Peak <br />flow-frequency curves for the "below Gunnison Tunnel" and "near Grand Junc- <br />tion" gages were based on the: <br /> <br />(1) Curves for natural conditions. <br /> <br />(2) Plotted peak flows since regulation of Blue Besa Reservoir (1966- <br /> <br />76). <br /> <br />10 <br />