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0052 3.4 ,r.p . 1 ~.. an extremely dry year (period of record 1948-1980). Average an~ual replace- ment storage under the present operational conditions is 1,000 acre-feet. The remainder of the conservation storage volume is available for other uses. Ruedi Dam is constructed of earth and includes a spillway, outlet works, auxiliary outlet works, and Rocky Fork Creek bypass. The dam is 285 feet high above the streambed, 30 feet wide at the crest, and 1,042 feet long. The concrete spillway capacity at maximum water-surface elevation 7,781.8 is 5,540 cubic feet per second (cfs). The outlet works are located through the rock formation under the right abutment of the dam at the bottom of the conser- vation pool (see Table 3.1). The main outlet work capacity at reservoir level 7,766 is 1,000 cfs. The auxiliary outlet works have a capacity of 600 cfs at reservoir level 7,766. The Rocky Fork Creek bypass consists of an earth dike and a 25-foot wide concrete overchute across the spillway stilling basin. The bypass has a capacity of 4,000 cfs. The Fryingpan River below Ruedi Darn is a cobble and boulder bed channel typical of high mountain streams in the Rocky Mountains. The average gradient of the river from Ruedi Darn to its confluence with the Roaring Fork River at Basalt is 69 feet per mile. Near Castleview Ranch the gradient of the Fryingpan flattens to 32 feet per mile and the river adopts a slightly mean- dering form. The general form of the Fryingpan River is controlled by the steep walls of the canyon and the river is quite restricted for any lateral movement. Average width of the river is approximately 100 feet with steep boulder banks. Because of the large size of the bed and bank materials that form the Fryingpan River, the channel is very stable. The interstitial areas in the channel bed are filled with coarse sand. Through most of its length to the town of Basalt the channel capacity is adequate to contain the pre-darn mean annual flood in excess of 1,000 cfs. Some flooding did occur into low- lying areas of the flood plain at these flow rates prior to construction of Ruedi Darn. The channel did not experience any significant bank or bed erosion from pre-dam, mean annual floods. Sources of sediment to the Fryingpan River below Ruedi Darn are from Rocky Fork Creek and numerous small tributaries. Rocky Fork Creek is the only tri- butary with a sustained discharge over the year. During the spring runoff, Rocky Fork yields fine sediments that produce turbidity. Other small tribu- taries will produce brief periods of turbidity in the Fryingpan River.