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o i- "t') N for gravity flows through Oak Ridge Tunnel. The pool could be con- veniently increased to benefit recreation and fish and wildlife if desired. The dam would be about 329 feet high with a crest length of 1,560 feet. The streambed elevation of 7,155 feet is 235 feet higher than at the Lake Avery site. An earthfi11 dam at Sawmill Mountain would have an estimated embankment volume of 5,733,000 cubic yards, which is about 1.1 million cubic yards more than the Lake Avery enlargement. Because of reservoir basin topography, Sawmill Mountain Dam would be about 115 feet higher than at Lake Avery for equivalent storage. Maximum physical storage capability of the site (if needed) is about 79,000 acre-feet. Because of the narrow reservoir basin at Sawmill Mountain, some of the construction materials would probably have to be borrowed from other areas. The construction of a concrete dam at this site might be warranted. An artist's concept of the Sawmill Mountain Dam and Reservoir is shown on the following page. Most of the Sawmill Mountain Reservoir basin is in private ownership with small areas of National Forest and National Resource Land in the upper reaches. The bottom land along the stream is presently irrigated pasture in long narrow tracts. The sides of the basin are relatively steep and mostly brush covered with some groves of spruce and aspen on north facing slopes. The entire area is used for livestock grazing and wildlife habitat. Based on a preliminary geologic examination of the area in 1966, no serious geologic problems at the Sawmill Mountain site are anticipated. On the abutments, shallow depths to bedrock are expected. Reconnaissance field surveys revealed no existing landslides in the basin. North Fork Feeder Conduit In order to accommodate the Sawmill Mountain Reservoir with gravity inflows, the North Fork Feeder Conduit would begin at a point on the North Fork between Lost and Marvine Creeks. This point is about 3.7 miles up- stream from the location intended under the Lake Avery Plan. An aerial view of the proposed location is shown on page 8. Because of possible icing problems, the North Fork diversion struc- tures at the head of the feeder system has been redesigned to allow free river flow and eliminate potential ice jams. Flows to be diverted would be channeled into the pipeline intlet and flows for fishery and downstream rights simply bypassed. The North Fork Feeder Conduit would be made up of 4.5 miles of buried concrete pipeline and the 4-mi1e long Bob Raley Tunnel. The location and alignment of the tunnel is shown in the photo on page 8. In addition to being the most economical conveyance, the tunnel should present fewer environmental problems than the Lake Avery plan. It would avoid laying a pipeline through a narrow valley section between Crooks Creek and Buford. Another major advantage to this feeder system is that it wu1d be an a11- gravity line, eliminating the need for the Avery Pumping Plant and the associated annual energy cost. 6