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<br />1300338 <br /> <br />Recreational Uses <br /> <br />Elkhead Reservoir is currently a popular recreation site for residents of Hayden and <br />Craig. The reservoir has a boat ramp, swimming and picnicking areas that are heavily used <br />during the summer months. Elkhead Reservoir is wideIy used for fishing, both from boats and <br />from the reservoir banks. Swimming is somewhat less popular at the reservoir, due in part to <br />high sediment loads of the water carried in from Elkhead Creek, Access to the reservoir is <br />excellent with paved roads to within a mile of the reservoir. <br /> <br />Proposed Elkhead Dam and Reservoir Enlargement <br /> <br />Physical Facilities <br /> <br />The proposed project calls for raising the crest of Elkhead Dam 45 feet to elevation <br />6,420 MSL. This elevation was judged to be the maximum reasonabIe height the existing site <br />topography permits, This produces a normal full pool reservoir elevation of 6,406 feet and a <br />storage volume of approximately 44,900 af. <br /> <br />The enlarged Elkhead Dam wouId be constructed in a manner simiIar to the construction <br />of the original dam. The enlarged dam would be an earthfill structure, with the original dam <br />Ieft in pIace to act as a portion of the new structure. The dam raise would proceed from the <br />downstream face, thereby not requiring full evacuation of the reservoir during the construction <br />process. <br /> <br />The existing spillway would be removed and replaced by a similar service spillway <br />immediately to its left. The new spillway would have a 100-foot long crest at elevation 6,406 <br />and wouId be capable of passing the 100-year flood. More infrequent floods wouId pass <br />through both the service spillway and the higher emergency spillway. <br /> <br />The existing primary outlet would either be removed or extended to the new spillway <br />chute. A new 6-foot diameter primary outlet would be constructed immediately to the right of <br />the new service spillway. An optional 2 MW hydroelectric power generation facility wouId be <br />positioned near the toe of the dam adjacent to the new spillway chute stilling basin. <br /> <br />A raise of the dam crest to elevation 6,420 MSL would pennit an emergency spillway to <br />be cut through a saddIe in the right abutment to an adjacent drainageway which joins Elkhead <br />Creek one mile downstream. The new emergency spillway would have a crest elevation of <br />6,409 feet, Features of the enlarged dam and existing dam are shown Figures 2 and 3. <br /> <br />Reservoir Operations <br /> <br />Contract Storage <br /> <br />Additional storage capacity created by enlarging Elkhead Reservoir would be used to <br />provide supplemental water directly to users with inadequate direct flow supplies below <br />Elkhead Creek. Water in the enlargement would also be used to augment reductions in <br />streamflows resuIting from subordination of the Juniper decree based instream flow right and <br />to maintain the instream flow regime that would otherwise result from a Juniper-based instream <br />flow water right on the lower Yampa River. <br /> <br />In order to maximize recreational opportunities, an enlarged Elkhead Reservoir would <br />likely be operated to maintain seasonaI recreation pooIs. Reservoir operation investigations <br /> <br />4 <br />