L - Alaska Energy Data Inventory

SUMMARY OF CHANGESGENERALField surveys during 1978 revealed that topography for Watana damshown in the 1976 Interim Feasibility Report was 15 feet higher thanactual conditions. Data in this report has base elevations correctedto the 1978 topography. Only plates or text revised for this submittalwill reflect the new elevations which are 15 feet lower. The top ofdam is now shown at elevation 2,195 feet and normal pool at elevation2,185 feet.Quantities and cost estimates have been revised and updated toOctober 1978 levels. The cost for Watana dam and reservoir (first-added)is $1,765,000,000 versus $1,088,000,000 in the 1976 report. The costfor Devil Canyon dam and reservoir (second-added) is $823,000,000(concrete gravity) and $665,000,000 (concrete arch) versus $432,000,000(concrete arch) in the 1976 report.A construction schedule reanalysis resulted in the extension of theconstruction period from 10 to 14 years. Initial power-on-line isanticipated in 1994.WATANAThe main dam cross section was revised to best utilize materials asdetermined in 1978 field investigationso A grouting gallery was addedunder a portion of the dam.The spillway was moved laterally and revised to take better advantageof rocklines and to discharge directly into Tsusena Creek at stream1 evel .The outlet works were revised to improve hydraulic layout andaccess into the intake structures.The diversion tunnel portals were relocated in better rock basedupon information obtained from the exploration program.The power intake selective withdrawal system was revised to be morecomparable with those currently in use at other projects.Rock excavationtinuous cut slope.should be terraced.are compatible withquantities in the 1976 report were based on a con­Foundation explorations concluded that the rock cutsData in this report is based upon rock cuts thatthis latest field information.B-1