1 - Alaska Energy Data Inventory

opening (in 0.2 seconds) valve. The WHAMO input file is shown in Appendix82 as figure 20. Using conservative (minimum) friction values for thetunnel and gate shaft and a realistic maximum lake elevation of 1,019 ft,it was found that an initial gate shaft water surface elevation of 995 ftwill result in a maximum surge elevation of 1,039.7 ft which will keep thecontrol room dry. This will provide an "initial head differential of 24 ftbetween the lake surface and the gate shaft (and the rock trap vicinity),which is approximately the same head differential used at Oks1a (26.2 ft).This differential is considered adequate to assure that the overburden andblast debris from the plug is carried into the primary rock trap.Water surface oscillations in the gate shaft following the blast ascalculated by "WHAMO" are shown on figure 21 in Appendix 82. The period ofthe initial oscillation is 26 seconds and maximum water surface elevationis 1,039.7 ft occurring 13 seconds after the blast. The peaks of theoscillations decrease rapidly with time due to friction losses. Max"imumdischarge through the plug area is 325 ft 3 /s and occurs 6 seconds afterthe blast. Maximum discharge up the gate shaft is 323 ft 3 /s and alsooccurs 6 seconds after the blast.Gate shaft water surface oscillations were also calculated manuallyusing an arithmetic integration procedure. Results compared well withthose calculated by "WHAMO". Maximum WSEL in the gate shaft was calculatedto be 1,038.7 ft, occurring 14 seconds after the blast.To determine the maximum force on the service gate due to the blast andsubsequent surge of water up the gate shaft, a summation of forces was madeat two second intervals up to 16 seconds after the blast based on the WHAMOresults. The forces considered were hydrostatic force due to standingwater in the gate shaft, momemtum force due to the change in direction ofthe water upon striking the gate, and the blast force. The maximumhydrostatic plus momentum force based on the WHAMO results is 765,000 "lb.An approximation of the force which will result from the blast is based on81-46