Stage 8 ended in Arch Lewis Lake. It will be filled mostly during the 5 hours of peak power generation. During the other 19 hours the fill rate will be very low leading to lowering water levels.
It has a 3000 feet wide and up to 480 feet high dam, topping out at 4620 feet, and the lake holds a volume of up to 60,000 acre-ft of water.
From the Arch Lewis Lake dam to the Martin Tank Lake the distance is 60 miles the way the aqueduct takes. It will first descend to 3720 feet before rising to 5190 feet. The descending drop is (4620 – 3720 – 2.2 x 9), or up to 890 feet. The Martin Canyon Lake will top out at 5200 feet with maximum water level at 5190 feet. The total lift of the water in this stage is (5190 – 3720 + 51×2.2) feet = 1582 ft. To lift 25,000 cubic feet per second (1582 x 1.03 – 890 x 0.97) = 766 feet requires three 500 MW LFTR nuclear reactors plus the use of 80 MW from the grid. The Martin Tank Lake dam is 22260 feet wide and 230 feet high. It will contain about 30,000 Acre-ft when full, about eighteen hours worth of storage. For 5 hours per day the three reactors can provide 1.5 GW of peak power to the grid.