The Transcontinental Aqueduct. Leg 11: Cove Tank Reservoir to San Carlos Lake, a distance of 70 miles.

Stage 10 was a true pumped hydro-storage peak power stage, producing up to 11.5 GW electric power for up to 5 hours a day. In stage 11 the flow will be a maximum flow of up to 25,000 cfs, but with periods of less flow during low electricity demand, all to accommodate both water needs and power demands.

The Cove Tank Reservoir dam is 1 mile wide and 250 feet high, the top of the dam is at 4,000 feet. containing up to 60,000 acre-ft of water, enough storage for more than a day’s flow.

The Cove tank Reservoir starts out nearly empty when peak power demand starts, and is rapidly filling up until peak demand ends

The power generating drop is on average (3800 – 2535 – 70×2.2) = 1,111 feet. This stage is capable of generating maximum 2.2 GW of power during peak power demand, adjusted down at low power demand to not exceed the daily water supply.

San Carlos lake is located within the 3,000-square-mile (7,800 km2) San Carlos Apache Indian Reservation, and is thus subject to tribal regulations. It has been full only three times, in 1993 it overflowed the spillway and about 35,000 cfs of water caused erosion damage to natural gas pipelines. The lake contains now (April 6,2021) less than 100 acre-ft of water. All fish is dead.

When former President Coolidge dedicated the dam in 1930, the dam had not begun to fill. Humorist Will Rogers looked at the grass in the lake bed, and said, “If this were my dam, I’d mow it.”[

When the Transcontinental aqueduct is built the lake will always be nearly filled, with flood control nearly automatic, it will never overflow, and it will look like this:

The San Carlos lake, when filled will hold 1,000,000 acre-ft of water.

The Coolidge dam will have to be retrofitted for a 25,000 cfs water flow

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Retired engineer, graduated from Chalmers Technical University a long time ago with a degree in Technical Physics. Career in Aerospace, Analytical Chemistry, computer chip manufacturing and finally adjunct faculty at Pennsylvania State University, taught just one course in Computer Engineering, the Capstone Course.

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