This leg will start with a free-flowing Gila River for 30 miles, followed by the painted Rock Reservoir for 20 miles, the Painted Rock Dam.
The dam is at elevation 661 feet and runoff starts at 550 feet. Drainage capacity is adequate and maximum storage is 2 million acre-feet. The population of Indians and early settlers are already resettled and compensated. To fill the dam with the 2,500 cfs flow available in phase 1 would take over a year. The reservoir will be used to even out seasonal demand.
After the dam Gila river will be free glowing for 90 miles until it joins the Colorado River in the first pass. In the second pass there will be an aqueduct built with a capacity of 7,100 cfs flow for 100 miles to the
To the Martinez lake it can deliver up to 7,100 cfs. ( The design capacity of the All American canal is 15,155 cfs.) The Martinez lake is puny, and would easily be overwhelmed by surges in the water flow. To accommodate this, the Senator Wash Reservoir will have to be upgraded to be able to pump up or release at least twice as much water as is its present capacity. Lake Martinez is at about 180 feet elevation, and Senator Wash Reservoir is at a maximum elevation of 240 feet.
The rest of the Transcontinental Aqueduct empties out where the Gila river joins the remainder of the Colorado river a few miles downstream. It will carry on average 2,100 cfs of water to accommodate the needs of Mexico and also provide a modest amount of water to assure the Colorado river again reaches the ocean, maybe restoring some shrimp fishing in the ocean.
The 1944 water treaty with Mexico provides Mexico with 1.5 million acre-ft per year, more or less dependent of drought or surplus. It will be increased only on condition that when the Transcontinental aqueduct is finished, the New River in Mexicali will be cut off at the border, and Mexico will have to do their own complete waste water treatment.
There will be water allocated to the Salton Sea. Proposed will be the world’s largest Lithium mine, mining the deep brine, rich in Lithium. (about a third of the world supply according to one estimate). This requires water, and as a minimum to allow mining in the Salton Sea the water needs to be cleaned. This requires further investigation, but the area around the Salton Sea is maybe the most unhealthy in the United States.
What’s in it for Mexico? Mexico will get sweet , reliable water, much better suited for agriculture..
What’s in it for Arizona? The farming downstream will be better served by reliable sweet water.
What’s in it for California? The All American Canal will get a reliable supply of sweet water.
What’s in it for Lake Mead? The lower Colorado river will get an infusion of about 15,000 cfs, or about 10 MAf, which will allow lake Mead to recover by 8 to 10 MAf per year. This should solve the Colorado River’s water problem until the population served by the Colorado River reaches 60 million people.