what is the relevance of needing to have a lot of pumps? Do you think the engineering involved is beyond the capability of the US, and your argument now is that it cannot be done?

The idea that californias water projects only direct water downhill is invalid anyway - the California aqueduct flows uphill quite a lot, and over mountains.

https://en.m.wikipedia.org/wiki/Edmonston_Pumping_Plant is one of at least 5 pumping plants along the aqueduct.

Kind of interesting though in that you kill two birds with one stone. Water for the desert and a massive pump storage battery.