With all that water you need to get from that big Orange basin to the Real blue one they come close to each other in North Cal and Oregon a few tunnels under the basin divide or a pressure pipeline and siphon system would work. Once in the teal basin the California water project existing system can get water all the way to San Diego and the Central Valley then California can stop taking 7+ million acre feet from the Colorado River system leaving it for Nevada , Arizona and the upper basin states to use no need for a pipeline over the Sierra Nevada mountains just stop California from taking so much in the first place. The Coronado river compact should be avoided anyway it is based on faulty science and a whole new negotiation should be had. One where California doesn’t get 7 million acre feet every year regardless of what the other states get even in drought years. F California and their agricultural mafia.
https://biggerpieforum.org/environment/veins-america-stunning-map-shows-every-river-basin-us/
Interesting map of river systems. Weather pattens are more unpredictable than most people realize especially in the mountains. In the Northwest any prediction more than 3 days out is typically pretty iffy unless you are already in the middle of a wet or dry spell.
I wouldn’t say that it is not possible, but there would be major issues trying to get water from Washington to California. First, the Columbia River is in the way, but if you take a look at the topography other more major issues arise. The elevation of the Columbia River is only about 150 ft AGL as it crosses from Eastern Washington to Western Washington. The plateau in Eastern Oregon is over 4000 ft. AGL and if one hoped to channel the water through Western Oregon the passes that one must travel through to get to Northern California reaches a similar elevation.
If one believes that California’s high speed train project is a boondoggle... A 1000 mile long pumping a massive amount of water to a 4000 ft. elevation gain would make it seem like a walk in the park.