I get that as I am a professional civil engineer. I live in the Columbia Basin in eastern Washington. The Tri Cities sits at 470 ASL.
300 miles at +/- 4000 feet of head will take some serious pumping.
Granted it wouldn’t be all uphill based upon the chosen route.
You would know then, if there is excess water in the northwest that washes away uncaptured. From time to time, surely, as in last month, but on a regular basis ?
I’ve spent little time there, so I’m searching blindly.