Part of the problem for “dry land” agriculture is the shift in what part of the year gets rain (and whether you get it all at once). It may be a matter of adding some reservoirs in the watershed to catch the erratic rain and release it more evenly for the sake of the river and agriculture.
Imagine if the Snake / Colombia / Kootenai Complex failed thus
All it takes is a dwindling snowpack …
Rivers run on rain, too.
Part of the problem for “dry land” agriculture is the shift in what part of the year gets rain (and whether you get it all at once). It may be a matter of adding some reservoirs in the watershed to catch the erratic rain and release it more evenly for the sake of the river and agriculture.
Also, bring in the beavers!
https://www.noaa.gov/sites/default/files/legacy/image/2021/Apr/30yrNormal_Precip_1901-2000_2480.png