> It was basically a desert with a river (or rivers) running through it and they built a series of irrigation canals. My understanding is that much of the Cent

> It was basically a desert with a river (or rivers) running through it and they built a series of irrigation canals. My understanding is that much of the Central Valley was actually a (seasonal?) marshland/grasslands ecosystem, not a desert environment. The irrigation and diversion to Southern California caused many large, shallow lakes (e.g., Tulare Lake) in the region to dry up entirely.