I think op mentioning damming dry washes is meant to emulate beaver dams that essentially slow down the water during rain events and let it recharge ground water and the close to surface water table. Many dry washes used to be more perennial. Poorly planned human agricultural development lead to desertification.
Hard_Six t1_j326flf wrote
Reply to comment by MacDugin in Satellites watch 'atmospheric river' bring extreme rain to California — Satellites of the U.S. National Oceanic and Atmospheric Administration (NOAA) are monitoring the weather system, revealing its various aspects including wind speeds and expected amount of rain. by BlankVerse
I think op mentioning damming dry washes is meant to emulate beaver dams that essentially slow down the water during rain events and let it recharge ground water and the close to surface water table. Many dry washes used to be more perennial. Poorly planned human agricultural development lead to desertification.
Beavers and salmonids go hand in hand