Zach Weiss is doing a lot to educate and mobilize people around local water storage and enhancement projects at
https://www.waterstories.com
I haven't taken any of their (somewhat costly) courses, but enjoy the highlight vids and community discussion on mighty networks.
Currently testing out some smaller scale collection ponds I was able to excavate with rented backhoe last spring, as I experiment with optimal configuration in somewhat challenging climate and hydrology. Good amount of surface water available during wet season, but pond basins will dry out usually by mid summer, and then I worry may contribute to greater *loss* of soil moisture during the rest of the year...
I think in semi-arid or Mediterranean climate like this, it's important to emphasize pond depth over surface area, and perhaps line the side walls with stone, clay, or synthetic liner to limit evaporative loss? And ideally, get trees established around the margin to help protect it.
Anyways, fun stuff to tinker with and see what works! Good to have more people aware and working together at watershed scale, ultimately.