So here are Zach's choices:
Sepp Holzer, Rajendra Singh, Waangari Maathai, Viktor Schauberger, Zepheniah Phiri Maseko, Josephine Mandamin, Erin Brackovich,
Willie Smits, Nicole Masters, and Peter and Kate Marshall.
I admit I've heard of many of these people, but not all.
However, I feel Zach missed a couple that I absolutely consider my Heroes of Water and that would be Mr. and Mrs. Beaver. OK, so maybe that's a whole species, rather than individuals, but for sheer volume of water slowed and infiltrated, ecosystem balance restored, and runoff of topsoil and nutrients prevented, Castor canadensis and Castor fiber are totally my heroes. They are self-replicating, work for food, know when it's time to move on to let an ecosystem's
trees recover, and they don't send me a bill at the end of the month.