Reading @grant_fisher's point about watershed monitoring, it reminded me of this collective in the Pyrenees that rigged up a micro-hydro system using an abandoned irrigation canal. They had to manually clear debris every spring, which honestly sounded like a nightmare, but the constant flow from glacial melt meant they rarely had downtime. Their whole setup was basically held together with zip ties and optimism, but it powered their communal kitchen and workshop for years. The original builders apparently scavenged most of the parts from a defunct mining operation nearby.