India has had good luck building solar panels over irrigation canals. The shade substantially reduces the evaporation losses in the canal system. The framing is a bit tricky of course.
Beavers are one of the sadly misunderstood creatures and are almost entirely responsible for all the good valley farmland we have thanks to their thousands of years of terraforming.
If you can afford the medium term loss of land, a beaver setting up a dam on your property is a good thing. Unfortunately, most cannot, or are unaware of the benefits they bring and only consider them pests.