[detritus]

They're also covering water canals with solar panels, which a) makes use of otherwise wasted space, b) reduces evaporation of the water, c) reduces algal and weed growth which causes toxicity and flow problems and d) encourages cool shaded zones beneficial to local wildlife.

[tuatoru]

And e) increases the output of the solar panels - they perform better when cooler, and water is better at doing that than soil.