if the pv bit works, adding some underwater robot scutters to deal with housekeeping the irrigation canal (flora, twigs, gators etc) tidy would be cute
It depends if the canal has any other uses. In the UK, canals were built more for transport than for water distribution, although some are used for both. Sounds a good idea across Arizona if it is mainly used for water though. We were watching a robot leaf remover yesterday and it works reasonably well. Other water intakes have mesh at the inlet to stop sticks and leaves going in. As you say, for algae and the like, fish would do a good job.