• not for nothing, but the reduced growth of algae from a lack of UV exposure also means an increase in pathogens that would otherwise be killed by UV. it doesn’t really matter if the water is being treated downstream, but this idea (cover the water!) was posited as a potential solution to algae issues in irrigation water catchment/recycling where the water was similarly nutrient loaded and prone to blooms, often toxic. and where evaporation losses are costly.

    it creates other, different problems in terms of pathogens to overcome the “loss” of UV that have to be dealt with. fortunately the power/energy generation could be applied to operational needs for whatever that infrastructure looks like. so probably a UV water treatment solution downstream at the point(s) of use, assuming its for drinking or irrigation.

    fyi: the global average for inland surface water losses from evaporation is 3 meters per year. so, on average, an olympic size pool (50m long x 25m wide x 3m deep) loses its entire volume (almost a million gallons) over a year. or averaging around 2700 gallons a day.