> Most of the water actually flows under the stones and isn’t exposed directly to the sun in order to reduce evaporation. Can somebody confirm this? it's not o

> Most of the water actually flows under the stones and isn’t exposed directly to the sun in order to reduce evaporation. Can somebody confirm this? it's not obvious to me that since the surface would be the same, that everything equal (average temperature of the water probably not?), the evaporation would be the less in this case vs normal stream.