Calculating lift is not simple and it has numerous variables.
My rule is - daily moving some water is "usually" but not always better than moving no water.
Bill I would have to think measuring the volume of water flowing through a plume of open water with no pipe surrounding it would have to involve a lot of estimation and speculation. Not that those estimations are not useful, just that it sure would not be any where near an exact measurement.
As far as "some" daily water movement usually being better than none I would suggest that is what nature does. Windy day, more water mixing, calm day less or none. Rainy day with inflows more water mixing, no rain no water mixing.
