20# should be more than enough when dropping in a lake. The curren tends to be spread out more because the dam is drawing from the lake as a whole. Only if you are placing in the far upper end of the lake where the river enters and creates the lake should you have concern. Once the river has dispered into the lake, the current tends to stabilize quite a bit. A very windy day will cause a current that might be opposite of normal flow direction. Also, the amount of cubic feet per second being released would contribute to the amount of current within the lake.Originally Posted by Henman