I am seeing few pumping station wet well levels start to drop down even before the pump turn on. Effectively the wetwell levels do not reach the duty cut off levels for number of times but going up and and down below the cut off levels.

Can this be explained please. I have pasted couple of examples. In one station the cut off depth is 0.804m. wet well rose many times but did not reach 0.804m all the times and had dropped down. Only the few time it reach 0.804m the pumps kicked on with spiky flows.

I was trying to paste or attach the model output graphs to this posting but not working for me.
Mathy