Unreal 5.6 water simulation

Hi. I have made a river through shallow water simulation. some times it looks good in the scene but some times goes very up from the ground or some times goes very down from the ground. While taking the render it is giving me lots of pain. Too much art effects are coming. I could not get a single render perfectly. I am very sad by this result. I have checked in all the necessary plugins and put collisions too in the ground objects. Please help me