No experience with a project like that but what you will need is a trash type pump or semi-trash type pump rather than a clear water pump. Trash pumps are centrifugal type pumps with internal clearances such that some sand and grit will not particularly hurt them. Clear water pumps can be made closer tolerances so they pump more efficiently but abrasive materials will significantly shorten life and rocks or gravel may totally destroy them.

John

I subscribe to Pond Boss Magazine