Here those dumps are usually in a washout, so its best to leave them, its no different than rip-rap and you might make it worse than it was. Just like in the town by us they used to dump all the old derby cars in the river in this one spot to keep it from washing, there were probably 100 cars there from the late 60s and 70s, the Corp of engineers decided that it was a "hazard" to all the fish, pulled them all out and now they wonder why the bank is washing away and filling the river with more sand.