The solution is to limit access to livestock on a waterway. Fence them off except for a small enclosed area that extends into the river. Livestock access is a major contributer to erosion and pollution in our rivers. It is illegal to fence across a navigable body of water and I have cut fences down while canoeing in southern ontario. Make sur your wire cutters are insulated. Some idiot actually run electric cattle fencing acroos canoeable waterways.