Mariners are warned that numerous uncharted piles, snags, pumps, pipes and wrecks, some submerged, may exist along the edges of the waterway. Numerous buoys and signs mark the wing dams along the Sacramento River. Mariners should never attempt to pass between the warning buoys and the shore. The backwaters, sloughs and cuts are not maintained by the Corps of Engineers and numerous uncharted shoals and obstructions have been reported.  