 The main tributaries are the Nonesuch River, Dunstan River, and Libby River, as well as smaller brooks and streams.In its natural state, it was a sediment sink for Saco Bay, storing sediment migrating northward up the bay from the beaches to the south and ultimately from the Saco River.The channel migrated regularly in response to natural events; as it did so, abandoned sand banks would replenish the sand on both Pine Point Beach to the south and Western and Ferry beaches to the north.