The main flow into the estuary comes from the Ballyboghil River and its terminal tributary, the Corduff Stream. Other watercourses entering the estuary include one from Portrane, Balleally Stream, and also Bride's Stream and Jone's Stream, from the Lusk area, and a number of small flows.

The estuary is made up of saltwater marshes, raised salt marsh, wet meadows and riverine shallows and creeks. It covers an area of 3.63