Sand budgets at geological, historical and contemporary time scales for a developed beach system, Saco Bay, Maine, USA

At the present time, 56 million m3 of sand reside in the shoreface and 22 million m3 of sand are beneath the barrier beach and dunes. The Saco River has been the major source of sand to the bay, providing an estimated 10,000-16,000 m3 of sand per year. The net direction of sand movement is to the north, where river-derived sand has historically fed growth of barrier spits. Construction of the north jetty at the Saco River mouth profoundly altered the prehistoric patterns of sand movement and storage in the bay, causing the northward migration of almost 6 million m3 of sand between 1867 and 1955. Contemporary dredging of tidal inlets involves sand volumes approximately equal to the influx of sand delivered by the Saco River.