Recovering the Sand Deficit from a Century of Dredging and Jetties along Florida's Atlantic Coast: A Reevaluation of Beach Nourishment as an Essential Tool for Ecological Conservation.

A sand deficit on Florida's Atlantic coast affects sea turtle nesting, dune ecosystems, and storm protection. Ecological benefits of restoring very large deficits could exceed ecological costs. Dredging and beach nourishment databases revealed sand disposal dynamics and deficit size. Dredge-and-fill activities increased after 1950, peaked in the 1980s, then declined somewhat. Most sand disposal accompanied channel and harbor deepening; little was primarily for beach nourishment. Until the 1970s most dredged material was placed outside the coastal sand-sharing system (offshore and upland). After 1970, beach and nearshore disposal rapidly increased, but generally involved sand already within the system. Moreover, offshore and upland disposal did not immediately decline. To date, little sand has been returned. By 2003, net removal totaled ∼130 × 10⁶ m³. Channels and harbors increased by ∼70 × 10⁶ m³, leaving 60 × 10⁶ m³ of standing sand deficit. Jetties could have redistributed another 70 × 10⁶ m³ from beaches and dunes to inlet shoals. Overall, loss of beaches and dunes could approach 130 × 10⁶ m³. Engineering responses to past objections have improved both habitat suitability and longevity of nourished beaches. Through field trials and adaptive management principles, ecologists could now develop beach nourishment into a management tool to rebuild lost habitat, restore the sand deficit, and stockpile additional sand before nonessential channels and harbors are allowed to refill. With large projects, sand from offshore, upland, and ebb shoal sites and natural wave energy for stable beach building, beach and dune habitat can be restored within decades, better preparing threatened animals for rising sea level. [ABSTRACT FROM AUTHOR]