Backdunes provide a layer of protection
Maui’s coastal dunes can be divided into four unique zones: the beach, foredune, trough and backdune. Backdunes are typically more complex than foredunes, with greater biodiversity and more developed vegetation. Backdunes are where you might find wetlands, dune crests and sand plains supporting a host of native plant and animal species like native seabird nesting sites.
In South Maui, UH Sea Grant has participated in helping volunteers develop and restore backdune areas wherever possible. In those areas, we are discovering that over time backdunes can contribute a considerable amount of new sand volume to the dunes after exotic or invasive plants have been removed.
Backdunes provide a secondary layer of safety for our inland developments, serving as a natural buffer from storm and flood inundation. Dune structural integrity is maintained as insurance against beach and landward erosion. Unfortunately, backdune areas have sometimes been used for roadways, parking lots, and developments like residential and condo buildings, making it impossible to ever recapture that important dune area.
The value of backdunes is known science and the Coastal Hazard Specialists from UH Sea Grant are always ready to help delineate dune space suitable for foredune and backdune areas as part of a comprehensive Foreshore Asset Management Plan. With the sea level rising, the passage of time with no plan or direction could make future response and course of action more difficult.
Lis and Bob Richardson