Modified foredune eco-morphology in southeast Australia
Ocean and Coastal Management
Human activities are playing increasingly significant roles in the dynamics and evolution of coastal dunes, one of the most intensively used environments on Earth. Not only do beaches and adjacent foredunes provide tourism and recreational uses but they also form an important buffer between coastal settlements and the ocean. Modified or “urbanised” foredunes often differ from their natural counterparts in terms of characteristics such as location, dimension, orientation, topographic variability, sediment features, mobility, and the degree to which they can initiate and/or develop further through natural processes (e.g. progradation). Much of this research has been focused on dunes found in Europe and the USA, with limited work done elsewhere. The availability of LiDAR-derived topographic data for the entire coast enables a state-wide assessment of foredune morphology in New South Wales (NSW), and a basis for determining the effects of human modification. This study examines the current morphological characteristics of foredunes in NSW, by comparing modified with natural settings, to understand how human activities and uses have impacted foredune morphology. Results show highly modified incipient and established foredunes were significantly narrower and reached lower elevations, consequently with smaller volumes of sand than their more natural counterparts. On average, both highly modified established and incipient dunes were half the size of the unmodified systems, and on average modified dunes had volumes of ∼350 m3 m−1, whereas unmodified dunes contained sand volumes of ∼740 m3 m−1. By lowering dune elevation and sand volumes, human modifications have created environments that are more exposed and potentially vulnerable to erosion, placing coastal properties, infrastructure and communities (especially those found behind modified dune systems) at greater risk of erosion, coastal flooding and inundation, particularly during storm events.
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University of Wollongong