Beaches and dunes of human-altered coasts

Abstract

Landforms are created, reshaped or eliminated to suit human needs. These alterations affect the mechanisms of change, freedom of movement, locations of sources and sinks for sediment, internal structure, outward appearance and spatial and temporal scales of landform evolution. The processes by which landscapes are transformed by human agency follows a progression of alterations that may be subtle or overt, planned or unplanned, but most of them are predictable. Models of change for human-altered coasts may be formulated by viewing them as open or closed systems. Alternative methodologies for examining evolution of these coasts include: 1) comparing and contrasting a developed area with an undeveloped area that is assumed to have the same process controls; 2) assuming that the kind of shoreline change that occurred in the recent past will continue unabated by local actions; or 3) basing predictions on probabilities of future human action. Evidence suggests that human alterations are an integral component of landscape evolution. Future challenges for scientists include: 1) formulating conceptual and predictive models of landform dynamics that evaluate humans as an endogenic process and include assumption about human actions; and 2) providing scientific criteria for maintaining landforms in developed areas in ways that safeguard or promote an optimal diversity of landforms, species and ecosystems. Controlled disturbance may be required to create landforms compatible with natural landforms in appearance and function if not in genesis.

An evolving research agenda for human–coastal systems

“…A 341 typical approach in assessments of coastal vulnerability -the exposure of valued 342 infrastructure to natural hazard -is to convert socio-economic data into 343 qualitative indices, which can raise complicated issues regarding methodological 344 subjectivity and how to account for temporal change (Gornitz et clean-up, despite the ubiquity of these interventions (Nordstrom, 1994). translate their knowledge into the research for greater insight (Hall et al, 2012; 520 Hall and Lazarus, 2015), but also to translate research insights into real societal 521 relevance: "Once society has become a laboratory -and the citizens objects of 522 the experiment -the door morally and politically opens to the public voice.…”

Natural and Human-Induced Dynamics on Big Hickory Island, Florida

“…Recent studies have shown that the implementation of groins designed specifically to retain beach fill material or stabilize the shoreline have proven effective in reducing erosion and mitigating downdrift impacts [6,[9][10][11][12]. Improved understanding of the influence of anthropogenic modifications on the morphodynamics of the coastal system [13][14][15] is critical as human impacts on these environments increase concomitantly with sea level and storminess [16,17].…”

Late Holocene dune development and shift in dune-building winds along southern Lake Michigan

“…Most of the southern Lake Michigan coast (Figure 1) was progradational throughout the Holocene (Chrzastowski and Thompson, 1992;1994), receiving sediments transported predominantly by the westward littoral drift from the erosion of eastern shores. A high sediment supply, low regional topography, and a favorable location, with respect to strong westerly and northerly winds, led to the formation of a barrier beach in the western part of the Tolleston Beach and large parabolic dunes in the eastern part.…”

“…The timing of coastal dune development and dune reactivation was estimated from the study of paleosols (Winkler, 1962;Gutschick and Gonsiewski, 1976;, and sedimentary structures (Thompson, 1989) at Mount Baldy dune in the IDNL. The evolution of the beach, spits, and beach ridges along the southern Lake Michigan coast was summarized by Chrzastowski and Thompson (1992;1994), Thompson (1992), and Thompson et al (2004). More recent studies in the area's coastal dunes have examined the sand transport rates in active blowouts (Olyphant and Bennett, 1994;Bennett and Olyphant, 1998;Fraser et al, 1998;Yurk et al, this volume).…”