Simulating dune evolution on managed coastlines: Exploring management options with the Coastal Recovery from Storms Tool (CReST)

Abstract

Despite the importance of coastal dunes to many low-lying coastal communities and ecosystems, our understanding of how both climatic and anthropogenic pressures affect foredune evolution on time scales of years to decades is relatively poor. However, recently developed coupled numerical modeling tools have allowed for the exploration of the erosion and growth of coastal foredunes on time scales of hours to years. For example, Windsurf is a new process-based numerical modeling system (Cohn et al. 2019a) that simulates the evolution of dune-backed sandy coastal systems in response to wave, wind, and water level forcings. CReST, developed as a front-end interface to Windsurf, aims to add the ability to incorporate beach nourishment and dune construction, beach and dune grading, dune grass planting scenarios, dune grass removal, and the presence of hard engineering structures into the model framework to better account for the complex dynamics of managed coastlines. Initial model sensitivity tests suggest that the model provides a flexible framework to investigate the complex interactions between beaches and dunes for a variety of exploratory and applied applications.

Examining the commonalities and knowledge gaps in coastal zone vegetation simulation models

“…Most models do not explicitly simulate anthropogenic influences such as potential management actions or the influence of invasive species, which limits their use for coastal management planning and adaptive management (Reichert et al, 2015). Newer versions of the MEM/CWEM (Morris et al, 2019) do include the effects of thin layer sediment placement at pre‐defined intervals, SedVeg (Brown et al, 2019) was explicitly designed to analyze the effects of freshwater diversions, a new interface with CDM is designed to simulate common beach and dune management actions such as planting, beach nourishment, or grading (Ruggiero et al, 2019), a few seagrass models explore growth dynamics under nutrient and sediment reduction scenarios (Cerco & Moore, 2001; Carr et al, 2012; Yoshikai et al, 2020), and some forest models such as LANDIS II (de Jager et al, 2019; Scheller et al, 2007; Scheller & Mladenoff, 2004) to simulate the effects of harvest and prescribed burning. This set of models is not unique in that sense as even terrestrial biosphere models grapple with how to simulate the effects of human interventions (Fisher et al, 2014).…”

The relative role of constructive and destructive processes in dune evolution on Cape Lookout National Seashore, North Carolina, USA

“…Recent efforts have coupled dune evolution models with nearshore hydro‐morphodynamic models (e.g., Windsurf; Cohn et al, 2019a, XBeach‐Duna; Roelvink & Costas, 2019, and the cross‐shore (CS) model; Larson et al, 2016) to coevolve the beach–dune system in a more holistic manner. These state‐of‐the‐art models may provide transformative tools for better predicting future coastal hazards and guiding resiliency planning as they can also be adapted to incorporate management decisions such as beach nourishment, dune construction, and dune grass planting designs (Ruggiero et al, 2019). However, this burgeoning suite of models often requires in situ datasets or knowledge of local boundary conditions that can be difficult and costly to acquire.…”