LARGE SCALE FLOOD HAZARD MITIGATION BY NATURAL AND NATURE-BASED FEATURES: A SPATIALLY DISTRIBUTED INVESTIGATION OF WAVE PROPAGATION OVER SALTMARSHES

Coastal areas provide a favorable setting, not only for the establishment of prosperous urban and economic centers but also for highly productive ecosystems. Yet, these regions are often exposed to natural flood hazards. Coastal floods are one of the most common and devastating natural hazards, annually causing significant loss of property, habitat, and human lives. These events are usually aggravated when associated with the further landward propagation of highly-energetic wind-waves which can expose infrastructure to unprecedented wave loads, cause large morphological changes due to sediment transport, as well as, disrupt the coastal vegetation. Moreover, damages caused by coastal flood hazards are expected to double by the end of the century due to climate change and sea-level rise, thus forcing current coastal management and engineering projects to account for these future scenarios.In this context, this study proposes the development of a comprehensive assessment of large-scale (i.e. statewide) wave and saltmarsh interactions during extreme flood events for current as well as future climate change-based scenarios. To meet this research goal four research objectives were defined: i) to identify coastal wetland exposure to maximum water depths and wave heights during major hurricanes using state-of-the-art methods for regional hydrodynamic and wave modeling; ii) to develop an effective tool for representing large-scale, spatially distributed wave transformation processes, including wave attenuation by vegetation; iii) to quantify the influence of sea-level rise driven marsh-migration on the overland hydrodynamic and wave processes during storm surge events; iv) to project the current and future coastal protection provided by saltmarshes composed of native and invasive marsh species. This study is based on the coupled ADvanced CIRCulation model (ADCIRC) and Simulating WAves Nearshore (SWAN) numerical model forced with spatially distributed Global Climate Model (GCM) wind and pressure products, during storm surge events for simulating total water levels and significant wave heights over coastal wetlands. This research also includes the coupling of the hydrodynamic and wave model ADCIRC+SWAN with the marsh migration and land transformation Sea Level Affecting Marshes Model (SLAMM) to account for future wave attenuation by vegetation for IPCC Representative Concentration Pathways (RCPs) based sea-level rise projections. In order to assess the influence of saltmarsh distribution as well as the predominance of native or invasive species on coastal hazard impacts, the aforementioned framework was implemented using explicit vegetation formulations. The present study stands out for being the first to implement an explicit, data-based, large-scale numerical modeling wave attenuation study. The research outcomes provide important insights for the future implementation of coastal management and engineering measures for protecting coastal habitats, communities, and infrastructure.

Author

• Cassalho, Felicio

• Accretion
• ADCIRC+SWAN
• Chesapeake Bay
• Storm Surge
• Wave Attenuation by Vegetation

Identifier

hdl:1920/14538

OAI identifier oai:identifier

oai:MARS:1920/14538