Alongshore variation in beach and dune coupling
Abstract
The height and alongshore extent of coastal dunes is an important control on the response of barrier islands to storms and sea level rise. Understanding the controls on dune height is key to managing beach-dune systems and predicting the response of these systems to sea level rise. Current models suggest that dune height varies in response to effective beach width, the cross-shore position of vegetation and the synchronization of aeolian transport and supply. Using ~100 km of data from Padre Island Texas, we examine how beach and dune morphometrics vary and are coupled alongshore. It is found that dune height is inversely related to the beach width, contrary to what is expected from the fetch length model of sediment supply to the dune. A machine learning analysis of the data further reveals that an increase in beach width leads to a decrease in dune height and crest elevation, and an increase in dune toe elevation and dune width. Based on a comparison with previously published data from Pensacola Beach, Florida it is argued that some beach dune systems are limited by transport and others are limited by the availability of sediment. This results in a more complicated relationship between beach width and dune height then previously expected.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMEP13B..01H
- Keywords:
-
- 3020 Littoral processes;
- MARINE GEOLOGY AND GEOPHYSICS;
- 4315 Monitoring;
- forecasting;
- prediction;
- NATURAL HAZARDS;
- 4316 Physical modeling;
- NATURAL HAZARDS;
- 4217 Coastal processes;
- OCEANOGRAPHY: GENERAL