Research Summaries

Back Long term morphodynamic stability at a bar-built estuary with implications for breach management (USCRP)

Fiscal Year 2021
Division Graduate School of Engineering & Applied Science
Department Oceanography
Investigator(s) Orescanin, Marko
Sponsor Army Corps of Engineers, Engineer Research & Development Center (Army)
Summary Beach breaching is one of the most drastic morphological processes that occurs at any coastline owing to the changes to morphology and to hydrodynamics affecting large areas. Such breaching events are capable of impacting the long-term sediment budget by rapid removal of material from the beach and generation of inlets. In California, much of this breaching occurs at bar-built estuaries, which undergo seasonal transitions from closed to intermittently open during the wet winter months. These systems span the California coast numbering over 100 unique estuaries from Southern Oregon to Southern California. The difficulty in predicting this breaching and quantifying its long- and short-term effects on coastal systems is challenging due to the rapid morphological changes. Consequently, mechanical breaching to control flooding and water quality is a common management practice, though its effectiveness is not well-understood. Several of these systems return to their original state, suggesting no loss of sediment to the system despite the breaching, though this long-term behavior is not well monitored nor understood.
To enhance the understanding of the variability in bar-built estuaries and the effectiveness of current breach management practices, this research will study the Carmel River State Beach to determine the inter-seasonal hydrodynamic and morphodynamic variability at a bar-built estuary during natural and mechanical breaching. To attain these objectives, existing datasets dating back to 2016, in-situ and remotely collected field observations, and numerical simulations will be used. Information from those sources will serve to identify natural breaching conditions and to evaluate the performance and evolution of mechanical breaching, as well as, to explore storm-induced morphological processes from the ocean and river sides. An idealized model for bar-built estuaries will be proposed and used to investigate the morphological response of these systems to management practices. Results from this project will inform stakeholders on when, where and how mechanical breaching should take place to improve efficiency and sustainability of this management practice.
The cost for this three-year project is $282,491. This cost will help support field campaigns, travel, researchers" salaries, and involvement of graduate and undergraduate students from the Naval Postgraduate School and the United States Naval Academy. Specific deliverables include a database with field data collected during field campaigns, annual reports, and a final report. The results from the project will be communicated to the scientific and engineering community at large via journal articles and presentations at conferences.
Keywords Littoral
Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal