Littoral Mud Flats and Shorelines: Soil-Sea-Ice-Air and Benthic Life Interactions
Abstract
This Abstract is Approved for Public ReleaseMud flats and shorelines represent 14% of the world s coastlines in non-permafrost environments and most coastlines in permafrost environments. While muddy sediments are generally considered less erodible than their non-cohesive counterparts, some of the most dynamic coastlines worldwide are muddy. Geomechanical properties of tidal mud flats affect visibility and sensor performance, as well as trafficability and navigation; these properties can vary significantly in time and space and are currently mostly unpredictable. At best, the interactions between geomechanical properties (such as undrained shear strength, water content, plasticity index) and hydrodynamic forcing as well as the cyclic exposure to air are poorly understood. Potential freezing and contact with ice, as well as the wide range of benthic lifeforms inhabiting mud flats add complexity to answering even basic questions such as, what conditions will erode it, can I walk on it, or can I drive on it? This lack of accessibility, for both humans and standard geotechnical instrumentation, has greatly hampered our basic understanding, leading to a significant gap in knowledge and predictability of coastline evolution, navigation, and trafficability. Recent investigations have measured the strength and fracture properties of tidal mud flat sediments, proposing that tidal mud flat strength properties can vary considerably over short distances and speculating that variability is associated with mud composition (sand versus clay content) and water content, but also with environmental conditions including the activity and abundance of benthic organisms, geochemistry, and freeze thaw cycleswhere applicable. These knowledge gaps limit our ability to predict mud flat soil strength and hence, trafficability and erosion thresholds. While physical access to mud flats is difficult, remote sensing from satellites is not and can be globally applied across littoral regions. Tothe degree possible, merging in situ measurements and understanding to remote sensing modalities will allow identification and comparison of the range of global mud flat types and of the processes governing the site-specific geomechanics. The proposed one-year study will aim to (1) formulate key interdisciplinary research hypotheses and questions, (2) identify the required disciplinary expertise and methods, and (3) develop an integrated research strategy to develop a fundamental understanding of the geomechanics of littoral mud flats and shorelines towards reliable prediction of geomorphodynamics, trafficability, and navigation from satellite images and geoacoustic surveying. This will be achieved through desktop study, interdisciplinary knowledge exchange, an in-person workshop, and field method demonstrations. The proposed work is a collaborative effort led by PI Stark (University of Florida) and with PIs Jung (University of Florida), Paprocki (University of New Hampshire), Eidam (Oregon State University), Dorgan (Dauphin Island Sea Lab), and Yang (University of Alaska Anchorage).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 08, 2024
- Source ID
- N000142412538
Entities
People
- Nina Stark
Organizations
- Office of Naval Research
- United States Navy
- University of Florida