Transport on Intertidal Flats, Washington


Willapa Bay and Skagit Bay, Washington

Processes controlling transfer of fine-grained sediment within and between channels and flats on intertidal flats

To understand the source-to-sink sediment transfer from rivers to marine deposition, we must develop our understanding of the gateway between the land and ocean — shallow-water regions spanning the tidally influenced river to the inner shelf. Here, the processes that transport and package sediment in suspension undergo dramatic changes. Tidal flats represent one type of environment found in this shallow-water realm. The transport and deposition of fine-grained sediment varies over the global range of tidal flats, which consists of systems that predominantly import or export sediment, yet our understanding of why these differ is limited. This project seeks to explore: 1) local transfer of sediment between the water column and seabed in both channel and flat environments, 2) the environmental linkages, or exchange of sediment, between channel and flat environments, and 3) place those in the long-term cycle in relation to river discharge, wind, and wave forcing.

Project publications:

Boldt, K.V., Nittrouer, C.A., Ogston, A.S., 2013. Seasonal transfer and net accumulation of fine sediment on a muddy tidal flat: Willapa Bay, WA, Continental Shelf Research, 60S: 157-172, doi: 10.1016/j.csr.2012.08.012.

Nowacki, D.J., Ogston A.S., 2012, Water and sediment transport of channel-flat systems in a mesotidal mudflat: Willapa Bay, Washington, Continental Shelf Research, doi:10.1016/j.csr.2012.07.019.

Webster, K.L., Ogston, A.S., Nittrouer, C.A., 2013. Delivery, reworking and export of fine sediment across the Skagit tidal flats: implications for the fate of fluvial discharge. Continental Shelf Research 60: S58-S70.

Hsu, T-J., Chen, S-N., Ogston, A.S., 2013. A numerical investigation of fine sediment transport across intertidal flats. Continental Shelf Research 60: S85-S98.

Funding source: Office of Naval Research

People: Chuck Nittrouer, Andrea Ogston, Kristen Lee Webster, Katie Boldt, Dan Nowacki