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Completed projects

Columbia TIFZ

Tidally-Influenced Fluvial Zones


All rivers that flow into the ocean contain a zone that is transitional between river and tidal environments. These zones, which can be hundreds of kilometres long, are among the most complex environments on the Earth’s surface because the competing forces of river and tidal currents are both significant in scale and vary daily, seasonally and annually.

Tidally-Influenced Fluvial Zones (or TIFZs) are important to humans and form some areas of highest population density: they are also strategically important because these zones are at the interface of competing demands for shipping, aquaculture, land reclamation and nature conservation. In order to better maintain, manage and protect these fragile zones, we must understand how and why these regions change and what factors control such change.


Lead researchers


Project funded by


Project partners

Center for Coastal Margin Observation & Prediction, Clatsop Community College, Deltares, ExxonMobil, Fulcrum Graphic Communications Inc., Lower Columbia River Estuary Partnership, Marine and Environmental Research and Training Station, Met Office, US Army Corps of Engineers, U.S. Geological Survey, University of Brighton, University of Illinois, University of Exeter, The University of Texas, University of Birmingham

This project used integrated field measurements and mathematical modelling techniques to achieve a step-change in our understanding of the TIFZ in the Columbia River estuary, NW USA.

It used single and multibeam sonar, acoustic Doppler current profiling and ground penetrating radar to yield unrivalled high-resolution datasets of bathymetry, flow, sediment transport and sedimentary structure that were used to construct and validate new numerical models of the TIFZ.

The Impact

Collected datasets were used to evaluate key unknowns with respect to the TIFZ, such as how such environments evolve under changing scenarios of tidal and fluvial contributions associated with sea-level change, and whether it is possible to differentiate between ‘fluvial’ and ‘tidally-influenced’ deposits.

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