CSDMS 2016 annual meeting poster AnastasiaPiliouras
Discharge controls on plant distribution and channel network formation in vegetated delta experiments
Abstract:
Increasing rates of relative sea level rise are depleting coastal land, causing scientists and engineers to propose solutions, such as river diversions, for coastal restoration. Success in delta restoration projects largely depends on the understanding of interactions between physical and biological processes that can drastically change delta morphology. However, the effects of vegetation on delta dynamics and morphology are still poorly understood. Here we show that there are clear differences in delta morphology between experiments conducted with high and low discharges but that vegetation has the same effects on large-scale delta morphology regardless of discharge. Lower discharge experiments had more, narrower channels that created more small, sparse patches of vegetation that aided in increased channel bifurcation. Deltas created with higher water and sediment discharges had fewer, wider channels that created fewer large, dense patches of vegetation that instead steered channels. Vegetation in both experiments made wider deltas and smoother shorelines, regardless of the differences in patch distribution, compared to experiments without plants. These results are important for coastal restoration as engineers decide whether to implement few large diversions of many small diversions: the discharge controls the morphology and the distribution of vegetation relative to the flow, and vegetation can change the channel processes and feedbacks to make a more or less distributive network of channels to build new land.
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