Collaborative Research: A theoretical framework for the evolution of distributary networks on wave-influenced deltas

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Our ability to predict and mitigate the response of deltas to natural and human disturbances is limited by a lack of understanding of the evolution of delta channel (distributary) networks. This project will fundamentally advance the ability to predict and mitigate the response of deltas to natural and human disturbances through a combined theoretical, experimental, and field-based approach. Satellite imagery and field data will be used to derive the statistics of channel networks for a wide variety of deltas, forming a target for modeling efforts. Mapping of subsurface deposits on the Mississippi Delta will examine environmental controls on distributary formation and evolution through time. Laboratory experiments will reproduce distributary networks at a much-reduced scale, and explore the fundamental control parameters (e.g., sediment and water supply, wave energy, sea level rise). Experimental results will guide the development of a theoretical model, which will mathematically describe the processes that create channel networks. The model will be used to help predict the growth of new river deltas in restoration schemes for the lower Mississippi Delta.Broader Impacts.River deltas are home to a significant fraction of the human population, and are ecologic hotspots that support diverse species. The network of channels on a delta forms its skeleton: channel locations determine patterns of deposition and dictate how sediment, nutrients and freshwater are delivered to the shoreline. The modeling framework will provide valuable predictive capabilities for individuals and agencies tasked with delta management. In particular, this research will help to guide the design of artificial diversions for land building on the Mississippi Delta, through collaboration with colleagues at the National Center for Earth-surface Dynamics, an NSF Science and Technology Center. This award will also support graduate students and the early career of a junior faculty member at the home institution.The award is supported by the Division of Earth Sciences's program in Geomorphology and Land-Use Dynamics.