CAREER: The Influence of Distributed River Inputs and Coastal Embayments on Dynamics in Large Estuaries

University Of Connecticut, Storrs CT

Investigators

Abstract

The project is designed to transform the understanding of the effects of distributed rivers and coastal embayments on dynamics in large estuaries like the Long Island Sound (LIS). The hypotheses to be tested are: 1) Wind-driven and tidal straining of across-estuary density gradients is quantitatively as large as straining of along-estuary gradients; 2) Distributed river inputs create focused areas of increased straining and areas of reversed straining conditions; 3) During storm response, smaller river inputs from coastal watersheds collectively have a first-order influence on circulation and density structure; 4) River waters follow regular transport pathways that shift during wind events; 5) Coastal embayments transition from areas of net mixing to increased stratification as tidal currents decrease along the estuary. The hydrodynamic simulations for the LIS will be coupled to a surface-runoff model for coastal watersheds. Straining conditions and the combined influence of the smaller river inflows will be studied to determine the transport pathways for fresh water from the distributed river inputs and quantify the effects of coastal embayments on estuarine circulation and density structure. Intellectual Merit: The proposed modeling research will transform the understanding of dynamics in large estuaries. The study will advance the understanding of how fresh water from multiple sources combines to determine estuary density fields; tracking these separate inputs also informs the study of riverine nutrient, contaminant, and carbon inputs to estuaries. The research will extend the study of estuarine density straining to large estuaries where a 3D approach is necessary and spatial variations in straining conditions are pronounced. Inputs from distributed smaller rivers from coastal watersheds will be accurately represented using a coupled surface-runoff model and an input method consistent with potential energy considerations. This study will quantify the effects of these smaller distributed rivers and coastal embayments on large-scale estuarine dynamics. The new coupled modeling approach and analysis techniques will increase the ability to model present and future estuarine conditions. The integrated multi-faceted education and outreach effort each year will inform several hundred K-12 students, undergraduates, graduate students, and the general public on estuarine dynamics, storm response, and research results. The main message that nearby rivers and embayments have far-reaching effects should foster interest in and encourage stewardship of the coastal watersheds and estuaries. Broader Impacts: This project will train a post-doctoral researcher and undergraduate student for careers in scientific research and education. Undergraduate and graduate students will be educated by the new 'Freshwater Transport and Mixing' course. Summer undergraduate interns will gain vital research experience. Several hundred students reached by the K-12 education and outreach efforts, through the Project Oceanology field education program and the annual 'Meet Your Estuary Day' for lower-income and minority students, will gain an understanding of the interconnectedness of watersheds and estuaries and a new interest in studying and protecting coastal waters. The new college course and the new Project Oceanology learning module developed will continue beyond the project span; adding to the project?s educational legacy. Research findings will inform research for large estuaries and compliment research on environmental issues facing LIS and other estuaries. This project will inform biogeochemical research on multiple riverine inputs of nutrients, pollutants, and carbon to estuarine systems. The coupling techniques combining the surface-runoff and hydrodynamic models will be shared with the coastal modeling community. Results will be published in scientific journals and presented at conferences. The program will improve the scientific infrastructure at the University of Connecticut and will improve partnerships between the university, Project Oceanology, Connecticut Sea Grant and other organizations.