Projects
Predicting flux partitioning in river delta networks using SWOT to produce global delta products and quantify the response of deltas to climate and human induced change
Principle Investigator: Paola Passalacqua (University of Texas at Austin)
Co-Investigator(s): Anastasia Piliouras, Jon Schwenk
Collaborator(s): Michael Lamb, Colin Gleason
River deltas around the world are highly complex systems that undergo change in response to climatic shifts and human-induced activities and regulate the transport of water, solids, and solutes from their inlets to the coast. The quantification of delta network topology, and particularly of delta network dynamics, is limited, as the partitioning of fluxes along these systems is not known. Additionally, delta channels are connected to their surrounding wetlands via mechanisms of hydrological connectivity that have been minimally quantified, thus little is known about how this hydrological connectivity impacts the transport of solids and solutes into wetlands, which regulates the sustainability of river deltas. SWOT products currently do not fully cover river deltas - and yet, these systems host hundreds of millions of people and provide important ecosystem services, including buffering the effect of storms. This project will build on the SWORD dataset to increase its coverage and accuracy in river deltas. We will leverage SWOT discharge information and use remotely sensed observations, network theory, and network-based modeling, to provide SWOT-based products of water, solutes, and solids partitioning in river deltas. We will validate the approach with numerical modeling and scale the approach to global river deltas to address the following critical knowledge gaps: (i) How are fluxes of water, solutes, and solids partitioned along delta networks? (ii) How are delta network structure (topology) and dynamics (fluxes of water, solids, and solutes) characterized across spatial and temporal scales? How are global river deltas responding to changes in climate and anthropogenic modifications? Which deltas are experiencing the most change (hot spots)? What timescales are associated with these changes (hot moments)? (iii) What mechanisms of hydrological connectivity characterize channel-wetland exchanges in global river deltas?
Tasks will leverage our team's previous work to apply image processing tools for the extraction and analysis of delta networks, a graph theory approach for estimating flux partitioning on deltas, and a Lagrangian numerical modeling approach to validate the graph-based results. The graph-based flux estimation is scalable to global river deltas. It will use SWOT discharge information and provide global delta products currently unavailable.
The proposed work will demonstrate the potential of SWOT observations to advance basic earth science and address a major knowledge gap in assessing land sustainability at global scales. With a focus on connectivity, we will address the flux exchange between channels and wetlands and modify graph-based approaches to account for river-wetland connectivity. This work will directly inform studies on the behavior of delta systems under global change and thus increase the resilience of the natural, human, and built environment in coastal areas.