Twin Cities WRS Seminar

Process Connectivity in River Deltas: Uncovering system dynamics using information theory and remote sensing


Alicia Sendrowski
Colorado State University

November 8, 2019


River deltas are complex environments that can host large human populations and extensive agricultural and industrial development. Many deltas are in a state of degradation due to natural and anthropogenic impacts from forces including sea level rise, subsidence, and channel modification. To mitigate these issues, it is critical to understand the relationships that build and maintain deltas; those between external drivers, such as river discharge, tides, and wind, and deltaic sinks of water, sediment, and nutrients. In this talk, I present a framework for understanding the interaction among these system variables, referred to as process connectivity. I use information theory, mathematics that quantify the communication of information between variables, to measure the strength, timescale, and direction of process connectivity over time in the Wax Lake Delta in coastal Louisiana, USA. By tracking how variables exchange information across different spatial and temporal extents, I capture the role of the structural connectivity of the delta in affecting process connections, finding that variables at locations with higher connectivity show stronger and more persistent relationships with external drivers. At the island scale, vegetation acts to disrupt hydrological process connectivity while promoting biogeochemical connections that influence nitrate fluctuations. Additionally, I will discuss my applications of remote sensing to understand wood and carbon transport in the Mackenzie River Delta in Northwest Territories, Canada.