CUERE Fall 2024 Seminar Series

Virginia Tech, Occoquan Watershed Monitoring Laboratory.

Admin Husic is an associate professor of Civil and Environmental Engineering at Virginia Tech and the Occoquan Watershed Monitoring Laboratory. His team works to advance our understanding of the connectivity and transport of sediment and nutrients in human-disturbed landscapes. His approach to science is that if something exists in a river, he ought to know about it. His team uses tools such as aquatic sensors, explainable AI, geochemical tracers, and numerical models to solve vexing problems in water resources. The team’s overall lab goal is to ensure the equitable access and security of water for all people. Prior to joining Virginia Tech, Dr. Husic was an assistant professor at the University of Kansas. He holds BS, MS, and PhD degrees in Civil Engineering from the University of Kentucky.

Built environments alter the production, transport, and fate of water, solutes, and particulate matter. Urbanization, in particular, shifts landscapes toward higher energy flows, which impacts the quantity and quality of water and sediment delivered to streams and rivers. Most delivery occurs during short-lived storm events that play a disproportionate role in the connectivity and export of upland and fluvial sediment. By investigating the asynchronous delivery of water and sediment to streams, a process termed “hysteresis”, insight can be gained to identify sediment sources and pathways, which vary spatially and temporally due to factors like land use and climate. Here, we analyze sediment-discharge, sediment-runoff, and sediment-baseflow relationships for 1,000 storm events occurring in three catchments in Kansas, USA, as well as for 38,000 storm events across 397 basins in the contiguous United States (CONUS). We employ hydrograph separation, hysteresis analysis, and random forest modeling to identify influential watershed characteristics that impact the timing of sediment arrival. Our findings reveal that while sediment delivery during most events (56%) is aligned with runoff arrival, a substantial fraction (44%) of sediment peaks are associated with baseflow arrival, highlighting the significance of subsurface pathways in sediment generation through piston-flow mobilization of erodible in-channel sediment. Population density and soil bulk density are identified as the primary contributors to runoff and sediment generation during storm events. Additionally, soil bulk density and topographic wetness index emerge as key parameters influencing sediment delivery timing and magnitude, respectively. These results emphasize the need for comprehensive analysis of sediment dynamics on a larger spatial and temporal scale to gain insights into sediment sources and pathways in built environments.

More details about the Fall 2024 CUERE Seminar Series are available at: