Longitudinal patterns in sediment type and quality during daily flow regimes and following natural hazards in an urban estuary: a Hurricane Harvey retrospective

Understanding the transport of sediments in urban estuaries and their effects on water quality and microorganisms is a convergent challenge that has yet to be addressed especially as a result of natural hazards that affect the hydrodynamics of estuarine systems. This study provides a holistic view of the longitudinal nature and character of sediment in an urban estuary, the Galveston Bay Estuary System (GBES), under daily and extreme flow regimes and presents the results of water and sediment sampling after Hurricane Harvey. The sediment sampling quantified total suspended sediment (TSS) concentrations, metal concentrations, and the diversity of microbial communities. The results revealed the impact of the substantial sediment loads that were transported into the GBES in terms of sediment grain type, the spatial distribution of trace metals, and the diversity of microbial communities. A measurable shift in the percentage of silt relative to historical norms was noted in the GBES after Hurricane Harvey. Not only did sediment metal data confirms this shift and its ensuing impact on metal concentrations; microbial data provided ample evidence of the effect of leaks and spills from wastewater treatment plants, superfund sites, and industrial runoff on microbial diversity. The research demonstrates the importance of understanding longitudinal sediment transport and deposition in estuarine systems under daily flow regimes but more critically, following natural hazard events to ensure sustainability and resilience of systems such as the GBES that encounter numerous acute and chronic stresses.