Controls on Estuarine Sediment Bed Erodibility: Statistical Model Formulation and Validation

Abstract:

Erosion of estuarine beds can lead to a number of ecological and commercially important implications, including the alteration of essential habitats, degradation of a system’s primary production, and sediment redistribution leading to dredging operations. Erodibility of sediment beds is temporally variable and has been linked to multiple sediment and water column properties. Additionally, relationships between sediment properties and erodibility in pure mud sediments are better understood than sand-mud mixtures, the latter of which are prevalent in estuarine systems. An extensive data set of erodibility measurements were collected in the York River estuary, Virginia, U.S.A. Erodibility was measured using a Gust microcosm, and supporting sediment properties and hydrodynamic data were compiled and utilized to create statistical models to predict the erodibility of the sediment bed. Through exploratory data analysis, relationships between eroded mass as a function of bed stress and sediment and water column parameters were identified and evaluated using multiple linear regressions, segmented linear regressions, and generalized additive models. Statistical models were then validated using historical shear stress and suspended sediment concentration time-series collected via long-term acoustic Doppler velocimeters in the same region. The preliminary results of this statistical model validation will be presented and discussed.