Browsing by Author "Shin, Jae hun"
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Item Open Access Catchment and climatic influences on spatio-temporal variations in suspended sediment transport dynamics in rivers(IWA Publishing, 2023-08-04) Shin, Jae hun; Grabowski, Robert C.; Holman, Ian P.Suspended sediment concentration (SSC) is an important attribute for water resources management. However, the interactions between climate and catchment characteristics that control the temporal variability of SSC in rivers are not fully resolved. The study aim is to evaluate how these variables influence spatial and seasonal variations in SSC dynamics at a continental scale. Daily SSC (mg/l) and site attribute data from 120 sites (USA) with minimum 10 years of record (1971–2000) were analysed. New indicators of SSC dynamics (magnitude and frequency) were developed and applied annually and seasonally. Geographically weighted regression (GWR) models were created for each ordinary least squares (OLS) regression model, and GWR coefficients were analysed by ecoregion. Land cover, rainfall and erosivity, baseflow index and soil texture were the most common variables in the OLS models. GWR coefficients displayed significant variation across the continent. Agricultural cover was positively associated with low frequency SSC events, while urban and forest cover predicted higher frequency events, except in the desert areas. PPT30 was generally a negative predictor for SSC magnitude, except the marine west coasts forests. These findings on catchment and climate controls on SSC will support future predictive models of SS transport dynamics.Item Open Access Indicators of suspended sediment transport dynamics in rivers(IWA Publishing, 2023-07-21) Shin, Jae hun; Grabowski, Robert C.; Holman, Ian P.Suspended sediment (SS) is a natural component of rivers, but elevated SS concentrations (SSCs) can impact aquatic ecosystems and engineering infrastructures. However, a significant gap remains in predicting SSC dynamics, which are influenced by catchment and climate factors that control sediment erosion, transport and deposition. The research aim is to develop and apply new SS transport dynamics indicators to determine how SSC varies spatially and temporally at a continental scale. Daily SSC data (mg/l) from 1,425 gauging stations in the US were used to calculate indicators of magnitude, frequency and timing (MFT). A filtering approach was applied to calculate frequency indicators that capture SSC events of differing durations. Spatial patterns in indicators were examined and integrated using K-means clustering. High SSC was identified at sites in dry and mountainous regions, but longer-duration SSC events were found in the northern US. The western coastal region and Puerto Rico had consistent timings of high SSC (winter and autumn, respectively). SSC magnitude had a decreasing trend over time across most of the US, but increasing trends were identified for the duration of SSC events. The use of MFT indicators is recommended for future studies to support prediction of climate change impacts on SSC.