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TEMPORAL CHANGES IN THE YADKIN RIVER FLOW VERSUS SUSPENDED SEDIMENT CONCENTRATION RELATIONSHIP 1
Author(s) -
Lamon E. Conrad,
Qian Song S.,
Richter Daniel D.
Publication year - 2004
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.2004.tb01581.x
Subject(s) - streamflow , sediment , environmental science , hydrology (agriculture) , seasonality , deposition (geology) , soil science , geology , drainage basin , mathematics , statistics , geomorphology , geography , cartography , geotechnical engineering
Dynamic linear models (DLM) and seasonal trend decomposition (STL) using local regression, or LOESS, were used to analyze the 50‐year time series of suspended sediment concentrations for the Yadkin River, measured at the U.S. Geological Survey station at Yadkin College, North Carolina. A DLM with constant trend, seasonality, and a log 10 streamflow regressor provided the best model to predict monthly mean log 10 suspended sediment concentrations, based on the forecast log likelihood. Using DLM, there was evidence (odds approximately 69:1) that the log 10 streamflow versus log 10 suspended sediment concentration relationship has changed, with an approximate 20 percent increase in the log 10 streamflow coefficient over the period 1981 to 1996. However, sediment concentrations in the Yadkin River have decreased during the decade of the 1990s, which has been accompanied by a concomitant increase in streamflow variability. Although STL has been shown to be a versatile trend analysis technique, DLM is shown to be more suitable for discovery and inference of structural changes (trends) in the model coefficient describing the relationship between flow and sediment concentration.