Sediment supply to the ocean: The temporal and spatial variability of rivers and plumes

Our research group (Delta Force) has undertaken a source to sink modeling effort, in which each of the major processes controlling sediment supply, deposition, reworking and ultimate burial are simulated. This dissertation focuses on the sediment and water supplied by rivers and the initial deposition of sediment from buoyant surficial plumes. The knowledge of riverine and plume processes gleaned from this effort is immediately transferable to societal concerns of water and sediment supply.; In order to achieve this goal we have created a numerical river basin simulator (HYDROTREND) which creates daily discharge and sediment load time series from either measured or modeled climate data, with some basic information of the river basin morphology. HYDROTREND is used to simulate past and future climate change scenarios in order to understand how the water and sediment supply vary temporally.; The second step in the source to sink chain of events is the surficial plume which sorts and disperses sediment through a basin. We have created a buoyant plume model (PLUME) based on momentum conservation which simulates the initial deposit of sediment in both fjords and open coastal environments, given the river discharge and sediment load and the along-shore current magnitude. This model is used to simulate the initial deposition of sediment under varying climatic scenarios.; Utilizing the HYDROTREND and PLUME models, a sedimentary basin simulator (SEDFLUX), and a data sets of North American and World wide rivers, we have analyzed the temporal and spatial flux of sediment from rivers and studied how the changing riverine sediment flux affects the sedimentary sequences.; Modeling the Eel River in northern California during the last glacial maximum with a colder and slightly wetter climate, showed an increased flood frequency but not a substantial increase in the maximum flood size.; A 12,000 year model run of the Klinaklini river in British Columbia from the last glacial maximum to present showed the river going through step changes in its supply of water and sediment to the ocean during slow and steady climate change. (Abstract shortened by UMI.)...