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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #396869

Research Project: Sustainable Intensification in Agricultural Watersheds through Optimized Management and Technology

Location: Agroecosystems Management Research

Title: Examination of a characteristic scale unit for sediment flux prediction

item ABBAN, BENJAMIN - Bureau Of Reclamation
item Papanicolaou, Athanasios - Thanos
item SIVAPALAN, M - University Of Illinois

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 9/21/2022
Publication Date: 12/14/2022
Citation: Abban, B., Papanicolaou, A.N., Sivapalan, M. 2022. Examination of a characteristic scale unit for sediment flux prediction [abstract]. American Geophysical Union.

Interpretive Summary:

Technical Abstract: A modeling framework to simulate sediment flux dynamics in intensively managed landscapes (IMLs) is presented developed and used tested in this study to examine the existence of a characteristic parametrization scale unit for adequately predicting capturing aggregated sediment flux variability across scales. The framework takes advantage of modeling advances from other IML studies to predict event-based sediment flux dynamics under different rainfall and land cover conditions in IMLs. An extensive field campaign covering terrestrial and instream fluxes at scales ranging from the plot to the watershed scale was performed in the South Amana Sub-watershed, IA, USA, to validate the framework model. The model was found to adequately represent the interactions/feedbacks of flow and topography on flux propagation, adequately predict flow and sediment fluxes, and predict the relative contributions of different source areas to the total sediment flux at the watershed outlet. The validated model was used to confirm the existence of a characteristic scale unit for sediment fluxes, and then compare it with the characteristic scale unit for water under different rainfall and land cover conditions. There were notable differences in the characteristic scale units for flow and sediment, with the flow rate and sediment concentration appearing to be correlated with the size of the characteristic scale unit for sediment. Sediment source had a notable influence on the size of the sediment characteristic scale unit. It was smaller whenever in-stream source contributions for sediment fluxes were dominant, and larger whenever terrestrial source contributions were dominant. This was found to be due to differences in sediment size characteristics between terrestrial and in-stream source contributions, which were finer and coarser, respectively. The identified sediment characteristic scale unit concept is unique in catchment geomorphology and can be used as a guidance for choosing the most optimal parameterization unit for modeling larger watersheds. It is also an appropriate scale for monitoring watersheds and evaluating the performance of best management practices.