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Simulating Flood-Induced Contaminated Soil and Sediment Transport with a Coupled HEC-RAS 2D and WASP Model (2020 AGU Fall Meeting)
Citation:
Shabani, A., M. Mehaffey, P. Whung, D. Cutt, R. Vargas, S. Woznicki, M. Ramirez, AND L. Drumm. Simulating Flood-Induced Contaminated Soil and Sediment Transport with a Coupled HEC-RAS 2D and WASP Model (2020 AGU Fall Meeting). 2020 AGU Fall Meeting, San Francisco, CA, December 01 - 17, 2020.
Impact/Purpose:
Abstract submission deadline is July 25, 2020. Purpose of the materials is to share most recently WASP update research results with public and at AGU 2020
Description:
Increased intensity and frequency of floods raises concerns about release and transport of soil and sediment and associated contaminants to and from streams and rivers. To model these processes during flooding events, we developed an external coupler in Python to link the Hydrologic Engineering Center-River Analysis System (HEC-RAS) 2D hydrodynamic model to the Water Quality Analysis Simulation Program version 8.4 (WASP). The external coupler aggregates flow and conserves mass when transitioning from HEC-RAS 2D to WASP. We applied the coupled model to simulate soil and sediment contaminants’ (i.e., arsenic (As), lead (Pb), benzo(a)pyrene (B(a)P) fate and transport for a 100-yr flood event in Woodbridge Creek, NJ. The sensitivity analysis of WASP sediment transport simulation showed that shear stress is the parameter with the most influence on the erosion and deposition processes. The surface sediment volume at the end of a 48-hr flood simulation ranged from a net loss of 661 m3 to a net gain of 291 m3 for each model segment (50 m). Change in surface sediment concentrations of As, Pb and B(a)P in the 100-year flood ranged from -16 to 2.8 mg kg-1, -266¬¬ to 16 mg kg-1, and -1.3 to 0.6 mg kg-1, respectively depending on model segment. Results demonstrate that there is significant potential for sediment-driven contaminant transport during extreme flooding, which can be quantified by the coupled models.
