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Evaluation of SWAT Impoundment Modeling Methods in Water and Sediment Simulations
Citation:
Jalowska, A. AND Y. Yuan. Evaluation of SWAT Impoundment Modeling Methods in Water and Sediment Simulations. JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION. American Water Resources Association, Middleburg, VA, 55(1):209-227, (2019). https://doi.org/10.1111/1752-1688.12715
Impact/Purpose:
This manuscript provides a comprehensive overview of the SWAT impoundment tools, demonstrates their incorporation into a SWAT application and develops recommendations for the use of these tools in future simulation and calibration exercises. Outcome of this publication will improve understanding of the impoundment tools in hydrologic modeling. Findings from this manuscript suggest that their appropriate use could play a crucial role in the design of Integrated Modeling Systems to understand nutrient and sediment loads, fate and transport in the Mississippi River Basin. Outcomes from this manuscript include direct recommendations to the Office of Water regarding their Hydrologic and Water Quality System (HAWQS).
Description:
Worldwide studies show 80%–90% of all sediments eroded from watersheds is trapped within river networks such as reservoirs, ponds, and wetlands. To represent the impact of impoundments on sediment routing in watershed modeling, Soil and Water Assessment Tool (SWAT) developers recommend to model reservoirs, ponds, and wetlands using impoundment tools (ITs). This study evaluates performance of SWAT ITs in the modeling of a small, agricultural watershed dominated by lakes and wetlands. The study demonstrates how to incorporate impoundments into the SWAT model, and discusses and evaluates involved parameters. The study then recommends an appropriate calibration sequence, i.e., landscape parameters calibration, followed by pond/wetlands calibration, then channel parameter calibrations, and lastly, reservoir parameter calibration. Results of this study demonstrate not following SWAT recommendation regarding modeling water land use as an impoundment depreciates SWAT performance, and may lead to misplaced calibration efforts and model over‐calibration. Further, the chosen method to model impoundments’ outflow significantly impacts sediment loads in the watershed, while streamflow simulation is not very sensitive. This study also allowed calculation of mass accumulation rates in modeled impoundments where the annual mass accumulation rate in wetlands (2.3 T/ha/yr) was 39% higher than mass accumulation rate in reservoirs (1.4 T/ha/yr).
URLs/Downloads:
DOI: Evaluation of SWAT Impoundment Modeling Methods in Water and Sediment Simulations