Calibration Parameter Selection and Watershed Hydrology Model Evaluation in Time and Frequency Domains

Abstract

Watershed scale models simulating hydrological and water quality processes have advanced rapidly in sophistication, process representation, flexibility in model structure, and input data. With calibration being an inevitable step prior to any model application, there is need for a simple procedure to assess whether or not a parameter should be adjusted for calibration. We provide a rationale for a hierarchical selection of parameters to adjust during calibration and recommend that modelers progress from parameters that are most uncertain to parameters that are least uncertain, namely starting with pure calibration parameters, followed by derived parameters, and finally measured parameters. We show that different information contained in time and frequency domains can provide useful insight regarding the selection of parameters to adjust in calibration. For example, wavelet coherence analysis shows time periods and scales where a particular parameter is sensitive. The second component of the paper discusses model performance evaluation measures. Given the importance of these models to support decision-making for a wide range of environmental issues, the hydrology community is compelled to improve the metrics used to evaluate model performance. More targeted and comprehensive metrics will facilitate better and more efficient calibration and will help demonstrate that the model is useful for the intended purpose. Here, we introduce a suite of new tools for model evaluation, packaged as an open-source Hydrologic Model Evaluation (HydroME) Toolbox. We apply these tools in the calibration and evaluation of Soil and Water Assessment Tool (SWAT) models of two watersheds, the Le Sueur River Basin (2880 km 2) and Root River Basin (4300 km 2) in southern Minnesota, USA.

The Power of Environmental Observatories for Advancing Multidisciplinary Research, Outreach, and Decision Support: The Case of the Minnesota River Basin

“…Kumarasamy and Belmont () argue for more robust and targeted calibration of hydrologic models and developed the Hydrology Model Evaluation Toolbox to guide model calibration procedures along with a suite of analytical tools to facilitate calibration and minimize problems of equifinality. Specifically, they show that different information contained in the time and frequency domains of streamflow signals can provide complementary insights to guide selection of parameters adjusted during calibration.…”

“…In addition, methods of analyzing river topology and the underlying landscape topography via two-dimensional wavelet transform and synthesis (Danesh-Yazdi et al, 2017) as well as river hydrochemistry using dynamic travel time distributions (i.e., Danesh-Yazdi et al, 2016;Foufoula-Georgiou et al, 2015;Goodwell & Kumar, 2017a, 2017b in conjunction with information partitioning and other nonparametric analyses provide templates for analyses of other systems that have been impacted by intensive management. Kumarasamy and Belmont (2018) argue for more robust and targeted calibration of hydrologic models and developed the Hydrology Model Evaluation Toolbox to guide model calibration procedures along with a suite of analytical tools to facilitate calibration and minimize problems of equifinality. Specifically, they show that different information contained in the time and frequency domains of streamflow signals can provide complementary insights to guide selection of parameters adjusted during calibration.…”

“…The value of the publicly available hydrology, topography, water quality, imagery, and land cover data sets cannot be overstated and gave the additional data sets here a rich temporal, spatial, and historical context. Many of the data sets were critical in the development of a series of reduced complexity models designed to understand key processes and linkages between processes at the watershed scale (Call et al, ; Cho, ; Cho et al, ; Czuba et al, ; Czuba & Foufoula‐Georgiou, , ; Hansen, Czuba, et al, ), while additional efforts focused on integrating new knowledge into existing mechanistic modeling frameworks like the Soil and Water Assessment Tool (e.g., Kumarasamy & Belmont, ; Mitchell et al, ).…”

Improved Curve Number Estimation in SWAT by Reflecting the Effect of Rainfall Intensity on Runoff Generation

“…SWAT is a quasi-distributed, physical-based hydrologic model developed by the Agricultural Research Service of the US Department of Agriculture to simulate water, sediment, and agricultural chemical transport at river-basin scale [27,28]. As a quasi-distributed hydrologic model, the spatial heterogeneity of the important physical properties of the watershed is delineated by first partitioning a basin or watershed into sub-basins; then further partitioning each sub-basin into hydrologic response units (HRUs) based on the land use, soil types, and topography maps.…”

Water quality attribution and simulation of non-point source pollution load flux in the Hulan River basin

“…More importantly, the SWAT model can effectively simulate the melting of snow and the process of glacial snowmelt 26 . The model has been successfully applied to rainfall 27,28 and snowmelt events 29 .…”