Effect of Watershed Delineation and Climate Datasets Density on Runoff Predictions for the Upper Mississippi River Basin Using SWAT within HAWQS

Manyu Chen,Yuanlai Cui,Raghavan Srinivasan,Philip Gassman

doi:10.3390/w13040422

Manyu Chen, Yuanlai Cui + Show 2 more

Open Access

https://doi.org/10.3390/w13040422

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Journal: Water	Publication Date: Feb 5, 2021
Citations: 11	License type: CC BY 4.0

Affiliation: Wuhan University, Texas A&M University, Iowa State University

Abstract

The quality of input data and the process of watershed delineation can affect the accuracy of runoff predictions in watershed modeling. The Upper Mississippi River Basin was selected to evaluate the effects of subbasin and/or hydrologic response unit (HRU) delineations and the density of climate dataset on the simulated streamflow and water balance components using the Hydrologic and Water Quality System (HAWQS) platform. Five scenarios were examined with the same parameter set, including 8- and 12-digit hydrologic unit codes, two levels of HRU thresholds and two climate data densities. Results showed that statistic evaluations of monthly streamflow from 1983 to 2005 were satisfactory at some gauge sites but were relatively worse at others when shifting from 8-digit to 12-digit subbasins, revealing that the hydrologic response to delineation schemes can vary across a large basin. Average channel slope and drainage density increased significantly from 8-digit to 12-digit subbasins. This resulted in higher lateral flow and groundwater flow estimates, especially for the lateral flow. Moreover, a finer HRU delineation tends to generate more runoff because it captures a refined level of watershed spatial variability. The analysis of climate datasets revealed that denser climate data produced higher predicted runoff, especially for summer months.

Highlights

Watershed models haves become an important technology to explore the effects of climate change and human activities on water resources and hydrological cycles [1,2,3]
Over 60% of the studies were performed for watersheds in the United States, and the majority of that subset were reported for locations in the Corn
Users can specify preferred values of parameters or climate data input instead of using the pre-defined sets, some default values of parameters are preliminarily calibrated in Hydrologic and Water Quality System (HAWQS)

Summary

Introduction

Watershed models haves become an important technology to explore the effects of climate change and human activities on water resources and hydrological cycles [1,2,3]. The Soil and Water Assessment Tool (SWAT) ecohydrological model [7,8] is a popular watershed model and has proven to be an effective tool for evaluating agricultural management simulations for complex landscapes and varying climate regimes worldwide [9,10]. Studies have been conducted to evaluate the effects of watershed delineation on SWAT simulated streamflow and other outputs [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34]. Over 60% of the studies were performed for watersheds in the United States, and the majority of that subset were reported for locations in the Corn

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Conclusion