• Xixi Wang,

  • Assefa M. Melesse

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    • Respectively, Research Scientist, Energy and Environmental Research Center, University of North Dakota, P.O. Box 9018, Grand Forks, North Dakota 58202; and Assistant Professor, Department of Environmental Studies, Florida International University, Miami, Florida 33199 (formerly at Upper Midwest Aerospace Consortium, University of North Dakota, Grand Forks, North Dakota 58202) (E-Mail/Wang: xixi_w@hotmail.com).

  • Paper No. 05022 of the Journal of the American Water Resources Association (JAWRA)


ABSTRACT: Soil data comprise a basic input of SWAT (Soil and Water Assessment Tool) for a watershed application. For watersheds where site specific soil data are unavailable, the two U.S. Department of Agriculture (USDA) soil databases, the State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) databases, may be the best alternatives. Although it has been noted that SWAT models using the STATSGO and SSURGO data may give different simulation results for water, sediment, and agricultural chemical yields, information is scarce on the effects of using these two databases in predicting streamflows that are predominantly generated from melting snow in spring. The objective of this study was to assess the effects of using STATSGO versus SSURGO as an input for the SWAT model's simulation of the streamflows in the upper 45 percent of the Elm River watershed in eastern North Dakota. Designating the model as SWAT-STATSGO when the STATSGO data were used and SWAT-SSURGO when the SSURGO data were used, SWAT-STATSGO and SWAT-SSURGO were separately calibrated and validated using the observed daily streamflows. The results indicated that SWAT-SSURGO provided an overall better prediction of the discharges than SWAT-STATSGO, although both did a good and comparable job of predicting the high streamflows. However, SWAT-STATSGO predicted the low streamflows more accurately and had a slightly better performance during the validation period. In addition, the discrepancies between the discharges predicted by these two SWAT models tended to be larger at upstream locations than at those farther downstream within the study area.