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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #256059
Title: Evaluation of a watershed model for estimating daily flow using limited flow measurements

Author
item DU, BING - Tarleton State University
item JI, XIAOYI - Utah Valley University
item Harmel, Daren
item HAUCK, LARRY - Tarleton State University

Submitted to: Journal of the American Water Resources Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2008
Publication Date: 4/15/2009
Citation: Du, B., Ji, X., Harmel, R.D., Hauck, L.M. 2009. Evaluation of a watershed model for estimating daily flow using limited flow measurements. Journal of the American Water Resources Association. 45(2):475-484.

Interpretive Summary: The Soil and Water Assessment Tool (SWAT) model was evaluated for estimation of continuous daily flow based on limited flow measurements in the Upper Oyster Creek (UOC) watershed. SWAT was calibrated against limited measured flow data and then validated. The Nash-Sutcliffe model Efficiency (NSE) and mean relative error values of daily flow estimations were 0.66 and 15 percent for calibration, and 0.56 and 4 percent for validation, respectively. Also, further evaluation of the model’s estimation of flow at multiple locations was conducted with parametric paired t-test and nonparametric sign test at a 95 percent confidence level. Among the five main stem stations, four stations were statistically shown to have good agreement between predicted and measured flows. SWAT underestimated the flow of the fifth main stem station possibly because of the existence of complex flood control measures near to the station. SWAT estimated the daily flow at one tributary station well, but with relatively large errors for the other two tributaries. The spatial pattern of predicted flows matched the measured ones well. Overall, it was concluded from the graphical comparisons and statistical analyses of the model results that SWAT was capable of reproducing continuous daily flows based on limited flow data as is the case in the UOC watershed.

Technical Abstract: The Soil and Water Assessment Tool (SWAT) model was evaluated for estimation of continuous daily flow based on limited flow measurements in the Upper Oyster Creek (UOC) watershed. SWAT was calibrated against limited measured flow data and then validated. The Nash-Sutcliffe model Efficiency (NSE) and mean relative error values of daily flow estimations were 0.66 and 15 percent for calibration, and 0.56 and 4 percent for validation, respectively. Also, further evaluation of the model’s estimation of flow at multiple locations was conducted with parametric paired t-test and nonparametric sign test at a 95 percent confidence level. Among the five main stem stations, four stations were statistically shown to have good agreement between predicted and measured flows. SWAT underestimated the flow of the fifth main stem station possibly because of the existence of complex flood control measures near to the station. SWAT estimated the daily flow at one tributary station well, but with relatively large errors for the other two tributaries. The spatial pattern of predicted flows matched the measured ones well. Overall, it was concluded from the graphical comparisons and statistical analyses of the model results that SWAT was capable of reproducing continuous daily flows based on limited flow data as is the case in the UOC watershed.