SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Assessing river low-flow uncertainties related to hydrological model calibration and structure under climate change conditions 
Authors:Trudel, M., P.L. Doucet-Généreux and R. Leconte 
Article ID:19 
URL (non-DOI journals): 
Broad Application Category:hydrologic only 
Primary Application Category:model comparison 
Secondary Application Category:climate change  
Watershed Description:4,784 km^2 Yamaska River, located in southeast Quebec, Canada. 
Calibration Summary: 
Validation Summary: 
General Comments: 
Abstract:Low-flow is the flow of water in a river during prolonged dry weather. This paper investigated the uncertainty originating from hydrological model calibration and structure in low-flow simulations under climate change conditions. Two hydrological models of contrasting complexity, GR4J and SWAT, were applied to four sub-watersheds of the Yamaska River, Canada. The two models were calibrated using seven different objective functions including the Nash-Sutcliffe coefficient (NSEQ) and six other objective functions more related to low flows. The uncertainty in the model parameters was evaluated using a PARAmeter SOLutions procedure (PARASOL). Twelve climate projections from different combinations of General Circulation Models (GCMs) and Regional Circulation Models (RCMs) were used to simulate low-flow indices in a reference (1970–2000) and future (2040–2070) horizon. Results indicate that the NSEQ objective function does not properly represent low-flow indices for either model. The NSE objective function applied to the log of the flows shows the lowest total variance for all sub-watersheds. In addition, these hydrological models should be used with care for low-flow studies, since they both show some inconsistent results. The uncertainty is higher for SWAT than for GR4J. With GR4J, the uncertainties in the simulations for the 7Q2 index (the 7-day low-flow value with a 2-year return period) are lower for the future period than for the reference period. This can be explained by the analysis of hydrological processes. In the future horizon, a significant worsening of low-flow conditions was projected. 
Keywords:low flows; hydrological uncertainty; climate change; calibration