| 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 |
| Year: | 2017 |
| Journal: | Climate |
| Volume (Issue): | 5 |
| Pages: | |
| Article ID: | 19 |
| DOI: | 10.3390/cli5010019 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | model and/or data comparison |
| Secondary Application Category: | climate change assessment |
| 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. |
| Language: | English |
| Keywords: | low flows; hydrological uncertainty; climate change; calibration |