Abstract
Rainfall–runoff models are not perfect, and the suitability of a model structure depends on catchment characteristics and data. It is important to investigate the pros and cons of a rainfall–runoff model to improve both its high- and low-flow simulation. The production and routing components of the GR4J and IHACRES models were combined to create two new models. Specifically, the GR_IH model is the combination of the production store of the GR4J model and the routing store of the IHACRES model (vice versa in the IH_GR model). The performances of the new models were compared to those of the GR4J and IHACRES models to determine components improving the performance of the two original models. The suitability of the parameters was investigated with sensitivity analysis using 40 years’ worth of spatiotemporally different data for five catchments in Australia. These five catchments consist of two wet catchments, one intermediate catchment, and two dry catchments. As a result, the effective rainfall production and routing components of the IHACRES model were most suitable for high-flow simulation of wet catchments, and the routing component improved the low-flow simulation of intermediate and one dry catchments. Both effective rainfall production and routing components of the GR4J model were suitable for low-flow simulation of one dry catchment. The routing component of the GR4J model improved the low- and high-flow simulation of wet and dry catchments, respectively, and the effective rainfall production component improved both the high- and low-flow simulations of the intermediate catchment relative to the IHACRES model. This study provides useful information for the improvement of the two models.
Highlights
Rainfall–runoff models are used in various studies to understand and predict hydrological phenomena
The IH_GR model had similar or lower NSE with log-transformed data (NSElog) values than the GR4J model, whereas its NSElog values were similar or higher than those of the IHACRES model (Figure 3). This means that the production component of the IHACRES model does not improve the performance of the GR4J model, whereas the routing component of the GR4J model improves the performance of the IHACRES model with respect to the low-flow simulation
The components of the IHACRES model improve the model performance for wet catchments, whereas the components of the GR4J model improve the model performance for intermediate and dry catchments
Summary
Rainfall–runoff models are used in various studies to understand and predict hydrological phenomena. The IHACRES model is strong for high-flow simulation, whereas the GR4J model is strong for low-flow simulation [5]. These findings were confirmed in the analysis of the effect of time-step data on the simulation results [6] or the hydrological modeling of catchments with various geological characteristics [7]. Improving their hydrological model structures to be able to capture both high- and low-flow simulations is important
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