Analysis of rainfall‐runoff relation in paddy fields by diffusive tank model

Abstract

Due to the occurrence of ponding during the period of rice growth, the analyses of rainfall-runoff in paddy fields are different from those in general lands. The diffusive tank model has been successfully applied in rainfall-runoff simulations in paddy fields because it can well describe the features of the local water flow. In most of the applications of this model, although the determination of the related model parameters is important, detailed investigations on each individual parameter are definitely needed to improve the accuracy of the results. In the study, an improved procedure is proposed to determine certain variables involved in the diffusive tank model and the application is conducted in a field area in Taiwan. In the application, the roughness of the river channel was assessed according to the actual field conditions. Instead of using the observed water levels in each rainfall event, the notch width of the rectangular contracted weir per unit area was evaluated by direct field measurements to calibrate the discharge coefficient. Test results from the selected field in six rainfall events showed that the local average value of the notch width of the rectangular contracted weir per unit area was 1.025 m/ha. Compared to the results of field measurements, the relative errors of the predictions were within 3% in all tests of rainfall events. In addition, for different types of catchment partitions, it was found that the corresponding weir discharge coefficients remained roughly unchanged. Copyright (C) 2003 John Wiley Sons, Ltd

Effect of growing watershed imperviousness on hydrograph parameters and peak discharge

“…The error of peak discharge and the error of the time for peak to arrive have also often been used to examine modelling result (e.g. Chen et al, 2003;Moramarco et al, 2005). These criteria are as follows:…”

Relating hydrograph components to rainfall and streamflow: a case study from northern Taiwan

“…Hence, differences in peak quantity and time to peak between observations and simulations were also examined herein. The EQ p and ET p have also been frequently used to examine simulated results (Chen et al 2003, Moramarco et al 2005. The evaluation criteria are calculated as follows:…”

“…Various studies have addressed the effects of different methods for estimating rainfall excess and baseflow on the accuracy of modelling surface runoff (Mays andTaur 1982, Cheng andWang 2002). Prior to development of the IHACRES (Jakeman et al 1990, Jakeman andHornberger 1993) and Tank models (Sugawara 1979, 1995, Madsen 2000, Yue and Hashino 2000, Hashino et al 2002, Chen et al 2003, Lee and Singh 2005, hydrological modelling frequently focused on generating direct runoff by a linear convolution with the specific input-output structures.…”

Optimal gate operation of a main drainage canal in a flat, low-lying, agricultural area using a tank model

“…In flat, low-lying agricultural areas consisting of paddy fields and canals, tank models have been introduced for rainfall-runoff analysis in order to overcome the model complexity and calculation time. For example, Shikasho and Tanaka (1985) executed the inundation analysis in a flat, low-lying paddy-cultivated area in Japan using a continuous tank model, and Chen et al (2003) and Chen and Pi (2004) used a diffusive tank model for rainfall-runoff analysis in local areas mixed with paddy and upland fields. Hiramatsu et al (2004) applied a continuous tank model to simulate and analyze the inundation in a flat, low-lying paddy-cultivated area in the Red River delta in Vietnam.…”