A Statistical Vertically Mixed Runoff Model for Regions Featured by Complex Runoff Generation Process

Abstract

Hydrological models for regions characterized by complex runoff generation process been suffer from a great weakness. A delicate hydrological balance triggered by prolonged wet or dry underlying condition and variable extreme rainfall makes the rainfall-runoff process difficult to simulate with traditional models. To this end, this study develops a novel vertically mixed model for complex runoff estimation that considers both the runoff generation in excess of infiltration at soil surface and that on excess of storage capacity at subsurface. Different from traditional models, the model is first coupled through a statistical approach proposed in this study, which considers the spatial heterogeneity of water transport and runoff generation. The model has the advantage of distributed model to describe spatial heterogeneity and the merits of lumped conceptual model to conveniently and accurately forecast flood. The model is tested through comparison with other four models in three catchments in China. The Nash–Sutcliffe efficiency coefficient and the ratio of qualified results increase obviously. Results show that the model performs well in simulating various floods, providing a beneficial means to simulate floods in regions with complex runoff generation process.

Quantifying the impact of climate change and human activities on runoff at a tropical watershed in South China

“…Lumped hydrological models commonly treats the watershed as a whole and ignore geographic variability, and many of their equations also lack obvious physical definitions (Zeng et al, 2013;Zuo et al, 2014). The benefit of distributed hydrological models is that, in addition to considering geographic heterogeneity, they can also describe the mechanisms of hydrological processes (Lin et al, 2020). On top of that, the simulation scenario may be set up flexibly.…”

Seamless Integration of Rainfall Spatial Variability and a Conceptual Hydrological Model

“…Typically, there are two underlying runoff generation mechanisms in conceptual rainfall-runoff models [38], i.e., the infiltration excess (Horton) mechanism [39] and saturation excess (Dunne) mechanism [40]. However, most of the models are developed based on a single mechanism, such as the Xinanjiang (XAJ) model [41], TANK model [42], Hydrological MODel (HYMOD) [43], Sacramento model [44], and Shanbei model [45].…”

“…Therefore, the mixed runoff that couples both infiltration excess and saturation excess mechanisms needs to be studied [46,[48][49][50]. For this purpose, the vertically mixed runoff (VMR) model was developed by [48,51] and has been successfully applied to several catchments in China [13,38,46]. The VMR model assumes that the two runoff generation mechanisms exist simultaneously in the vertical direction at the same time where the Horton runoff occurs when rainfall intensity is greater than the infiltration capacity, and the Dunne runoff occurs when the soil moisture capacity is satisfied [52].…”