HESS Opinions: Are soils overrated in hydrology?

Traditional hydrological theories are based on the assumption that soil is key in determining water's fate in the hydrological cycle. According to these theories, soil hydraulic properties determine water movement in both saturated and unsaturated zones, described by matrix flow formulas such as the Darcy–Richards equations. They also determine...

Frozen soil hydrological modeling for a mountainous catchment northeast of the Qinghai-Tibet Plateau

Increased attention directed at frozen soil hydrology has been prompted by climate change. In spite of an increasing number of field measurements and modeling studies, the impact of frozen soil on hydrological processes at the catchment scale is still unclear. However, frozen soil hydrology models have mostly been developed based on a bottom...

A simple topography-driven and calibration-free runoff generation module

Reading landscapes and developing calibration-free runoff generation models that adequately reflect land surface heterogeneities remains the focus of much hydrological research. In this study, we report a novel and simple topography-driven runoff generation parameterization – the HAND-based Storage Capacity curve (HSC), which uses a topographic...

Comparing the Normalized Difference Infrared Index (NDII) with root zone storage in a lumped conceptual model

With remote sensing we can readily observe the Earth’s surface, but direct observation of the sub-surface remains a challenge. In hydrology, but also in related disciplines such as agricultural and atmospheric sciences, knowledge of the dynamics of soil moisture in the root zone of vegetation is essential, as this part of the vadose zone is the...

Global root zone storage capacity from satellite-based evaporation

This study presents an "Earth observation-based" method for estimating root zone storage capacity-a critical, yet uncertain parameter in hydrological and land surface modelling. By assuming that vegetation optimises its root zone storage capacity to bridge critical dry periods, we were able to use state-of-the-art satellite-based evaporation...

Accounting for the influence of vegetation and landscape improves model transferability in a tropical savannah region

Understanding which catchment characteristics dominate hydrologic response and how to take them into account remains a challenge in hydrological modeling, particularly in ungauged basins. This is even more so in nontemperate and nonhumid catchments, where—due to the combination of seasonality and the occurrence of dry spells—threshold processes...

Spatial transferability of landscape-based hydrological models

Climate controls how ecosystems size the root zone storage capacity at catchment scale

Integrated glacier and snow hydrological modelling in the Urumqi No.1 glacier catchment

Using expert knowledge to increase realism in environmental system models can dramatically reduce the need for calibration

Conceptual environmental system models, such as rainfall runoff models, generally rely on calibration for parameter identification. Increasing complexity of this type of models for better representation of hydrological process heterogeneity, typically makes parameter identification more difficult. Although various, potentially valuable,...

Climate controls how ecosystems size the root zone storage capacity at catchment scale

The root zone moisture storage capacity (SR) of terrestrial ecosystems is a buffer providing vegetation continuous access to water and a critical factor controlling land-atmospheric moisture exchange, hydrological response, and biogeochemical processes. However, it is impossible to observe directly at catchment scale. Here, using data from 300...

Testing the realism of a topography-driven model (FLEX-Topo) in the nested catchments of the Upper Heihe, China

Although elevation data are globally available and used in many existing hydrological models, their information content is still underexploited. Topography is closely related to geology, soil, climate and land cover. As a result, it may reflect the dominant hydrological processes in a catchment. In this study, we evaluated this hypothesis...

Using expert knowledge to increase realism in environmental system models can dramatically reduce the need for calibration

Conceptual environmental systems models, such as rainfall runoff models, generally rely on calibration for parameter identification. Increasing complexity of this type of model for better representation of hydrological process heterogeneity typically makes parameter identification more difficult. Although various, potentially valuable,...

Testing the realism of a topography driven model (flex-topo) in the nested catchments of the Upper Heihe, China