The use of physically-based distributed hydrological models demands comprehensive amounts of data both to parameterise and force the model as well as to validate it. Conventionally measured data are mainly restricted to point measurements which are less optimal for use in a spatial distributed context. However, remote sensing can offer such area integrated measures albeit through a more indirec...

The first step in the dynamic modelling of pesticides is a reliable hydrodynamic model. SWAT (Soil and Water Assessment Tool) calculates both the dynamic hydrological response and the associated diffuse pesticide supply towards surface waters. In this study, we focus on the hydrodynamic part. First, an intensive data collection for the Nil-catchment was performed. During model set-up, a reducti...

A large number of local and global databases for soil, land use, crops, and climate are now available from different sources, which often differ, even when addressing the same spatial and temporal resolutions. As the correct database is unknown, their impact on estimating water resource components (WRC) has mostly been ignored. Here, we study the uncertainty stemming from the use of multiple da...

Abstract. Soil water content (SWC) sensors are widely used for scientific studies or the management of agricultural practices. The most common sensing techniques provide an estimate volumetric soil based on dielectric permittivity. These include frequency domain reflectometry (FDR), time (TDR), capacitance and even remote-sensing such as ground-penetrating radar (GPR) microwave-based techniques...

The newly-developed cosmic-ray method for measuring area-average soil moisture at the hectometer horizontal scale is being implemented in the COsmic-ray Soil Moisture Observing System (or the COSMOS). The stationary cosmic-ray soil moisture probe measures the neutrons that are generated by cosmic rays within air and soil and other materials, moderated by mainly hydrogen atoms located primarily ...

In arid regions, water resources are a key forcing factor in ecosystem circulation, and soil moisture is the critical link that constrains plant and animal life on the soil surface and underground. Simulation of soil moisture in arid ecosystems is inherently difficult due to high variability. We assessed the applicability of the process-oriented CoupModel for forecasting of soil water relations...

Soil water content is one of the most important parameters for estimating irrigation frequency and providing the plant’s water requirement. Since measurement of soil water content is both expensive and time consuming, water movement models are used to estimate these values. In this study, LEACHW model was used to estimate soil water content for two “dry” (20-29 Aug) and “wet” (1-6 Jul) periods ...

Spatially variable soil properties influence the performance of soil water content monitoring sensors. The objectives of this research were to: (i) study the spatial variability of bulk density (ρ(b)), total porosity (θ(t)), clay content (CC), electrical conductivity (EC), and pH in the upper Mākaha Valley watershed soils; (ii) explore the effect of variations in ρ(b) and θ(t) on soil water con...

Soil depth is an important input parameter in hydrological and ecological modeling. Presently, the soil depth data available in national soil databases (STATSGO, SSURGO) is provided as averages within generalized map units. Spatial uncertainty within these units limits their applicability for spatially distributed modeling. This work reports a statistical model for prediction of soil depth in a...

This study was conducted to investigate the effects of soil moisture content on the absorbance spectra of sandy soils with different phosphorus (P) concentrations using ultraviolet (UV), visible (VIS), and near-infrared (NIR) absorbance spectroscopy. Sieve sizes were 125, 250, and 600 m for fine, medium, and coarse, respectively. The medium size of the samples was used for the study. Investigat...