- Copyright © 2004 Society of Exploration Geophysicists
The global increase in demand for water, the dominant agent in all biological processes, calls for sustainable management of water catchments and better understanding of water and solute movement. At Kiel, we have started joint studies with eight European partners in such disciplines as botany, agronomy, and hydrology (projects “WATERUSE” and “GeoModel”) to develop integrated techniques to quantify water flow through the soil-plant-atmosphere-continuum that will be adequate for use in heterogeneous stands in dry regions. To develop novel integrated hydro-/biogeophysical 3D techniques with high resolution, we erected a unique, full-scale tank analog (3 m × 5 m × 2 m and named GeoModel) at the Kiel campus for controlled experiments on simulated soil models in their natural scale. It forms a bridge between scaled laboratory models (typically 1 m3) and field surveys (several km3) that takes advantage of both. GeoModel is used to study the static water content and dynamic flow in soils and plants using infiltration of varying scenarios and soils of varying textural and structural properties.
This paper deals with observation and mapping of static and dynamic water or moisture in soils and trunks. Specifically, this work aims at: (1) deriving water content from empirical hydro-petrophysical relationships established from in-situ and laboratory data, (2) mapping objects and structures in the heterogeneous vadose zone (e.g., root zones) and imaging trunks (e.g., internal ring structure), and (3) exploring the capability of geophysical techniques to monitor processes (e.g., water flow in vadose zone, water uptake by roots, sap flow in trunks).
Soil water content is linked to petrophysical parameters of specific formation dc-resistivity and radar velocity by empirical laws developed by Archie (1942) and Topp et al. (1980), respectively. Hydrogeophysical techniques, based on these relationships are able to find the (static) amount of water content and even determine its …