Monitoring the soil water content of flood-protection dikes over large areas using geophysical methods
(MODIWAC - MOnitoring of DIke WAter Content)
(MODIWAC - MOnitoring of DIke WAter Content)
MODIWAC
Measurements of soil moisture are defining for questions of geotechnics, hydrology and meteorology in natural 
disaster research, especially for flood protection dikes. Known methods either measure on too coarse scales (satellite data) or on too small scales to cover a complete dike. The aim of this work is a system to monitor the moisture in a dike over a large area. It should combine measurements and modeling, and work as an early warning system. For this purpose the soil moisture distribution has to be measured and its development be calculated with respect to precipation and evaporation data. Existing and prognosed high resolution weather data must be combined with measurements of hydraulical and geotechnical conditions. A model of the dike has to be able to estimate the soil moisture development over the next days from these boundary conditions. To this end, meteorological influences have to be coupled with a soil hydraulics model. In the first phase of the project (2005) measurements were taken on model dikes. Two laboratory scale dikes and a full-scale outdoors model at the Federal Waterways Engineering and Research Institute were examined during flooding and sprinkling experiments. Applied measurement techniques were geoelectrics, spatial TDR (by the Institute for Rock and Soil Mechanics) and GPR (by the Geophysical Institute). The soil moisture content will be quantified by using GPR for an initial guess, then using geoelectrics to determine changes in water content. In this first phase, these results are compared to STDR measurement. 
Scientific support:
disaster research, especially for flood protection dikes. Known methods either measure on too coarse scales (satellite data) or on too small scales to cover a complete dike. The aim of this work is a system to monitor the moisture in a dike over a large area. It should combine measurements and modeling, and work as an early warning system. For this purpose the soil moisture distribution has to be measured and its development be calculated with respect to precipation and evaporation data. Existing and prognosed high resolution weather data must be combined with measurements of hydraulical and geotechnical conditions. A model of the dike has to be able to estimate the soil moisture development over the next days from these boundary conditions. To this end, meteorological influences have to be coupled with a soil hydraulics model. In the first phase of the project (2005) measurements were taken on model dikes. Two laboratory scale dikes and a full-scale outdoors model at the Federal Waterways Engineering and Research Institute were examined during flooding and sprinkling experiments. Applied measurement techniques were geoelectrics, spatial TDR (by the Institute for Rock and Soil Mechanics) and GPR (by the Geophysical Institute). The soil moisture content will be quantified by using GPR for an initial guess, then using geoelectrics to determine changes in water content. In this first phase, these results are compared to STDR measurement. Scientific support:
- Dr. Christian Hauck, Institute for Meteorology and Climate Research, Forschungszentrum Karlsruhe/University of Karlsruhe
- Prof. Christoph Kottmeier, Institute for Meteorology and Climate Research, Forschungszentrum Karlsruhe/University of Karlsruhe
- Dr. Andreas Bieberstein, Institute for Rock Mechanics and Soil Mechanics, University of Karlsruhe
Project partner:
- Holger Wörsching, Institute for Rock Mechanics and Soil Mechanics, University of Karlsruhe
- Dr. Alexander Scheuermann, Institute for Rock Mechanics and Soil Mechanics, University of Karlsruhe
- Kwasi Preko, Geophysical Institute, University of Karlsruhe
- Prof. Helmut, Wilhelm Geophysical Institute, University of Karlsruhe
| Title | Image | Source | Short Description |
|---|---|---|---|
| Soil water content monitoring on a dike model using electrical resistivity tomography | Near Surface Geophysics (2006) |
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| Geophysical monitoring of dike water content | EGU general Assembly, Vienna, Austria, 03.-07.04.2006 (Vortrag) | ||
| Geophysical Monitoring of Dike Water Content | 66. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, Bremen, 06.-09. März 2006 (Proceedings) | ||
| Comparing Time-Domain Reflectometry and Electrical Resitivity Tomography on a Dike Model | 11th European Meeting of Environmental and Engineering Geophysics (Near Surface 2005, Palermo), Extended Abstract | ||
| Comparing Time-Domain Reflectometry and Electrical Resistivity Tomography on a Dike Model | 11th European Meeting of Environmental and Engineering Geophysics (Near Surface 2005), Palermo, Italien, 4.-7.September 2005 (Proceedings) |
Vortrag/Poster | |
| Forward-inverse resistivity modelling and numerical simulation of small-scale water processes in the shallow subsurface | Abstracts der 67. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, Aachen, 26. bis 29. März 2007 |