Multilateral Working Group on Water Resources
Water Data Banks Project
Entry from Directory of Selected Israeli Water-related Projects
| NOTE: It is recommend that all information posted here be checked with primary sources before use. |
| TITLE: | Groundwater pollution due to preferential flow in the unsaturated zone |
|---|---|
| PROBLEM: | Agricultural chemicals, such as fertilizers or pesticides, are indispensable in modern agriculture. Fertilizers and pesticides are highly beneficial to the crops being grown, but only as long as they remain in the root zone of the soil. Dissolved chemical transport downward can take place through the main soil bulk or through preferential pathways. Preferred pathways may result from biological and/or geological activity (e.g., macropores, earthworm burrows, channels consisting of highly conductive media) or from farm management practice. The water and chemicals are moving much faster through these pathways and contribute to the pollution of groundwater. A better understanding of the factors affecting the percolation of water and the mobility, extent and nature of chemical transport and biological degradation of solutes is required to improve modeling efforts and management practices. |
| OBJECTIVES: | To study and quantify the mechanisms that control the interaction between preferred pathways and the main matrix and their effect on the spatial and temporal distribution of chemicals in the unsaturated zone |
| APPROACH: | Formulation of an analytical model which simulates the advective-dispersive transport of a solute through a vertical slit coupled with diffusion through a boundary layer of contact between the slit and the matrix. Effects of density instability are also taken into account. |
| BEGINNING DATE: | January 1994 |
| ENDING DATE: | October 1997 |
| COMMENTS ON DATES: | |
| CURRENT PROGRESS OR INTERIM RESULTS: | The model was successfully used to predict breakthrough curves in experimental structured blocks and granite cores at Cornell and Wisconsin Universities |
| PRINCIPAL INVESTIGATOR NAME: | Rony Wallach |
| ADDRESS: | Department of Soil and Water Sciences, Faculty of Agriculture, Hebrew University of Jerusalem, P.O.Box 12, Rehovot 76100 |
| TELEPHONE: | 972-8-948-1170 |
| TELEFAX: | 972-8-9475181 |
| EMAIL: | wallach@agri.huji.ac.il |
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