Phreatology: Characterising groundwater recharge using remote sensing, GIS, ecology, hydrochemistry and groundwater modeling

Okke Batelaan

Onderzoeksoutput: PhD Thesis

Samenvatting

Phreatology is a new field of research that is defined as `The science of the geological, hydrological, biological and chemical processes at the interface of the phreatic water with the vadose or surface waters, it focuses on the part of the surface and subsurface in which over time the groundwater table and capillary zone reside'. The concept of phreatology is defined and its interdisciplinary character is stressed. Methodologies supporting phreatology are developed and applied to analyze groundwater discharge areas, and recharge areas. Tools and techniques from groundwater modelling, hydrochemistry, vegetation ecology and remote sensing are used and integrated; GIS technology combines the approaches. Applications from regional to site level are given for the Dijle, Demer and Nete catchment, Belgium.It is concluded that the regional context is often not explicitly taken into account in the ecohydrological analysis of wetlands, which hampers the identification and quantification of regional abiotic factors for ecohydrological site modelling. The developed spatially distributed water balance model `WetSpass' shows that recharge has a complex spatial pattern, depending to a large extend on the soil texture and land cover. The identification and delineation of regional groundwater discharge areas is proven more accurate by using the SEEPAGE package.Important consequences for vegetation patterns and groundwater sampling networks in wetlands are that very different groundwater fluxes and qualities can be expected at very short distances. Geochemical processes in the feeding aquifer and the convergence of flow paths strongly determine the hydrochemistry of discharging groundwater. It is the most important factor in the explanation of the occurrence and spatial distribution pattern of vegetation types. The synergy of hydrological modelling, vegetation mapping, hydrochemistry and remote sensing proves advantageous and reveals ecological differences in the catchment. The results contribute to an increased understanding of the phreatological functioning of the studied areas.
Originele taal-2English
Toekennende instantie
  • Vrije Universiteit Brussel
Begeleider(s)/adviseur
  • De Smedt, Florimond, Promotor
Plaats van publicatieBrussels
StatusUnpublished - 2006

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