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Borehole measurements for hydrogeological investigations
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 8th EEGS-ES Meeting, Sep 2002, cp-36-00110
- ISBN: 972-789-071-7
Abstract
The chalk aquifer is the most important aquifer in the United Kingdom; providing more than 50 % of the abstracted groundwater. The Chalk is a dual porosity aquifer with a high matrix porosity of approximately 35 % in the northern chalk province of England but due to the small pore diameter of 0.2 to 2.0 μm the matrix has a very low hydraulic conductivity (per-meability) of about 10-4 m/d. The bulk permeability is enormously increased by fractures and faults. The Flamborough Chalk, which is the youngest formation of the northern province, is characterised by marl bands. These calcareous clays can act as aquicludes and could result in channelled horizontal flow as well as restricted vertical flow. The investigation site is situated in the northern chalk province of England. The chalk is confined at the field site by a ca. 11 m thick, drift layer. Five boreholes were drilled for (future) tracer and flow experiments (see figure 1).