Methodology for Hydrogeochemical Sampling to Characterise Groundwaters in Crystalline Bedrock: Developments Made within the Swedish Radwaste Programme

Figure 4

(a) Installed equipment for pressure, groundwater sampling, and groundwater flow monitoring in a telescopic borehole. A maximum of 10 pressure sections can be installed in a telescopic borehole, of which generally two are equipped for water sampling and circulation of tracers during flow measurements. These circulation sections are connected to three tubes. Two of them connect the section to the two standpipes for pressure measurements and groundwater sampling (the wider pipe), respectively, in the uppermost part of the borehole. The third tube leads all the way to the ground surface for the circulation experiments. (b) Lowering of a pump connected to a minipacker (for isolating the standpipe from the atmosphere) and a 50 μm filter (polyamide) into a large diameter standpipe. To collect samples, pumping is conducted in the closed standpipe (cf. (a)); when the pressure decreases, groundwater from the connected borehole section is sucked into the standpipe and pumped to the ground surface. Modified from [48].

(a)

(b)