Gas and groundwater
We can install the full range of groundwater and gas monitoring instruments, including standard standpipe piezometers set in sand cells within boreholes and slotted standpipes with internal diameters of 19–50 mm or larger. Groundwater and product levels are measured using interface and dip meters, with ground gas and vapour monitored using infrared analysers and photoionization detectors. Waterlogged sites can be monitored for ground gas using our flux boxes in combination with gas analysers or flame ionization detectors for low-range flammable gas.
In addition to water level monitoring within boreholes and waterbodies, permeability testing is a core task to establish the conductive potential of the ground. Variable head tests are done using well slugs to displace water within boreholes with dataloggers set to record recovery. For highly permeable ground, we use pneumatic initiation slug tests in combination with rapid-intensity dataloggers, which can record water levels up to seven times per second.
Ground movement
One of the simplest techniques to monitor ground movement is to install and monitor the level of settlement by placing plates into the ground. More sophisticated monitoring includes using extensometers with spider magnets placed at multiple levels in boreholes; changes in depth are measured at rerun visits using reed switch meters. Horizontal movement can also be measured by installing borehole inclinometers that are subsequently monitored using a biaxial probe. Data from the equipment can be graphed using dedicated software to visually express movement. Vibrating wire piezometers can be installed alongside a datalogger to record data at set intervals, and downloads or spot readings can be recorded at subsequent return visits to site. Shape arrays, inclinometers, extensometers and slip indicators are all available for installation on projects.
