Groundwater surveys are performed by GWS and its affiliates on location using the most advanced geophysical instruments and equipment. Our technology’s ability to detect underground water and create accurate images of possible subsurface groundwater bearing formations has been useful to thousands of our clients over the last 8 years.
AGRICULTURAL AND INDUSTRIAL GROUNDWATER EXPLORATION SURVEYS
Consult all available geological, topographical and geohydrological maps for the area, including aerial photos to identify potential groundwater bearing structures that can be targeted during the ground geophysical survey.
On request of the client, an intensive desk top study (remote sensing) of the entire farm, with focus on the desired location, can be done. The output will be in the form of four digital maps (A1), including a conclusive “water resource map” that will be produced and handed over to the client in digital (electronic) format.
Briefly, GWS make use of a Geophysical Instrument that measures the variations of natural electric fields of subsurface geological structures, thereby identifying fractures in rock formations and other anomalies like possible dykes, faults, contact zones etc. After data collection by the unique built in computing functions, a 2D subsurface profile map is processed, illustrating the fractured rock, the depth and shape of possible subsurface water.
We propose a sufficient number of measurements to cover all areas of potential groundwater bearing structures, identified by our desktop study. A final report will provide estimates for approximate minimum and maximum depths of possible water bearing rock formations. We provide an experienced crew of two people, a vehicle and the necessary instrumentation to record the data.
In order to record the electrical signals two electrodes have to be inserted vertically into the ground 10 metres apart, and the instrument records 32 measurements per point. The electrodes are then moved 3 metres in a straight line and always perpendicular to the possible fractured zone identified by the desktop study and marked on the water resource map. The process gets repeated at least 15 times, but not more than 20 times on the same line. A minimum of two lines and a maximum of three is done parallel to the first line, and not more than 5 metres apart. A minimum of 1440 readings per site gets recorded, and these readings are automatically processed into a resistivity curve graph and a 2D subsurface profile map.
RESIDENTIAL AND URBAN GROUNDWATER EXPLORATION SURVEYS
Desktop study: Consult geohydrological maps for the area, to identify potential groundwater bearing structures that can be targeted during the ground geophysical survey
Where groundwater is relatively easy to find, it is usually not cost-effective to use complex siting techniques. Furthermore, the infrastructure associated with most urban areas (electrical cables, telephone lines, buildings and pipelines) create interferences for the geophysics rendering the interpretation of the results virtually impossible. The shear smallness of the properties is another contributing factor as areas of several hectares of open ground are required for meaningful geophysical surveys to be undertaken. The more popular method in urban areas is to make use of water diviners. Groundwater Surveys, however makes use of an imported water detection device designed by a German Engineering Company. This device has proven to be 85% – 90% accurate in determining underground water sources in urban areas over the last 5 years! We propose a sufficient number of soundings to cover all areas of potential groundwater bearing structures, identified by our desktop study.