Most of the world's liquid freshwater resources are stored underground as groundwater. Its distribution on earth is varied, however, and depends mainly on climatic conditions and the geology of the subsurface. A large amount of this groundwater is recharged in the hydrologic cycle by infiltrating precipitation.
Airborne geophysics have been used for more than 40 years to find ground water. Methodology universally employed include regional reconnaissance techniques, such as aero-magnetic surveys and/or helicopter-borne electromagnetic (HEM) surveys.
McPhar recommends a three phase approach to groundwater exploration / aquifer detection and mapping:
Phase One - Satellite image analysis using Landsat Thematic Mapper, SPOT, Soyouz, and others
Phase Two - Airborne reconnaissance using a high-sensitivity aeromagnetic system (fix-wing or helicopter depending on the terrain where the survey is to conducted)
Phase Three - Detailed helicopter-borne follow-up of Phase 2 results, using HEM (frequency– or time-domain as circum-stances dictate) and magnetics .
An Integrated interpretation/analysis, wherein all of the re-sults of the three phases discussed above would be integrat-ed, modelled and reported, providing information on Aquifer locations.
Read more...Groundwater Info Sheet »
Read more...Kraaipan Ground Water Exploration, South Africa Case Study »