Groundwater level decline and water quality / salinity determination were possible with existing geophysical equipment available in Malawi.
Groundwater quantity (available shallow groundwater) and quality (salinity) are two key limitations in the Lower Shire. Implementation of modern Geophysical techniques can provide much needed hydrogeological data for planning.
Geophysics should be used much more extensively for monitoring groundwater levels and for placing of boreholes.
GEOPHYSICS FOR GROUNDWATER EVALUATION
The use of Geophysics for Groundwater Evaluation is not used to full potential
Geophysics methods are well known for groundwater resource exploration and development. However, limited resources and equipment has resulted in geophysical surveying being highly under used in rural Africa. Many geophysical surveys provide little more than verification and there is a need to build capacity in groundwater science and the use of modern geophysical methods to enhance groundwater resource planning.
Local Scale (Group Village) geophysical survey of Kakoma village, Chikhwawa
Monitoring of local scale water level decline
Salinity profiles in boreholes and 3-D subsurface details
Salinity and reducing groundwater availability are problems faced by those living in the Kokoma group village. A 1 week detailed geophysical survey provided new understanding of the sources of salinity and decline in water table resulting from groundwater use.
There is no detailed study of groundwater level changes with time in the Lower Shire. Geophysical methods can be used to measure local scale water table changes due to pumping of groundwater for local use. The figure above clearly shows the cone of depressions around the most used wells in this group village in Chikhwawa.
Salinity of groundwater (salty wells) remains a major problem in the Lower Shire. Detailed geophysical surveys can identify zones of fresh and salty water. This data can be used to inform drilling and installation requirements under the Water Resources Act (2013) Malawi.