## 4 Discussion
### Potential for Technology Deployment  
#### 4.2.1 Applications  
The resistivity technology implemented may be deployed in Malawi as a stand-alone operation for fundamental hydrogeological research. For instance, a collaborative programme of use by a Malawian university consortium with the Ministry could regionally better characterise groundwater bodies and their aquifer potential than has hitherto been possible. The most powerful technology application foreseen though is its integration to Water and Sanitation Hygiene (WASH) borehole drilling programmes. Technology applications of significance include the following:  
* Integration with drilling: The most important application in Malawi would be assisting improved sitting of supply boreholes. It may also help identify lithologies, faults and fractures, and thereby would help anticipate the mechanical behaviour of formations to be drilled and aid optimal selection of drilling methods.
* Integration with other surface geophysics: Combined deployment with MP may be beneficial, as, although only qualitative answers are provided by MP about the subsurface configuration, it may still enable the identification of lineaments or help distinguish lithologies with different magnetic signatures that may appear similar on resistivity cross-sections. There is no benefit associated with combining the resistivity method implemented with conventional VES or EMP used in Malawi.
* Integration with borehole logging: Borehole-scale geological calibration and validation of the geophysical survey section (not possible in the current study due to a lack of nearby logged boreholes) will increase confidence in its geological interpretation and predictive use. Geomechanical parameters of drilled formations (hardness, stiffness, abrasivity, etc.) may be compared to resistivity cross-sections, to check for any correlations. Drill-cutting analyses and borehole CCTV image may help identify geological features too small or of insufficient contrast to be identified by resistivity. They may help identify unexplained features observed on resistivity cross-sections and whether transitions are real or artefacts of inversion smoothing. Conversely, large-scale featureson cross-sections may help interpret much smaller-scale drill cutting or CCTV image observations.
* Integration with aquifer testing: Aquifer shape and dimensions, presence and continuity of confining units and aquifer boundaries, and aquifer heterogeneity and zonation are critical parameters to inform the analysis of aquifer pumping test data and may all be determined on the resistivity cross-sections. Likewise, pumping test and borehole rest water-level measurements permit more quantitative hydrogeological conceptualisation of the resistivity section.  
In relation to achieving the UN's SDG Target 6.1 [4], technology application may assist the Government of Malawi's current ambition is to improve the rural drinking water service from a basic level of service, currently focused on hand-pumped boreholes albeit with functionality concerns [5; 6; 7], to a safely managed level. Plans for larger groundwater supply projects involving solar powered submersible pumps from multiple borehole \"well fields\" feeding reticulated piped networks will need to be supported by advanced geophysical subsurface imaging reconnaissance with tools such as that implemented that are viable in developing country settings.