Guinea-Bissau is a small West African Country characterized by a tropical savannah climate and an almost flat morphology. Although the yearly rainfall is high (around 2000 mm in Bissau), about 30% of the total population has no access to safe water (2015) and several villages are not reached by mechanized drilling programs. Exploitation of groundwater is fundamental to improve this situation, but the scarcity of information and the low quality of the data limit the hydrogeological knowledge of the territory by technicians and scientists.
The research has been developed through a positive collaboration between University of Milano-Bicocca, University of Padova, UNICEF Bissau and the national water authority (DGRH – Direção Geral dos Recursos Hidricos). Our purpose is to support DGRH in the systematic organization of the large amount of information available and in the efficient management of a well-structured groundwater database.
Borehole-log data have been processed with specifically designed software (i.e. TANGAFRIC and spMC) that allow the extraction of hydrogeological parameters from the logs and the spatialization of the textural characteristics.
The collaboration UNICEF-DGRH started in 2016, with the introduction of a new database structure and procedure for data collection and organization. This method is based on the web platform mWater Portal (portal.mWater.co) which allows to manage a Water, Sanitation and Hygiene (WASH) information system at national scale, with the possibility to display and monitor the inventory of water points. With the technical support of the Italian Universities, a clean dataset of about 800 litho-logs has been extracted. The stratigraphic description is standardized and organized in such a way that TANGAFRIC could process the data automatically. Through this software a limited number of standard categories, describing the lithological characteristics of each log, were assigned meter by meter. This allows the automated extraction of different textural parameters and the estimation of hydraulic conductivity at log level. In the following step TANGAFRIC’s output have been integrated into the spMC package which allows the spatial simulation and prediction needed for the lithological reconstruction of subsurface. In particular, we are looking for possible correlation between the water quality and the lithological bodies geometry and trend, focusing on the Catiò Sector (SW Guinea-Bissau), where groundwater is affected by salt intrusion and high iron concentration.
The research is demonstrating the potentiality of a properly organized groundwater database, developed from the information available in a low income African Country. The integration of specific tools for data collection and organization, together with software for hydrogeological interpretation has made possible to improve the knowledge of the hydrogeological context at national level.
The proposed procedure is simple, innovative and easily replicable in other African Countries where an adequate strategy for groundwater exploitation and management could contribute to improve living conditions.