Egis has outsourced to Bertone & Associates the direction of the study of new sources of raw water for the city of Arusha (Consultancy Services for Additional Water Sources Investigation) which was conducted as part of the vast Arusha Sustainable Urban Water and Sanitation Delivery project funded by the African Development Bank. This study mobilized up to 30 people for 11 months, from July 2016 to May 2017.
As part of this work, the team led by François Bertone has set up a particularly intensive field campaign in the Upper Pangani Region, south of Mounts Meru and Kilimanjaro. In order to explore the geological and hydrogeological patterns of the area, a deep geophysical survey was conducted with not less than 195 vertical electrical sounding and 87,210 m of geomagnetic measurements distributed over 60 sites. This survey was supplemented with the drilling of 13 deep vertical boreholes (including at altitudes of over 1,800 masl o the slopes of Mount Meru and Mount Kilimanjaro), mobilising up to 4 drilling rigs at a time. In addition, the water level were measured in 120 water wells and 91 springs, supplemented with the accurate measurements of elevations for all water points. This data allowed the construction of the first piezometric map of the area. As a complement to the investigations conducted by the Pangani Basin Water Board, a total of 27 river flow measurements were taken at 16 different points in 4 different campaigns with the aim of precisely determining the flow pattern of most of the rivers in the area. A detailed topography and geology of the main river valleys was surveyed in order to identify dam sites. Environmental and social conditions were screened at every potential water source with the aim of establishing the effects abstracting water from rivers and aquifer.
The results of this study will allow the implementation of a major infrastructure project: 3 well-fields are already under construction around the city of Arusha. They will also be the subject of a scientific publication.