Assessment of groundwater development potential for Kinondoni Coastal aquifer in Dar es Salaam city, United Republic of Tanzania

In this study, a combination of geophysical and hydrogeological data has been used to assess the hydrogeological characteristics and determine limitations for groundwater development potential for Kinondoni coastal aquifers. The aquifers were delineated using data from 100 boreholes drilled between 2009 and 2016 with a maximum depth of 180m by the Drilling and Dam Construction Agency (DDCA) under the Ministry of Water of the United Republic of Tanzania. Hydrogeological information and interpreted Vertical Electrical Sounding (VES) results were used to classified groundwater development potential areas, aquifer types and their hydrogeological characteristics. It was established that, groundwater occurrences in the coastal aquifers (Kinondoni Municipality) are confined into two main aquifer types that are Quaternary in age. These include: an upper unconfined sand aquifer and a lower semi-confined sand aquifer. The upper and lower aquifers are separated by a clay aquitard except in areas close to the Indian Ocean. Nonetheless, a limestone aquifer exists near the coastline. This aquifer comprises reef limestone of Pleistocene to Recent age, and is often in contact with the sandy aquifer (unconfined), either underlying it or connected laterally. Deep seated aquifers situated at 100m to 180m deep are the most important in study area for supplying groundwater, compared to the upper water bearing horizons. The study area is mainly characterized by sand to sandy clay, which allows a high infiltration potential.