Abstract:
Study region: Coastal areas of Kenya (Kilifi County), Tanzania (Kilwa district) and Comoros
(Ngazidja island), East Africa.
Study focus: Research aimed to understand the physical and societal drivers of groundwa-
ter accessibility and identify critical aspects of groundwater access and knowledge gaps
that require further monitoring and research. Interdisciplinary societal, environmental and
hydrogeological investigations were consistently undertaken in the three areas consid-
ered as exemplars of the diversity of the coastal fringes of the wider region. This paper
focuses on the hydrogeological outcomes of the research, framed within the principal
socio-environmental issues identified.
New hydrological insights: Results confirm the fundamental importance of coastal ground-
water resources for the development of the region and the urgent need to match
groundwater development with demographic and economic growth. Hydrogeological
knowledge is fragmented, groundwater lacks a long-term monitoring infrastructure and
information transfer from stakeholders to users is limited. Current trends in demog-
raphy, climate, sea-level and land-use are further threatening freshwater availability.
Despite possessing high-productivity aquifers, water quality from wells and boreholes is
generally impacted by saltwater intrusion. Shallow large-diameter wells, following the tra-
ditional model of these areas, consistently prove to be less saline and more durable than
deeper small-diameter boreholes. However, promoting the use of large numbers of shallow wells poses a significant challenge for governance, requiring coherent management of the
resource at local and national scales and the engagement of local communities.
