Physical and societal challenges in groundwater security in coastal East Africa: case studies in the Comoros Islands, Kenya and Tanzani

African coastal regions are expected to experience the highest rates of population growth in coming decades.Fresh groundwater resources in the coastal zone of East Africa (EA) are highly vulnerable to seawater intrusionand increased water demand is leading to unsustainable and ill-planned well drilling and abstraction. Wells supplying domestic, industrial and agricultural needs are, in many areas, too saline for use. Climate change,including weather changes and sea level rise, is expected to exacerbate this problem. The multiplicity of physical,demographic and socio-economic driving factors makes this a very challenging issue for management. At presentthe state and probable evolution of coastal aquifers in EA are not well documented. The UPGro project 'Towards groundwater security in coastal East Africa' brings together teams from Kenya, Tanzania, Comoros Islands andEurope to address this knowledge gap. An integrative multidisciplinary approach, combining the expertise of hydrogeologists, hydrologists and social scientists, is investigating selected sites along the coastal zone in eachcountry. Hydrogeologic observatories have been established in different geologic and climatic settings representative of the coastal EA region, where focussed research will identify the current status of groundwaterand identify future threats based on projected demographic and climate change scenarios. Researchers areengaging with end users as well as local community and stakeholder groups in each area in order to understanding the issues most affecting the communities and identify sustainable strategies for addressing these