We focus on the appropriation, conflicting uses and meanings of water in a semi-arid environment marked by resource spatiotemporal variability. The Amboseli ecosystem, inhabited by semi-nomadic Maasai pastoralists and many wildlife species of the East African savanna, has likewise long been a stage for enacting a multitude of top-down governmental and non-governmental conservation policies. Agriculture has also taken hold in the rangelands as a result of development initiatives, thereby contributing, along with complex interactions between numerous other social, political, economic, and ecological factors, to the sedentarization of Ilkisongo pastoralists whose livelihoods have thus recently diversified. In a context where rains are erratic and groundwater reserves are poorly known, water is often a limiting resource for forage, agriculture, and wildlife, so thus often contentious in numerous dimensions regarding access, social relations and in human–wildlife interactions. Through a collection of narratives collected in the field we examine the challenges raised by water scarcity and analyse the situation through a postcolonial, marxist, and postdevelopmental approach. The ethnographic survey involved long immersion periods among Maasai stakeholders, interviews with farmers, conservation NGOs and other institutional leaders, and participatory events were generated around role-playing games focused on water, land use and land tenure. By articulating political, economic, cultural and gender dimensions this multi-pronged methodology showcases socio-hydrology as a situated science. Our participatory approach gauges how current tension around water management can be addressed by integrating the local population, environmental managers and outsiders, with consequences for decision making at individual and collective level and for the ecosystem.