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In 2012, about 1.3 million people lived on the slopes of Merapi, one of the most active volcanoes in the eastern part of Java Island in Indonesia. A majority of Merapi inhabitants, grouped together in small villages, live off agricultural income, relying on hydraulic infrastructures for their daily activities. Not only do these farming activities require a substantial amount of water, but an entire community in one village also depends on water resources to maintain its organization and functioning. The proximity of water availability and its access with community dependence on it is well illustrated by the first water management position in the community initiatives: the term socio-hydraulic system highlights the dependency of the community organization profile on water resources. However, the eruption of Merapi in 2010 and the following pyroclastic flow or lahar-related crises have recently made water availability and access to water the main challenges to be addressed by the hydraulic community. Many research projects have highlighted actions taken by the Merapi communities to face successive disasters using the resilience concept, which is closely linked to sustainability. However, the interviews we carried out in 2013, 3 years after the eruption and a few months after lahar recurrences, revealed persistent fragilities and readjustments to water management in hazard-prone areas. This present work first aims to discuss multiple social vulnerabilities and in some cases, the capacity to adapt, by investigating the hydraulic community’s responses in the face of lahar issues after the 2010 Merapi eruption. In order to reassess the resilience concept and to draw the limits of its operative aspects, studies of multi-dimensional responses to the interviews and of explicative factors have been developed within the Merapi community. Focusing on resources, people’s roles and socio-environmental risks, we discuss the main influence of the ‘cultures of risks’ observed through a 1-month period of fieldwork, a notion that add another focus to the notion of local resilience(s): in doing so, we defend the idea that risk assessments must be undertaken through a systemic approach, focusing on the coupled-notion vulnerability/resilience, and we question the limits of the operative aspect and the durability of the resilience concept on longer temporality and geographical scales.

This study examines the fluvial readjustment of a Javanese river impacted by the major eruption of the Merapi volcano (Indonesia) in October and November 2010. The basin of the Opak River, located on the southern flank of the Merapi, was subject to substantial sediment input related to massive pyroclastic deposits that were remobilized by numerous lahars during the year after the eruption. Two study sites were equipped in order to evaluate the morphodynamic evolution of the riverbed of the Opak River. Topographic surveys, bedload particle marking, and suspended sediment sampling revealed an important sediment mobilization during efficient flash floods. Surprisingly, no bed aggradation related to the progradation of a sediment wave was observed. Two years after the eruptive event, marked bed incision was observed. The Opak River readjustment differs from that of other fluvial systems affected by massive eruptions in two ways. Firstly, local population extracted the sand and blocks injected by the eruption as they represent a valuable economic resource. Secondly, several dams trapped the major part of the sediment load remobilized by lahars.

Trois equipes du Havre racontent la mise en place d’un partenariat de travail autour de personnes en situation de demande d’asile. Les difficultes existentielles extremes de celles-ci entrainant difficultes sociales et mal-etre psychologique, necessitaient ce partenariat fonctionnel indispensable. Cet article ecrit par les intervenants des differentes structures parties-prenantes est le reflet de ce travail en commun.