Socio-economic impact assessment downstream of hydropower infrastructures : case study of Nam Mang 3 Hydropower dam in Lao PDR ; Évaluation de l'impact socio-économique en aval des aménagements hydroélectriques : Exemple du barrage hydroélectrique de Nam Mang 3 au Laos

Since two decades, hydropower projects are multiplying in Laos. These projects are often criticized in the media and civil society organizations for their negative social and environmental impacts, which can also generate regional geopolitical tensions in Southeast Asia. In this sensitive context, our interest has focused on rural populations downstream of hydropower dams; these populations are often ignored by compensation programs reserved for displaced populations from upstream. The objective of the research is to identify and assess the socio-economic effects in the Nam Nyam Valley (Vientiane Province, Lao PDR), downstream of the Nam Mang 3 hydropower dam. A current diagnostic-analysis of the agrarian system of the valley, together with a characterization of the recent evolution was conducted by household surveys in different villages. The diachronic study of agrarian dynamics and understanding the links of causality enabled us to model a counterfactual scenario to isolate, by difference with the current situation (scenario "with project"), the specific effects of the dam. In parallel, a similar approach was employed downstream of the Nam Lik 1-2 hydropower dam in the Meuang Feuang basin (Vientiane province, Lao PDR) in order to compare with the results of the Nam Nyam Valley, to better characterize the specific effects of hydropower infrastructure developments.As a result, the evolution of agrarian systems in the valleys downstream depends on the combination, variable over time, of several political, economic, demographic, environmental, technical, social, etc. factors. A hydropower dam, like the one of Nam Mang 3 is part of complex and continuous dynamics of transformation; its impact is not only the sole cause of changes affecting the communities. The socio-economic effects influence over time a much larger population downstream than upstream, even if the media attract the attention on punctual displacement of villages (and their compensation) to fill the reservoir.The hydropower dam project effects ...