The Cambodian Mekong floodplain under future development plans and climate change

Abstract. Water infrastructure development is considered necessary to drive economic growth in the Mekong region of mainland Southeast Asia. Yet current understanding hydrological and flood pattern changes associated with infrastructural still contains several knowledge gaps, such as interactions between multiple drivers, which may have serious implications for water management, agricultural production, ecosystem services. This research attempts conduct a cumulative assessment basin-wide hydropower dam construction irrigation expansion, well climate change, on discharge, Cambodian floodplain. These floodplains offer important livelihoods considerable part 6.4 million people living them, they are among most productive ecosystems world – driven by annual pulse. To assess potential future impacts, we used an innovative combination three models: distributed model IWRM-VMod, delta 1D propagation MIKE-11 2D duration extent IWRM-Sub enabling detail floodplain modelling. We then ran scenarios approximate possible conditions expected around 2050. Our results show that monthly seasonal regimes (discharges, levels, dynamics) will be subject substantial alterations under scenarios. Projected change impacts decrease dry season flows increase wet flows, opposition consider both irrigation. The likely impact decreasing discharge early (up ?30 %) pose critical challenge rice whereas mid-dry +140 indicates improved availability coping drought stresses sustaining environmental flows. At same time, these would drastic total extent, projected decline 20 %, having potentially negative productivity aquaculture, whilst reducing risk more densely populated areas. findings demonstrate planned area, impacting people's livelihoods, calling actions mitigate planning adaptation strategies.