Impact of dam development and climate change on hydroecological conditions and natural hazard risk in the Mekong River Basin

The Mekong River Basin, one of the largest river basins in Asia, is facing a great challenge to meet escalating water, food, and energy demands due to rapid development. Meanwhile, climate change and dam development intensify the security issues of these water-related resources. These changes have resulted in flow regime variations that may affect local hydroecological conditions (HEC) further influencing the ecosystem and have resulted in potential economic losses (especially agricultural losses caused by natural hazards). This study explores the impacts of dam development and climate change on baseline local HEC and natural hazard risk (NHR) using a coupled agent-based model that simulates interactions between autonomous agents in the whole basin. A cross-system analysis between the impact on baseline HEC and NHR is conducted to inform future policy in this transboundary basin. The impact on baseline HEC is evaluated from the flow regime variation perspective based on the Range of Variability Approach and the Indicators of Hydrologic Alteration. The impact on NHR depends on variations in the risk of lowest flow and peak flow. The results primarily show that HEC and NHR in the upstream region are more sensitive to precipitation change. The negative impact on baseline HEC by joint dam development and climate change is more significant in the upstream region as well. Under the hot and dry climate condition, dam development can potentially mitigate both ecological and economic loss in the middle and downstream regions: Central and Southern Laos, the Kratie area, and Mekong Delta, if additional storage can be used in a flexible manner.