Basin-Wide Water Resources Management Strategies Improve Cooperation Effectiveness and Benefits

Basin-wide cooperation is an approach to resolve water disputes and improve the resilience of transboundary river basins to extreme droughts under climate change. However, the effectiveness of cooperation among various stakeholders has disputes in moving from theoretical research to practical application. This paper aims at developing basin-wide water resources management strategies to improve cooperation effectiveness in the Lancang-Mekong River Basin (LMB). An interdisciplinary physically based integrated hydroeconomic water system model is developed for strategy evaluation, and is shown to have good performance in reproducing historical events. First of all, we find that agricultural benefits in downstream countries are primarily affected by hydrological conditions, without significant impacts from reservoir construction. Second, the cooperative action—three-phase emergency water supply—by upstream reservoirs discharge can alleviate the agricultural drought of downstream countries, and it is further improved by better spatial and temporal water reallocation among different stakeholders. Last but not least, we characterize the cooperation effectiveness under different hydrological conditions by two indicators (i.e., incremental benefit and cooperation efficiency). They show two opposite trends: from extremely high-flow years to extremely low-flow years, the incremental benefit brought by basin-wide cooperation increases by nearly six times, whereas the cooperation efficiency (measured by how many times benefits are gained by downstream from upstream unit loss) decreases by 80 percent. This study provides guidance and support for transboundary basin cooperation and sustainable management.