Estimation of sedimentation in Manwan and Jinghong reservoir of the Lancang river

The Lancang reservoirs play an essential role in the national economy and life, and the study of reservoir siltation is of great significance to ensure its sustainable service for the nation and people. In this paper, reservoir sedimentation is quantified in stages by empirical models and theoretical methods using reservoir information and sediment data to reveal the latest status of siltation in Lancang reservoirs. Results show that the storage capacity loss of Manwan and Jinghong reservoirs has reached 51.4% and 1.54% until 2019, which illustrates that the situation of siltation is serious. The theoretical trapping efficiency of Manwan reservoir was about 69% and the estimation result of Brune method performed best with a value of 67.5% among the empirical methods. Brune method was then modified with a correction coefficient and the revised Brune method can be used for the estimation of trapping efficiency in other reservoirs. Overall, this paper can present relatively accurate information for managers to understand the current state of siltation in Lancang reservoirs, and provide scientific guidance and data support for them to take measures to reduce sedimentation and ensure the sustainability of reservoirs.