China Three Gorges Corp has begun filling the Three Gorges reservoir for 2026, with all cascade reservoirs on the Yangtze River mainstream under its operation now in the impoundment phase.

The Three Gorges reservoir officially started this year's filling on September 10, according to a plan approved by the Ministry of Water Resources. The Wudongde, Baihetan, Xiluodu and Xiangjiaba reservoirs had already begun filling on August 1 and September 1 respectively, starting from their previous operating levels.

The company began drafting a joint filling plan for the cascade reservoirs in mid-July, coordinating with relevant units and factoring in flood control and drought relief conditions, upstream reservoir storage, inflow forecasts and water demand in the middle and lower reaches. The plan was submitted in late August and approved by the Yangtze River Water Resources Commission.

Since July, upstream inflows to the Yangtze River have generally shifted from abundant to low. In mid-July, the middle reaches entered the post-flood season, with a low probability of basin-wide flooding. Three Gorges adjusted its strategy from flood control to building water reserves for drought relief, raising reservoir levels during minor inflow increases while ensuring flood safety.

In August, the company further optimized outflow based on inflows, forecasts and grid load changes, keeping the reservoir level below 158 meters at month-end to facilitate later filling. Forecasts indicate upstream inflows in September-October will be more than 20% below the historical average for the period. Combined with relatively low starting levels and large pending storage in upstream reservoirs, filling conditions this year are challenging.

Three Gorges will follow the ministry's approval requirements, account for inflow uncertainty and downstream water demand, and dynamically adjust the filling schedule. It will also ensure project safety and reservoir area security during filling to meet water supply, irrigation, ecological, navigation and energy supply needs along the Yangtze River through this winter and next spring.