Emergency forces successfully sealed the main dyke breach at Dongting Lake, China’s second-largest freshwater lake, on Monday night. A secondary flood defense line is currently being tested, according to local authorities.

The breach occurred in Dongting Lake, located in Hunan Province, on Friday, flooding over 47 square kilometers (18 square miles) including the town of Tuanzhou. At least 7,000 residents were evacuated, with no reported casualties. By Saturday, the breach had widened to 226 meters (741 feet). Repair efforts progressed at an average rate of 4 meters per hour by midnight on Sunday, according to mainland media reports.

Hunan Vice-Governor Zhang Yingchun stated on Sunday that an emergency barrier, set up to contain a water release caused by erosion, had failed on Friday afternoon, less than two hours after its installation.

To seal the breach, mechanized operations were employed to build up the dyke from both sides, while rocks and other materials were continuously dumped into the water from barges, as reported by state broadcaster CCTV.

At a press conference on Monday, Zhang announced that nearly 500 personnel, more than 3,000 dump trucks, and 85 vessels of various types were involved in the repairs.