TAIYUAN - Repair work started Sunday on part of a reservoir dam that collapsed in north China's Shanxi Province, local authorities said.

The top of an irrigation aqueduct of the Quting Reservoir in Hongtong County caved in on Friday morning, leading to the collapse of a 100 meter-long stretch of the dam.

Nearly 18 million cubic meters of water gushed out of the reservoir, flooding 19 downstream villages and blocking nearby railway and highway traffic.

Flooding had forced the relocations of more than 10,000 residents and resulted in the death of one elderly man from Nanyangxie Village, witnesses told Xinhua.

By Sunday night, sludge had been cleared, allowing both railway and highway traffic to resume, sources with the emergency communications headquarters said.

Some residents have moved returned home, while others remain in temporary shelters, the source said.

The reservoir was built in 1959, with a designed storage capacity of 19 million cubic meters of water. The dam of the reservoir was fortified in 2004.

Further investigation into the collapse is underway.