Southwest China's Guizhou Province will spend 11 billion yuan(1.73 billion U.S. dollars) to protect and restore the largest wintering ground for migratory birds in southwest China, local authorities said Wednesday.

Several anastomus oscitans prepare to fly at the Caohai Nature Reserve in Weining, Southwest China's Guizhou province on Dec 16, 2012. [Photo/icpress]

Caohai Lake, located in the county seat of Weining, accommodates over 100,000 migratory birds every winter, including black-necked cranes. It is also a national nature reserve.

"We start the protection work before the black-necked cranes come this year," said Chen Bo, the head of Weining County.

Caohai Lake, the largest natural freshwater lake in Guizhou, provides about 1 billion cubic meters of water to the upper reaches of the Yangtze River.

Chen said protection of the lake will be positive in protecting the environment along the upper reaches of the Yangtze.

Currently more than 8,000 tonnes of sewage are being drained into the lake every day and about 120 tonnes of household waste are dumped around the lake. The water area of the lake has shrunk from 200 square km in in the middle of the last century to 25 square km now.

The protection will include 47 projects, 28 of which were launched on Wednesday, including sewage and garbage disposal, rural environment improvement and ecosystem restoration.

It is hoped to increase the water area to 33 square km by 2020 and to improve the water quality.