Lake areas within the region known as "Asia's water tower" have been expanding thanks to an increase in rain and snow, according to data published on Tuesday by the China Meteorological Administration.

The amount of precipitation in Sanjiangyuan, or Three Rivers Nature Reserve, has risen on average by about 3.6 millimeters a year since 2000, although there are huge variations among different years, the administration said in its National Eco-meteorology Bulletin.

Sanjiangyuan forms part of the Tibetan Plateau in Qinghai province. It is home to the headwaters of three of major waterways — the Yangtze, Yellow and Lancang rivers.

Satellite monitoring in 2017 found that the region's lake areas have expanded by 7.5 percent since 2006, the bulletin said.

It added that the vegetation coverage has also risen by about 0.1 percent a year since 2000.

Protection efforts have been intensified in Sanjiangyuan in recent years. The central government designated the region as a nature reserve in 2005.