(Photo/Baidu Baike)

Lake Hongjiannao, the largest freshwater lake in a desert in China, has been reduced in size by 50 percent since 1969, after years of development both up- and downstream.

Now occupying 32.8 square kilometers, the lake is located at the meeting point of Shaanxi province and the Inner Mongolia Autonomous Region. Both the areas upstream and downstream of the lake now blame each other for the severe damage caused to the “pearl of the desert.”

The reduction of water in the lake has led to a hike in its pH level, which now reads 9.8. As a result, 17 kinds of freshwater fish in the region have died out, and the population of a local gull is also dwindling, according to Dang Yabo, head of Hongjiannao Tourism Resort in Shaanxi’s Shenmu County.

Dang said the shrinking lake is a result of decreased river inflow, which is caused by two dams operating in Inner Mongolia’s Ejin Horo Banner since 2006. He said the lake’s evaporation capacity every year is 2,000 millimeters, but the annual rainfall is between 350 and 400 millimeters. The two rivers that flow into the lake used to be the main water supply for the lake, China National Radio (CNR) reported.

Xiao Zailin, a local villager near one of the two dams in Inner Mongolia, also pointed out that the river began to dry up starting in 2004 when dam construction was completed. The riverway has transformed into a sort of wetland in years with more rainfall, but it is nothing more than a dirt path in dry years.

However, authorities of Inner Mongolia’s Ordos have argued that the dams were constructed to guarantee water supply for local residents. The decrease in surface runoff is due to dry weather in recent years, said Jiang Yuan, deputy water bureau chief of Ordos.

Jiang argued that Ordos began to restore the local ecology in 2000 through the relocation of residents and more protective measures.

“The plants’ root systems have made the soil porous, which makes it easier to absorb rainfall … Hongjiannao is a low-lying land. We can supply it with underground water,” Jiang told CNR.

To improve the situation of Hongjiannao Lake, Shaanxi submitted an application in 2015 to make the lake a national wetland nature preserve, so as to coordinate the two provincial regions’ resources and strengthen protection at a national level. Meanwhile, Inner Mongolia has pledged to supply 1 million to 1.5 million cubic meters of water to the lake, according to CNR.