June is a busy time at Hongjian Nur (Nur means lake in Mongolian language) in Shaanxi Province. Tourists come in droves to admire the stunning lake surrounded by desert. But something about the lake is amiss, raising concern among environmentalists.

The water level of the lake is dropping with each passing year, according to a recent Shaanxi Daily report. "Its ecological function may disappear in about 10 years, and what is more, the lake may become totally dry by then," the report says.

Ms. Lei, from nearby Yan'an City, was there with her daughter. As the first-grader marveled at the scenery, Ms. Lei grasped the severity of the problem. "That means we would only see a little puddle left by the time my daughter finishes high school," she said.

Located in the Maowusu Desert in northwest Shenmu County, Hongjian Nur is the largest natural desert freshwater lake in Shaanxi and the second largest in the country. But in the last 10 years, its average water level has fallen from 8.3 meters to 5 meters, with the deepest part falling from 15 meters to 10.5 meters. The total water area has fallen from 6,600 hectares to 4,620 hectares, declining an average 396 hectares each year.

A relict gull in Hongjian Nur, northwest Shenmu County of Shaanxi Province. The rare bird is under state first-class protection. [Photo from the Shaanxi Daily]

The lake, which marks the convergence of seven seasonal rivers, also provides a good ecological environment. It is home to 26 rare birds under state second-class protection and 16 wild fish species. It is also the largest breeding ground and habitat of relict gulls under state first-class protection.

According to Ornithologist He Fenqi, the drop in water level has led to the formation of mid-lake islands where relict gulls can build nests and lay eggs.

"But if the water level continues to drop, the gulls will have to move again," He says. "Because there are particularly strict requirements for the living environment of this species, we are worried about where to find a suitable place for them."

Shenmu County began developing a tourist industry in 1993 and has received about 150,000 tourists a year, generating more than 20 million yuan (US$2.93 million) in revenue for the county. But with the continuous drop in lake levels, many water entertainment projects are delayed and tourist development space is decreasing.

Yang Fengming, head of the lake's management committee, says the fall in water level has been accompanied by growing salinization.

"This has not only greatly affected egg-laying activities and living environment of the fish, but also led to the degeneration of vegetation around the lake, and thus aggravated the desertification process of the whole area," Yang adds.

Yang cites multiple causes for the drop in the lake's water level. The main reason is a decrease in precipitation and water supply from the seven seasonal rivers. Annual precipitation is currently about 350 millimeters, but annual evaporation is more than 1,300 millimeters – so the lake is losing more water than it is receiving.

Another reason is people. In 2004, the local government of Yijinhuolo Banner in neighboring Inner Mongolia Autonomous Region built a dam on the Yingpan River. The Zasake Reservoir Dam sits just 4 kilometers from Hongjian Nur.

"All the water has been blocked since then," says Chang Shengjun, who is in charge of Yulin City's environmental affairs. "Previously, nearly 40 percent of water in the lake came from the Yingpan."

The region is now building an underground reservoir on the Manggaitu River, another main water source.

"Human damage is proving fatal to sustainable development of the lake area," Yang said.

Hongjian Nur sits at the juncture of Shaanxi and Inner Mongolia, and the two regions have not been able to reach any agreement to solve water use conflicts between their villages, Yang says. "Local governments can do nothing but wait for the central government to mediate the water issue of Hongjian Nur."

In Shenmu County, geological boring led by the county's development of coal resources also has contributed to water draining from Hongjian Nur. The lake area is rich in coal, and the closest coal mine is 15 kilometers away.

"Unreasonable development is one of the important factors leading to the drop of water level," says He Lifa, director of the Shaanxi Provincial Bureau of Environmental Protection.

Local officials have racked their brains for a solution to the water shortage. Since 2005, governments have invested more than 6 million yuan (US$877,600) in ecological and environmental protection projects in the lake area. More than 1,320 hectares of trees have been planted, with forestation rising from 20 percent to 45 percent.

In 2008, Shaanxi and the Ministry of Forestry added Hongjian Nur to their lists of important wetland protection sites. Polluting enterprises in the area have been ordered to shut down.

"Ecological function in Hongjian Nur is an issue that has a direct bearing on climate change on the whole Loess Plateau and Maowusu Desert areas," says Chang. "Current protective measures are still not enough. How can we just sit here and watch the country's second largest desert lake run dry and become desert?"