NANCHANG - The surface area of Poyang Lake, China's largest freshwater lake, has shrunk to less 200 square km, the Jiangxi provincial hydrographic bureau said Wednesday.

Poyang Lake, located in eastern Jiangxi province, is fed by five rivers in the province and empties into the nation's longest river, the Yangtze.

Persistent droughts caused by lack of rainfall in the upper reaches of the rivers have been blamed for the lake's shrinkage, said Tan Guoliang, head of the provincial hydrographic bureau.

Water levels on the middle and lower reaches of the Ganjiang River, one of five rivers that discharge into the lake, have reached a record low of 12.35 meters, 0.47 meters lower than the previous record low, according to the bureau.

Cities along the Ganjiang River are even preparing to tackle a possible water shortage, according to the bureau.

Human activity is also partially to blame for the shrinking lake. Multiple construction projects have sprung up around the lake, including an international resort and commercial buildings. Provincial authorities said local governments have approved more construction in recent years, with the situation becoming more serious as time goes by.

"Jiangxi saw a rare and severe drought in 2011, causing water levels to continue to decline. The environment of this area has been heavily affected," said Dai Nianhua, deputy director of the Poyang Lake Research Center under the Jiangxi Academy of Sciences.

"However, filling in the lakes to create more usable land during the low-water season has worsened the situation," Dai said.

Some areas of the lake have been filled in to create more room for construction. A park near the village of Hedong was built by filling in part of the lake and building on top of it.

Local officials have reiterated that it is illegal to build on the lake.

"Construction is absolutely forbidden on Poyang Lake, and our department has not approved any fill-in or reclamation projects in recent years," said an official from the provincial Department of Water Resources.

Dai said related departments often manage their responsibilities in a confusing and disorderly fashion, preventing them from working together to manage natural resources.

"For long-term development, Jiangxi must set up a comprehensive management organization to take care of the lake," said Tan Huiru, a researcher at the Jiangxi Academy of Sciences.

"We lack effective and enforceable methods to protect the lake, " said Tan.