Many fish species in rivers in one city of Central China's Hubei province haven't laid eggs this reproduction season due to insufficient water flow, one of the by-products of the country's large-scale water diversion project, the Beijing News reported.

Cai Yan, an expert from the local fisheries research institute, found the abnormal phenomenon in the first week of July, while inspecting the fish reproduction and water environment as usual in Xiangyang city.

"It is unbelievable," Cai said, adding that the fish are supposed to lay eggs before July, but the flow in the river is insufficient for fish to lay eggs, he said.

It is connected to the nearly completed Danjiangkou Reservoir, part of the South-to-North Water Diversion Project, on the upstream of Han River. The reservoir aims to alleviate water shortage in the north, compromising nearly half of Xiangyang city's water supply.

Around 9.5 billion cubic meters of water will be stored and transported to the north in the first stage, which is equivalent to more than 20 percent of the flow of the Han River in a normal year, and the river's water levels will drop by 0.41 meters, data showed.

Besides endangering the fish species in the Han River, a report has warned the project could also harm the river's self-cleaning capabilities.

Jin Qi, director of the local sewage facilities office, said that in the past the flow flushed away all the pollution, but now the water quality is deteriorating, despite the government establishing 10 sewage disposal plants, and shutting down or moving 97 polluting factories.

Yicheng, a city under the administration of Xiangyang, has cut water three times since last year, one of which lasted for 48 hours. Li Guodong, head of the local liaison office of the South-to-North Water Diversion Project, said, "We support the project, but the impact on us is so huge."