The construction of the Three Gorges water-control project will not greatly affect the hydrological conditions on the lower reaches of the Yangtze River, according to a long-term investigation by experts.

The total storage capacity of the Three Gorges reservoir will reach 39.3 billion cu m, according to design. The reservoir will have a total length of 600 km and an average width of 1.1 km.

After the Three Gorges Dam blocks the river, it will have a water surface of 1,084 sq km. The total water volume flowing into the sea will remain the same upon completion of the dam. It will only vary in the discharge of the water flow in different seasons of the year.

During the dry season, in the January-May period, the discharge of water will increase slightly by probably 1,000 cu m to 2,000 cu m per second. While in other months the flow volume will remain basically the same, within normal changes.

The mouth of the Yangtze River and the offshore areas are important fishing grounds. About 20 percent to 30 percent of the nutrients such as nitrogen and phosphorus in the river mouth area comes from the section of the river beyond the site of the Three Gorges Dam.

After the dam cuts the river it will block only about 10 percent of the nutrients in the water flow. Thus, the nutrition content in the river mouth and offshore areas will remain at a high level.