Average sediment concentration (kg/m3) Three Gorges Project 1.2 Aswan Project 1.6
Annual sediment transport (100 million tons) Three Gorges Project 5.3 Aswan Project 1.34 Water loss in the reservoir area Three Gorges Project: evaporation loss on the reservoir surface is very small, and it is still about 45 10/000 million m3 when leaving the reservoir. Aswan Project: The annual evaporation loss is about 1000 million m3. With the increase of water consumption, the annual water output of the reservoir is reduced to 57 billion m3, which is nearly10 lower than that before the completion of the Three Gorges Project.
After the completion of the Three Gorges Project, the annual sediment discharge is about 1/3, and the sediment discharge is increasing year by year. After 90 years, about 90% of the sediment is transported to Aswan Project every year: after the reservoir is completed, the sediment entering the delta is only 2-5 million tons, and the sediment will basically be deposited in the reservoir within 100 years.
Impact on organisms Three Gorges Project: Water storage starts from June+10 in 5438 every year, reducing the discharge compared with natural flow, which may interfere with the habitat and spawning activities of Chinese sturgeon downstream of Gezhouba Project. Strengthen monitoring, cultivate a large number of young sturgeons, and improve the survival rate after being released into the Yangtze River; Aswan project, it is planned to establish a nature reserve for juvenile Chinese sturgeon in the Yangtze River estuary: the fishing ground in the estuary is degraded and the catch of famous sardines is reduced. The annual runoff of the Three Gorges Project is much higher than that of the Aswan Project, mainly due to its superior water system and climate conditions. The Three Gorges Project has adopted an effective reservoir operation mode of "storing clear water and discharging muddy water" to solve the problem of sediment deposition, which was summarized by China sediment experts and engineers from the construction practice, that is, discharging muddy water (actually discharging sand) in flood season and pouring clear water after flood season. However, the sediment of Aswan dam is deposited in the reservoir, which reduces the sediment and water entering the delta, leads to the surface subsidence of the delta, seawater erosion and retreat, and brings ecological and environmental problems. After the completion of the Three Gorges Project, it will have the following beneficial effects on the ecological environment in the middle and lower reaches of the Yangtze River: reducing floods and improving living environment; Reduce the shrinkage and siltation of Dongting Lake; Increase the flow in dry season and improve the water quality in dry season; Adjust the local climate; Reduce environmental pollution and acid rain hazards; Conducive to the prevention and treatment of schistosomiasis.