Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences,Shijiazhuang,Hebei
Supported by the project of China Geological Survey (DD20190336, DD20221752)，basic scientific research project of Chinese Academy of Geological Sciences（SK202118, SK202216）
[Objective] The Beijing-Tianjin-Hebei Plain is short of water resources, and the contradiction between supply and demand is very prominent. Increasing the use of unconventional water resources and forming a diversified water supply pattern is of great significance to alleviate the contradiction between supply and demand and support the socio-economic development and ecological civilization construction of the Beijing Tianjin Hebei Urban Agglomeration.[Methods] Systematically carry out classified data statistics on the development and utilization scale, water supply direction and utilization mode of unconventional water resources.Analyze their development and utilization prospects and ecological environment effects according to the planning and allocation objectives of unconventional water resources in Beijing-Tianjin-Hebei Plain.[Results] Unconventional water resources in the area include brackish water, Recycled water, desalinated seawater, rain water. The brackish water is mainly distributed in Tianjin, Cangzhou, Hengshui in the central and eastern plains, with a water supply prospect of 5.43×108m3； Recycled water is mainly used in large industrial cities such as Beijing and Tianjin, with a water supply prospect of 34.22 ×108m3；Desalinated seawater is mainly used in Tianjin and other coastal cities, with a water supply prospect of 4.19 ×108m3；The use of rain water is relatively scattered. [Conclusions] (1) There is a risk of soil salinization when brackish water is used for agricultural irrigation, so a reasonable irrigation and drainage system should be provided and water salt regulation should be strengthened. (2) The recycled water is used for ecological replenishment of rivers,the surface water is eutrophic and the groundwater is not polluted; Irrigation with recycled water in shallow groundwater buried areas will increase the risk of nitrate pollution; It is suggested that high-risk emerging pollutants be included in the monitoring system of recycled water use. (3) The concentrated brine and cooling hot water from the tail liquor of seawater desalination may change the distribution, composition and diversity of natural marine ecosystems, which should be paid attention to. (4) The use of rain water can reduce the water quality risk of sewage entering the river, but excessive use may affect the stability of the regional ecosystem. It is recommended that urban areas appropriately expand the use.