ydavidchen@cuhkeduhkwaterproblemsinchina中国的水问题.ppt

Water Problems in China中國的水问题 Yongqin David Chen (陳永勤) Department of Geography and Resource Management The Chinese University of Hong Kong Email: ydavidchen@cuhk.edu.hk Presentation Outline Characteristics of water resources in China Three major types of water problems in China Severe water shortage and water pollution problems in recent years Measures for alleviating the water shortage problems Relatively large total but small per-capita amount Total annual renewable water resources: 2812.4 billion m3 (streamflow 2711.5 Bm3, groundwater 828.8 Bm3, duplication subtracted) Total amount - No. 6 after Brazil, Russia, Canada, US, Indonesia in the world Per-capita amount - 2200 m3, only about 1/4 of the world average, ranked 109 in 149 countries and one of the 13 countries in severe shortage of water resources Water per unit area of farmland - 1888 m3/mu, about 80% of the world’s average 中国水资源在世界上的位置 Highly uneven temporal and spatial distribution Monsoon-dominated climate causes very distinctive wet (Apr - Sep) and dry (Oct - Mar) seasons in a Water Year (1 April – 30 March in Hong Kong) Seasonal variation of streamflow: 60% from April to July in the South and over 80% from June to September in the North Interannual variation of streamflow: ratio of maximum over minimum greater 10 in the North and less than 5 in the South From humid to arid: a gradient from SE to NW Why do many rivers across the country have flooding almost every year? Why does the Yellow River dry up in the middle and lower reaches in sequential years? Why has the groundwater table in the northern plain been dropping to a lower and lower level? Why has water shortage become a key factor in the socio-economic development in the northwestern China? Why is eutrophication so severe in many lakes, notoriously Taihu (太湖), Dianchi (滇池), and Chaohu (巢湖), causing enormous threats to the security and safety of water supply in nearby cities? Why does the fisheries suffer from red tides s