Li Pingri, Fang Guoxiang, Huang Guangqing
The natural environmental characters of the Zhujiang Delta are:1. The area is crisscrossed by waterways and many outlets. 2. Rivers and sea water act alternately. 3. The area has very low altitudes，almost half of the delta area is below+ 0. 9m Zhujiang Datum(mean sea level in the mouth of Zhujiang)and 803. 65km2 of the delta area (or 12. 99% of the delta plain)is below Zhujiang Datum. The economic environmental characters of the Zhu}iang delta are:1. A number of important commercial centers lies within the delta area which has high population densities and intense economic activity. 2. It is close to Hongkong and Macao，and is the biggest native place of overseas Chinese. 3. It has important external trading ports. The possible physical， social and economic effects of future sea level rise are considerable. The average rate of sea level rise along the coast of Guangdong(in the past 100 years) is 2. 19mm/a,and 2. 31mm/a in the past several decades，4. 8mm/a in the last decade and 9. 7mm/a in the last three years in the Zhujiang Delta. The acenario of sea level rise for the next 50 years is 50一60cm. It is a great threat on the delta. The immediate harmfulness from sea level rise will be:1. A large area would be submerged. About 1500km2(23. 76%of the delta plain ) will be submerged，if the sea level rise 0. 4m. 2. Many important commercial centers，such Guangzhou，Fushan，Zhuhai， Zhongshan，Jiangmen，Dongguan， Panyu and Shunde，will suffer from the threat of flood. 3. Many impotant economic facilities and factories will be hit by flood. Also it will cause the increase in the investment in capital construction，increase the strength and frequency of the incidence of storms especialy storm surges，increase flood level，raise the salty table of water enter，and threat the agriculture. All this will postpone the economic development. We have to do some researches on the impacts of sea level rise on each city in the Zhujiang Delta,rearrange rationally the distribution of macroeconomics，investigate the land use program work out a appropriate national economic plan to suit the rising of sea level，reconsider the environment construction standard，and do some researches on the water transportation , channel evolution，and the environment for water supply and drainage in advance.
