Remote Sensing Monitoring on flood damanages and its evaluation system
Chen Shupeng
National Remote Sensing Center, SSTCC,
NLREIS, IRSA Chinese Academy of Sciences,
Beijing, China
Experimental flood management system in China
The flood disasters in china have been being fairly rigorous from ancient times just like other Asian countries because of monsoon climate influences. Especially most flood prevention dikes and flood storage and diversion projects have been built in the middle and lower reaches of Chinese seven rivers which the following along the alluvial plains and deltas, their elevations are no more than 100 meters above the seal lever. The scales of those projects can be compared favorably with the Great Wall. Some 200,000,000 people and approximate 100 cities are protected by these water conservancy projects. Take the lower reaches of the Yellow River as an example; the dikes along the riversides up to Zhenzhou city are 400 kilometers long and 5 to 12 meters above the ground. The biggest width between the dikes is 21 kilometers. Inside the dikes there are 1, 200,000 transient people and some scattered-distributed small ' productive dikes. There are two flood storage areas, Beijin Dike Area and Dongping Lake outside the dikes. Its population is 1,300,000 and also some flood prevention dikes in the shape of island surrounded the villages. So are the other rivers such as the Yangtze River, the Hua the River the Liaohe River, and the Yongding River. It is almost like a world full of dikes in the Eastern beritages handed down through thousands years, but also the success emblem of Eastern agricultural civilization.
The monitoring on dikes and flood in China is based both on the multilevel earth observation system and geographical information system (GIS). It is proved through the experiments that dikes and flood can be distinctively identified even on the image of meteorological satellite with 1.1 kilometer ground resolution and also highly effective for the real time. Them more detailed understanding about dikes and flood can be achieved by suing higher-resolution satellites such as Landsat, SPOT and other scientific and technological experiment satellites lauched by China and Japan. The real time receiving, however, is required. In recent ten years, China has been more actively engaged in aerial remote sensing monitoring including color infrared photo, infrared scanning and all - weather side-looking Radar. The Image transmission process from real time receiving to the flood Control Command Center in Beijing has been compressed within 20 hours. The daily monitoring range has been over 10,000 square kilometers. Especially that the micro digital terrain model and geographical statistics database, comprehensive analysis methods and digital simulating software have been established and applied to disaster monitoring and forecasting, its accuracy has been remarkably raised.
It is proved through ten years practices that we can attain the time of flood prediction and forecasting to reduce and even avoid the losses of disasters provided that we make full use of remote sensing and GIS techniques procedure of flood information receiving, processing and analyzing within that of flood dynamic courses. Its social and economic benefits are tremendous.
The remote sensing evaluation of flood damage started from the early 80's in China. The first application was on the compensation evaluation and emigration investigation for small reservoirs. It has been proved through several years' practices that both the efficiency and the accuracy can meet the needs of project planning. The real time monitoring and transmission experiments for flood disasters have been carried out in the Liaoh River, the Yongding River, the Yellow River and the Dongting. Lake since 1985. The experiment in the Jinjiang River and the Dongting Lake has been just finished in 1989. The all-weather aerial monitoring and multiple elements flood central database construction have been also realized
