Study on Key Technologies of Flood Forecasting System in China

China is pretty vulnerable to flood disasters due to its location in the Asia monsoon area. Severe floods repeat across China every year, causing huge damages to properties and lives especially with rapid economic growth, urbanization and the subsequent concentration of population and property recently.

To prevent such potential great flood disasters, many structure measures for disaster prevention have been made over the main rivers of China. But, the results are not so fruitful because for every flood preventing structures, there is a certain standard limit. It is not economic and impossible to raise the standard without limit. For this reason, versatile non-structural measures should be taken in addition to structural measures to promote prevention measures against over standard floods. As one of the most important non-structure measures, flood forecasting and warning system has been developing for some decades in China.

A very powerful flood forecasting system, which has been performing pretty well in the whole country of China, Chinese National Flood Forecasting System (NFFS) will be introduced in this paper. NFFS is a robust, full-functional and user-friendly system, which is capable of providing timely and accurate flood forecasts as well as multi- schemes analysis to assist decision makers in decision making process.

For the requirement of capability of software reuse, independence, unification and expansion, NFFS adopts complete modular structure so that every main function is independent of the system and can be developed, modified, updated and transplanted conveniently by different users. Based on the standard structure of forecasting database which store the forecasting model, parameter, state and other forecasting information, NFFS can develop various standard forecasting models and imbibe the available experienced forecasting methods to form model-base. The model-base enable users found and manage forecasting schemes flexibly by selecting a set of models and methods considering the features of related rivers for single or consecutive forecasting from upstream to downstream. With the functions of perfect man-machine interface, data processing, model calibration, real-time forecasting and results displaying, the system can make interactive forecasting and automatic timing forecasting easily and quickly. NFFS also has powerful system management functions including user management and forecasting management.

In this paper emphasis will be focused on key technologies for construction of flood forecasting model-base and flood forecasting schemes, coupling mechanism of model calibration with optimization algorithms, and interactive operating forecasting which fully exerts forecaster's knowledge and experience, quickens the speed of forecasting analysis and promotes the quality of forecasting production.