Study On Mid-and-Long Term Prediction Of Runoff In ShiYang River Basin

Hydrologic forecasting is making a qualitative or quantitative forecast of the hydrologic state within a certain period , according to known informations. Mid-to-long-term hydrological forecasting has always been a difficult research topic in the natural and technological science field , due to the complicated hydrologic regime and the incomplete hydrological data. As a result,how to improve forecasting accuracy with limited hydrological data becomes a problem concerned by hydrologies. Mid-to-long-term forecast of runoff is an important type of hydrological forecasting , which has a great effect in flood prevention , fight against drought , water resources development , guarantee of industrial and agricultural production and exploiting water conservancy facilities'advantages to the full. In order to improve ecological environment in ShiYang river basin ,make rational use of water resources and work out a dispatching plan , accurate and timely Mid-to-long-term hydrological forecasting is very necessary. Accurate and timely Mid-to-long-term hydrological forecasting not only help people to plan as a whole in the course of water dispatch ,but also help people to gain maximum economic benefits in the condition of meeting ecological water requirement. For increasing the forecasting accuracy,three typical methods of forecast are researched in the paper and the result of the forecasting is analysed. The main contents and results as follows:(1) Analysis of the forecast method. Based on existing data and regional feature of ShiYang river basin, the regression analysis,grey-Markov series analysis and the artificial neural network of phase space reconstruction prediction methods are researched and selected in the paper in order to predict the runoff of ShiYang river basin.(2) Programme of the forecast software. In view of above-mentioned reasons,this paper developed VB software for the regression analysis and grey-Markov series analysis forecast methods; the paper adopted Matlab software ,which has a powerful matrix function of treatment,to the artificial neural network of phase space reconstruction predict method.(3) Predition and Analysis of the different methods. Both traditional predition methods and recent new prediction technology are taken into account in ShiYang river basin. The comparative analysis of results shows that three theoretical and practical applications of predition method in ShiYang river have advantages and disadvantages. But with respect to prediction accuracy, the artificial neural network of phase space reconstruction prediction method is obviously better than other methods,it has a wider application prospects.