Study On Method Application Of Mid-long-term Runoff Forecast Of Dahuofang Reservoir

When human society comes into 21st century, water resources, being as the supporting of the social, economic and ecological sustainable development, whose crisis becomes more and more worsening. So carrying on Mid-long Term Runoff Forecast is great significant to exploit and optimize water resources rationally and to promote regional socio-economic development better. Correct and timely Mid-long Term Runoff Forecast plays an important role in flood-control, drought-resistance and economic benefits of water conservancy facilities, which will enable people to settle contradictions between each water department and take early measures to maximize integrated efficiency. Therefore, Mid-long Term Hydrologic Forecast has importantly reference value in the rational allocation and the full utilization of water resources, and it's necessary for us to carry out Mid-long Term Hydrologic Forecast actively.There are kinds of models about Mid-long Term Hydrologic Forecast, but none is suitable to each basin. The paper takes DaHuofang Reservoir as the research object, based on the long term change characteristics of its annual runoff time series of 50 years from1956 to 2005, uses time series analysis and forecasting method of SPSS, multiple regression analysis of main component analysis method, and wavelet analysis method, to carry out the hydrological forecast of Dahuofang Reservoir. The aim is to establish a Mid-long Term Hydrologic Forecast model has higher reliability prediction result, which can provide a valuable reference for flood-control, irrigation, power generation, water supply, water-provide. The paper's main research results are as follows:(1)Based on the long term change characteristics of its annual runoff time series of 50 years from1956 to 2005, combined with SPSS, establishes a mathematics model of time series analysis and forecasting method of SPSS, takes five-year annual runoff data from 2001 to 2005 to calibrate the model. The result shows that the predictions are relatively low that the model can not be used extensively.(2)According to two approaches physical cause analysis and mathematical statistics analysis, preliminarily selects 10 annual runoff impact factors of Dahuofang Reservoir, combining with main component analysis method to screen the initial impact factors, receives five integrated factors, conducts logistic curve fitting to the integrated factors by SPSS, and establishes multiple linear regression forecast model. The results show that this model has higher simulation accuracy. (3)With the wavelet analysis package tool in Matlab software to decompose the annual runoff series of Dahuofang Reservoir, combining with DPS9.5 on its basis, sets up Dahuofang Reservoir mid -long term forecast model based on wavelet analysis method. The results show that the model has higher prediction accuracy, but whose inside fitting forecast result are lower than the multiple regression model established based on principal component analysis.