Study On The Coupling Utilization Of Rainfall Forecast Information At Different Time Scales In Dahuofang Reservoir

Reservoir operation has played an important role in flood disaster reduction and flood resources utilization,and has received extensive attention and research.In general,reservoir operation is based on current water and rain information,As the level of rainfall forecast continues to increase,rainfall forecast information has also been gradually used in reservoir operation.However,at different stages of reservoir operation,the use of rainfall forecast information at different time scales tends to have different focuses.Therefore,in order to take both the flood control safety and the benefit of water storage into account,it is particularly important to study how to couple and use multi-time scale rainfall forecast information in reservoir operation.This article uses Dahuofang Reservoir basin as its background,first of all,checked the accuracy of rainfall forecasting information at different time scales;Secondly,considering different purposes of each stage of reservoir operation,the availability of rainfall forecast information at different time scales is analysed;Then,studied the coupled utilization method of rainfall forecast information at different time scales;Finally,this utilization method is applied to the real-time operation of Dafang Reservoir.The main research contents and conclusions are as follows:(1)Use June to September each year from 2008 to 2015 for the study period in Dafanfang River Basin,selected three agencies of ensemble forecast products:CMA,NCEP and ECMWF,and used TS scores,bias B to evaluate their forecast skills.The results show that the ECMWF agency has a more stable forecast in the basin and has the best forecast results.(2)In view of the different purposes of each stage of reservoir operation,used the ECMWF agency rainfall forecast information in Dahuofang River Basin as the research object,and study the error eigenvalue statistics,the frequency distribution curves,and the pattern of weather system energy release,to analyse the availability of rainfall information at different time scales.The results show that using a single time scale rainfall forecasting information to make reservoir operation decision,is difficult to take both the flood control safety and the benefit of water storage into account simultaneously.(3)In order to make full use of the rainfall forecast information,studied the coupled utilization method of rainfall forecast information at different time scales.Firstly,a reservoir operation strategy that considered rainfall forecasting information at different time scales which is universally applicable to all river basin was formulated.Based on this,combined with the availability analysis results,the coupled utilization method of rainfall forecast information at different time scales in the Dahuofang Basin was formulated.(4)The coupled utilization method of rainfall forecast information at different time scales was applied to real-time operation of Dafang Reservoir with the “20130816” flood in the Dahuofang basin.Compared with the regular operation results,the maximum flood level was reduced by 0.25 m,and the maximum discharge flow was reduced by 159 m3/s,the flood peak staggered time increased by one time period,significantly increased the flood control safety of the reservoir and downstream;The water level at the end of the flood was not changed,so there was no reduction in benefit of water storage.Finally,giving a summary about the full text,and discussing the problems in this paper and the work to be studied in the future.