Distributed Hydrological Simulation And Reservior Operation Optimization On Suppressing Saline Water Of Pearl River Basin

Because of the saline water intrusion occured in the Pearl River downstream inthe dry season and dry year, the safety of drinking water has always been a seriousthreat in Macao, Zhuhai, Guangzhou and other city. Large reservoirs of Xijiang andBeijiang River Basin have been real-time scheduling to ease the delta’s water crisis;however, water quality at present has not been fundamentally solved.The flow in dryseason cannot completely meet the requirements of suppressing the saline water indownstream, with large range of Pearl River Basin and the uneven distribution ofrainfall and annual runoff, so on the basis of fully understanding the process of the dryseason flow it is also need to further analyze the influence of the reservoir groupsetting up and operation to dry season runoff.In this paper, the main research contentsand results are as follows：(1) Based on the distributed hydrological model EasyDHM, the hydrologicalsimulation model of Pearl River Basin was built and the runoff process of each hydrostation in dry season were studied in detail as well as the changing of major reserviors’inflow.Aiming at the effects of reserviors, the watershed delineation module has beenimproved so it can provide acess to reservior operation model. The analysis of inflowprocess shows that it has been reduced after2000compared to annual mean; inflowbetween qianjiang and wuzhou station contributed the most in runoff of wuzhoustation; inflow of longtan and yantan has also decreased in recent years.(2) As the inflow of reservoir operation model was obtained from the result ofdistributed hydrological model, the operation chart has been used to guide reservoiroperation.By coupling hydrological model, the cascade reservoirs simulation model ofthe Xijiang River Basin was built, and the effect on runoff, power generation,suppressing saline water, and flood control were analyzed according to the differentscenarios such as nature scenario, single reservior operated, cascade reservioroperated now and future which were divided from the existed and proposed of largereservoirs.(3) As the outflow differences existed between actual and reservoir simulatedoperation, inversion of reservoir operation rule has been explored in this paper bydiscussing the operation process and rule generalization. An inversion identificationmethod of real reservior operation has been presented according to whether there wereactual outflow. Results indicated that the accuracy of reservior outflow can be improved by comparing the inversed simulated reservoir outflow to actual outflow.Therefore, it was benefit to reduce the uncertainty of inflow from upstream reserviorsin downstream.(4) In view of the demand of suppressing the saline water in downstream, furtherexplored ofoperation scheme has done based on the modified reservoir operation chart,using the method of multi-objective optimization.Through further optimization, theecological operation schemes were given aiming at sloving the saline water intrusionin dry season.The results indicated that it can achieve the demand that suppressing thesaline water in normal dry year and the ecological assurance rate had improved to0.83even in the special dry year after optimization where the power generationbenefit was guaranteed at the same time.