Multi-objective Optimal Operation Of Key Reservoirs In Ganjiang River Considering Power Generation,water Supply And Ecological Water Demand

With the increasingly ultilization of water resource,the conflict of water consumption between water generation,instream ecological water demand,living,industry and agriculture is becoming sharper and sharper.Traditional multi-objective reservoir operation usually study on reservoir,thus it is of great necessity to take ecological object and the allocation of regional water consumption into consideration.It is helpful to balance the objectives of power generation,water supply,and ecology and to pursue the maximum of comprehensive benefits.This thesis,considering power generation,water supply and ecological water demands,studies on the multi-objective water allocation of the Ganjiang River.The content and relative results of the Thesis are as follows:(1)Based on 60 years monthly flow data from 1952 to 2011 of the control station of the four key reservoirs,Shangyoujiang Reservoir,Wan'an Reservoir,Xiajiang Reservoir and Jiangkou Reservoir,Flow Duration Curve method is adopted to calculate the minimum output flow of every reservoir.We choose 95% accumulative frequency in the flow duration curve as the ecological flow downstream the reservoirs.(2)Desktop Reserve Model,which is based on the building block method,is applied to separate the monthly flow series into base flow and high flow.According to different inflow conditions,calculate the annual value of maintenance low instream flow requirements,maintenance high instream flow requirements,drought low instream flow requirements,drought high instream flow requirements.And then use appropriate rules to obtain ecological flow process.Finally,combining Tennant and the characteristics of inflow,draw the guaranteed rate frequency curve of ecological flow.(3)Considering the impacts of reservoir operation and water consumption process on water allocation,the multi-objective model was designed to obtain the maximum of power generation of four reservoirs,the minimum of water deficit rate of the seven regions,and the minimum of ecological flow deviation of Waizhou Station.The multi-object particle swarm optimization method is used to solve the model and then gain the non-dominated solution set of typical years under different inflow frequencies of 50%,75% and 95%.And the relationships between these three objectives and corresponding output process,water level process,water deficit rate and the comparison of flow after multi-objective allocation and ecological flow are analyzed of typical schemes.Results show that there are competition relationships between power generation,water supply and ecology under 50%,75% and 95% inflow frequency,and the relationship between power generation and ecology is most fierce.Because the water deficit rate of 50% inflow frequency is a small value,the relationship between water supply and other two objectives are not significant under this circumstance.And each reservoir raise the water level when it is in dry season to increase the whole power generation benefit.Region 6 is the most serious water shortage area and all other regions owns higher water deficit rate in July,August and September due to the large water demand for agricultural irrigation.Water deficit rate is about 10% under 75%inflow frequency and 15% under 95% inflow frequency.By comparing the flow after multi-objective operation and ecological flow processes,it is shown that the reservoir can make good use of its storage function and control the discharge to meet the downstream ecological demand in non-flood season.In flood season,the outflow and ecological flow deviation will increase with large inflow,because of the limited storage capacity.