The Research On Runoff Evolution And Allocation Of Water Resources In Area Of Qianzhong Water Diversion Project

The Central Guizhou Province is the most important economic and social development central of Guizhou Province,which has location advantage and occupies a pivotal position in this region.While with a speeding development,the issue of water shoutage appears to be more serious in the area.According to the international standards,the imbalance between water resources supply and demand tends to be more serve at irrigation area,both in resources and engineering water shortage,with high frequency of periodicity and regularity water shortage;in the meantime,troubled by the continuous water shortage,the urban area of Guiyang and Anshun city face the crisis of economic downturn and lower life quality,leaving water problems as the most prominent contradiction in the region.The construction of Qianzhong water diversion project would relieve the pressure on water shortage,optimizing the scheduling of water resources and improving the eco-environment in the Central Guizhou Province.However,as the huge scale,large coverage area and management complexity druing and after the operation of the project,it has much necessity to do research on safety assessment of water resources scheduling and optimal allocation.In this paper,based on sustainable and reasonable utilization of water resources in area of Qianzhong water diversion project and a fully comprehension of Sanchahe River basin,main evolution law of water resources by multiple mathematical statistic methods in water source region were analyzed,and the observiation and analysis on construction and opetation of reservoirs proved taht turbulence in historical water resoueces was mainly caused by human activities.Afterwards,runoff encountering analysis was conducted based on long-serie rainfall data of water source region and water-receiving region,with both probability statistical model and copula-constructed joint distribution.To simulate hydrologic section and reservoir runoff more accurately,a hydrologica model was improved based on stored-full runoff model.Multiple-linear reservoirs and lag-and-route method were introduced in the model,which better reflect the characteristics of karst area and provide a more scientific model for hydrological computation.Finally,the Central Guizhou Provinve water resources model optimal allocation model provides the assessment on the multiple water resources allocation schemes,which help to verify the necessity and rationality of Qianzhong water diversion project,improve utilization efficiency of water resources water,protect ecosystems and prevent the decline of groundwater.(1)To analyse multi-dimensional change characteristics of trend variation,mutation test and period test of annual precipitation,annual evaporation,average annual flow data of last 50 yeaers,the consequence shows that all data series do not appear significant trends.The annual precipitation increased,the annual evaporation decreased,while and average annual flow reducd.The reservoir construction and operation materials since 1954 indicate that the phenomenon related much with the growing reservoir group and it proved that the construction of large reservoir project change the runoff obviously,also reducing the flood risk downstream.(2)Based on copula-constructed joint distribution and probability statistical model,the runoff encountering analysis were performed respectively between the water source region and two water-receiving areas,the Yangtze River water-receiving area and the Pearl River water-receiving area.The favourable water diversion probability was over 69% between years,which could ensure the benefit of Qianzhong water diversion project;The Yangtze river water-receiving area has slightly greater safety probability on water diversion than the Pearl River,and the probability in flood season is greater than the dry season.(3)In order to develop a hydrological model that suitable for runoff simulation in Guizhou karst mountain area,the multiple linear reservoirs were added in stored-full runoff model to simulate the complex karst fissure system,and lag-and-route method were introduced in runoff concentration calculation to decrease the error on the runoff peak flow and peak time.The intelligent MOPSO-CD(Multi-objective Particle Swarm Optimization Algorithm with Crowding Distance)to optimize model parameters,the simulating results proced that the modelis suitable in karst area of the Central Guihou Province and can be applied in hydrological computation and inflow simulation of reservoirs.(4)A rule-based water resources allocation model in the irrigation area and urban area of Guiyang and Anshun city was developed finally.The model considers useing priority of all water supply sources,sets the corresponding constraints in water diversion modules,controls configuration order in aspact of space,time and users,and then designs scenarios according to high flow years and low flow years in 2020 and 2030.The balance of supply and demand of water resources in different scenarios were analysed,and the results show that the Qianzhong water diversion project can supply enough water of Guiyang and Anshun city,and basically solve the water shortage problem of irrigation area;the priority use of transferring water would help to decrease the utilization of groundwater,which will reduce the probability of geological disasters and be beneficial to ecological restoration.