| Water source reservoirs are an important guarantee for urban water use and agricultural irrigation.In the 1950s and 1980s,China built a large number of water source reservoirs,most of which used the bottom water intake method to fully ensure the water supply capacity of reservoirs under low water level conditions.However,with the improvement of urban domestic water standards and the growth of reservoir service life,reservoirs have generally encountered problems such as increased water supply turbidity,excessive water supply turbidity during flood season,and even supply interruption,seriously threatening regional water safety and economic and social development.The layered water intake method is a commonly used method to reduce the turbidity of water supply in water source reservoirs,which has been widely applied in new reservoirs.However,the technology of layered water intake renovation for existing reservoirs is complex,involves multiple factors,and has a wide range of impacts,making it difficult to choose the optimal layered water intake renovation project plan,which affects the quality and efficiency of the renovation project construction.Therefore,how to objectively compare and select reasonable layered water intake renovation schemes has become the key and difficult point to solve the problem.This article takes the Shitouhe Reservoir in Shaanxi Province as the object,and based on on-site research and monitoring,studies the distribution and variation of water turbidity in the reservoir area under flood conditions.Three types of layered water intake renovation schemes are designed,and a multidimensional indicator system for the comparison and selection of layered water intake renovation schemes is established.Based on the improved hesitant probability fuzzy language,a comparison and selection model is constructed to eliminate decision-making preferences,and the comparison and selection of layered water intake renovation schemes for the Shitouhe Reservoir is carried out,Finally,based on the comparison of calculation results,optimization and improvement suggestions were proposed for the selected layered water intake renovation plan.The main research results are as follows:(1)Based on the layered distribution law of turbidity in the reservoir area,a comparison and selection plan for the layered water intake renovation of Shitouhe Reservoir was designed.Based on the monitoring of turbidity and sediment concentration in the Shitouhe Reservoir area under incoming flood conditions,as well as the simulation of sediment transport process,the layered distribution pattern of turbidity in the reservoir area is determined,and the optimal water intake point is selected.Based on the goals of water supply turbidity,water supply quantity,and water supply guarantee rate,three renovation plans were designed from the aspects of building structure,construction plan,engineering cost,and schedule arrangement,including floating boat water intake,new discharge tower layered water intake,and adding a sedimentation tank to the diversion channel.The environmental impact and technical risks of different plans were analyzed,and finally,improvement directions for plan comparison were proposed from the perspectives of plan comparison process and method.(2)A hierarchical water intake scheme comparison index system for Shitouhe Reservoir was constructed from a multidimensional perspective.Based on the theory of sustainable development of the project and the people-oriented theory,combined with theoretical practice and literature,from the dimensions of cost-benefit,technical risk,social impact,resources and environment,and project sustainability,the dimensional indicators for the comparison and selection of layered water intake schemes of Shitouhe Reservoir were constructed,and 16 indicators were identified and screened,and a multi-dimensional indicator system for the comparison and selection of layered water intake reconstruction projects of Shitouhe Reservoir was constructed.(3)A hierarchical water intake scheme comparison model for Shitouhe Reservoir was established based on the hesitant probability fuzzy language set(HPFLS).The language value semantics of HPFLS have been expanded by introducing possibility to reflect the possible decision-making preferences during expert evaluation.A new aggregation method has been introduced to improve the preference elimination method.At the same time,a full multiplication proportional multi-objective analysis optimization model has been introduced to calculate the utility value of alternative solutions.Based on the advantage theory,comparisons between solutions have been conducted,eliminating the subjective preferences that experts may have when evaluating solutions,Improved the objectivity and credibility of the model.(4)The optimal plan for the layered water intake renovation of Shitouhe Reservoir has been determined through comparison and selection.Five experts from different fields were invited to evaluate the layered water intake renovation plan of Shitouhe Reservoir.The evaluation results were analyzed using a reservoir layered water intake scheme comparison model.It was found that the utility values of the three schemes under the ratio system method were 0.198,0.223,and 0.167.The utility values of the three schemes under the reference point method were 0.636,0.427,and 0.365,respectively.The utility values of the three schemes under the full multiplication method were 0.554,0.435,and 0.497,respectively.Based on the advantage theory,it was determined that the floating boat type stratified water intake scheme is generally superior to the other two schemes.Finally,optimization and improvement suggestions were proposed based on the comparison of calculation results for the selected stratified water intake renovation scheme. |
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