Optimization Of Water Resources Allocation In The Liaohe River Basin Of Jilin Province Based On Hydrological Connectivity

Water is an important natural resource and a necessary factor of production.Intense anthropogenic disturbances have led to an increasing degradation of the structure and function of water ecosystems.Regional water shortage has become a serious problem worldwide.The Liaohe River basin in Jilin Province is located in a semi-humid and semi-arid region and is an important national base for commercial grain production.The spatial and temporal distribution of water resources in the basin is extremely unequal,and the resource-based water shortage seriously restricts the sustainable development of the regional economy and society.In order to guarantee the national strategic food security and alleviate the contradictions in regional socioeconomic development,Jilin Province has fully launched the construction of a large water network and Central City Diversion Pine Water Supply Phase II Project in 2022.While the project guarantees water supply,how to improve the scientific management and efficient use of regional water resources has become an urgent issue to be tackled.The 2019 IUCN report presents the concept of Nature-based Solutions(NbS).It advocates the use of nature’s forces as a central part of solutions to effectively and adaptively address societal challenges through the conservation,sustainable management and restoration of natural or man-made ecosystems.This paper introduces the NbS concept to the study of optimal water resources allocation,recognizing that ’hydrological circulation is a key driver of water ecosystem structure and function,and an important pathway for optimal water resources allocation in basins’.Firstly,the current situation of hydrological connectivity in the Liaohe River basin of Jilin Province is assessed and an optimization path is proposed to give full play to the conditions of natural forces.Further,on the premise of ensuring optimal river and lake connectivity,the scientific use of technical forces and the use of artificial intelligence algorithms are used to optimize the allocation of water resources in the basin in a qualitative and hierarchical manner.The main research findings are as follows,(1)This paper constructs a landscape connectivity index system for the Liaohe River Basin of Jilin Province,which includes both structural connectivity and functional connectivity,and proposes a quantitative conceptual model of landscape connectivity in the Liaohe River Basin of Jilin Province,which is“LC=0.15×β 0.15×γ 0.2×IIC 0.15×CNNNECT 0.15×CNHESINN 0.05×NP 0.05×PD 0.05×DIIISINN 0.05×AI”.The model can visually reflect the changes in the strength of landscape connectivity of a watershed under different scenarios,and provide a relevant reference for other similar watersheds.The final LC index of the Liaohe River Basin in Jilin Province is 1.65.The fragmentation of water bodies in the basin has increased,the spatial structure has become complex and discrete,and the degree of biological mobility has generally shown an increasing trend.(2)The results of the hydrological connectivity optimization show that the upstream areas have more the higher level optimization paths that are shorter and optimize a relatively small water body area,while the downstream areas have more low level optimization paths that are longer.Urban areas have fewer optimization paths compared to county-level administrative areas.This suggests that county-level administrative districts,which bear the main production burden of the primary industry,are relatively deficient,especially in areas such as surrounding villages and towns.These areas are in urgent need of coordinated water distribution and the development and construction of relevant hydrological linkage paths meets the current needs.According to the results of the hierarchical optimization,the hydrological connectivity of the basin tends to increase as the level of optimization increases.Grade 1 optimization is imperative,and connectivity increases abruptly after grade 4 optimization to achieve optimal results.Therefore,special attention should be paid to the measures of Level 1 and Level 4 optimization in the study of the optimal allocation of water resources in the Liaohe River Basin of Jilin Province.(3)Based on the NSGA2 non-dominated genetic algorithm to solve the allocation model,the Pareto optimal solution was obtained for different water demand scenarios in the study area,and the water allocation to water users was ranked as ecology > primary industry > domestic >secondary industry > tertiary industry.The water allocation in each scenario was Siping >Liaoyuan > Gongzhuling.Under the premise of guaranteeing the bottom line of water for domestic use and food security,the water shortage rate scenarios of the sub-regions in each scenario were slightly different,with the largest water shortage sub-region being Liaoyuan for the combined ecological and economic scenarios,and Siping for the ecological scenario.The tertiary industry in the basin has the lowest water demand,the highest unit water production value and the lowest water deficit,followed by the ecological water demand,the secondary industry and finally the primary industry,which has a relatively low water use efficiency and unit water production value.This study is based on the optimal allocation of water resources in the basin under the premise of optimizing the hydrological path,and the allocation results can provide a new perspective and reference for the management and allocation of water resources in the Liaohe River Basin of Jilin Province.The results of the study can provide scientific basis for water resources management and water ecology protection in the Liaohe River Basin and even in the water-scarce plains in the north,and provide methodological support and case references for the application of NbS in the construction of water ecology projects and optimal allocation of water resources in the basin.