Evaluation And Study On Carrying Capacity Of Agricultural Water Resources In Xinxiang Irrigation Area Of People’s Shengli Canal

With the continuous development of China’s social economy,coupled with the negative impact of unreasonable human activities and the uncontrolled arbitrary exploitation of water resources,the problem of deterioration of the water environment has been intensified.In order to alleviate the malignant problem caused by water shortage and control the problem of water environmental pollution,the carrying capacity of agricultural water resources was evaluated for the Xinxiang irrigation area of People’s Shengliqu.Based on the concept of sustainable development and agricultural water resources,this study comprehensively considers various influencing factors of agricultural water carrying capacity.Firstly,the balance between supply and demand in each county in Xinxiang Irrigation District from 2015 to 2019 was preliminarily analyzed.Secondly,the coupling coordination degree analysis method is used to explore the coordination relationship between social and natural influencing factors in different regions.Based on the above analysis,eight evaluation indicators were selected to establish an evaluation system for the carrying capacity of agricultural water resources in irrigated areas.The fuzzy set analysis method and TOPSIS model analysis method were used to evaluate and estimate the carrying capacity of agricultural water resources in each county in the irrigation area from 2015 to 2019.Finally,according to the three-factor constraint of the "barrel theory",the actual bearing capacity is determined,and the accuracy of the two evaluation results is studied through the difference comparison,correlation coefficient and relative error.The results of the study showed that:(1)The timing results of coupling coordination degree show that the coordination relationship in Xinxiang Irrigation Area except Xinxiang County basically shows a trend of improvement in coordination relationship,and their coordination index is increasing year by year.This shows that with the improvement of social production level,the degree of coordination of social influencing factors on natural influencing factors gradually increases.From the spatial distribution analysis,the coordination degree of Yanjin,Fengqiu and Weihui is relatively poor,indicating that the ability of social activities in these three regions to affect natural precipitation,water resources and ecological flow is still relatively weak,on the one hand,it is manifested in the poor ability of local economy and science and technology to resist drought and other disasters,on the other hand,it shows that the local water ecological environment is less affected by human activities,and people’s awareness of ecological protection has not been paid enough attention.(2)The spatial distribution results of coupling coordination showed that Xinxiang County had less precipitation and more ecological water demand in 2015,but the largest population and relatively high water resources,and the coordination relationship between social and natural factors was high-quality coordination.The counties of Fengqiu and Yanjin have the smallest precipitation and the smallest population,but the water-saving irrigation area is low,and the degree of coupling coordination is manifested as a moderate imbalance.This shows that in counties with more population and agriculture,there is too much demand for water for life and agriculture,the contradiction between water use is more prominent,the quality of water environment is poor,and the social influencing factors have a greater impact on the carrying capacity of agricultural water resources.In areas with less population,agricultural science and technology are less applied,the quality of water environment is relatively improved,and the carrying capacity of agricultural water resources is more obviously limited by precipitation and water resource availability.(3)The comprehensive weight analysis results show that the weights of the three indicators of water-saving irrigation area rate,water resource development utilization rate and ecological water demand ratio are higher,and the impact on the carrying capacity of agricultural water resources in Xinxiang irrigation area is more significant.Among them,the arable land irrigation rate had the greatest influence on the carrying capacity of agricultural water resources in this irrigation area,and its weight accounted for 0.37.The proportion of water-saving irrigation area,water resource development utilization rate and ecological water demand ratio were 0.15,0.12 and 0.11,respectively,and ecological-related indicators accounted for 26% of all weights,which had a critical impact on the carrying capacity of agricultural water resources.(4)The evaluation results of fuzzy set analysis and TOPSIS analysis show that the carrying capacity of agricultural water resources in 2015 and 2016 has the highest value,that is,the worst carrying capacity.From the time series analysis,it shows that the evaluation values in 2015 and 2016 are the highest,that is,the bearing capacity is the worst.This is mainly due to the severe drought in 2014 and the exceptionally heavy rainfall in 2016,resulting in successive droughts and floods,which seriously affected the management of agriculture and irrigation areas,and seriously weakened ecological attributes.Spatial analysis shows that the carrying capacity of agricultural water resources in Yuanyang County and Fengqiu County is poor,while the carrying capacity of agricultural water resources in Weihui and Yuojia County is the best,among which Xinxiang County has a strong influence on the carrying capacity of agricultural water resources due to the large planting area and large population,and the bearing capacity trend is also more variable.(5)The accuracy comparison results show that except for 2015,the evaluation results of the two evaluation methods are basically consistent with the bearing capacity grade of the actual irrigation area,and the comparison results are relatively stable,and the relative error RMSE between the evaluation results of fuzzy set analysis and TOPSIS analysis and the actual bearing capacity status is less than 2%,which indicates that the evaluation system of agricultural water resources carrying capacity in irrigated areas based on ecological considerations has good rationality,and can accurately reflect the dynamic changes of agricultural water resources bearing in irrigated areas.