Measurement And Application Of Water Resources System Resilience In Irrigation District

Heilongjiang Province is located in the northeast of my country,rich in water and soil resources.It is an important country’s commodity grain supply area,and it provides the country with about 9million tons of commodity grain every year.Among them,the Sanjiang Plain and Songnen Plain provide more than 90%.However,due to the one-sided pursuit of increasing grain production and the use of unreasonable water and fertilization patterns,a series of ecological and environmental problems such as groundwater over-extraction and deterioration of the water environment have become increasingly serious,which has damaged the agricultural water resources system of the irrigation area.This has caused a series of ecological and environmental problems such as water pollution and the sudden drop of groundwater level.In view of the above-mentioned water resource problems in the irrigation area of Heilongjiang Province,this article takes 12 sample irrigation areas including Chahayang Irrigation District in Heilongjiang Province as examples.Construct an evaluation index system for water resources system resilience of irrigation areas by establishing an evaluation index optimization model,and use multiple models to calculate the water resources system resilience index of irrigation areas.And through the comparison of model performance to determine the optimal model to evaluate the resilience of the irrigation area water resources system,and then analyze the key driving factors affecting the resilience of the irrigation area water resources system,and analyze the characteristics of temporal and spatial evolution.On this basis,in order to further ensure the sustainable development of agriculture in the irrigation area,an optimization model of agricultural planting structure under the constraints of resilience is established to provide guarantee for the safety of agricultural water resources.The research content and conclusions of this article are as follows:(1)This paper analyzes the connotation of water resources system resilience in irrigation districts by referring to research in related fields,and selects indicators covering 43 evaluation indicators in five systems including water resources system,technical management system,agricultural system,ecological environment system,and socio-economic system.Through the index screening model of multiple correlation coefficient-R clustering-variation coefficient,the evaluation indexes were finally selected to 13 and based on this,the water resources system resilience evaluation index system of the irrigation area was constructed.By comparing with research in related fields in terms of the number of initial evaluation indicators,the evaluation index screening model,the number of screening evaluation indicators,and the rejection rate,it is concluded that the evaluation index system constructed in this article is more reasonable.Through the reliability analysis of the constructed evaluation index,it is determined that the evaluation index system constructed in this paper is reliable and stable(2)According to the constructed evaluation index system of water resources system resilience of irrigation area,support vector machine model(SVM),gravity search algorithm optimization support vector machine model(GSA-SVM),gray wolf optimization algorithm optimization support vector machine model(GWO-SVM)),the improved gray wolf optimization algorithm optimization support vector machine model(IGWO-SVM)four models of the 12 sample irrigation areas including Chahayang Irrigation District,Heilongjiang Province,changes in the resilience of the irrigation area’s water resources system during the ten years from 2007 to 2016 and 2016 Analysis of the resilience level of water resources in the 12 sample irrigation areas.Analyzed from the time dimension,the four models are exactly the same in the other 9 years except for the slight difference in 2009,with a similarity rate of 90%.Analyze from the perspective of resilience level of spatial dimension.There are 10 irrigation districts with the same evaluation results,and the similarity rate is as high as 83.3%,only the evaluation grades of the 859 and Erdaohe irrigation districts are slightly different.At the same time,the performance of the four models is verified by classification accuracy,mean square error,determination coefficient R~2 and running time.From the results,the IGWO-SVM model is better than the other three in the four verification aspects.According to the theory of serial number summation,the Spearman correlation coefficient is calculated to verify the stability of the model,and the conclusion is obtained that IGWO-SVM model>GWO-SVM model>GSA-SVM model>SVM model.Therefore,it can be proved that the IGWO-SVM model has certain advantages in terms of model accuracy and model stability.(3)Through entropy weight method,CRITIC method and support vector machine weight coefficient method,respectively,the weight analysis of 13 optimal driving factors is carried out,and rainfall,per capita arable land area and effective utilization coefficient of irrigation water are determined as the key driving factors.Through the IGWO-SVM model analysis on the time scale of12 sample irrigation areas in Heilongjiang Province,it is concluded that the resilience of the water resources system has increased first and then decreased during the decade.Determine the typical years of 2008,2012,and 2016 by fitting a quadratic function to determine the spatial variability of12 sample points in the irrigation area.The spatial distribution of resilience levels in different years drawn by Arc GIS mapping software can be drawn:Although the overall resilience level of the western Songnen Plain irrigation area is lower than that of the eastern Sanjiang Plain irrigation area,its water resources system resilience level is gradually increasing;the water resources resilience level of the irrigation area along the river is significantly higher than that of the inland areas;The resilience level of water resources system is relatively stable in irrigation districts with a larger area proportion;the resilience of water resources system in small irrigation districts and well irrigation districts is generally better than that of large and medium-sized irrigation districts.From the perspective of spatial structure,no matter how the resilience level of the 12 sample point irrigation districts in Heilongjiang Province changes,the restoration level of the water resources system has been gradually decreasing from east to west.(4)Through the analysis of the agricultural planting structure pattern of 12 sample irrigation areas in Heilongjiang Province during the ten years,the proportion of food crops in the total planting area,and the proportion of each crop in the food crops,rice,soybeans,and corn are finally determined as the final decision variables.By considering the influence of water resources system,agricultural system,ecological environment system,socio-economic system,etc.on the agricultural planting structure,determine the total crop output,crop net output value,fertilizer application,and irrigation water consumption as the objective function.After determining the values of the related variables in the short-term year 2025 and the long-term year 2030,substituting the relevant data into the multi-objective evolutionary algorithm based on decomposition(MOEAD)model to analyze the changes in the planting structure of the 12 sample irrigation areas in Heilongjiang Province in the future years.In the end,compared with the current year of 2016,the rice area has slightly increased,and the soybean planting ratio has been declining.The corn planting area in 2025 is on a downward trend,and the corn planting area in 2030 is on the rise.In order to further strengthen the sustainable agricultural development in Heilongjiang Province,the analysis of resilience constraints was introduced,and the optimization of agricultural planting structure in 12 sample irrigation areas in Heilongjiang Province was compared with and without constraints.The results show that after the restriction of resilience is added,the agricultural planting structure is restricted to a certain extent.Therefore,in the process of optimizing the agricultural planting structure,more attention should be paid to the resilience of the water resources system.