Ecological Environment Problems Analysis And Regulation Study In The Development Of Jinghui Canal Irrigation District In Shaanxi Province

Agriculture has always been the lifeblood of the national economy in China.The development of agriculture is directly related to the stability and development of the society.In recent years,affected by climate change and human activities,the development of agriculture was confronted with important challenges due to the shortage of agricultural resources,excessive exploitation and severe pollution.The irrigation district is the most concentrated place of agricultural production activities which is a composite system integrating production,life,resources,environment,economy,society and ecology.This study focused on the Jinghui Canal irrigation district in Shaanxi province to capturethe resources and ecology problems in the development of irrigation district,and dialectically analyzed the mutual influence and interaction between the development and ecological environment of the irrigation district.Aiming at the sustainable development of irrigation district,this study regulated the ecological environment problems to supply support for sustainable development of resources,sustainable development of ecological environment and steady development of economy and society.The main results and conclusions of the thesis are as follows:(1)Experienced the process from the sproutperiod,the precursor period(programming),the construction period(constructing),the supporting period(improving)the elevated period to the scientific development period,the construction of irrigation district has been continuously improved,and agricultural production has been widely used in science and technology.However,in the process of developing the resource,ecological environment problems of irrigation district occurred frequently,and becoming increasingly fierce.For example,the unreasonable utilization of water resources,the degradation of land and soil resources,the aggravation of the pollution of agricultural sources and the change of biodiversity and so on,which were mainly caused by human activities.(2)This study used trend analysis and wavelet analysis method to analyze the spatial and temporal characteristics of hydrological elements in Jinghui Canal irrigation district.The rainfall,runoff and sediment load showed a tendency of increase,all of which did not occur obvious mutation.With basically similar periodic variation characteristics,the rainfall,water inflow at canal head and sediment concentration measured at Zhangjiashan monitoring section all had a primary period of about 43a.With the change of time,the groundwater buried depthof Jinghui Canal irrigation district has been declining.That reached to about 10-20m in 2012 from 3-11m in 1978,some regions reached 28m.Luqiao county,Xi zhang and Zhang bu village were deeper.(3)This study established the function and feedback relationship between human activity-resources-ecological environment-social-economic complex ecosystem in Jinghui Canal irrigation district.Then we analyzed the effect change of ecological environment to the soil and water resources,industrial development,food security and social environment.Market value method was used to calculate the functional value of the material production in the irrigation district and the substitution method was used to calculate the function value of the service.The results showed that the value of the production function of the irrigated area was increasing.Therefore,Water,climate adjustment function value,purification environment function value and biological habitat function value of irrigation area were all decreased obviously.(4)The change trend of agricultural planting structure in Jinghui Canal irrigation district is that the planting area of grain crops was declining,and the planting area of economic crops such as vegetables and fruits were rapidly expanding to adapt to the rapid development of urbanization in the Jinghui Canal irrigation area and the demand of surrounding towns.The water requirement and net irrigation water requirement of the irrigation area in the Jinghui Canal irrigation area showed the same trend with the planting area,and total water requirement of crops and net irrigation water requirement decreased from 7.13×108m3 and 3.17×108m3 in 1988 to 4.95×108m3 and 2.48×108m3 in 2014.At the same time,the process of domestic water demand changed,the peak water demand showed a decreasing trend with time from April to May,July to September in the past,and the total amount of water required in June showed a trend of slow increase.(5)Through multi-sources information fusion,the reliability of ecological environment evaluation index of Jinghui canal irrigation district was calculated,and the optimized order of index was defined.The model of thematic evaluation was constructed.And the study evaluated the water resource utilization,land resource utilization,irrigation area pollution and irrigation area drought.The themed evaluation results of ecological environment showed that affected by the overexploitation of groundwater,the status of development and utilization of water resource was changing worse.The development and utilization of land resource was changing worse,the main reason was that it was influenced by the rapid development of urbanization and decrease of planting area.Due to the effect of the increasing pollution of pesticides and fertilizers,the pollution in the irrigation district was gradually serious with time.Drought is the most important natural disaster in the irrigation district,which has had a high frequency since the 1990.(6)In this paper,the key problem of the imbalance of surface and groundwater supply in irrigation of Jinghui canal irrigation district was focused to regulate.The regulation model was established with the target of optimal ecological,social and economic benefit,planting area as variable,and water resources availability as constraint.That was solved by the method of optimization,simulation and scheduling.We obtained two kinds of regulation schemes,which are optimized for ecological and social benefit.The economic benefits of the two schemes were not very different,and the protection and restoration of groundwater resources can play a positive role.Therefore,the agricultural planting interval between these two schemes was defined as a reasonable development interval.