Research On Supply And Demand Analysis And Optimal Allocation Of Water Resources In Tailai Irrigation District

In recent years,in response to the common problems of low design standards,poor supporting facilities,serious aging and damage,low water efficiency,poor management system,and ineffective management system in large and medium-sized irrigation areas across the country,especially in the northern irrigation areas of my country,there are ditch erosion,siltation,Problems such as insufficient lining of backbone channels and serious waste of water resources affect the overall performance of irrigation areas.my country has carried out extensive and systematic rectification to speed up my country’s agricultural development,promote rural economic prosperity,and increase farmers’income.In order to make full use of the natural advantages,ensure the normal operation of the irrigation system,and improve the grain output and quality,my country has implemented supporting and water-saving renovation policies for the backbone projects of large-scale irrigation areas in recent years.Economic benefits still need to be resolved.Taking Tailai Irrigation District in Heilongjiang Province as the research object,this paper analyzes the balance of water supply and demand in the water-saving transformation of the irrigation district,designs the paddy field irrigation system,and uses the nonlinear programming model and the dynamic programming model to optimize the water resources allocation for insufficient irrigation in the irrigation district.The optimized results are compared and analyzed with the original adequate irrigation system in the irrigation area,so as to maximize the yield per unit area,the irrigation area’s net benefit per unit area and economic benefit per unit water volume The paper’s research substance and findings reveal that:(1)Analyze the water supply and demand before and after the water-saving renovation of the irrigation area.After the project is completed,the water supply capacity of the water conservancy project is 43.86 million m~3,the total water demand is 40.33 million m~3,and there is still a surplus of 3.53 million m~3,which saves 3 million m~3 of water compared to before the project.According to the water and soil resources and climate requirements for the construction of the irrigation area,the irrigation design guarantee rate was determined to be 75%,the paddy field irrigation system design research was carried out,and the range of the designed irrigation rate was clarified.(2)Water-saving renovation project has changed the poor operation of rural irrigation areas,and is necessary ways to effectively promote the sustainable development of rural economy,improve agricultural ecological environment protection,and expand the income of employees,with good economic benefits and obvious social benefits.After the reconstruction of the irrigation area,the backbone water conservancy engineering equipment is complete,creating favorable conditions for the establishment of high-standard fertile fields that can be drained and irrigated in case of drought in the area.The utilization rate of water resources in the irrigation area has been greatly improved,the new water-saving production capacity has been increased by 3 million m~3,the irrigation water utilization coefficient has increased from 0.65 to 0.70,the irrigation area of paddy fields has been improved by 50,000 mu,and the drainage area has been improved by 72,800 mu.(3)The Jensen model in the crop water production function is used as the objective function of the nonlinear programming model to optimize the allocation of water resources in the irrigation area under the inadequate irrigation system.When the irrigation guarantee rate P=50%,75%,and 90%,the optimal irrigation quotas for rice were 6320m~3/hm~2,9050m~3/hm~2,and 11370m~3/hm~2,respectively.And the irrigation quota of shallow-humid and full irrigation in Tailai Irrigation Area is 7230m~3/hm~2,10845m~3/hm~2,13260m~3/hm~2 under the condition of irrigation guarantee rate P=50%,75%and 90%,respectively.If the irrigation area adopts this optimized irrigation system,it will save13%,16%,and 14%of water respectively compared with the existing irrigation system.Adopting the insufficient irrigation system is more in line with the concept of water-saving irrigation,and the water use efficiency is higher.(4)In order to rationally arrange the water resources in the irrigation area and allocate the irrigation water during the crop growth period reasonably,on the basis of the Jensen model,it is linked with the economic benefits of the irrigation area.Combined with mirror genetic algorithm(ASGA),a mirror genetic dynamic programming model(AS-GA-DP)was established.After optimization,under the conditions of P=50%,75%,and 90%of the irrigation design guarantee rate respectively,when the irrigation water volume in the irrigation area is 8120m~3,10850m~3,and13170m~3,the economic benefit per unit area of the irrigation area reaches the maximum value,which is 8715 yuan/hm~2,9132 yuan/hm~2,9048 yuan/hm~2.The analysis found that under the condition of different irrigation design guarantee rates,with the increase of irrigation water volume,the net benefit per unit area of the irrigation area showed an upward trend,but the increase rate gradually decreased,indicating that when the irrigation water volume gradually increased,the water supply in the irrigation area gradually increased.The influence ability of quantity on the net benefit per unit area is getting smaller and smaller.Therefore,it is not advisable to increase the overall economic benefit of the irrigation area by increasing the amount of irrigation water.In the case of insufficient water resources or rising water prices,it is more reasonable to use an insufficient irrigation system.