Study On Water Supply And Demand Balance And Water-saving Potential In Irrigated Areas

Based on the investigation of water supply,use,consumption,displacement and socio-economic status of irrigation area,this paper analyzes the characteristics of water supply,water use and water consumption in irrigation area,using fuzzy comprehensive evaluation model and analytic hierarchy process(AHP)to establish the evaluation system of water use in irrigation area and evaluate the current level of water use in irrigation area.According to the current situation of water resources and the condition of water supply,the time series prediction model is used to predict the industrial and domestic water demand of irrigation district planning year,and the agricultural water demand based on the different guarantee rate under the adjustment of planting structure is predicted,and the balance relationship between supply and demand of water resources in planned irrigation area is analyzed.Based on the research results of water demand of winter wheat and summer corn crops,the irrigation system with high efficiency and water saving is worked out,and the water saving potential under this system is calculated.The main research contents and results are as follows:(1)Typical survey results of water use level in the irrigation area show that the main water supply sources in the irrigation area are the Yellow River water,the south-to-north water diversion project and shallow groundwater.From 2007 to 2016,the average water supply in the irrigated areas was 217 million m~3,of which the minimum water supply in 2013 was 185.3379 million m~3 and the maximum water supply in 2016 was 225.6465 million m~3.According to the data of water supply and rainfall over the years,the water supply in the irrigation area varies with the amount of yellow water diversion and is related to the amount of rainfall in the irrigation area.The law of water use in irrigated areas is seasonal,and agriculture accounts for more than 82%of the total water used by the main users.The types of water consumption in irrigated areas can be divided into five categories:farmland irrigation,industry,urban life,rural life and natural ecological water consumption.In 2016,the the irrigation area consumed 182.1822 million m~3 of water,81.56%of which was for farmland irrigation.The displacement of the irrigated area is composed of flood water and irrigation water.In 2016,the total displacement of the irrigated area was 251.4908million m~3.The level of water use in irrigated areas is lower than the national average.According to the water resources status and characteristics of the irrigation area,the evaluation index system of water use level was established,and the fuzzy comprehensive evaluation model was established.(2)Based on the analysis of perennial rainfall data in the irrigated areas and the calculation of the transit water amount and the amount of shallow groundwater resources,the available water supply in the irrigated areas in 2025 is:220.8630million m~3 in the year of abundant water,203.4962 million m~3 in the year of plain water,and 182.7714 million m~3 in the year of dry water.Using the time series prediction model,the data stability test and model identification of the industrial and domestic water consumption in the irrigation area in recent ten years were carried out respectively.The results show that the industrial water consumption in the irrigation area conforms to the AR(1)model,and the domestic water consumption conforms to the ARMR(0,1,0)model.Based on the prediction of planting structure,the agricultural water demand in irrigated area was predicted.The predicted results are as follows:the annual total water demand of the irrigated area is 176.1635 million m~3,that of the plain water is 204.9418 million m~3,and that of the dry water is 239.8055 million m~3.According to the balance analysis of water resources supply and demand,in addition to the year of abundant water,both the plain water year and the dry water year in the planned irrigation area will be in a state of water shortage,of which the agricultural water shortage in the plain water year is 1.90523 million m~3,and the agricultural water shortage in the dry water year is 5.60505 million m~3.The water shortage rate in dry years is 23.78%.(3)Based on the research on the water demand of winter wheat and summer maize,an efficient water-saving irrigation system was developed.This system and use engineering technology and adjustment of agricultural planting structure improve the utilization efficiency of agricultural water resources,irrigation area to calculate the potential theory of agricultural water-saving irrigation area of 36.7425 million m~3,the results are further proved the validity of the efficient water-saving irrigation system and improve the feasibility of planting structure,for the development of water-saving agriculture provides the theory basis.