Coefficient And Threshold Calculation Analysis Of Gansu Agricultural Irrigation Water Use

Agricultural irrigation water use coefficient is guiding the government control the scale of investment in water conservancy project construction, water and water conservation plan cost indicators such as important basis, is the guide and guide irrigation water-saving irrigation area tap potential, regulating the reference index of the water supply cost. Gansu is the resources and project type and lack of province, agricultural production mainly depends on irrigation. Research and analysis of coefficient of irrigation water, to investigate present situation of irrigation district in gansu, irrigation water, various constraints, and predict water saving trends, to provide reference and basis for regional irrigation planning and design, to promote health and promote the province’s water resources sustainable utilization and development is of great significance.Paper adopt coefficient calculation method of choice in provincial114measure sample irrigation area each year based on the observed data, in2006and2012, seven years in a row of gansu agricultural irrigation water use coefficient calculated result as the basis, through comparing the long series data analysis, conducted the province the influence factors of irrigation water use coefficient, in2012the province irrigation water use coefficient is calculated;2012achievement evaluation, irrigation water use coefficient of the agricultural irrigation water use coefficient of prediction, the threshold value of coefficient of irrigation water, etc.Through the analysis of study:the influencing factors of irrigation water use coefficient have irrigation area natural condition, economic and social situation, engineering condition, the types of irrigation area, irrigation area scale, seepage control measures, field irrigation technology, management level, etc., in2012the province irrigation water use coefficient is0.5232; Using the measured data of20typical irrigation area, take the penmen-montes reference crop water demand calculation analysis of net irrigation quota, the method of measuring the analysis in2012the province irrigation water use coefficient, and the irrigation area is calculated at114sample results analysis and comparison of the two comparison error is1.6%, the dunhuang DangHe typical irrigation area by adopting typical canal section measurement, measurement, coefficient of irrigation water use coefficient were0.5007and0.5012, the results are basically identical; Using the fuzzy comprehensive evaluation method to2012to evaluate results of irrigation water use coefficient; Using the grey model and system dynamics model for the future to predict the agricultural irrigation water use coefficient, grey model predicted results, in2015to0.5515,0.6001in2020; Prediction of system dynamics model, in2015was0.5233,0.5876in2020. Respectively using the actual maximum water capacity method and hydrological method, calculation of irrigation water use coefficient threshold range:PingShuiNian (P=50%)0.4897-0.5405, general drought years is0.6047～0.7157(P=75%), dry year (P=90%) of0.6348～0.7346. Fill the blank of irrigation water use coefficient threshold in gansu province. Finally, the paper analysis and research is put forward to improve the agricultural irrigation water use coefficient of concrete measures and Suggestions.