灌溉工程设计标准选择

灌溉工程设计标准一般用灌溉保证率表示，常采用经济分析方法进行比较选择，笔者建议采用财务动态分析法，要求灌区内部回收率必须大于12％，净现值必须大于零．其财务分析基本参数包括不同灌溉保证率的灌溉面积、灌溉工程投资、作物多年平均减产系数、灌溉效益、灌溉工程年运行费．基本参数的确定可用公式算出，根据这些基本数据，按财务现金流量，分别计算不同灌溉工程标准的财务内部收益率、经济效益费用比和财务净现值，最终进行灌溉工程设计标准的选择．

Selection of Design Standard of Irrigation Project

The design standard of irrigation project is usually represented by irrigation ensuring rate and selected comparatively by the method of economic analysis. The writer here proposed to use dynamic financial analysis with the request of that internal rate of return (IRR) must be larger than 12% and net present value (NPV) has to be larger than zero. Basic parameters needed in the analysis include the irrigation area, cost of the irrigation project, average annual yield reduction rate of the crop, irrigation benefit and annual oPeration fee of the irrigation project under different irrigation ensuring rate. These parameters can be fixed by calculation. Based on these basic parameters, IRR, economic benefit-cost ratio and NPV can be calculated under different standard of irrigation project by financial cash now method. Then the selection of design standard of irrigation project could be made.