The Study On The Calculation Method Of Saving Water Amount Of The Water-saving Irrigation Project

China is a large population and a large agriculture country, at the same time, is serious shot of water, especially in North area, water recourse is more serious absence, "resources-type" absent water situation has presented, water crisis has been the limit factor that country and agriculture economy, what is more, the whole nation economy develop. So water-saving agriculture is the development trend of the future agriculture, and water-saving irrigation is the primary content. Therefore, it is necessary to study on the water-saving irrigation in "resources-type" absent water area, from the angle of the water cycle the value method of water-saving effect and saving water amount is put forwardThis research is based on social economy development situation and the conflict of water resource absence, especially "resources-type" absent water appearing, and in 21 century the trend that saving water project will develop, from the angle of water cycle, considers repetition using of the irrigation water. From the angle of hydrologic cycle, the papers puts up water balance model of all kinds of saving-water irrigation project, by the numbers analyses wastage and use way of irrigation, put forward the concept of water use efficiency, and educe the corresponding formulas of "the irrigation water use efficiency" and "resources-type" real water saving of all kinds of saving-water irrigation project. Apply the formulas to Tanghe irrigation district, using the change of the groundwater level to analyse correctness of the formulas.The main content of papers consist: ①according as water balance principle, the papers puts up water balance model of all kinds of saving-water irrigation project, by the numbers analyses wastage and use way of irrigation, and analyses effective wastage and invalid wastage. ②From the angle of water cycle considers repetition using of the irrigation water. From the angle of hydrologic cycle, amends saving-water effect index of the saving-water irrigation project and elicit a more practical loss-water effect index, put forward the concept of water loss efficiency, and educe the corresponding formulas of "the irrigation water loss efficiency". ③Basing on the formulas of "the irrigation water loss efficiency", educe the corresponding formulas of "resources-type" real water saving of all kinds of saving-water irrigation project. ④Take Hebei province for example, by coordinating and calculating the datum of Water Resource Communique and Water Stat. yearbook, and analyzing the datum of the experiment station, confirms the parameter of the formulas. ⑤Applying the way to calculate the formulas of "resources-type" real water saving and "the irrigation water use efficiency" of all kinds of saving-water irrigation project to Tanghe irrigation district, make up the real water saving of all kinds of saving-water irrigation project of Tanghe irrigation district. Use the change of the groundwater level to analyse correctness of the formulas.The papers 'aim is, by researching the real water saving of all kinds of saving-water irrigation project, to seek more scientific value means of the irrigation water use efficiency of all kinds of them, to provide more external decision-making foundation for developing saving-water irrigation project in "resources-type" absent water area, to look forward to being good for carrying out water resources continue Using and social economy sustainable development.