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The Effect of Water Saving and Production Increment by Drip Irrigation Schedules

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Wuhan University Journal of Natural Sciences 2004年第4期9卷 493-497页

作者： QIUYuan-feng LUOJin-yao MENGGe statekeylaboratoryofwaterresourcesandhydropowerengineeringscience WuhanUniversityWuhan430072HubeiChina statekeylaboratoryofwaterresourcesandhydropowerengineeringscience WuhanUniversityWuhan430072HubeiChina

Drip irrigation system can achieve high uniformity. When the system is designed for uniformity coefficient equal or more than 70%, the water application in the field can be expressed as a normal distribution and further simplified to a linear distribution. This paper will describe the irrigation scheduling parameters, percent of deficit, application efficiency and coefficient of variation by simple mathematical model. Using this effective model and the irrigation application, the total yield affected by the total water application for different uniformity of irrigation application can be determined. More over, this paper uses the cost of water, price of yield, uniformity of the drip irrigation system, crop response to water application and environmental concerns of pollution and contamination to determine the optimal irrigation schedule. A case study shows that the optimal irrigation schedule can achieve the effect of water saving and production increment compared with the conventional irrigation schedule in which the whole field is fully irrigated. Key words drip irrigation - linear cumulative frequency curve - optimal irrigation schedule - water saving - production increment CLC number TV 139.1 Foundation item: Supported by the National Natural Science Foundation of China (59379407)Biography: QIU Yuan-feng (1973-), male, Ph. D, research direction: water saving irrigation theory and techniques.

关键词： drip irrigation linear cumulative frequency curve optimal irrigation schedule water saving production increment

RESEARCH ON THE CONDITION TO SET A TAILRACE SURGE TANK

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Journal of Hydrodynamics 2004年第4期16卷 486-491页

作者： ZHAOGui-lian YANGjian-dong XUYuan-jie LIJin-ping statekeylaboratoryofwaterresourcesandhydropowerengineeringscience WuhanUniversityWuhan430072China SchoolofCivilandArchitecturalEngineering WuhanUniversityWuhan430072China

When using the draft-tube vacuum to be less than 8.0 m as the rule to set atailrace surge tank, a mixing function that describes the process of water-hammer vacuum andvelocity-head vacuum varied with time is proposed, on the assumption that the guide vane of thehydraulic turbine and the turbine discharge were all changed linearly. An exact maximum of thedraft-tube vacuum for the first-phase water-hammer and the last-phase water-hammer is *** a much more reasonable formula of critical tailrace length is derived. The results of twocases show that the formula proposed can determine correctly and reasonably whether a tail-racesurge tank is needed or not, and are more suitable for project design than the formula suggested bythe specification.

关键词： water-column separation tailrace surge tank critical tailrace length first-phase water hammer last-phase water hammer

EFFECT OF GROUNDWATER TABLE CONTROL ON WATER SAVING IRRIGATIONSTRATEGIES IN THE QINGTONGXIA IRRIGATION DISTRICT

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Journal of Hydrodynamics 2004年第2期16卷 166-175页

作者： WANGXiu-gui HOLLANDERSP.H.J. statekeylaboratoryofwaterresourcesandhydropowerengineeringscience WuhanUniversityWu-han430072Chinae-mail.xgwang@wuhee*** InternationalInstituteforInfrastructural HydraulicandEnvironmentalEngineeringTheNetherlands

This paper focuses on the analysis of the effects of groundwater tablecontrol under different irrigation water amounts on the water and salinity balance and on cropyield. Two experimental areas, the Pingluo and Huinong experimental sites, were selected to collectthe required data. The agro-hydrological model Soil-Water-Atmosphere-Plant (SWAP) was used toanalyse the water flows and salt transport processes for different groundwater levels and irrigationscenarios. Six scenarios, which resulted from different groundwater table regimes combined withdifferent irrigation amounts, were simulated. The results show that high ground-water tables due tothe excessive irrigation are the main cause of the large amount of drainage water and low cropyield; reducing irrigation water without a lower groundwater table will not lead to a largereduction of the drainage water, and will reduce the crop yield even more; to lower the groundwatertable is a good measure to control the drainage water and increase crop yield.

关键词： water saving irrigation field drainage saline water irrigation watermanagement

COMPOSITE ELEMENT METHOD FOR SEEPAGE ANALYSIS OF GEOTECHNICAL STRUCTURES WITH DRAINAGE HOLE ARRAY

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Journal of Hydrodynamics 2004年第3期16卷 260-266页

作者： CHENSheng-hong XUQing HUJing statekeylaboratoryofwaterresourcesandhydropowerengineeringscience WuhanUniversityWuhan430072 CollegeofEnvironmentScienceandEngineering HohaiUniversityNanjing210098China SchoolofWaterResourcesandHydropower WuhanUniversityWuhan430072China

Air element concept and Composite Element Method (CEM) were introduced inthis paper firstly, and then an explicit drainage holes element model was developed. The mainadvantage of the new model is that it allows drainage holes to be located within soil *** the mesh generation of complicated geotechnical structures with a large number of seepagedrainage holes becomes relatively convenient and feasible. This will further facilitate the optimaldesign of seepage control system, and in this case the calculation mesh can be kept unchanged whenthe number, position and orientation of drainage holes are adjusted. The model was been implementedin software. A sluice foundation seepage control problem was studied, by which the validity and therobustness of the new model were verified.

关键词： seepage drainage hole air element composite element geotechnicalengineering

CONTACT MODEL BASED ON AUGMENTED LAGRANGE METHOD AND ITS ENGINEERING APPLICATION

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岩石力学与工程学报 2004年第9期23卷 1568-1573页

作者： ChangXiaolin ZhouWei （statekeylaboratoryofwaterresourcesandhydropowerengineeringscience WuhanUniversityWuhan430072China）

A kind of improved contact frictional model on basis of traditional Coulomb Friction model is adopted. Corresponding contact element is also given. The contact algorithm on basis of augmented Lagrange method is introduced and successfully applied to complex contact friction problem. Test example and actual engineering case all show that the algorithm of the model is efficient and computation results agree well with general rules.

关键词：增强型拉格朗日法接触模型岩石力学摩擦非线性特性