Study On Effective Utilization Coefficient Of Irrigated Water In The Vine Irrigation System

The effective utilization coefficient of irrigation water(EUCI)is an important index to consider the effect of the most stringent water resources management system in China and the achievements of water saving society construction.It plays an important role in rationally assessing the water saving effect of agriculture.The vine irrigation system is a typical irrigation system model in the southern hilly area.The main features are a wide range of water supply projects.complicated multi-water multi-user dispatching,criss-cross irrigation and drainage engineering.The recommended method of calculating the effective utilization coefficient of irrigation water shows the limitation.Therefore,it is of great practical significance to explore the new method to calculate EUCI and the influencing factors of that.On the basis of summarizing the relevant research results,this paper focuses on the following work:(1)We do three experiments,including the field experiment,the canal experiment and the pond experiment;(2)Based on the principle of water balance,We find two new methods,the sub-area method and the generalized method to calculate the canal-system water use coefficient(CWUC).And we also find two new methods,the water-balance head-tail method and the water-balance cannal method to calculate EUCI.(3)The influencing factors of CWUC and EUCI are discussed,and the empirical formula was gave to calculate irrigation water supply in ponds.The basic conclusions of this paper are as follows:(1)We examine the suitability of the new methods in the vine irrigation system through the two-year experiments.(2)The EUCI is related to the scale of the study area and rainfall year types.The EUCI in Pond supply region is higher than that of Single pond-reservoir region and multi pond-reservoir region.The EUCI in rainy year is higher than that of normal and drought years.(3)The field water utilization coefficient(FWUC)is related to crop type.And FWUC of organic rice is lower than that of high quality rice.The growth period of Organic rice is longer.It needs more water and has lager amount of leakage,so it's FWUC is low.(4)The CWUC is related to the canal series,the lining condition,the channel flow,the fractal characteristics and so on.With the increase of the canal series,the CWUC is gradually reduced;lining one side of canal can reduce by 28%of leakage;the loss rate per unit length of canal decreses as the flow increases.After the flow exceeds 3.5m3/s,the loss rate is stable at 0.003.When the fractal dimension value is about 1.12,the CWUC is higher,they are in "inverted U".(5)Through the regression analysis,it is found that the irrigation water supply of Tongyu is related to the net irrigation quota and the water supply of the reservoir.And according to the historical data,we establish the empirical formula of the water supply of ponds.