The Role of Lining in Water Use Efficiency of Irrigation Canals
XIAO Xue;WANG Xiugui;TAN Dan;BAI Xue;BA Qian;Water Resources Department, Yangtze River Scientific Research Institute;State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University;China Railway Siyuan Survey and Design Group Co.Ltd;Xinjiang Water Conservancy and Hydropower Survey, Design and Research Institute;Xinjiang Yili Kazakh Autonomous Prefecture, Kashigaer River Basin Management Section;
【Objective】Irrigation-canal lining reduces water loss from percolation and in this paper, we studied the change of water use efficiency after lining the irrigation canal in the low reach of Kashi River in Yili Autonomous Prefecture of Xinjiang Autonomous Region.【Method】Water loss from the canals with different linings were calculated based on the observed data. The canal water use coefficient and the irrigation water use coefficient were estimated based on the water loss rate per unit length at different position along the canal. The variation of the loss rate was analyzed and the relationship between the canal lining rate and the irrigation water use coefficient was calculated.【Result】The calculated results showed that at business as usual condition, the irrigation water use coefficient was 0.485. If all levels of the canals were concrete-lined, the irrigation water use coefficient could be increased to 0.691. Lining pre-casted U-shape concrete was most efficient in improving water use efficiency,followed by concrete lining and stone-masonry lining. Lining the proximity of the inlet of the canal was more effective in improving canal water use coefficient than lining the vicinity of the outlet. Consecutively lining different levels from the main canals, branch canals, up to lateral and sub-lateral canals can gradually increase the irrigation water use coefficient from 11.8%, 14.0%, 6.8% to 4.7%. The relationship between lining rate(λ) of all canals and the irrigation water use coefficient followed η =0.377 + 0.068 × ln(λ-2.748).【Conclusion】Pre-casted Ushaped concrete was the best lining for improving water use efficiency. To achieve best results, the lining should start from the inlet of the main canal. Lining the main and branch canals is superior to lining the lateral and sublateral canals. There is an relationship between the canal lining rate and the irrigation water use coefficient. When the canal lining rate reaches a certain degree, the irrigation water use coefficient increases slowly. Therefore, in terms of investment return, fully lining all level canals is not economically sound.
【CateGory Index】： S274
【CateGory Index】： S274