Abstract
Seasonal time‐dependent seepage data are very useful for irrigation system managers to reduce canal conveyance seepage losses. Determination of canal seepage is complex due to the transient fluctuations in canal stages and other factors. Here we propose an indirect method for estimating seasonal canal seepage using a calibrated stage–seepage relationship and a monitored canal stage. The method was applied to the Nanguan Main Canal (NMC) in Gaoyou Irrigation District, China. The stage–seepage relationship was calibrated using the least squares method and the observed data from a ponding test. We estimated the time‐dependent canal seepage for two irrigation seasons through the canal stage monitored by water‐level loggers installed along the canal. The estimated average seepage rates were consistent with the results from acoustic doppler current profiler tests; and the seasonal seepage losses from the NMC were estimated to be 3.08 million m 3 in 2013 and 2.81 million m 3 in 2014, accounting for 4.5 and 5.1% of the water diverted to the canal respectively. With the dominant time‐dependent factor influencing canal seepage taken into consideration, the proposed indirect method provides a rapid and timely monitoring of seasonal canal seepage. Copyright © 2016 John Wiley & Sons, Ltd.