Estimation of transmission losses in irrigation canals - A case study

The transmission losses which include leakage losses, seepage losses, evaporation losses, operational losses and losses due to any other mean through a canal network depend on a number of physical, operational, and climatic factors. Some of these factors can be quantified but most of them are not easy to be incorporated into precise calculations. Due to climatic and other uncertainties, prediction of the reliable amount of losses in irrigation projects cannot be done confidently. In the present study, the transmission loss was observed in one of the Indian irrigation canals. The measurements were taken at four sites and all outlets, branch canals, distributions were closed during the measurement. The main canal was under free flow condition. The Transmission losses were (from 0 km to 145 km canal length) worked out by using inflow/outflow method. The discharges at each site were arrived by area velocity method. The losses were worked out on the basis of data analysis which was collected at four measurement sites during field studies. The Transmission losses from 0 to 145 km were worked out to be 8.10 m³/s (i.e. 286.72 cusecs). These losses are within 1.5% accuracy which is in the permissible limit.