Abstract
In this paper a hydrodynamic model was applied for evaluation of water‐saving strategies in systems where there is wastage of water due to oversupply in periods of low demand. The one‐dimensional hydrodynamic model CanalMan was used to assess water saving in a secondary canal. Different operational scenarios were evaluated in comparison with the existing operational strategy. This included the operation of the canal at different discharges combined with night closure, in periods of low demand. Time–discharge hydrographs were prepared using the numerical model for operation of canals having daily opening and closing with full supply, 80 and 70% of design discharge. These hydrographs were used to estimate possible time duration of canal operation for these discharges in the case of night closure. Water saving by night closure was compared with that from operation having weekly rotations. Study of the existing operational practices indicated extremely high oversupply to the canal compared with crop water requirements, especially in the months of August, November and December. Significant water saving was found by night closure and operating the canal at reduced discharges. Copyright © 2008 John Wiley & Sons, Ltd.