Water allocation and optimization of minor canal operation

Abstract

In this study a mathematical simulation of canal operation is presented for optimizing water allocation within a multiple crop rotation canal. Zero-one linear programming algorithm was made for optimal flow regulation and to optimize irrigation water allocation and sequencing of different outlets in the irrigation canal under the constraints of fixed canal capacity and irrigation interval. The model was coded in a personal computer using Excel -visual basic application language (VBA) and designed to serve as a decision-making tool for operating an existing canal or for appropriate sizing of canal capacity (flow rate and cross-sectional area) of a new one.The model is verified statistically in comparison with published models. The allocation model is applied to the real cases of wet and dry regions of Gezira Scheme -Sudan for sequencing canal outlets for the cases of early and peak season at Sunni Minor canal and Ugud Minor canal. The model sensitivity to changes in outlet inflow rate (working time per outlet) was made for the said two cases. This indicated the model capabilities to effectively provide a constant flow rate into the canal during the operating period, and consequently minimize the need to frequently adjust the settings of canal head regulator. The model capabilities to optimize water scheduling and allocation process can be used to save irrigation water during early stages of crop growth and to upgrade the operation of minor canals in the irrigated schemes in the Sudan.

Strategies for Crop‐Based Scheduling of Secondary Canals: Case Study of Mirpurkhas Subdivision, Pakistan

“…The water saving results are almost similar to those reported by Zhenmin (1992), who estimated about 28.5% water saving when canal was scheduled on 10 days instead of 14 with optimum water in China. The results of the study area are also in agreement with Mohamed et al (2010), who observed 33% in canal water saving when canals were operated on actual water duties and 50% water saving when they operated on design water duties. In the present case, the optimum water allocation to secondary canals has been allowed separately for kharif and rabi seasons rather than on a design basis.…”

“…It was observed that the second and third methods with less variability in cluster demand were more efficient than the first CBIO method and save maximum volume of water. Results on canal scheduling through the second and third CBIO methods, in terms of water saving, are in close agreement with the results obtained by Zhenmin (1992) and Mohamed et al (2010) on Sunni canal in Sudan and the North main canal scheduling in China, respectively. The present scheduling would also save more water as compared to alternate scheduling (7-7 days) as designed by Mishra et al (2002Mishra et al ( , 2008, where 13 and 10.3% water saving was calculated.…”

“…Results on canal scheduling through the second and third CBIO methods, in terms of water saving, are in close agreement with the results obtained by Zhenmin () and Mohamed et al . () on Sunni canal in Sudan and the North main canal scheduling in China, respectively. The present scheduling would also save more water as compared to alternate scheduling (7–7 days) as designed by Mishra et al .…”

“…The results of the study area are also in agreement with Mohamed et al . (), who observed 33% in canal water saving when canals were operated on actual water duties and 50% water saving when they operated on design water duties. In the present case, the optimum water allocation to secondary canals has been allowed separately for kharif and rabi seasons rather than on a design basis.…”