Optima water allocation in canal system under unequal discharges in subordinate canals based on Bi - Level PSO Method

Taking No. 1 Sub - branch Canal of the Yingke Forth Branch Canal in Ganzhou Region of Zhangye City located in middle reach of the Heihe River as the research object, based on the present canal optimal water allocation model, aimed at the situation of unequal discharge in subordinate canals, carried out research of optimal water allocation in canal system. Selected the minimal water losses by canal water delivery and minimal time difference among rotation groups, set up the multi-objective optimal water allocation model. Taking the switch state of the subordinate canals and actual discharge a the decision variables, the optimal combination of rotational irrigation group has been solve by using the Bi - level PSO Method. The optimal water allocation model in canal system was successfully constructed under unequal discharge in subordinate canals. The result obtained by using the Bi - level PSO Method has been showed: The rotation irrigation groups were divided rational. It suggested that the discharge at lateral canal of change range was 74. 3 % 77. 6 % and the discharge of branch canal was flowed smoothly, the maximal water allocation time was 113.4 h, which was less than the 168 h in original water allocation plan constituted by hand. Each canal discharge was changed within the allowable range, the allocation time combination in the process of optimal water allocation in canal system was rational. The allocated discharge in superior canal was equalization to avoid the effects of discharge suddenly change in superior canal to the subordinate canals. Not only the surplus water in canals was decreased, meanwhile let each irrigation rotation group was close in same time, the gate regulating times were effectively reduced, the decision-making can be provide for the irrigation management division to draw up the water allocation plan.