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During late nineteenth century, Khuzistan was considered to be the most fertile land of Persia which at one time had yielded $ 50 million if calculated on 1962 price index. Many British officials presented in Iran and India office have recorded the abundance of water through a network of five rivers and canals, making Khuzistan a fertile ground for major staple and cash crops. At the time when the general populace was affected by the famine, Khuzistan stood unaffected. But thoroughly and gradually Khuzistan had faced deplorable condition owing to the British policy and power struggle. With the opening of the Karun River, the British influence had reached to the extent that they started interfering in the appointment of governors and granting of Khuzistan developmental projects to French, Dutch or Germans. The present article highlights the increasing influence of British in the political and economic affairs of Iran especially Khuzistan which was considered to be the 'second Egypt' next to Seistan. They had even assisted by the principle Arabs and Bakhtiaris tribes of Khuzistan as well as the influential trading and commercial figures to sabotage the irriga-tion project which could hamper the water flow to Karun River, a back bone for their commercial interest. In the first quarter of 20th century the British policy in Khuzistan proved detrimental to their vested interest.

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In the face of limited water resources, better utilization and operation of irrigation networks is essential. Use of control systems is considered as one of the most assured ways to achieve the aim. In the course of the present study, two centralized controllers are applied to the west canal of Aghili irrigation district in I. R. Iran. The proposed control algorithms consist of a distant Downstream PI Feedback control (DPIF), and a distant Downstream PI Feedback along with Feedforward control (DPIFF). In the controllers, each water-level regulator is adjusted as based on water levels in all the pools of the canal. The test case canal and flow scenarios are simulated using SOBEK. The controllers are evaluated using the simulation results. The results indicated that both of the proposed controllers possess the considerable needed potential to closely match the discharge (at the cross regulators) with those ordered by water users while properly maintaining the water level throughout the length of the canals of the irrigation system. It is apparent that the DPIFF controller is more effective than DPIF controller in providing a desirable performance. Use of these algorithms makes demand oriented water distribution as well as a better performance of the system possible. The DPIFF controller as the main control system accompanied by a local controller as a backup system can be recommended to present an efficient robust control system for the canal.

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Factor  is introduced for direct head loss calculation and sizing in dual-diameter laterals of sprinkler and trickle irrigation systems when the Hazen-Williams equation is to be applied. Application of this factor prevents trial and error and uses fewer head-loss equations in calculating the total friction loss and designing dual-diameter laterals. The proposed factor is a function of total number of outlets on the lateral, number of outlets on the smaller-diameter section of the pipe and ratio of smaller diameter to the larger diameter pipe. By solving two practical examples, the advantage of this factor over other approaches was shown. It was also demonstrated that design of lateral sizing by the given equations is simpler, easier and more accurate than the previous methods.