عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The goal of innovation of modern irrigation networks was to increase efficiency. Negligence in operating and maintaining of irrigation network infrastructure is the main source of inefficiency. In order to achieve the optimum efficiency, effective factors should be classified and ranked, and all criteria be considered for making decision. Analytical hierarchy process (AHP) is one of the generalist systems in cases of decision making. The method was developed by Saaty in 1994. In this study, AHP was used to evaluate operating situation of command units of Fumanat irrigation network as a part of the Sefidrud river irrigation and drainage network, Guilan, Iran. The network is located on left side of the Sefid-rud River, between Pasikhan and Shafarud rivers, and limited to Anzali wetland and the Caspian Sea from the north and Fumanat main channel from the south.
In the current study, hierarchy structure was made in three levels by criteria and alternatives (command units) of the network and was developed based on the axis of irrigation network operation program include of "control and water resource allocation" and "control and water distribution". Collecting the requirement data, an application has designed based on hierarchy structure and pairwise comprise. Pairwise comparison and number of elements (number of criteria and alternatives) and their required judgments are the factors that the test questions designed based on them. Four effective criteria involved in operation of irrigation network included: type of water regulation and distribution structure, water allocation, method of water distribution and adherence to cultivation pattern. Weighing the criteria, the opinion of experts of Guilan irrigation network operation company (GINOC) via questionnaire and farmers via interview, with difference policies were considered. By the application of criteria and based on Saaty's numeric weight table (1994), the pairwise comparison tables were created with individual involved components. Then, according to Aczel and Saaty (1983), individual pairwise comparison matrix converted to grouping judgment matrix, by computing geometric mean of components. Collected data points which computed and analyzed were introduced to Expert Choice (EC) software to compute the weight of criteria and commend area. Hierarchy structure was made in EC software and the elements were compared in pairwise. The hierarchy model was solved from the lowest level to the highest. Results of pairwise comparison were displayed on the diagram of weights that showed the inconsistency ratio, as well. Considering the pluses in AHP, for example existence of the consistency between decision maker’s opinion and existence of the pairwise comparison in the giving criteria, the suitable method would be obtained. This model evaluated scale of the effect of criteria in the irrigation network operation problems with simplifying the unintelligibility and complexity in the hierarchy analysis, by high accuracy.
This research validated the command unit's priority and showed conformity between results and reality. Based on the results, F1 command unit with the most weight of 0.422 had the best situation in term of operation. This command unit was the first one that was operated by modern irrigation network and being on the upstream could lead it to have the better situation. Also, F1 achieved the first ranking in term of evaluating opinions, while F2, F3 and F4 were in the next ranking. According to final weight results, "type of water regulation and distribution structure" with the weight equal to 0.512 was the most effective criteria in term of operation. So, finding the most effective method for improving the operation of these units would need especial consideration and focus on the case of water regulation and distribution structure. Regulation and fixing are two factors involved in ranking in order to prevent illegal withdrawal by farmers. Final weight of alternatives ratio for difference criteria in F1, F2 and F3 command units showed that the most effective factors in ranking were water allocation, type of water regulation and distribution structure and adherence to cultivation pattern, respectively. Also in term of water allocation, F1 command unit had the first rank ratio and the other criteria (F2, F3 and F4) set in the next ranking. The same ranking of the command units was also observed in term of "type of water regulation and distribution structure". Also, the inconsistency ratio of the model was 0.07 that confirmed grouping judgment.