مقایسه ﺗﮑﻨﯿﮏﻫﺎی ﺗﺼﻤﯿﻢﮔﯿﺮی ﭼﻨﺪ ﻣﻌﯿﺎره تاپسیس و ویکور در اولویت‌بندی زیرحوضه‌ها برای انجام اقدامات آبخیزداری (مطالعه موردی: حوزه آبخیز سد ایلام)

ﻣﺪیران و ﺑﺮﻧﺎﻣﻪریزان ﺣﻮزهﻫﺎی آﺑﺨﯿﺰ اﻏﻠﺐ ﺑﺎ ﻣﺸﮑﻼﺗﯽ در ﺗﺼﻤﯿﻢﮔﯿﺮیﻫﺎی ﭘﯿﭽﯿﺪه ﻣﻮاﺟﻪ ﻫﺴﺘﻨﺪ. ایﻦ ﭘﯿﭽﯿﺪﮔﯽﻫﺎ ﻋﻤﺪﺗﺎً ﺑﻪ دﻟﯿﻞ این واﻗﻌﯿﺖ اﺳﺖ ﮐﻪ تعداد زیادی از ﻓﺎﮐﺘﻮرﻫﺎ موثر و ﻣﺘﻐﯿﺮﻫﺎ وﺟﻮد دارﻧﺪ که باید در تصمیم‌گیری ﻟﺤﺎظ ﺷﻮﻧﺪ و ازآنجاکه اﺛﺮات و واﺑﺴﺘﮕﯽﻫﺎی داﺧﻠﯽ این ﻋﻮاﻣﻞ ﻣﺘﻔﺎوت اﺳﺖ، ﻣﺪیﺮان ﺑﺮای درک ﻣﺴﺌﻠﻪ ﺑﺎ ﻣﺸﮑﻞ ﻣﻮاﺟﻪ ﻣﯽﺷﻮﻧﺪ. در این رابطه ﺗﮑﻨﯿﮏﻫﺎی ﺗﺼﻤﯿﻢﮔﯿﺮی ﭼﻨﺪ ﻣﻌﯿﺎره راﻫﮑﺎر ﻣﻨﺎﺳﺒﯽ ﺑﺮای ﺣﻞ این ﮔﻮﻧﻪ ﻣﺴﺎﺋﻞ اﺳﺖ. درواقع ﺑﺎ اﺳﺘﻔﺎده از این ﺗﮑﻨﯿﮏﻫﺎ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻣﻌﯿﺎرﻫﺎی ﻣﺨﺘﻠﻒ ﺗﺼﻤﯿﻢﮔﯿﺮی، ﻣﯽﺗﻮان ﺑﻬﺘﺮین ﮔﺰینه یا ﮔﺰینهﻫﺎ را از بین گزینه‌های ﻣﻮﺟﻮد ﺗﺼﻤﯿﻢﮔﯿﺮی اﻧﺘﺨﺎب و اﺟﺮایی ﻧﻤﻮد. در این تحقیق کارایی دو مدل  vikor و topsis برای اولویت‌بندی زیرحوضه های حوضه سد ایلام برای انجام عملیات آبخیزداری مورد مقایسه قرار گرفت. برای این منظور، ابتدا 18 معیار تاثیرگذار توسط روش آنتروپی شانون وزن دهی شدند سپس ماتریس تصمیم بر اساس 12 زیرحوزه سد ایلام تشکیل شد و با استفاده از مدل های فوق، اولویت‌بندی این 12 زیرحوزه انجام شد. بر اساس نتایج حاصل از روش تاپسیس، زیرحوضه idbint_02 و بر اساس نتایج روش ویکور، دو زیرحوضه idbint_02 و idb_09 به‌عنوان گزینه‌های دارای بالاترین اولویت شناخته شدند. مقایسه نتایج مدل‌های فوق، نشان می‌دهد که هر دو مدل زیر حوضه idbint_02 را به عنوان زیرحوضه اول جهت انجام عملیات آبخیزداری معرفی کردند؛ اما نتایج این مدل ها در اولویت های بعدی متفاوت بود و نتایج مشابه را ارائه ندادند. به طورکلی با توجه به بازدیدهای میدانی انجام شده و در نظر گرفتن وضعیت کلی زیرحوزه‌‌‌های مورد مطالعه مطابق با نظر کارشناسی مدل ویکور می‌تواند به عنوان گزینه مناسبتر در موارد مشابه مورد استفاده قرار گیرد.

comparison of topsis and vikor multi-criteria decision-making techniques in prioritizing sub-basins for watershed management operations (case study: ilam dam basin)

1- introductionnowadays, watersheds have been raised as the focus of planning for sustainable development in many management issues. evaluating the ecological capacity of watersheds and ranking them according to various ecological criteria for watershed management operations is one of the important issues in planning and comprehensive management of watersheds. watershed managers and planners often face problems in complex decision-making. these complexities are largely due to the fact that there are a large number of influential factors and variables that must be considered in decision-making, and since the effects and internal dependencies of these factors are different, managers face difficulty in understanding the issue. since the cost of watershed management projects is high and the budget for development projects is limited, it is necessary that projects be carried out based on prioritization of watersheds. in this regard, multi-criteria decision-making techniques are an appropriate approach to solving such problems. in recent years, with the growth and development of management software and programs, these decisions are made using models, including topsis and vikor. so far, various studies have been conducted using multi-criteria decision-making methods in relation to watershed issues. a review of the sources and research records shows that the use of the above methods for prioritizing soil erosion has been widely used, but there are no records of the use of the above methods in prioritizing watershed management operations with respect to the design and calculation of the volumes of check dams for each sub-basin and their financial burden separately for each sub-basin, which are two determining factors in the implementation of watershed management plans, along with other factors. therefore, this study aims to compare the two vikor and topsis models in prioritizing the sub-basins of the ilam dam basin for watershed management operations by considering 18 factors, including the volumes of check dams and their financial burden, and determining the importance of the main factors of soil erosion in the basin.2. methodologythe ilam dam basin, located in western iran, was selected as the case study area. the basin was divided into 12 sub-basins, and 18 decision-making criteria were identified. these included factors such as area, slope, drainage density, sediment load, operation cost, and vegetation cover, number of residential zones, and soil /geological erodibility. the weights of these criteria were determined using the shannon entropy method, which quantifies the uncertainty or variability associated with each factor. topsis and vikor methods were then applied independently to prioritize the sub-basins. topsis involves calculating the geometric distances of each option from the ideal and anti-ideal solutions based on weighted normalized decision matrices. the alternatives are then ranked based on their closeness to the ideal solution. vikor, on the other hand, focuses on ranking and selecting from a set of alternatives with conflicting criteria, providing a compromise solution that is closest to the ideal based on satisfaction and regret measures. both models used the same input data and weights to ensure a fair comparison.3- results based on the results of the entropy method, the highest weight belongs to the criterion of the number of residential points (0.188) and the lowest weight belongs to the erodibility of geological formations (0.002). two important criteria, including sub-basin sediment load and operation cost of proposed structures (operation volume), also have weights of 0.039 and 0.104, respectively. also, the sediment load criterion and many other criteria are very closely and directly related to each other, and if their total weight is calculated, we will find that the sedimentation status of the sub-basin is given a large weight in total. based on the results of prioritization using the topsis method, the obtained similarity index, which theoretically can be between zero and one, varies between 0.274 and 0.571 for the options in this study, which generally indicates the closeness of the options to each other. accordingly, sub-basin number 2 has obtained the highest priority for the construction of watershed structures. also, sub-basins numbers 1 and 6 have the lowest rank or priority for structural construction operations. based on the results of prioritization using the vikor method, both options idbint_02 and idb_09 are recognized as superior options. in other words, sub-basins idbint_02 and idb_09 have the highest priority for watershed operation.4- discussion & conclusionsalthough, according to the results obtained from the topsis and vikor models, both models introduced the idbint_02 sub-basin as the first sub-basin for watershed management operations; however, the results of these models were different in the subsequent priorities and did not provide similar results. so that these two models have selected the first four priorities from among the 12 options with a slight displacement of the options, and both models have selected the same option as their first priority, namely sub-basin number 2. comparing the results of the two models in selecting priorities 5 to 12 shows that except for the twelfth priority (sub-basin number 12), which is common in both models, the other priorities in the two models have significant differences. accordingly, considering the field visits and considering the general condition of the studied sub-basins, according to the expert opinion of the experts of the ilam dam sedimentation study plan, the vikor model can be used as a more appropriate method in similar cases.