Prioritization of Irrigation Construction Projects in Intermontane Plateaus using AHP and FAHP: A Case Study of Lampang and Phayao Provinces

Abstract

Background and Objectives: Delivering irrigation water in intermountain plains differs from the water delivery in river basin plains or plains. In the intermountain plain areas, the topography is similar to hills, alternating high and low slopes. This makes it quite difficult to deliver water to agricultural areas, causing farmers to have problems in farming. Although the government has assisted, due to a limited budget, it has been unable to implement all the desired projects. This study aimed to study and select projects that are ready and necessary. The study area lies in the plain area between mountains in Lampang and Phayao provinces. This case study covered all five projects in the construction plan for fiscal year 2024 of the Royal Irrigation Department.

Methodology: The study employed Analytical Hierarchy Process (AHP) and Fuzzy Analytical Hierarchy Process (FAHP) methods. The analysis was divided into 3 parts: finding the factors affecting the project selection, prioritizing the project, and comparing the results from the two methods. The data were obtained by interviewing the personnel involved in the project implementation. These personnel were executives and experts involved in the construction projects and prioritizing the projects of the Royal Irrigation Department.

Main Results: The results of the weighted values of the main and secondary factors as obtained from AHP and FAHP methods reveal that the main important factors are agriculture and engineering aspects, with AHP’s weighted values of 0.364 and 0.259, respectively, and FAHP’s values of 0.577 and 0.332. The main secondary factors are the area of dry season crop growing that increased after the project, the number of irrigation buildings, water supply, and benefit areas, with weighted values obtained via the AHP method of 0.276, 0.100, 0.101, and 0.100, respectively, and via the FAHP methods of 0.306, 0.111, 0.108 and 0.105, respectively. The consistency ratios (C.R.) of the data are consistent and noted to be reasonable, with the values of less than 0.10. The prioritization results obtained via AHP method are: (1) Mae Wang Operation and Maintenance Project (Mae Pung Weir) On-farm Water Development, Phase 1; (2) Lam Nam Yao - Lower Mae Wang Right Bank On-farm Water Development Project (Khao Son Weir); (3) Mae Tam Reservoir Left Bank Canal Improvement Project; (4) Mae Klang Reservoir On-farm Water Development Project, Phase 2 and (5) Mae Phrik Reservoir (Pha Wing Chu) On-farm Water Development Project, Phase 2, with weighted values of 0.292, 0.238, 0.172, 0.151, and 0.147, respectively. The first and second ranking results by FAHP method were the same as those by AHP; the 3rd and 4th ranks were similar but in the reverse order. The final order result was the same with the following weights: 0.375, 0.318, 0.138, 0.094, and 0.075, respectively.  

Conclusions: When comparing the ranking of projects as depicted from the two analysis methods, FAHP method resulted in projects that are already outstanding in some aspects to be even be more outstanding; conversely, the projects with less outstanding aspects become even less impressive. If there is a clear and complete project information, AHP method, which is a more basic method, can be used to arrive at similar results. In this case, the results of selecting the first- and second-ranked projects were the same, no matter which selection methods were used. The first two ranked projects received high priorities because both projects were outstanding in agriculture aspect and could increase the planting area during the dry season, resulting in an increased agricultural production. From engineering viewpoint, these projects also consist of many irrigation buildings, allowing agricultural areas to benefit more from the irrigation system.

Practical Application: FAHP is a suitable alternative in decision-making as it can handle uncertain decisions due to unclear project information. However, if the information is clear and adequately complete, AHP is an effective method, which is simpler for an analysis. The results here reveal the factors affecting the prioritization of irrigation construction projects in the intermontane plateaus. Planning agencies can use the model to analyze rankings of similar agricultural projects, so that projects that benefit communities would receive support, helping farmers benefit and provide sufficient water.