A Communal Irrigation System, Farming Productivity and Water Use Efficiency: The Case of ''Muang fai'' in Northern Thailand

This study analyses administrative arrangements and water resource management of a traditional small-scale irrigation system, and identifies the determining factors that contribute to a farmer's decisions to participate in the system. The study aims to compare two kinds of irrigation system: the community-based muang fai irrigation and underground pump irrigation. The assessment was based on identifying their effectiveness in managing irrigation: which system is better in terms of farming productivity and water use efficiency. In northern Thailand, the local northern Thai or Lanna people are primarily employed in rice farming, orchards, or growing cash crops. Hence, water is a necessary resource for their agricultural activities throughout the year. The muang fai system is a traditional, small-scale, communal irrigation system that has been practised for centuries in the region. The muang fai irrigation relies on surface water from rivers and streams and is managed through community-based participation that has undergone little change for generations. The muang fai system is characterised by common property management, under which a set of pre-established rules are used to distribute water among members. It has its own water user's association which is administered by its committee, and managed by group leaders. The muang fai Sop Rong system which is located in Chiang Mai province in northern Thailand was chosen as a case study. The system was chosen primarily because it still preserves certain traditional characteristics, most notably its physical features. The irrigation system was built by using natural materials similar to the earliest period. The value of this traditional system is currently being challenged by modernisation that has been occurring in the region through the introduction of various alternative irrigation technologies, including privately-owned, underground pump irrigation. Underground water for irrigation is freely available for those who can access it.1The objective of this study is twofold. The first is to explore various factors that influence farmers' participation in the muang fai irrigation system. The second is to compare the two different kinds of irrigation system, by identifying which regime is better in terms of generating economic benefit (measured by farming productivity), and environmental benefit (measured by water use efficiency). The results are based on data collected from a survey of 481 farmers who grow Longan which is the main crop growing in the muang fai Sop-Rong system, one of the largest muang fai irrigation systems in Thailand. Longan fruit or 'Euphoria Longan' is a tropical fruit. It is native to Southern Asia. The fruit is shelled and has a black seed shows through the translucent flesh (as shown in Appendix A). The survey was conducted among both farmers who are in the muang fai system and underground pump users, and collected information on various farming and socio-economic characteristics. Additionally, the research team collected samples of water from both muang fai and underground (non-muang fai) irrigation sources from randomly selected areas to investigate whether the price and quality of Longan fruit were related to muang fai water quality. An econometric analysis was used together with descriptive qualitative information. The survey data were used to estimate a Logistic model of muang fai participation in an attempt to explain what factors affect the likelihood of a farmer joining the muang fai instead of adopting other methods of irrigation, i.e., underground pump irrigation. Then the Propensity Score Matching (PSM) technique was applied to estimate the impact of muang fai participation on farm productivity and water use efficiency. The findings suggest the following. Topographical factors, measured by the farm'sdistance to the closest muang fai canal, strongly affect a farmer's participation in muang fai.