An Integrated Water User Group (IWUG) plays an important role assisting an irrigation project to control water distribution, expand the cropping area, operate and maintain irrigation facilities, and disseminate crucial information about the water situation to all farmers based on water supply from an irrigation agency. In this article, we present our analysis of the management of a newly established IWUG, based on a field survey in Thailand. We attempt to clarify the characteristics of irrigation management in the IWUG, while focusing on four functional processes: decision, operation, monitoring, and feedback. Thus, we analyze the water management structure and provide suggestions for better management of the IWUG. The main results of our analysis are as follows: (1) the current state of the IWUG 18R canal is not fully successful. There are second generation problems that need to be solved; (2) The upstream farmers dominate the use of the IWUG 18R canal because the establishment process of downstream WUGs was loosely performed because of a limited budget for on-farm irrigation development; (3) Water distribution structure and membership charging are not simple and uniform along the lateral irrigation canal because of the water availability of return flow from the downstream area. Such structure should be recognized and discussed to improve the future water distribution in relation to membership fees.

A good water users' organization (WUO) is a significant factor in the practical success of an irrigation project. The major duties of WUOs are to operate and maintain their irrigation facilities and to perform the financial and organizational management. This paper analyzes the history and present situation of three WUOs in the Chao Phraya Delta, Thailand which have been awarded for their successful activities: namely, two pilot integrated water user groups (IWUGs) and one pilot water users' association. The results of a field survey and questionnaire revealed the users' past experience, methods of irrigation management, and social mobilization efforts. The main results of our analysis are as follows: (1) among the three WUOs, only the IWUG Sao Hi Unity Agriculture Irrigation (IWUG SHUAI) can be regarded as a successful case in terms of long-term management, (2) as a pumping irrigation project, the IWUG SHUAI entails an upfront electricity cost, which gives farmers added impetus to organize a management system and budget, and to learn from past failures, and (3) in contrast, the member farmers in the gravity irrigation projects lack the impetus to realize the necessity of a common management budget, a situation which can be improved only by the education of the leaders and clear explanation to the member farmers.