The dye laser excitation spectrum of the Ã2A′(004)←\~{X}2A″(000) vibronic band of HSO was observed and analyzed in the frequency range from 17132 to 17182 cm−1. 414 spectral lines were assigned to an ordinary c-type transition and 21 lines to an axis-switching transition. The rotational constants of HSO in the Ã2A′(004) state were used to calculate the inertia defect of 0.518 u Å2 for this state. A relatively large dependence of the centrifugal distortion constant on the vibrational quantum number was also found.

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.

The centuries-old, self-organizing Muang Fai community irrigation institution in northern Thailand has high potential in illustrating exemplary practices in irrigation cost sharing. This paper examines the cost sharing structure of the Pongsak Muang Fai Irrigation System in Mae Hong Son Province and its relationship with the system water management and sustainability. Results show that this primitive and high cost system accepts costs of the weir, the entire length of main ditch, not only the individually related ditch sections, and the management as common costs that should be equally shared so that it can gather sizeable membership to support the system. The capacity of this small scale run-of-the-river irrigation system with no river flow limitation is a simple summation of all determined farm intake capacities. The maintenance cost of the system every year depends on how much water should be diverted and conveyed, hence the use of "relative" scale of each farm intake capacity as the basis for sharing cost in the wet season paddy farming. Such structure is directly related to the water management under which every intake shall be served with continuous supply without permitting mid-canal water check-up and the members prefer to take collective action to keep enough water supply without leaving any room for suspicion of unfair water distribution. The direct relationship makes the members understand the purpose of payment and be willing to share the costs which T. Ounvichit ( ) Planning Division, Royal are transparently estimated in easily understood terms and clearly de-aggregated into categories.

In the transition to a market economy, in the rural Vietnam areas, the right to conduct production subjectively has been returned from cooperatives to the farm households. This individualization motivates the farmers to carry out their farming practices effectively. However, onfarm water management, because of physical interdependency among the farmers, can hardly be effectively carried out without cooperation of all the interdependent farmers. This paper, based on case studies of the main types of onfarm water management prevailing in the Red River Delta, analyses the changes in onfarm water management in the transition. It is found that, while the farmers carry out farming practices individually, the diminishing of the cooperative's role in onfarm water management is the main cause of the onfarm facilities' damages and unreliability of water supply to downstream area.The downstream farmers, depending on the changes in the role of cooperative in water management, take different countermeasures.In the best cases where the cooperatives can mobilize resources for a supplemental water supply, the farmers have to spend much more money and labour than the upstream farmers. In the other cases, they could not do anything other than to suffer from water shortage and delay water fee payment.The equity policy in water distribution and cost payment would enable the downstream farmers to invest in water recycling, thus increasing the system's efficiency. The integration at the village level of hamlet traditional organizations would be an effective body for onfarm water management.

Thai national irrigation systems, serving a large number of small paddy farmers, require water users' organization for effective and sustainable joint management; however, water users' organizations (WUOs) presently cover only 27% of the total irrigation area. This three-year action research investigated the difficulties in organizing water users in the Khlong Thadi Weir System in southern Thailand by immersion into the socio-economic conditions of Muslim farmers in farm turnout No. 4 of the 1L-4R-LMC canal and the conventional on-farm irrigation development there. We found the following: (1) subsistence farming and unstable tenancy discourage farmers from increasing their formal participation in irrigation management; (2) kinship is important but effective only in a limited space; (3) the conventional method of providing short ditches in a limited project timeframe creates a structural bias; (4) intrinsic internal water conflicts make the hydraulic relationship alone an inadequate basis for water users' organization; (5) alternatively, the social relationship between individual farmers and their community emerges as a promising scaffold for water users' organization; (6) the state irrigation agency should consider adopting a more vital role by supporting WUOs, tambon administration organizations and villages with needed incentives, technical information, and capacity building so that the WUOs are ultimately the decision makers. RÉ SUMÉLes périmètres publics d'irrigation thaïlandais, qui desservent un grand nombre de petits riziculteurs, ont besoin d'organisation des usagers de l'eau pour une gestion commune efficace et durable; cependant, les associations d'usagers de l'eau (AUE) existantes ne couvrent que 27% de tout le domaine irrigable. Ce travail de recherche active de trois années a étudié les difficultés rencontrées dans l'organisation des usagers de l'eau du périmètre du Déversoir de Khlong Thadi, dans la partie australe de la Thaïlande, par immersion dans le contexte socioéconomique des riziculteurs musulmans du lot n84 du canal 1L-4R-LMC et dans les pratiques traditionnelles d'irrigation à la parcelle. Nos résultats sont les suivants: (1) l'agriculture de subsistance et la tenure précaire des terres découragent les riziculteurs de participer de façon effective à la gestion de l'irrigation; (2) les relations de parenté sont importantes mais elles ne sont efficaces que dans un espace limité; (3) la méthode traditionnelle de desservir les fossés courts dans une programmation de courte durée crée un bias structurel; (4) les conflits d'eau internes intrinsèques font que la relation hydraulique seule ne constitue pas une base adéquate pour le dével-oppement des AUE; (5) en revanche, les relations sociales entre les agriculteurs individuels et leur communauté apparaissent comme un levier prometteur pour le développement des AUE; (6) l'agence publique d'irrigation devrait jouer un rôle plus vital en soutenant les AUE, et en fournissant à l'organisation administrative tambon et aux villages les incitati...