Objectives of this dissertation were: 1. To study the water resource management of the Royal Irrigation Department.  2. To study the factors affecting the water resource management of the Royal Irrigation Department. and 3. To present the development of water resource management of the Royal Irrigation Department by applying Buddhadhamma conducted with the mixed methods. The quantitative research used questionnaires with a total reliability value of 0.991 to collect data from 392 samples analyzed data with frequency, percentage, mean, standard deviation, and multiple regression. The Qualitative research, data were collected from 18 key informants by in-depth-interviewing with in-depth-interviewing script. Data were also collected from 9 participants for focus group discussion. The data were analyzed by content descriptive interpretation.

Findings were as follows:

1. The water resource management of the Royal Irrigation Department, by overall was at high level (x̅= 4.22). Each aspect under the framework of sustainable development, holistic development, and unity. networking, interdisciplinary aspects, and public engagement was found to be at high level. The organization has developed sustainability, including clearly defined strategies and objectives to be able to utilize the water to full potential. Technology has been used to play an important role in water development, and experts in various professions were selected to help manage water more efficiently, both in terms of establishing a development framework that was appropriate to the current situation and could be supervised including making correct, prompt and accurate decisions.

2. Factors affecting the water resource management of the Royal  Irrigation Department included: 1) Information technology management was to develop, and test the installing and problem searching of organization, appropriateness and preventive maintenance affected  the water resource management of the Royal Irrigation Department at statistically significant level of 0.01 and predicted the affected results by 83.6 percent, 2) Sappuristham Principles 7, Atthanyuta, knowing effects, Kanlanyuta, knowing time, Puggqalanyuta, knowing individual and Dhammanyuta, knowing cause affected water resource management of the Royal Irrigation Department with statistical significance at 0.01 level and predicted by 91.2 percent. Factors affecting the water resource management of the Royal Immigration Department regarding information technology including development and testing, installing, organization problem searching, appropriateness, preventive maintenance, This could be used to improve the water resource management of the Royal Irrigation Department to be more efficient by integrating Suppurisadhamma, namely Dhammanyuta, knwing cuase, Atthanyuta, knowing effects, Attanyuta, knowing self, Mattanyuta, knowing moderation, Kalanyuta, knowing time, Parsanyuta, knowing community and Puggalanyuta, knowing persons.

3. The proposed water resource management of the Royal Irrigation Department by applying Sappurisadhamma was found that 1. Dhammamanuta, Knowing Causes, Development of Information Technology systems for Water Resource Management needed to know the core of the cause. by applying Dhamma principles to reach the root cause of the problem, 2. Atthanyuta, knowing effects, consequences after knowing the causes of the problem, both in the area of the flood, drought and other water problems there should be considering other effects as well. 3. Attanyuta, knowing self, there should have the knowledge and understanding of one’s potential, whether one had the capacity to manage the problems in terms of the readiness of the personnel performing the work. tools, equipment, and information technology systems for water resource management, including the amount of water available. It was necessary to know and understand the timing of the water, both seasonal and weather forecasting, relying on more modern technology. 4 Mattanyuta, knowing moderation, knowing the appropriateness of personnel, tools, equipment, and information technology for water resource management including available water quantity, 5 Kanlanyuta, knowing time. It was necessary to know the water timetable in seasons, weather forecast, depending on the modern technology, 6 Parisanyuta, knowing community, knowing traditions and cultures and the norms of the communities. The Royal Irrigation Department, a single agency, cannot unilaterally complete the task so it sought the cooperation from other agencies 7. Puggalayuta, knowing persons, there should have an understanding of the personnel selection system, including knowledge, ability, integrity, maturity in various fields, to perform with excellent technology, and to use technology to manage water more successfully.