In the late reign of King Chulalongkorn or King Rama V had an initiative to construct South Pasak Irrigation Project, but the project construction was started in the early reign of King Rama VI in B.E.2467 (A.D.1924). The name of project, therefore, is called “Rama VI Barrage”; and it is the first diversion dam in Thailand, located across the Pasak River at Tha Luang sub-district, Tha Rua, Ayutthaya province.
In B.E.2495 (A.D.1952), the Government approved a construction of “Greater Chao Phraya Project, By Chao Phraya Barrage was constructed across the Chao Phraya River in Chainat province and was completed in B.E.2500 (A.D.1957). Then, canals were excavated such as Chainat–Pasak Canal starting from the north of Chao Phraya Barrage at Manorom district, Chainat province, and ending by linking to the Pasak River at the north of Rama VI Barrage; and Chainat–Ayutthaya Canal starting from the north of Chao Phraya Barrage and ending at Phranakhon Si Ayutthaya district, Ayutthaya province, this project was completed in B.E. 2507 (A.D.1964).
In B.E. 2517 (A.D.1974), Regional Irrigation Office 8 had been approved by Royal Irrigation Department to construct its office at Phra Ngam sub-district, Muang district, Lopburi province. After that Regional Irrigation Office 8 was raised its position in B.E. 2543 (A.D.2000). Later, Royal Irrigation Department under Ministry of Agriculture and Cooperatives was divided the organization structure into 25 offices and 6 divisions, the objective was to define clear duties of each department and to reduce redundancy of their implementation by gathering group which had similar mission. It was a significant base for restructuring in order to formulate goals and directions of implementation of the related department with efficiency and effectiveness. Thus, Regional Irrigation Office 8 was renamed to “Regional Irrigation Office 10”.