Royal Irrigation Department is a government agency which has had long history and development. The water resources development with universal and systematic formats was in the reign of King Chulalongkorn the Great or King Rama V of the Rattanakosin Dynasty. His Majesty graciously established the "Canals Department" in B.E.2445 (A.D.1902), having the responsibility for canals maintenance to prevent the shallowness and canals excavation in the suitable area for transportation and storage for agriculture, assigned the government to recruit Mr. Yehoman vander Heide, a Dutch expert on irrigation to study and undertake the irrigation project planning in Thailand. Later His Majesty graciously appointed him as the first Director General of the Canals Department of Thailand and then the construction of a diversion dam across the Chao Phraya River in Chai Nat Province was proposed.