State Irrigation Act B.E. 2485.

The Act makes provision for the construction, maintenance and use of irrigation waterways. For the purpose of this Act, irrigation waterways are divided into the following four categories: 1) Waterway used for supplying, draining, conserving or retaining water for irrigation purposes; 2) Waterway used for navigation in common with irrigation within the area benefited from irrigation works; 3) Waterway reserved for irrigation purposes; 4) Waterway which is accessory to irrigation. The Minister of Agriculture and Cooperatives shall have the power to collect irrigation rates from the owner or possessor of cultivated land which will receive benefit from irrigation (irrigation area). Moreover, there shall be established in the Royal Irrigation Department a revolving fund called the Revolving Fund for Irrigation. The irrigation rates shall be credited to the account of the Revolving Fund for Irrigation.