Irrigation in plains of upper northern region of Thailand has a very long history as long the evidences were found. From the Lanna legend, weirs were constructed since B.E.1100-1200 (A.D. 557-657). During B.E.1839-2101 (A.D.1296-1558), the Mangrai Dynasty had governed the Lanna Region and enacted a law for irrigation and water utilization. In this period, irrigation was strongly involved in social, economic and political conditions. The weir management system by farmer was set up and applied for a long time until it became to the northern tradition. It may be said that the people in the northern region have high-level knowledge and understanding on irrigation.



     Since B.E.2472 (A.D.1929) Royal Irrigation Department (RID) has played a role in irrigation in the northern region by constructing the Sinthukitpricha weir across Mae Ping river at Ban Sahakorn, Mae Faek sub-district, San Sai district in Chiang Mai province, which was the first project; besides, government agencies started supporting irrigation to farmers. Later, RID established the Payap Irrigation Project in Lampang province, covering responsible areas in 7 provinces; namely, Lampang, Phrae, Nan, Chiang Rai, Chiang Mai, Lamphun and Mae Hong Son. In B.E.2518 (A.D. 1975) the Royal Decree Organizing Royal Irrigation Department, Ministry of Agriculture and Cooperatives defined to classify an organization structure of the Payap Irrigation Project to Irrigation Area 1 (Chiang Mai province) and Irrigation Area 2 (Lampang province).