The Royal Irrigation Department (RID) on Sunday issued a flood warning for seven provinces in the Chao Phraya River basin as large volumes of water are flowing from the North. Floods, the worst in 50 years, have already caused widespread damage in Chom Thong district of Chiang Mai which has been hit by heavy rain. Some 237 households in seven provinces — Chiang Mai, Chiang Rai, Lamphun, Tak, Lampang, Mae Hong Son and Kanchanaburi — have been badly affected by flooding. The Irrigation Office Region 12 sent a warning letter to seven governors in Chao Phraya basin provinces — Chai Nat, Uthai Than…