The Royal Irrigation Department has opened all 10 gates of the Mae Soi regulator in Chom Thong to move water down the Ping River after heavy rain in Omkoi and Chom Thong. Officials say the situation is still normal and no flooding has been reported.
Kuekul Manasamphansakul, director of the Chiang Mai Irrigation Project, visited the regulator today (28 September). Mae Soi is the last gate on the Ping, and water passing through it was running at 156.41 cubic metres per second, on its way to Doi Tao Lake and Bhumibol Dam.
He said Omkoi got the worst of the rain. Ban Muser in Mon Jong sub-district recorded 82.5 millimetres, well ahead of Ban Luang in Chom Thong at 30.4 and Pa Pae in Mae Taeng at 29. He ordered gates along the Ping raised enough to handle what is coming from upstream, with Mae Soi fully open to take runoff from the Mae Klang, Khan and Wang streams as they drain into the main river.
The two big dams have room to spare. Mae Ngat Somboon Chon holds 245 million cubic metres, or 93 percent of capacity, leaving space for another 48 million. Mae Kuang Udom Thara is at 186 million, or 71 percent, with 77 million of headroom. The 13 medium reservoirs are at 83 percent and the 116 small ones at 68 percent, both described as good.
In the city, the Ping at the P.1 gauge by Nawarat Bridge stood at 1.12 metres, which is 2.58 metres below the bank and falling. The Mae Taeng and Mae Rim streams were also normal, at under 30 percent of capacity.
Omkoi is the place to watch. Readings there are all still below the banks but rising: 4.79 metres below at the P.64 station, 1.74 at Mae Tom bridge, 3.40 at Phaya Athitrat bridge and 2.26 at Huai Mae Tuen. The Mae Tuen stream at Khu Rak bridge is under watch, though no flooding has been reported.
The department says it will keep monitoring as more rain is forecast, and will announce it immediately if things start to look serious.
