The first wave of water from floods that ravaged the upper northern provinces eight days ago has flowed down the Chao Phraya to Bangkok following an expedited discharge of the water by the Chao Phraya dam barrage in Chai Nat, reports the Bangkok Post.
The barrage gauges and adjusts the water levels in downstream waterways in the Chao Phraya river basin which directly impacts the water situation in the Central Plains provinces and Bangkok.
On Thursday (Aug 29), the barrage released 1,300 cubic metres of water per second, up from 1,100 cubic metres per second.
The swelling of the Yom and Nan rivers, two of four tributaries of the Chao Phraya, has forced the barrage to increase the rate of water discharged.
The discharge level will be maintained at 1,300-1,400 cubic metres of water per second in the coming days as large volumes of water are now passing through, said Thanet Somboon, director of the Bureau of Water Management and Hydrology.
The bureau will be monitoring rainfall patterns in flooded and flood-prone areas during Sept 1-4 when further heavy rains are predicted.
The regions to watch are the lower North and the upper Central Plains provinces.
Mr Thanet said floods pose a major concern for provinces in the upper Central Plains region where rice is in the middle of being harvested.
These floods could wipe out this staple crop and push farmers to economic ruins, he added.
The director said the priority was to first manage the main rivers, which receive excess water.
After the rice harvest is completed, any excess water will be diverted to the empty fields to reduce water flow downstream, he said.
"People shouldn’t panic," he said, adding the surging water is not adversely impacting Bangkok as it is being managed according to the plan.
However, the authorities are bracing for more wet weather. Yesterday, more than 100 millimetres of rain was recorded in each of the upper northern provinces of Chiang Mai, Lamphun, Nan and Phrae, which are all reeling from several days of flooding.
The rainfall is causing water levels to rise in the Yom and Nan river basins.
In Sukhothai, the main sluice gate at Hat Saphan Chan has helped keep levels under control in the Yom River and canals with any overflow being averted in Sri Satchanalai, Sri Samrong and Muang districts.
Provincial authorities in Sukhothai, one of the provinces worst-hit by floods in recent days, have reported more than 70,000 rai of land being inundated. Damage to farmland was most widespread in Sawankhalok district.
Water that toppled flood walls has flowed into open fields while excess water from Klong Hok Bat, Klong Yom Nam, the Yom River and the Nan River will be pushed into the vast Bang Rakam field, which has a catchment capacity of up to 62 million cubic metres of water.
The flooded open fields in Sukhothai will then be drained to make room for the impact of more downpours forecast over the next month.
According to the bureau, it may be necessary to siphon water from the Chao Phraya into irrigation canals.
The bureau expects more open fields will be available for water catchment after crop harvesting is finished in the middle of next month in the Central Plains region.
The National Water Command will decide which fields will be opened to take the water.
In Bangkok, governor Chadchart Sittipunt received a donation of 50 sheets of fencing to reinforce the hydro fence and help maintain lower water levels along the Chao Phraya.
Meanwhile, the flooding has forced the closure of five state-run clinics in Phrae, said Public Health Minister Somsak Thepsutin.
They are expected to reopen on Sept 2.