They said the acceleration of water flow without causing floods to low-lying areas along the canals will provide the basis for a water management system.
Royol Chitdorn, director of the Bangkok Drainage Drill Operation Centre, said he was confident the lessons learned from the exercise will enable officials concerned to tackle flood management work more effectively.
"All I can say is that we have obtained enough information to draw up a model of the water flow in the west and east of the capital. It will be a significant tool in the future for the water drainage system in Bangkok," Mr Royol said.
Sluice gates at Khlong Thawi Watthana were opened yesterday afternoon to increase the water flow to 17 cubic metres per second from 10 cu/m per second. The water was then directed through Khlong Bang Phai, Khlong Bang Weg, Khlong Praya Ratchamontri and Khlong Pasicharoen. There were no reports of flooding in low-lying areas.
Mr Royol said 16 water-pushing machines along the canals helped reduced the water level to 20 centimetres above the mean sea level from 30cm.
"Although we had a higher amount of water, the level was still low due to the quick drainage work," he said. "In the future, there will be no need for us to close the sluice gates to prevent flooding. We can just leave them open and let the water flow through quickly."
He said if the water flow through each canal was increased to 45 cu/m per second, it would mean that as much as 3,000 cu/m of water per second would pass into the sea via the Chao Phraya, Bang Prakong and Tha Chin rivers.
Khlong Thawi Watthana was designed to have the capacity to drain 45 cu/m of water per second, but the capacity has been reduced to only 10 cu/m per second because the canal has become narrower over the years.
Meanwhile, Chatchom Chompradist, director of the Water Management Division from the Department of Royal Irrigation, said the centre planned to conduct a similar test on canals in the east of the city tomorrow.
Sucharit Pultanakulwong, chief of the Department of Water Resources Engineering, Chulalongkorn University, said that the drill showed the relevant state agencies including the Bangkok Metropolitan Administration and the Department of Royal Irrigation have cooperated closely in their work.
While the tests showed satisfactory results, more water should have been used. Instead of 17 cu/m. The water volume used during the tests should have been 45 cu/m per second, he said.
Science and Technology Minister Plodprasop Suraswadi said yesterday's tests showed the water flow in the canals has improved by 20% to 30% after a full year of work to repair the sluice gates and the installation of water flow-accelerating devices.
Bangkok Governor Sukhumbhand Paribatra said the drainage tests ran smoothly as none of the seven spots being watched closely for possible flooding during the trials were affected as had been feared.
MR Sukhumbhand, however, said he was more concerned about the next round of drainage tests to be carried out tomorrow in eastern Bangkok where the drainage route runs through several large communities.
The opposition Democrat Party, meanwhile, countered that the measurement of improved water drainage capacity that was seen in the trials yesterday did not represent the actual drainage capacity of the canals in a real-life situation.
Party deputy spokesman Nat Bantadtan said the government needed to ensure that all the seven major locations found to have overflowed with water on the drainage route during last year's floods were completely fixed.