Bangkok tap water may turn brackish as seawater intrudes into Chao Phraya
The Office of National Water Resources (ONWR) is keeping a close watch on the intrusion of seawater into the Chao Phraya River, to the extent that it may affect the production of tap water.
ONWR secretary-general Somkiat Prajamwong said that they have been coordinating with the Royal Irrigation Department and the Electricity Generating Authority of Thailand (EGAT) to increase the release of water from four main reservoirs by about 10 million cubic metres/day until January 5th, in order to flush seawater out of the river.
He admitted, however, that there might not be sufficient flow from the reservoirs, namely Bhumibol, Sirikit, Pasak and Kwae Noi Bamrungdaen, to have the desired effect in late January and February and that this might affect the quality of tap water.
Water is drawn from the Chao Phraya River at Samlae in Pathum Thani province into Klong Prapa for treatment and distributed to consumers in Bangkok and its suburbs.
Informed sources in the ONWR said that the combined volume of usable water in all reservoirs across the country, estimated at 260 billion cubic metres, has been falling steadily since the beginning of this year due to drought, which could be worse than that in 2015. Data from NASA shows that the Earth is experiencing the hottest period in 120 years.
The four main reservoirs currently contain a combined volume of 4.461 billion cubic metres of usable water, but the expected demand for consumption and ecological preservation is estimated at 5 billion cubic metres.
At present, the salinity of tap water is measured at 0.21 grams/litre, which does not yet exceed standard levels. If the salinity exceeds 0.5 grams/litre, the tap water may turn brackish.