Southeast Asia & the Pacific: Water deficits to emerge in northern Vietnam; surpluses persist in Phetchaburi, Thailand

26 June 2017

The Big Picture
The 12-month composite (below) indicates some areas of severe deficits in central Cambodia, just north of Kuala Lumpur in Malaysia, near Medan in northern Sumatra and across central Papua New Guinea. In Indonesia, moderate deficits are forecast over southern Borneo, western and central Sulawesi, as well as the island of Java.

Exceptional surpluses are indicated for southeast Sulawesi and West Papua. More moderate surpluses are forecast for Mindanao in the Philippines, portions of northern Borneo and select regions in Laos, Vietnam, and Myanmar.

Impacts
Heavy rainfall has produced flooding in several provinces of the Philippines, including Cotabato and Maguindanao, with over 200,000 people affected since early May. Flooding forced the closing of 30 schools and damaged houses and cropland.

Flooding in Riau Province, Indonesia submerged 800 homes; 526 families were affected by flooding in North Sumatra Province.

Pounding rain flooded Bangkok, Thailand, as well, closing schools, major roads and intersections, and poured into homes along the swollen Lat Phrao canal.

Malaysian Borneo and Ho Chi Minh City, Vietnam, have also experienced recent flooding. A US$440 million project to control flooding in Ho Chi Minh City is progressing at a slower pace than planned, and the city has targeted an additional US$21 million to prevent flooding in the outlying district of Binh Thanh.

Well over a year after El Niño-fueled fire burned through nearly a third of the area around Cambodia's Tonlé Sap Lake, a UNESCO designated conservation area, the rich wetland that provides breeding grounds for freshwater fish is not returning to its former state. Historically, the Tonlé Sap fishery accounts for 75 percent of the Kingdom’s protein intake, according to the International Union for the Conservation of Nature (IUCN). But the fish habitat has not returned, and without fish as income and food source villagers have begun cultivating crops on the land.

Forecast Breakdown
The 3-month maps (below) show the evolving conditions in more detail.

Widespread exceptional surpluses observed over most of the region will moderate in the June – August period. Thailand’s Phetchaburi Province may continue to experience exceptional surpluses over the next three months. Central Vietnam is also likely to continue with surpluses though deficit conditions are also indicated for that region and time period.

Conditions evolve in the September-November forecast period with moderate deficits indicated across most of the region. Deficits may intensify over mainland Malaysia in the Dec-Feb 2018 period.

(It should be noted that forecast skill declines with longer lead times.)