Southeast Asia & the Pacific: Water deficits forecast for Malaysia & Indonesia

16 August 2019

The 12-month forecast through April 2020 indicates water deficits throughout most of mainland Thailand, with severe to extreme anomalies in the northwest. Elsewhere in Southeast Asia, surpluses are forecast for Myanmar, northern Laos into northwestern Vietnam, southernmost Laos into Cambodia’s eastern half, and across the border into southern Vietnam. Surpluses will be intense in western and southern Myanmar.

Deficits are forecast for Indonesian Borneo, southern Sumatra, the tip of the Malay Peninsula, Java, Sulawesi, East Timor, Papua New Guinea, and southern Luzon Island, Philippines. Deficits will be moderate to severe overall, but could reach exceptional intensity in eastern Java, pockets of East Timor, and around the Gulf of Papua.

Surpluses are forecast in central Philippines around Cebu and isolated pockets of Indonesia.

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

The forecast through October indicates that deficits in Thailand will shrink and downgrade considerably, leaving a few pockets of moderate to extreme anomalies. Surpluses will shrink and downgrade in Cambodia, Laos, and Vietnam, leaving severe surpluses in northern Laos and moderate anomalies in northwestern Vietnam, Laos’ far south, and from Cambodia’s eastern quarter into Vietnam. Surpluses in Myanmar, however, will remain intense in the west and south, with moderate anomalies in pocket of the north.

Severe deficits will emerge in Borneo, southern Sumatra, Java, and parts of Sulawesi. Extreme to exceptional deficit anomalies are forecast for the southern Malay Peninsula, Singapore, and pockets along Borneo’s northern coast. In Papua New Guinea deficits will shrink and moderate overall. Deficits are also forecast for southern Luzon, Philippines, but surpluses are expected in central Philippines around Cebu.

From November 2019 through January 2020, much of Southeast Asia will normalize, though moderate surpluses will persist in northern Laos and more intense surpluses in western and southern Myanmar. Some moderate surpluses will emerge in northernmost Sumatra. Deficits, primarily moderate, are forecast for southern Sumatra, Java, Indonesian Borneo, Sulawesi, and southern Papua New Guinea. Deficits may be more intense in pockets of western Borneo and eastern Java.

The forecast for the final months – February through April 2020 – indicates nearly normal conditions in much of the region with some deficits in southern Papua New Guinea, moderate surpluses in northern Laos, and some areas of transition in western Myanmar as deficits emerge in areas of prior surplus.

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

[updated 26 Aug 2019]
Flash flooding after heavy rains in Luang Prabang, Myanmar at the end of July affected nearly 400 families in the Nan district. By early August, monsoon rains had displaced over 89,000 people in nine states and regions. And in mid-August, torrential rainfall triggered a massive landslide in southeastern Myanmar, killing at least 59 people. Over 80,000 people across the country have been housed in evacuation centers.

Delayed monsoon rains as well as damming in China and Laos have dropped the Mekong River to its lowest level in 100 years. Rice farmers in Southeast Asia were unable to plant their main crop, raising fears of reduced harvests this fall. The Mekong Basin is home to the largest inland fishery in the world, supporting the livelihoods of over 60 million people. Rice plantings in Laos this year covered less than half of typically-cultivable land due to the basin’s recent drought.

Thai rice export prices rose this month on speculation that the current drought, the country’s worst in nearly ten years, will diminish supply. In July, the Thai federal government asked farmers to delay rice planting, citing concerns over reservoir supplies. By late July, eight Thai provinces were listed as being in a critical water situation, with officials describing it as the worst drought in 50 years in the region. The University of Thai Chamber of Commerce estimated that drought this year has affected 1,300 square kilometers (502 square miles) of farmland, amounting to damages estimated at 10 billion baht (USD $323 million). Sugar futures, too, rose over rising crude prices and drought concerns. Prolonged drought in Vietnam dried up irrigation lakes in Thua Thien-Hue Province, choking 80 hectares (198 acres) of rice and vegetables.

Drought in Indonesia is expected to worsen fires that have burned over 42,000 hectares (104,000 acres) of forest and plantations since January.

Tropical Storm Wipha killed at least 10 people, collapsed 91 homes, and destroyed more than 471 hectares of crops (1164 acres) in northern and north-central Vietnam early this month. In 2018, natural disasters in Vietnam killed 224 people and caused almost 20 trillion Vietnamese dong (USD $859 million) in damages.

There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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Many analyses reported in ISciences-authored blog posts are based on data generated by the ISciences Water Security Indicator Model (WSIM). Other sources, if used, are referenced in footnotes accompanying individual posts. WSIM is a validated capability that produces monthly reports on current and forecast global freshwater surpluses and deficits with lead times of 1-9 months at 0.5°x0.5° resolution. This capability has been in continuous operation since April 2011 and has proven to provide reliable forecasts of emerging water security concerns in that time-frame. WSIM has the ability to assess the impacts of water anomalies on people, agriculture, and electricity generation. Detailed data, customized visualizations, and reports are available for purchase.

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