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

18 September 2019

The 12-month forecast through May 2020 indicates water deficits of varying intensity in Indonesia, the tip of peninsular Malaysia, Papua New Guinea, parts of Thailand, and northwestern Cambodia. Deficits will be intense in Java, East Timor, and along the western shore of the Gulf of Papua in Papua New Guinea.

Widespread surpluses are forecast for Myanmar, Laos, Vietnam and eastern Cambodia ranging from moderate to exceptional.

Intense surpluses are forecast in central Philippines around Cebu, and surpluses of lesser intensity are expected in northern Luzon.

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

The forecast through November indicates that surpluses will be the dominant anomaly in Southeast Asia. Surpluses of varying intensity will persist in much of Myanmar and will be especially intense in the west. Moderate to extreme surpluses are forecast for Laos, eastern Cambodia, and Vietnam, though the extent of surplus will diminish somewhat in Vietnam and Cambodia. Surpluses are expected to reach exceptional intensity on the Mekong River through eastern Cambodia. Thailand will transition from intense deficit to surpluses in the north and generally normal conditions in the south. Some moderate to severe deficits will linger in Cambodia north of Tonlé Sap.

Deficits will emerge throughout much of Malaysia and Indonesia and will be exceptional in Malaysia, and severe to extreme in southern Sumatra, Java, and Indonesian Borneo. Deficits in Papua New Guinea will moderate, but some intense deficits will persist on the southwestern shore of the Gulf of Papua. Surpluses will diminish in Papua, Indonesia and some mild deficits will emerge. Surpluses will diminish in the Philippines as well, but severe surpluses will persist in the central islands.

From December 2019 through February 2020, surpluses will persist but downgrade somewhat in Southeast Asia. Conditions of both deficit and surplus (pink/purple) are forecast for western Myanmar as transitions occur. Deficits in northwestern Cambodia will nearly disappear. Conditions in Malaysia will return to normal with some mild surpluses forecast for Malaysian Borneo. Deficits will shrink in Sumatra, and Indonesian Borneo but remain intense, and deficits in Java and Sulawesi will elevate in intensity, with exceptional anomalies forecast. Moderate to severe deficits will increase on New Guinea, particularly in Papua New Guinea. Surpluses in the central Philippines are expected to disappear and some mild deficits will emerge in the central islands and Mindanao.

The forecast for the final months – March through May 2020 – indicates nearly normal conditions in Malaysia and Indonesia, and some deficits in southern New Guinea and the Philippines. Surpluses are forecast in southern Myanmar, northern Laos into Vietnam, and pockets of eastern Cambodia and southern Vietnam but nearly normal conditions elsewhere in Southeast Asia.

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

Flooding in Cambodia this month killed at least seven people, flooded nearly 46,000 houses, and damaged nearly 1,500 hectares (3,700 acres) of crops. Over 700 pigs at a farm in Cambodia’s Preah Vihear Province drowned or broke loose in the flooding.

Floods in northeastern Thailand submerged homes, roads, and bridges, displacing 23,000 people to evacuation shelters amid torrential rainfall starting in late August. Nearly half of the country’s provinces have experienced floods and mudslides, and residents are reportedly frustrated with the government response to the disaster.

Tropical Storm Podul killed at least 16 people and flooded over 240,000 hectares (593,000 acres) of agriculture fields in Thailand in late August. The floods came less than two months after the government’s request that rice farmers delay planting rice due to drought in over a dozen provinces in the same region.

In Laos, Podul killed at least 14 people as it flooded six southern provinces. Hundreds of schools were closed and over 100,000 people displaced. Heavily flooded roads hampered official emergency response by blocking access to some communities.

At least five people were killed when heavy rains flooded northern Vietnam and caused a factory wall to collapse.

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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