Southeast Asia & the Pacific: Water deficits will shrink; surpluses increase

22 May 2020

THE BIG PICTURE
The 12-month forecast through January 2021 indicates moderate water deficits in central and western Thailand and moderate surpluses in Vietnam’s Central Highlands. Some small pockets of surplus are expected in west-central Myanmar and mixed conditions in the south. Nearly normal conditions are forecast for the remainder of Southeast Asia.

ISciences_Southeast_Asia_Composite_Adjusted_202002-202101_12mo_twitter.png

The Philippines, too, can expect nearly normal water conditions.

Surpluses will be the predominant anomaly in Indonesia and will reach exceptional intensity in Java, Flores Island, and New Guinea’s Bird’s Head Peninsula (Doberai Peninsula). Surpluses of varying intensity are forecast for Sumatra’s western coast, while pockets of primarily moderate deficit are expected in the northeast. Surpluses of varying intensity are also forecast for much of Borneo, eastern Sulawesi and many of the smaller islands, and Papua, Indonesia. Intense deficits are expected around the western shore of the Gulf of Papua in Papua New Guinea, some moderate deficits in the southeast, and surpluses in the country’s Western Highlands region.

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

The forecast through July indicates that deficits will shrink and downgrade in the region, leaving surpluses as the predominant anomaly, particularly in Indonesia. In Southeast Asia, deficits in Thailand and Cambodia will shrink and downgrade, leaving primarily mild anomalies. Widespread surpluses in Myanmar will nearly disappear, as will anomalies in much of Laos. Some moderate to severe surpluses are forecast for northeastern Laos and through northern Vietnam; moderate surpluses will persist in Vietnam’s Central Highlands. In the Philippines, moderate deficits will increase on Mindanao and scattered, relatively mild deficits are forecast for the remainder of the nation, transitioning from surplus in the northern regions. Surpluses of varying intensity are forecast for many parts of Indonesia and will be extreme to exceptional in southwestern Sumatra, a few pockets of Java, and the eastern Bird’s Head Peninsula in New Guinea. Deficits in Papua New Guinea around the western shore of the Gulf of Papua will downgrade but will be severe to extreme, and moderate surpluses are forecast for the nation’s Western Highlands region.

ISciences_Southeast_Asia_Composite_Adjusted_202002-202101_3mo_twitter.png

From August through October, water conditions in many parts of Southeast Asia will normalize, though moderate deficits will emerge in western Thailand and Vietnam’s northwestern corner, and some surpluses will persist in Vietnam’s Central Highlands. Conditions in the Philippines will be nearly normal with some surpluses emerging in the extreme northeastern and southeastern points of Mindanao. Surpluses, primarily moderate, are forecast throughout Borneo and much of the remainder of Indonesia, increasing in Java, many small islands, and in New Guinea but decreasing in northern and central Sumatra. Exceptional deficits will emerge in the western half of Timor Island. Deficits will shrink around the Gulf of Papua.

The forecast for the final months – November through January – indicates that deficits will increase in Southeast Asia and surpluses will decrease in Indonesia.

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

IMPACTS
A state of emergency has been declared in drought-stricken Binh Thuan Province on Vietnam’s southeastern coast. Rivers have dried up, groundwater levels have dropped, and saltwater has entered wells. The region’s irrigation system has only 11 percent of capacity, reducing agricultural productivity, and 97,000 residents are facing shortages of water for daily use.

Southwest of Bihn Thuan, the largest reservoir in the Mekong Delta has dried out due to drought and saltwater intrusion.

Drought in Mindanao, Philippines is among the culprits in what is projected to be a 40 percent drop in banana exports this year. Dry conditions along with disease have affected up to 40,000 hectares. Philippines is among the world’s top banana producing nations.

Following heavy rainfall, flooding and landslides affected 12,000 people in Sumatra, Indonesia in early May, with floodwaters reaching 2.5 meters (8 feet). Flooding was reported in Aceh in northern Sumatra, damaging several schools, and in Central Kalimantan on Borneo. Java, too, suffered flooding when the Cikarang River overflowed.

NOTE ON ADMINISTRATIVE BOUNDARIES
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.

Subscribe to our monthly Water Watch List

Search blog categories

Search blog tags