When will this year’s Tonle Sap reversal occur?

The Tonle Sap Lake must reverse to drive Mekong economies and the tens of millions living in the basin. This year drought severely delays the reversal for millions.

Even with rains and flooding in August throughout the Mekong Basin, flow volume is not yet high enough to bring about the annual reversal and flooding of the TonleSap Lake. Compare these images from 8.15.2019 (drought) and 8.15.2017 (healthy lake).

All eyes should be on the Tonle Sap River and where it flows into the Mekong Mainstream at Phnom Penh. If that river reverses direction in the next 3-4 weeks, then the Mekong’s heart will beat again. If it doesn’t, the Mekong will likely flatline putting the main source of protein for 15 million Cambodians at risk. The annual reversal which causes the Tonle Sap Lake to expand 5X its dry season area is necessary to produce Cambodia’s annual Tonle Sap fish catch of 500,000 tons – the world’s largest freshwater catch.

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