Commentary: Droughts and dams are drying up the Mekong river
Commentary
Commentary
The combination of drought and the construction of dams in China, and now in Laos, has created a new situation in the Mekong Valley, says Milton Osbourne.
Men sit at their collapsed houses damaged by landslide along Mekong river in Can Tho city, Vietnam December 17, 2018. (File photo: REUTERS/Kham)
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CANBERRA: It has been a bad year for the Mekong.
An unusually long period of drought brought water levels to some of the lowest measurements in recent years.
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There are fears that the drought will have a particularly negative effect on the Tonle Sap River, connecting the Mekong to Cambodias Great Lake and which plays a key role in the maturing of the fish stocks on which population of the Lower Mekong Basin depends.
If its normal flood pulse is sharply reduced, minimising the flow of the tributary backwards to the lake, there will be serious negative effects.
RECURRENT DROUGHTS
Upstream from Cambodia, in Laos there have been complaints about declining fish stocks due to the drought.
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Droughts have been a recurrent issue for the Mekong over the centuries, reflected especially in Luang Prabang, Laos, in April 2009, when the section of the riverbed through which water was flowing had been diminished to a width of about 10m.
READ: When the rain doesnt come: Thailand in grip of severe drought as monsoon season fails to deliver
These were compounded by unannounced water releases from Chinas Jinghong dam in southern Yunnan in early July that flooded paddy fields in both Laos and Thailand.
A NEW SITUATION
But there seems little doubt that the combination of drought and the construction of dams in China, and now in Laos, have created a new situation.
And this is reflected in the recent notification that the Jinghong dam will cease to release water for some days while repair works are taking place.
So, on the one hand, a release of water last month took place without proper warning, while on the other a notification that water will be held back are both events over which downstream populations have no control.
Combined with these problems are the reports suggesting that the Xayaburi dam in Laos has affected downstream flows as it tests its operating practices.
Yet again, the issue of who controls the Mekong River is raised by these developments. Its not just melting glaciers that endanger the Mekong and its region.
Chinas 11 dams on the upper reaches of the river have already had a substantial effect on another aspect of the rivers h
