Salinity is killing the trees of this farmer in Go Dat District, Kien Giang Province. The Mekong Delta is seriously short of fresh water this dry season.Saturday, March 14, 2009
Thanh Nien News
The Mekong Delta is at risk of losing its eminence as Vietnam’s rice bowl as river levels drop from upstream irrigation and sea water encroaches farther inland.
Drying rivers and increasing encroachment of seawater are leaving farmers in the Mekong
Delta short of freshwater for their crops, yet no solution has been advanced for reversing the situation.
Last month the water was brackish up to 50 kilometers upstream in some of the delta’s many channels, the Southern Institute of Water Resources Research says in a recent report.
With two or three months left to go before the wet season arrives, the encroachment could extend up to 70 kilometers inland in places before the rain arrives.
While the salinity can be as low as one percent, it can be as high as 25 percent, the institute says.
Turning more land into paddy fields upstream of Vietnam and taking more water from the river to irrigate the extra crops has had a profound impact on the Mekong.
Since eight years ago, the highest level of the Tan Chau River in An Giang Province has dropped nearly 80 centimeters, a local newspaper reports.
In the past 30 years, the water flow where the Mekong crosses into Vietnam has declined by an estimated 36 percent.
In almost the same period, from 1979 to 2006, the water flow along the delta’s two main channels, the Tien and Hau rivers, declined from 2,500 cubic meters to 1,600 cubic meters per second, the paper says.
Duong Van Ni, director of Can Tho University’s Hoa An Biodiversity Application and Research Center, says the Mekong Delta has 60 percent less naturally wet or moist land outside of the wet season compared to 1968.
“It’s a crisis, this shortage of freshwater in the dry season and the seawater moving farther inland and worsening the salinity,” says Ky Quang Vinh, head of the Can Tho Center for Natural Resources and Environment Observation.
It only takes a saline level of four parts per thousand to kill many freshwater fish, rice and fruits, the Mekong Delta Rice Research Institute says, adding that this year’s summer-autumn crop will begin in drought conditions.
Although the delta’s farmers can turn to hardier crops and livestock for their livelihood, says Ni, it doesn’t change the fact that there is not even enough water for daily household use by the region’s inhabitants.
Because the Hau River is so low in the dry season, like now, Can Tho City’s water treatment plants are getting their water from the river surface, which implies risks of salinity and pollution, according to Ni.
“The water plants do not have an alternative water source,” he says.
The water level has fallen so far that any oil spill or chemical overflow from the factories on the riverbanks will take a considerable time to clean up, he adds.
Groundwater too is at risk of drying up or at least becoming too saline to use because of overuse and misuse, and the experts have warned about this previously.
An international conference on groundwater held in Greece last year reported that groundwater levels had decreased by five to eight meters at some places in the Mekong Delta over the past 10 years.
Contamination of the region’s groundwater is a big problem.
For instance, the residents of Hau Giang Province’s Long My District have been ferrying and trucking in freshwater from elsewhere since their wells turned brackish a little while back.
In Ca Mau, Soc Trang and Bac Lieu provinces, the groundwater is diminishing and what can be retrieved is increasingly saline, the Ministry of Natural Resources and Environment reports.
Worse still, traces of arsenic have been detected in the wells in Dong Thap and Long An provinces.
In excess of one billion liters of groundwater is taken each day from the hundreds of thousands of wells in the region, the ministry says.
Duong Van Ni suggests that, in the absence of proper solutions, the dozen provinces that make up the Mekong Delta build large freshwater reservoirs, while agricultural officials urge farmers to conserve water as much as possible.
Drying rivers and increasing encroachment of seawater are leaving farmers in the Mekong
Delta short of freshwater for their crops, yet no solution has been advanced for reversing the situation.
Last month the water was brackish up to 50 kilometers upstream in some of the delta’s many channels, the Southern Institute of Water Resources Research says in a recent report.
With two or three months left to go before the wet season arrives, the encroachment could extend up to 70 kilometers inland in places before the rain arrives.
While the salinity can be as low as one percent, it can be as high as 25 percent, the institute says.
Turning more land into paddy fields upstream of Vietnam and taking more water from the river to irrigate the extra crops has had a profound impact on the Mekong.
Since eight years ago, the highest level of the Tan Chau River in An Giang Province has dropped nearly 80 centimeters, a local newspaper reports.
In the past 30 years, the water flow where the Mekong crosses into Vietnam has declined by an estimated 36 percent.
In almost the same period, from 1979 to 2006, the water flow along the delta’s two main channels, the Tien and Hau rivers, declined from 2,500 cubic meters to 1,600 cubic meters per second, the paper says.
Duong Van Ni, director of Can Tho University’s Hoa An Biodiversity Application and Research Center, says the Mekong Delta has 60 percent less naturally wet or moist land outside of the wet season compared to 1968.
“It’s a crisis, this shortage of freshwater in the dry season and the seawater moving farther inland and worsening the salinity,” says Ky Quang Vinh, head of the Can Tho Center for Natural Resources and Environment Observation.
It only takes a saline level of four parts per thousand to kill many freshwater fish, rice and fruits, the Mekong Delta Rice Research Institute says, adding that this year’s summer-autumn crop will begin in drought conditions.
Although the delta’s farmers can turn to hardier crops and livestock for their livelihood, says Ni, it doesn’t change the fact that there is not even enough water for daily household use by the region’s inhabitants.
Because the Hau River is so low in the dry season, like now, Can Tho City’s water treatment plants are getting their water from the river surface, which implies risks of salinity and pollution, according to Ni.
“The water plants do not have an alternative water source,” he says.
The water level has fallen so far that any oil spill or chemical overflow from the factories on the riverbanks will take a considerable time to clean up, he adds.
Groundwater too is at risk of drying up or at least becoming too saline to use because of overuse and misuse, and the experts have warned about this previously.
An international conference on groundwater held in Greece last year reported that groundwater levels had decreased by five to eight meters at some places in the Mekong Delta over the past 10 years.
Contamination of the region’s groundwater is a big problem.
For instance, the residents of Hau Giang Province’s Long My District have been ferrying and trucking in freshwater from elsewhere since their wells turned brackish a little while back.
In Ca Mau, Soc Trang and Bac Lieu provinces, the groundwater is diminishing and what can be retrieved is increasingly saline, the Ministry of Natural Resources and Environment reports.
Worse still, traces of arsenic have been detected in the wells in Dong Thap and Long An provinces.
In excess of one billion liters of groundwater is taken each day from the hundreds of thousands of wells in the region, the ministry says.
Duong Van Ni suggests that, in the absence of proper solutions, the dozen provinces that make up the Mekong Delta build large freshwater reservoirs, while agricultural officials urge farmers to conserve water as much as possible.
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