Mekong region needs better irrigation

Phu Hiep sluice in Phu Tan District in the Mekong Delta Province of An Giang. The irrigation system in the delta needs improvements to better manage the potential threats posed by climate change. — VNA/VNS Photo Thanh Vu

HA NOI — It was time for the Cuu Long (Mekong) Delta to build a flexible, multi-functional irrigation system to better respond to socio-economic development and the impact of climate change, said Deputy Minister of Agriculture and Rural Development Dao Xuan Hoc.

The ministry was working towards an overall plan to build a strategic irrigation system in response to the significant negative impacts the increasing tidal range has had on agricultural production in a region that is heavily reliant on agriculture, he said.

The Cuu Long Delta is expected to be one of the hardest areas hit by sea level rise because its coastal area lies in the low basin of the Cuu Long River. In some areas it only reaches 20 to 30cm above sea level.

Experts have observed that the length of the Cuu Long Delta flood season has increased from a three-to-five-month period to the current six-to-seven month period. "This has made it nearly impossible for farmers to plant two crops of rice per year without irrigation works," Hoc said.

The highest priority for the irrigation system was to sustain the current rice farming area to ensure food security, said Nguyen Ngoc Anh, head of the Southern Institute for Water Resources Planning, adding that the irrigation system would also be used to support aquaculture because of the significant contributions it makes to the country's exports.

He said the new irrigation system should also help deal with the scarcity of fresh water that has occurred with the onset of saline intrusion. Although the annual surface runoff through the Cuu Long Delta is about 400 billion cubic metre, there is still a severe shortage of freshwater to flush salt out of the rice fields.

Building more reservoirs could also be a good solution to alleviating water scarcity, Anh said.

Experts said the existing irrigation system was only capable of dealing with a sea level rise of under 30cm. New works would focus on reinforcing the sea dikes in closed areas while in the long run, modifications would adapt to the realities of climate change.

Nguyen Huu Nhan from the Institute of Water Resources and Environment said the upgrades should consider and adapt to transportation infrastructure and population growth.

He said one measure was to utilise the criss-crossing myriad of drainage systems to hold the initial freshwater supply by building dams at both ends of the canals and diverting them into reservoirs.

It is estimated that the country's main rice producing region invests VND10 trillion (US$530 million) annually to improve the irrigation system. — VNS