How will the waters flow?

HAMISH ROBERTSON: Water scarcity is becoming a concern for several countries on the Mekong delta in Southeast Asia.

Scientists say that Vietnam and Cambodia in particular will face food production shortages and environmental damage over the coming years unless steps are taken to solve the problem of over-use of the Mekong river system.

Well, last week saw the launch of an international research effort to discover new ways to produce food using less water in the region.

Our Southeast Asia correspondent Peter Lloyd has been talking to Australian water research expert Dr Robyn Johnston, who works at the Mekong River Commission in Cambodia.

ROBYN JOHNSTON: The Mekong's one of the world's great rivers. The basin covers almost 800,000 square kilometres. The river rises in China in the Tibetan plateau and runs down through Yunnan along the thin portion there, then broadens out to include most of Lao PDR, about a third of Thailand in the north-east, the Isan Plateau, about 85 per cent of Cambodia, and about 20 per cent of Vietnam in the Mekong Delta, but with a small part in the central highlands as well.

PETER LLOYD: Is it in crisis?

ROBYN JOHNSTON: No. It's not in crisis. It's a very big river, there's a lot of water. But it is an area where populations are growing quite rapidly, where there is significant poverty, and there's a very great demand for development, so the river is under increasing pressure.

PETER LLOYD: So what are the problems? What's wrong with the use of the Mekong?

ROBYN JOHNSTON: It's not so much what are the problems as what will the pressure points be in the future, and it's about two things, competition for water between different sectors, and competition for water between different countries. The river has huge flows in the wet season, just enormous, but in the dry season very low flows, and it's those dry season flows which are under the most pressure.

PETER LLOYD: But people have lived here for thousands and thousands of years. What are the pressures that are being brought to bear now?

ROBYN JOHNSTON: Populations have grown quite dramatically. But also for all of the countries of the lower Mekong poverty alleviation is a very significant priority, so it's about not just feeding more people but improving their standard of living, improving their livelihood.

Another issue for the basin is that the Chinese Government has planned a cascade of very large dams in the upper basin in Yunnan, and these will also have an impact on the flow in the river.

Two are very large storage dams. One of these is Yuwan Dam, which is, they've just begun construction on. It will have a gross storage of something like 15 cubic kilometres of water, which is a huge amount of water.

The impact will not be so much about China withholding water, but about a change in the flow of pattern. The reason you have a dam is to collect abundant wet season flows, so it's available for power generation in the dry season. So the impact is likely to be an increase in dry season flows downstream. This can obviously have some advantages if we're running short of dry season water for irrigation then this may be something that the lower basin countries will be happy about.

PETER LLOYD: You've touched on the very sensitive geo-political dimension of this issue, five or six nations share the Mekong area. How much cooperation is there between these nations?

ROBYN JOHNSTON: The lower basin, the four countries of the lower basin, formed the Mekong Committee in the late 50s, and that's now evolved into the Mekong River Commission. China is an observer and has also in the last couple of years agreed to provide hydrological data from their monitoring stations on the river in Yunnan. So there is a degree of cooperation, and I think that is opening up. China are showing interest in the process.

PETER LLOYD: What is the Australian interest in the Mekong?

ROBYN JOHNSTON: The Mekong River Commission was reconstituted in the mid 90s when Cambodia rejoined after a period where it had withdrawn from the process, and at that time the Murray Darling Basin Commission from Australia provided the model for the institutions for the Mekong River Commission, and there's been quite a close collaboration both institutionally and technically between the Murray Darling Basin Commission and the Mekong River Commission over the last ten years. That's ongoing and some of that collaboration is funded by AusAID as part of aid presence in the region.

PETER LLOYD: So there's a bit of Australian know-how in the region?

ROBYN JOHNSTON: There is. There's quite a large contingent of Australians at the Mekong River Commission. We have an input to the Hydrological Monitoring Network, an improvement of that, and there are a couple of senior scientists in fisheries and environment at the Mekong Secretariat in Phnom Phen.

HAMISH ROBERTSON: Australian water research expert Dr Robyn Johnston, who is currently working with the Mekong River Commission in Cambodia. She was talking to our South East Asia correspondent Peter Lloyd.

Reporter: Peter Lloyd