There is also pressure on fish stocks, with shortages leading to steadily rising prices. Warnings about the downstream impact of dams, particularly those built by China, have been growing and there are now calls for ASEAN - a body frequently criticised for inaction - to take a stand. The issue was raised at talks in the Cambodian capital Phnom Penh, organised by the Melbourne University based Asialink, and was also an opportunity to assess Cambodia's overall progress.
Presenter: Linda Mottram
MOTTRAM: Though still deeply impoverished, Cambodia has without doubt been transformed from the horrors of the Khmer Rouge, through a difficult and volatile peace process and into a more hopeful future based on broadly democratic principles. Former Australian foreign minister, Gareth Evans, was a key playing in the peace process.
EVANS: You do get a sense that things are coming together. I mean, the physical fabric of the place is impressive. I am back here now for the first time in eight or nine years and you can sense the difference, the number of high rise buildings, just the sense of prosperity that's out there, and the growth rates reflect that, in terms of the formal statistics.
MOTTRAM: Gareth Evans and Australia more broadly are held in genuine affection in Cambodia for their efforts in pulling the country from its dark past. And Cambodia's prime minister, Hun Sen, reflected that at the formal, public opening of the Asialink Conversations.
HUN SEN: I would like to extend a particular heartfelt welcome back to Cambodia to the honourable Professor Gareth Evans.
MOTTRAM: But while Gareth Evans is optimistic for Cambodia, assessing that the proverbial glass is probably more than half full, he also acknowledges there's a way to go on governance, on human rights and, centrally, on the judiciary.
EVANS: Just about everyone acknowledges that that is the totally unfinished business, that it is basically not reliably independent. Take your life in your hands if you go to the judiciary, to the courts, and this is not something that encourages either confidence by ordinary Cambodians in the quality of their own governance or, of course, it doesn't do much to encourage investor confidence in the country.
MOTTRAM: But economic pressures are seen by Professor Evans and other observers as playing a key role in pressing Hun Sen's government to continue reforms. There's also the associated professionalisation of the population. And for all the criticisms of his big man style of government, there is broad acknowledgment that Hun Sen understands that change has to come. He appears to harness anyone with an exceptional level of expertise to an advisory role. And he has moved on some problem areas, closing down gambling operations and enacting anti-corruption measures, even if enforcement is incomplete.
Still some of the particular problems are immense. Take the headline issue of land grabs. Ambassador Pou Sothirak is a former humanitarian coordinator on the Thai-Cambodia border and a former MP and minister in the Cambodian government, who's now on leave from an advisory position to the Cambodian Government, for a stint at the Institute of South East Asian Studies in Singapore.
SOTHIRAK: First of all, it's the exploitation by powerful people and rich business men who go out and buy off land from the poorer ones. I just hope that the poor can have their own land title because land is very important. It is known to be a wealth creation asset for the poor and if one wants to see Cambodia move away from poverty, land issues need to be settled for the sake of the poor.
MOTTRAM: But even if Cambodia's largely rural poor get land title and are rescued from land grabs, their fate could lie elsewhere - to be precise in China, whose dam building activities on the upper Mekong River, to quench its great thirst for energy, have an almost permanent alarm ringing in downstream countries, like Cambodia.
Ambassador Sothirak again.
SOTHIRAK: Many of the Cambodian farmers, they also live on fishing and the price of fish lately has gone up two, three times, because of fish species under threat now because of this dam building and some places are now dried up, so no water for irrigation, so the crop cannot survive. So, this effect we have now seen it happening in Cambodia. My view about how to go about it if one country wants to exploit common natural resources, one country has to ensure that this type of development will not have drastic effects on the environment, on the one hand, and on livelihood, on the other hand.
MOTTRAM: Others at the Asialink Conversations called for ASEAN to take a stand, though its reputation for more talk than action precedes it.
Ambassador Sothirak puts it this way.
SOTHIRAK: Can China live without the Mekong River? In my opinion, China can live without the Mekong River. But if you ask the same question of Cambodia, I don't think we can live without the Mekong River.