DON SAHONG, LAOS —
Editor’s note: Laos is moving ahead with a contentious Don Sahong dam project just a few kilometers above Cambodia, despite misgivings from Mekong River countries and environmental groups. Lao officials maintain they have performed the requisite studies and are sure the environmental and ecological damage from the dam will be manageable. VOA Khmer’s Say Mony interviewed Mega First Corporation’s senior environmental manager, Peter Hawkins, during a field visit to the project site in December.
You mentioned in your presentation that the Don Sahong dam would have no significant impact on downstream Cambodia and Vietnam and upstream Thailand. But these countries have expressed their concerns over impacts of the dam project you are developing, especially on sediment and fish migration. How would you respond to those concerns?
I’ve read in the press that people downstream have many concerns. For example, in Vietnam, I read that people are concerned that this project would affect the amount of sediment that is being transported down into the delta, that the project would change the flow pattern in the Mekong River and cause an increase in salinization. And in the past there has been salinity increase in the Mekong Delta. So these are two issues that particularly the Vietnamese press has been publicizing, and they have been relating those to this particular project.
Now, as I have said today, that those concerns are not warranted; they are not real. The reason is this project in the scale of hydro development in this Mekong basin, this project is tiny; it’s tiny, very small, compared to other major dams upstream in Laos and particularly in China and I have shown today some data to demonstrate that in the last four years, two Chinese dams have doubled the amount of water that is being stored and available for release.
Now in hydropower reservoir risk assessment, size is almost everything. The bigger the dam, the bigger the reservoir and the more likely this is to trap sediment, the more likely this is to change the water quality. Definitely it will change the flow pattern if you store a very large volume of water.
This project, the storage is called a hedge pond, it’s a tiny volume. It’s 27,000 cubic meters. Now the storage in the basin is now 46 cubic kilometers of water. So, this is .01 percent of that storage represented by this project.
Those two Chinese dams? They represent 23 cubic kilometers, half the storage in the last four years being added.
I understand that there’re concerns, but I think those concerns coming from Vietnam are really about Chinese dams. They’re misplaced if they think that this project is causing those problems, salinization or sediment trapping, because it’s not. It cannot because it’s too small.
There is one concern which has been expressed by the people in Cambodia and by the people in Vietnam about fish passage. And this concern comes from work that was done in the 1990s by Dr. Ian Baird, who actually lived here in this area, downstream from us, at the village called Han Kong. He lived there for five years. And what he did was observe the fishermen, observe what they did, what fish they caught and how they caught them. And he wrote a number of scientific papers about that. And one of the papers that he produced has now got a famous quote in it which says that Hou Sahong is the only passage available all year round for upstream migrating fish. So his argument has been that it’s the vital channel for fish migration. And that particular sentence has been taken from his report in 1995 and repeated by many, many other people since then by the press, by the NGOs even by scientists.
My concern was that the data to support that argument was not scientific. There was no data about fish catch, fish passage through the channel. There was no quantitative measurements of how many fish enter Hou Xang Pheuak and this Hou Sadam and how many enter and how many exit.
You need to record the success of fish passage. You need to know how many fish are coming in and how many are going out at the other end.
But people are also criticizing your reports, saying there is no transboundary impact assessment in them.
Well, I have explained the major transboundary impacts, downstream impacts from hydropower project, they have to do with changing water quality, trapping of sediment, changing of flow behavior, displacing people, by downing impacts by releases.
This project does not do any of those things. It’s too small. It does not change the flow pattern downstream. It does not trap sediment; it does not change water quality. So those concerns, they’re baseless; there’s no justification for it. There’s ample scientific evidence to support what I’m saying. That leaves one question. Will there be a downstream and upstream impact of fish migration? And I’m trying to answer to that by saying that we are now for the first time collecting evidence; we’re collecting the baseline, which is based on rigorous scientific monitoring of fish passage in these channels. And we are seeing that this channel, for example, is quite successful as a fish passage.
Now Ian Baird wrote in 1995 that this passage, Hou Sadam, was an important passage for migrating fish at some time of the year. And that Xang Pheuak, the other channel this project is targeting as a passage to be improved, Ian Baird also wrote, was an important passage at certain time of the year. The question I asked this morning was why?
Why was it important at a certain time of the year and not at the other time?
Now, Ian Baird did not present any data on flow in those channels at the time he was collecting data from the fishermen or listening to their stories. So what I showed you this morning was our simulation of what the flow would have been in the Xam Pheouk and Sahong in those years he was here in 1992, 1993, 1994, 1995. In those years, the water in Xang Pheuak and Sahong were very low in the dry season.
In Xang Pheuak, it was predicted that the daily flow could be less than 10 cubic meters per second. Now, 20 years later, it’s a different world. The difference is because of the Chinese dams. Those two major upstream dams which are trapping an additional 23 cubic kilometers of water. They are trapping in the raining season and they are releasing it in the dry season. So, the observation we have now show the daily flow in Xang Pheuak are nearly 10 times. The minimum daily flows that we have now are 10 times what they were when Ian Baird was collecting data from the fishermen. So, we have water now that was not available before in the dry season. So, Xang Pheuak was a successful fish passage in the wet season and the swallow season but not at the peak in the dry season because it was dry. There’s no water for the fish to swim.
But, because of the Chinese dams and because of the other hydropower development as well, don’t forget, there has been another 25 percent has been added since Ian Baird’s time by dams in Laos, by dams in Thailand. So all of that water together can contribute to the opportunities to improve fish passage in Xang Pheuak without this project doing anything. That water is available now that wasn’t there before.
But the project can do other things to improve fish passage. The way that can be done is simple modification of two channels like this one. Slightly deepening of the entrance to increase the flow and looking at the hydraulic conditions of where points of passage that fish are difficult to pass. And modify those conditions to make it easier. These are not difficult things to achieve.
The first thing is the survey to find out where those hydraulic barriers are the modification to the rocks, to the channels to improve the passage.
But, there is another thing as well. And that is human activities. That’s the fishermen catching the fish. And in this area, it’s the hotspot for fishing. It’s very easy to catch migrating fish downstream of these waterfalls during the migration season. And the traps they use are very expensive at the scale of this village, they are quite expensive, but also illegal.
So the company’s plan is to provide those fishermen an alternative livelihood, a different way to make money, so that they don’t rely on catching fish that are swimming upstream to spawn. These fish are coming upstream to spawn, upstream of Khone falls, and they are going back downstream into Cambodia to hatch and grow into large fish.
Now, this project can have no control over what’s happening in Cambodia to those fish during their life cycle. An example is from here about 100 kilometers away you have a dam being constructed as we speak with the Lower Sesan 2. This dam is documented to reduce the productivity of fish in the basin by 10 percent. There is no information available at all about what the dam developer is doing to improve fish passage around that dam. It would probably be a difficult task. No one knows. It’s not available to the Cambodian people. It’s not available to us, the developer here.
But you’ve seen today that we’re very free in exchanging information that we are collecting, the methods we are developing and the fish passage technologies that we are employing. So people can see what we are doing and what we intend to do in the future.
The company has given the assurances that it will continue to modify the channels in this area to improve them until the success of fish passage through this area is the same as it was Hou Sahong was operating. And actually the company aims to improve that.
When will the construction of the dam start?
The construction cannot start until the concession agreement between the developer and the government of Laos is signed. And that has not yet happened.
Will it happen early this year?
I do not know. I have some experience working in Laos. And I can tell you that sometimes the processes of the government of Laos are quite slow. They are definitely unpredictable. So I would not assume that I can tell you when they are going to make this decision. But I can tell you that after the decision is made, the construction is expected to last something like four-and-a-half to five years to reach the completion and for the project to start operating.