Five decades later, the now 83-year-old took a plane from Germany to the Dutch city to listen to a Romanian expert on Thailand’s legal team – co-counsel Alina Miron – make a presentation to the court on maps relating to the Preah Vihear land dispute between Cambodia and Thailand.
“I have nothing to do with the hearing this time, but it’s my personal interest, and I’ve come to see my old friend Donald [McRae], who is an expert on mapping and boundaries,” Ackermann told The Nation in an interview outside the courtroom. McRae is a member of the legal team arguing Thailand’s case this time around.
Ackermann briefly chatted with Miron after the hearing on April 17 and told her that he was impressed with her presentation.
During the original case, Ackermann was called to testify as a geological survey expert to brief the ICJ on behalf of Thailand on a field survey of the border area near Preah Vihear Temple he conducted in 1961. He was then only 32 years old.
“I spent many days appearing at the court to tell what we did and explain the watershed,” he said.
Before the 1962 trial, Ackermann had no association with Thailand. He worked at the Institute of International Photogrammetry under the directorship of Prof Willem Schermerhorn, who was also Dean of the International Training Centre for Aerial Survey.
The Thai delegation approached Schermerhorn and gave him aerial photographs of the area near Preah Vihear. The problem is the aerial picture showed nothing much more than forested, mountainous terrain. It did not give a clear idea of the location of the watershed line, which was used in the Franco-Siamese Treaty of 1904 to demarcate the border between the two kingdoms. Schermerhorn gave the photograph to Ackermann, dispatching him to survey the border area near the temple.
Watersheds are areas of land – often ridges or similar features – from which rainwater drains into a river system or a body of water. They often separate two or more water basins.
A 15-strong team, including two officers from the Thai Royal Survey Department, took a train to Ubon Ratchatani before being taken by helicopter to the temple. Ackermann said he was saddened to find out later that the first helicopter sent to take him from Ubon Ratchathani had crashed, killing the pilots.
The team spent two weeks camping at the temple. “At that time, the temple was not very well known. When we were there I rarely saw a visitor. I walked over there every day seeing only the ruins and the trees covering the temple. The temple was a ruin, of course; I think nobody [except] archaeologists knew about it. Nobody lived there,” he said.
From his survey, Ackermann found that the watershed used to establish the boundary line was located at the edge of the cliff atop which the temple sits.
“From the temple, there is a creek. The water runs down there, and I could prove it did not [flow] to the north, but in the [other direction], which [supports the use of] the watershed to make the boundary, and I could [verify] that,” he said.
“And if the argument is based on the watershed, the temple would have stayed with Thailand,” he concluded.
The 1:200,000-scale Dang Rek map produced by France in 1908 indicates a boundary line that does not correspond to the watershed, he said.
“I was not sure whether it was done intentionally by the French. I don’t think they did a survey of the watershed – they just drew the line,” he said.
Ackermann’s survey took place in 1961, more than 50 years after the French map was drawn. It was possible the terrain was altered by a natural disaster. “But this piece of land is very stable, there was no major earthquake, no volcano erupted, no landslide there over the [previous] half century,” he argued.
The French map shows the O’Tasem River as running around Phnom Trap, pushing the boundary line to the North of the temple. Ackermann said the map is wrong on this point.
“O’Tasem is not a river, it’s a small creek. It passes to the south of Phnom Trap, and the watershed goes to the cliff, not the other way,” he said.
“My point of view is based solely on the watershed. As a matter of fact, I would declare the French map was in error on that particular point,” he said.
Maps, watersheds and the boundary line were heavily debated in the court trial 50 years ago, before the ICJ’s 1962 verdict that the temple is situated on territory under the sovereignty of Cambodia. As part of the verdict, Thailand was ordered to withdraw troops from the temple and its “vicinity”.
“That’s a long story but at the end, when the court said, ‘Okay, the watershed is not important anymore,’ the court ruled on this ground, but I saw this as a mistake,” Ackermann said.
The majority of the border between Thailand and Cambodia was delimited more than a century ago, but the boundary near Preah Vihear has yet to be demarcated. The line has not yet been settled. Cambodia, 50 years after the initial judgement, submitted a request for an interpretation of the judgement to define precisely the “vicinity” of the temple.
The name of Prof Schermerhorn and the work of Ackermann were mentioned in the court hearing last week. This time the watershed is no longer an issue, but the boundary of the temple’s vicinity is very much a topic of interest.