Most Israelis and Jordanians are probably unaware that the border between their countries isn't really fixed. The boundary runs directly through the center of the Jordan River, but should the river naturally change its course, so too will the border. It is one of many secrets held by Dr. Haim Srebro, director-general of the Survey of Israel center. For decades, Srebro has been working to give the State of Israel its final borders. When the peace treaties with Egypt and Jordan were signed, Srebro and his Arab counterparts worked behind the scenes, away from the limelight and photo-ops of leaders shaking hands, to draw up some of the Middle East's best-known frontiers. "The Jordan River is constantly changing. If it alters its route naturally, according to our agreement with the Jordanians, we recognize the change. But if the river is redirected artificially and suddenly, the border remains fixed," he said this week, speaking from his spacious office at the Survey of Israel's Tel Aviv headquarters. Since the 1994 peace treaty, Srebro has remained in close touch with his counterpart, Nedal al-Sagarat, of the Royal Jordanian Geographic Center, as issues pertaining to the border continue to arise. "We have a belief in one another, a trust. Each of us knows the other is not going to cheat," he said. The signatures of both men are on the peace treaty. Jordan is now working to develop a luxury complex in Aqaba, complete with hotels and lagoons, funded largely by investment from the Gulf states. The proximity of the development to the Israeli border means that Srebro and Sagarat have had to be called in for advice. "The border fence in this area isn't actually on the border. It's on Israel's side, meaning that the Jordanians could have crossed into Israel without knowing it. That's why they are now building a border fence on their side, too," Srebro explained. DURING THE 1979 peace negotiations with Egypt, Srebro employed the cutting edge technique of using bridged straight aerial photographs (known as orthophotos) to draw up a new border between the countries following Israel's withdrawal from the Sinai Peninsula. "I told the Egyptians, we'll do something together. Let's set up a committee, so that you can check on us and we'll check on you," Srebro recalled. At first, the Americans, who were brokering the talks, handed both sides an abstract map of the new proposed border, but Srebro said the map, which lacked any physical features, was useless. "For the first time in a peace treaty, aerial photographs were used to plan a border," he said. The Egyptians were so pleased with the result that they sent Srebro a statue of Nefertiti to thank him. "I hope all of these lessons we have learned over the years can help in future agreements, like with Lebanon," he said. But the northern frontier with Lebanon and Syria could prove a far more explosive case. Syria and Lebanon both claim a tiny plot of land, known as the Shaba Farms, and Hizbullah uses it as a pretext to continue hostilities. "The Blue Line was marked by the United Nations in 2000. It is almost identical to the 1923 French-British line," Srebro said. When Israel withdrew from southern Lebanon in 2000, it pulled back to the international border stipulated by UN Security Council Resolution 425, Srebro said, but kept the Shaba Farms, which it had captured from Syria in the 1967 Six Day War. "While there were Lebanese civilians in Shaba, it has never been part of Lebanon. It was Syrian," Srebro said. "The old maps show that Shaba is Syrian." Hence, Srebro argued, Hizbullah's claim to it is baseless. Srebro's comments on the line drawn on maps to separate Israel from the West Bank, known as the Green Line, may come as a surprise to many. "There is no Green Line," he said. "There was an armistice agreement between Israel and Jordan in 1949," and the line was drawn to mark the position of the Israeli and Jordanian forces after hostilities ceased. "The Green Line was originally purple," Srebro recalled. "But because revisions and updates to the maps appeared in purple too, the line was switched to green to avoid confusion." In 1967, war between Israel and Jordan resumed, and the armistice line was canceled. The Green Line was given some validity by the 1993 Oslo Accords, but was never treated as an official boundary. In subsequent agreements between Israel and the Palestinian Authority, new maps containing areas of jurisdiction were drawn up by the Survey of Israel. "We did draw up those maps, but I can't discuss our involvement further," Srebro said. Today, the Survey of Israel operates a network of 19 GPS-enabled mapping stations across the country, and has geared its activities to provide the civilian sector with as much useful information as possible. The center has made available an on-line map of the country which contains 120 layers of information, including a map of property boundaries, as well as figures on the local population.