鈥淣OT for a minute,鈥� yells the cop when I ask if I can park my car near to his heavily fortified post beneath the southern wall of Jerusalem鈥檚 Old City. He鈥檚 clearly taking seriously his task of overseeing this high-security project. Above us, Jordanian engineer Raef Nijem negotiates a narrow scaffold in the driving rain. Along with a team of engineers, he is on a mission to investigate and repair a mysterious bulge that has appeared on the side of this historic site.
Anywhere else it would have been merely a technical problem, albeit one that called for a complex and careful solution. But in this volatile region it threatened at one stage to spark serious violence.
The site, known as al-Haram al-Sharif to Muslims and the Temple Mount to Jews and Christians, is a 15-hectare walled plateau. It stands on the site of the first Jewish temple, built by King Solomon almost 3000 years ago. Within the walls stands the Dome of the Rock, a shrine built by Muslim Caliphs in the 7th century to mark the place where the Prophet Mohammed rose to heaven. To one side is the famous Wailing Wall, or Western Wall, which is the most holy place in the world to Jews since it survived Roman destruction of the second temple in AD 70.
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Control of the mount is a burning issue in the Israeli-Palestinian conflict. Israel took control of the Old City during the six-day war in 1967. But the Palestinian Islamic authorities, known as the Waqf, continue to exercise civilian control over the top of the plateau, where thousands of Muslims visit daily for school or prayer.
Last year there were fears of riots when engineers from the Israeli Antiquities Authority (IAA) warned a section of the Temple Mount was on the brink of collapse. They said that a bulge in the towering wall (see Graphic) on the southern side had moved outwards by about 5 millimetres in the past year and could eventually give way 鈥� a claim that is at odds with the Waqf鈥檚 assessment of the problem.
With hundreds of thousands of Muslim worshippers expected at the site for Ramadan in November, Israeli officials and prime minister Ariel Sharon met IAA engineers in late September to draft plans for a worst-case scenario. On the other side of the bulging wall is an underground structure called Solomon鈥檚 Stables, home to a second mosque, the bustling al-Marwani Oratory. If the outer wall collapsed, the fear was that its floor or ceiling could cave in, harming worshippers.
Even just a few rocks falling out of the wall could spark fighting in Jerusalem as both sides vie for control of the situation. A security official, quoted in the Israeli tabloid Ma鈥檃riv last September, said that a collapse during Ramadan could trigger a third world war.
Sharon called the security meeting after an open letter from 21 Israeli archaeologists warning of an impending 鈥済rave tragedy鈥�. But engineers employed by the Waqf described the bulge as a cosmetic problem and suggested that Israeli concern was a cover for an agenda to control the mount. 鈥淭he goal is control,鈥� says Isam Awad, the Waqf鈥檚 head engineer.
Against this background, it has taken more than a year of political wrangling for the two sides to agree on a compromise. Nijem and his team were finally charged with the role of carrying out an impartial investigation, to find out what, if anything, is wrong with the wall, and to decide what to do about it.
I first met Nijem this year, on a chilly January night in the Arab half of the city. He is a soft-spoken man who enjoys reminiscing about his childhood in Jerusalem in the 1940s. He recalls passing through the buildings atop al-Haram al-Sharif after school, praying at the mosques and relaxing in the gardens. The war that preceded the setting up of the state of Israel in 1948 led to the division of Jerusalem into East and West. Nijem moved to Cairo, Egypt, where he earned a degree in engineering, and then to Amman, Jordan, where he took a job with the Jordanian Construction Committee. From there he has led previous restoration efforts at the Dome of the Rock and the al-Aqsa Mosques.
鈥淓ach stone in this city can talk history,鈥� he says. But tonight, we try to avoid archaeology 鈥� akin to politics around here 鈥� and stick to engineering. He grabs my pen and sketches the southern wall. He shows me that when his team first arrived in October, they found a bulge roughly 33 metres across, 11 metres high, and sticking out by about 40 centimetres. There was no agreement on how it had got there. The bulge is mentioned in a 1974 document and seen in a grainy photograph, but it is not clear how big it was then. Archaeologists from both sides say they have known about the bulge for years, but they think it used to be smaller.
All we know for certain about the progress of the bulge, says Nijem, diplomatically, is that it has moved by at least the 5 millimetres that the IAA engineers measured in the last year. 鈥淣o one knows when the bulge first appeared.鈥� To find out what was causing the problem, the team took five core samples straight through the 2-metre-thick wall, at points in and around the bulge. Like most Roman walls, the southern wall of the Temple Mount is built from two layers of carefully cut and mortared limestone blocks with a filling of debris and lime-based mortar in between (see Graphic).
Walls like this are known to deteriorate as a result of repeated cycles of heating and cooling that make the outer layers expand and contract at a different rate to the core mortar. This stresses and breaks the bonds between the blocks and the core mortar, causing the outer walls to separate from the core. Sometimes, blocks in the outer walls fall out, but if the whole structure remains well glued together it may bulge outwards instead. Outside experts say this is a common explanation for ancient wall failure, but the investigation of Nijem鈥檚 team pointed to a more substantial problem. Two samples revealed voids of 20 to 40 centimetres between the two outer walls 鈥� voids that should have been packed full of lime. Years of temperature variation cannot explain this erosion. In fact the presence of voids suggests that water has been seeping into the wall and washing away the mortar.
Fritz Wenzel, an engineer at the University of Karlsruhe in Germany, has rescued a number of similar ancient Roman walls. He agrees that damage most often stems from the infiltration of rainwater over the centuries. In the ruins of the Roman city of Pergamon in Turkey in the early 1990s, Wenzel saw hundreds of square metres of a 12-metre-high wall bulge out and collapse in just a few years following centuries of serious water decay.
But according to Nijem, even a localised collapse of the bulge in the al-Haram al-Sharif wall would not be a major disaster for the structure as a whole. If a section of the outer wall itself buckles, the inner wall sitting 2 metres inside it should still hold, buttressed by the stones or earth beneath.
The Israelis saw it differently. They worried about a worst-case scenario in which there is enough intact mortar between the two walls to cause the inner wall to move with the outer one. This movement, they suggested, could pull out the floor or the roof of the underground al-Marwani Oratory.
Nijem does not think this will happen because the outer and inner walls are not directly connected to the mosque structures. However his formal report does not include a detailed analysis of the forces. It is possible that the inner and outer walls are supporting the mosque structures by their weight.
The cause of the water infiltration is just as unclear. Rain could easily filter through cracks in the wall behind the bulge. In his report, Nijem writes that work planned on the roof of Solomon鈥檚 Stables, close to the wall, should correct any slope towards the external wall, and ensure that any water that collects there will be diverted into drainage pipes. But Nijem will not comment directly on whether there is currently a drainage problem here.
The plan Nijem recommended in October 2002 was to replace the missing mortar with a stronger modern grout. The standard procedure when injecting grout is to first brace the bulging wall with steel pins, to ensure it does not give way during the process. But when I am there in January, Nijem doesn鈥檛 bother. Asked about the risk of a breach while his team works several storeys above ground, Nijem simply shrugs and says that he is using a very quick-setting cement, more usually used in mineshafts than restoration. It seems a fitting metaphor for the need to move quickly before the fragile political agreement collapses.
As the rain comes down on the second day of the injections, he directs a team in the drilling of holes below the bulge. The workers mix and inject concrete grout through a tube, raising and lowering a funnel to maintain pressure. Over the course of 12 days, the team injects 9 tonnes of grout behind the bulge. When it is done, they replace the stones in the outer wall with thinner limestone tiles, effectively smoothing the area out.
Yet just as Nijem is completing his work, controversy has erupted. Restoration experts tend not to believe that stronger is necessarily better. Preservation architect Gustavo Araoz, executive director of the US Committee of the International Council on Monuments and Sites, says concrete contains a high concentration of soluble salts. These can be picked up in water passing through and deposited elsewhere in the pores of stones, eventually cracking them as they grow. 鈥淲e try to use grouts that are compatible with the existing mortar,鈥� he says.
Araoz and others also worry about concrete鈥檚 impermeability to water. If water enters the wall, it will be channelled around the concrete so that there is a higher water flow through other sections of mortar. These could give way quicker than they would have done. A limestone mortar would drain more efficiently and last for centuries. Wenzel says his choice would have been 鈥渁 custom mixture鈥� of lime made to match the wall鈥檚 ancient mortar.
Nijem, however, is an engineer, not a conservator, and the Israeli officials and the Waqf are both, so far, satisfied with his work. After the strife of the past few months, the sheer strength of the material and the fact that it dries fast are the most important aspects to them. 鈥淲hen this wall was built they only had lime. Thank God we have concrete today,鈥� says Nijem.
In fact, violence, not water infiltration, is the greatest threat to Temple Mount, and in this regard Nijem鈥檚 work is a success. Even given the conservation concerns, the best solution may be for the work to fade into the forgotten history of the facade, joining a stony patchwork of quick fixes from centuries past.