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Rising Water Table Threatens Egypt's Monuments

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  • Djehuti Sundaka
    http://news.nationalgeographic.com/news/2002/05/0531_020531_TVwatertable.html Rising Water Table Threatens Egypt s Monuments Chad Cohen National Geographic
    Message 1 of 1 , Jun 1, 2002
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      http://news.nationalgeographic.com/news/2002/05/0531_020531_TVwatertable.html

      Rising Water Table Threatens Egypt's Monuments

      Chad Cohen
      National Geographic Today
      May 31, 2002

      In the crowded, garbage-strewn alleys and market
      streets of Mataraya, one of Cairo's poorest and
      busiest neighborhoods, lies one of Egypt's most
      sacred sites—Ancient Heliopolis. The city and
      other archaeological treasures in Northern Egypt
      are under serious threat from forces above the
      ground, but perhaps even more from below.

      A leaking sewage system, exacerbated by a rising
      population, has caused the water table—the upper
      level of groundwater—to rise and threaten to turn
      the ancient tombs and temples to dust, said Zahi
      Hawass, National Geographic
      Explorer-in-Residence and Secretary General of
      Egypt's Supreme Council of Antiquities.

      "The water table brings salt, and this salt damages
      the
      limestone—it turns the limestone to a powder,"
      Hawass
      said.

      Heliopolis dates back 6,000 years. It was the first
      great
      priestly city of Egypt. It is where the sun god Ra
      had his
      temple, where great scholars first invented the
      obelisk and
      the solar calendar, and where the legendary phoenix
      set
      itself on fire and rose from its own ashes.

      But Heliopolis is destined to join the desert sands
      if the
      salty waters are not stopped. Hawass has proposed
      building a new sewage system just for this area.

      In addition to faulty sewers, Richard Stephenson, a

      professor of civil engineering at University of
      Missouri-Rolla, hypothesizes that the Aswan Dam
      also
      contributes to the rising water table. It enables
      farmers to
      irrigate year-round and may also cause a build-up
      of salt.

      The Nile Plateau was originally a seabed, and the
      sands
      and soil are naturally salty. Before the dam was
      built in the
      1960s, the annual Nile floods would wash the salt
      into the
      Mediterranean. Now it prevents flooding, allowing
      natural
      and fertilizer salts to accumulate, says
      Stephenson, who is
      collaborating with Egypt's National Research
      Institute of
      Astronomy and Geophysics to investigate Luxor's
      disintegrating monuments.

      The pore structure of the soil encourages "strong
      capillary
      action," Stephenson said, which draws the salty
      water to
      the surface and into the porous sandstone
      foundations of
      the monuments. The dry desert heat then causes the
      water
      in the stones to evaporate, leaving behind "salt
      crystals
      that cause the sandstone to split, flake and
      crack,"
      Stephenson said.

      Last July, while in Luxor, Stephenson found white
      salt
      deposits on the foundation stone of temples in
      Luxor.

      Possible solutions include installing wells to
      lower the
      water table, replacing foundation stones with less
      porous
      material, and injecting chemical sealant between
      structures
      and the soil to create water barriers—all of which
      are
      tremendously expensive and risk damaging the
      monuments.

      When archaeologists discovered a 2,500-year-old
      tomb
      of a palace worker in Mataraya, it was soaking in
      sewage.
      The water was seeping through the exterior
      limestone and
      causing the precious hieroglyphs to disintegrate.
      Hawass
      says that for a tomb its size, it is one of the
      most
      beautifully decorated in all of Egypt.

      In a race against time, Hawass and colleagues
      dismantled
      the tomb, numbered, labeled, and treated the
      blocks, and
      restored the drawings.

      The restoration was completed earlier this month
      and the
      tomb now sits on a concrete base in a dry area well
      above
      the water table. "If we had waited more than one
      month,
      this tomb could have been gone."

      It's not just small tombs that could crumble to
      dust.
      Hawass first realized how serious a threat the
      rising water
      levels were to Egypt's monuments when water crept
      to
      within two feet of the great sphinx of Giza.

      To rescue it, a massive three-year project to build
      sewage
      systems in surrounding villages caused the water
      level to
      drop to about 27 feet (8 meters) below the surface.

      But rising water is riddling the whole of Egypt.
      And
      nowhere is the problem more severe than in northern

      Egypt, where the Nile branches off into the delta
      before
      emptying into the Mediterranean.

      In Zagazig, the site of another once great temple
      about 50
      miles (80 kilometers) north of Cairo, workers
      recently
      discovered an 11-ton (10-metric-ton),
      well-preserved
      head, most likely of queen Nefertari, wife of
      Pharaoh
      Ramses II, who ruled about 3,300 years ago. The
      find is
      special because the artifacts in the north don't
      usually fare
      as well as the ones in the south, which has a much
      drier
      climate.

      Hawass said Zagazig is just one of hundreds of
      sites in the
      delta, and he's convinced this area still holds
      many more
      treasures.

      "But I need the help of foreign expeditions,"
      Hawass said.
      "Therefore I'm going to direct and make rules that
      any
      new expedition [Egyptian or foreign] that wants to
      come
      and work in Egypt should work in the Delta to save
      the
      monuments before they are destroyed by the water
      table."

      Building a sewage system for the entire Delta is
      impractical, says Hawass. The only way to save the
      monuments is to excavate and remove them from
      danger.
      "You have to start working right now," Hawass said.

      With help, like that mythical phoenix, Egypt's
      ancient
      mysteries will also rise, not from fire, but from
      water.
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