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May 26, 2006
Planning for the desert
Scientists take care of trees in the Negev.
BAILA LAZARUS
It's not often when you talk of water problems in the Negev Desert
that too much water is the challenge, but that's exactly
one of the major issues facing scientists who study the geography
of Israel's desert.
Eilat, being on an alluvial fan, used to be subject to frequent
flooding due to the flash floods that propelled rivers of water
into the city, causing severe damage. After studying the problem,
scientists and engineers determined the water had to be allowed
to flow through the city but only if it was diverted through special,
man-made pathways that would take it out to the sea.
This is just one example of the issues faced by those who make the
study of the Negev Desert their life's work – people such as
Simon Berkowicz, a science researcher who spoke at the Norman Rothstein
Theatre last week on the topic Putting Soul in the Soil: Desert
Science in the Negev.
The event was jointly sponsored by the Canadian Friends of Hebrew
University and the Jewish National Fund of Canada.
Throughout the course of the talk, Berkowicz outlined several different
projects that scientists were working on as they used historical
evidence and current scientific methods to try to bring the desert
to life; or keep it from destroying life.
In the case of Eilat, under the area of "urban hydrology,"
numerous experiments had to be done around the city where test floods
were created in order to examine the water flow. It was only through
these tests that it was determined that the answer was not to try
to divert the water around the city, but to allow it to flow through
Eilat in a controlled manner. Now, however, there is a new danger.
As the water flowing down from surrounding hills brings sediment
with it, that sediment threatens to cover the choral reefs, smothering
the fish habitat and killing it.
Paying tribute to numerous scientists and researchers who have been
studying the Negev for more than half a century, Berkowicz underscored
the importance that studying desert ecosystems has on a global scale.
"There's desertification and land degradation and these are
international issues," said Berkowicz, who hails originally
from Montreal. "In Israel, we have real opportunities to study
this on a small scale and transfer our knowledge to other countries."
Almost a third of the world's land area is arid or semi-arid and
it holds 20 per cent of the world's population, said Berkowicz.
"Now with climate change and increasing use of marginal land,
we'll see more and more problems dealing with land use in these
regions."
Turning to discussions of long-term solutions, Berkowicz presented
several other projects that are under way at the Arid Ecosystems
Research Centre, where he works. It's part of the Jewish National
Fund Nizzana Uri Gordon Centre of the Hebrew University of Jerusalem
and is located on the Israel-Egypt border. Among the studies they've
done are digging mini catchments, in which a tree or several trees
were planted in order to determine how much water was required for
that tree to survive. By digging the catchment to the minimum size
needed to collect just enough water to grow the tree, they ensured
no water wastage.
Scientists also studied Nabatean ruins dating back to the ninth
century BCE, where various structures such as stone mounds, troughs
and terraces had been used to maximize water collection. The terraces
were an ingenious way of ensuring at least a minimum of harvest
every year. The top terrace, for example, was built in a way that
would collect runoff and hold it within its area until it got to
a certain level (the level needed to ensure adequate water for the
farm). Then the water overflowed into the second terrace and farm.
That way, at least one farm always received enough water for harvest.
Another discovery in the area was of living organisms that form
a thick crust on the sand dunes that actually stabilize the dunes.
This crust changed runoff patterns and reduced the amount of water
that seeped into the ground. By studying how this crust was created,
and perhaps duplicating the conditions, scientists may be able to
recreate the runoff patterns in order to collect the maximum amount
of water possible.
Besides runoff from the minute amounts of rain the Negev receives,
water also comes from two other sources – dew and fog –
the only meteorological variables that don't have a standard sensor
for measurement, according to Berkowicz.
By putting up square metre "collectors" and allowing the
fog to simply wash over them, water was condensed on the surface
and then dripped into a container. In certain areas of the desert,
as many as five litres per square metre could be collected in one
night.
These are just a few of the varied projects on which Negev scientists
are working in order to develop areas of the Negev for future settlement,
while not over-developing it.
"There's no contradiction between developing and conservation,"
said Bercowicz, "as long as you do good planning."
Baila Lazarus is a freelance writer, photographer and
illustrator living in Vancouver. Her work can be seen at www.orchiddesigns.net.
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