Å®ÉúСÊÓƵ

While news headlines this past week highlighted flood and devastation on the
Mississippi in the US, Europe has been agonising about the long-term drought
in the Mediterranean (see Focus, this issue). Both catastrophes have their
own timescales, and both inflict devastating human misery.

In an effort to tame great rivers, many have inadvertently been made worse.
For two centuries, engineers have raised the Mississippi’s levees ever
higher to keep it from inundating its natural flood plain. But, with more
than $7 billion spent in the past 60 years, the work has been
largely self-defeating.

The Mississippi’s swamps and flood plains, from Iowa to Louisiana, were once
natural reservoirs, receiving water from rivers when they flood and evening
out the seasonal variation in flow. Raise the levees and the flow in the
river becomes greater during floods, bringing new threats downstream.
Meanwhile, with no water stored on the flood plains, the river’s flows are
ever lower in drought. The Mississippi nearly dried up in the summer of
1988.

An economic assessment of the Mississippi basin by Howard Odum and
colleagues at the University of Florida a couple of years ago called for
renewed inundating of the flood plain. As well alleviating the flooding,
this could restore important benefits – such as a free supply of fertile
silt and better fisheries – which he valued at up to $22 billion per
year. Such a policy is already being considered for the River Rhine where,
as New Å®ÉúСÊÓƵ reported a few weeks go (‘Greenprint for rescuing the
Rhine’, 26 June), dykes have also increased the risk of major floods.

Meanwhile, as the Mediterranean suffers long-term drought, the average flows
in Greece’s largest river, the Acheloos, have fallen by 40 per cent in the
past 30 years – a fact which, as New Å®ÉúСÊÓƵ reported last week, has
escaped the attention of the Greeks as they prepare a large water diversion
project on the river.

But the real threat to the region’s water supplies is profligacy. More than
two-thirds of its water is used to irrigate crops, many of them building up
food mountains within the European Community.

The lesson from the Mississippi and the parched lands of the Mediterranean
is the same: stop blaming nature and start planning water use intelligently.
Or, as Denis Healey once put it in a very different context: ‘If you’re in a
hole, stop digging’.