50 Things That Made The Modern Economy

With Tim Harford

Not far from Cairo stands a remarkable dam, the Sard El-Kafara.

It is more than 100 meters long and 40 meters high and could store about half a million cubic meters of water.

These statistics are modest by modern standards, but the Sard El-Kafara is not a modern dam.

It is nearly 5,000 years old and it was a spectacular failure.

Archaeologists believe the dam burst almost immediately.

One cannot fault the ancient Egyptians for trying.

Water was scarce and rainfall uneven.

A sudden storm would have delivered a valuable resource free of charge literally falling from the sky.

A dam would have allowed water to be stored until needed.

Ancient Egypt isn't the only place to have found itself trying to deal with uneven rainfall.

Much of the world's population lives in places where the availability of water is seasonal or increasingly unpredictable.

The plentiful year round water we've come to expect in developed countries often relies on a system of dams and reservoirs.

Where such a system is lacking, the effects can be brutal.

Kenya lost more than 10% of its economic output to drought in the late 1990s,

followed by an even larger economic loss because of flooding.

With dams offering the potential to manage both droughts and floods, small wonder they've been tempting projects for millennia.

As a bonus, dams can include hydroelectric power stations.

Hydroelectricity is a bigger energy source than nuclear, solar, wind or tidal.

What's not to like?

The citizens of Hanan province in central China could tell you.

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