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When Germany’s Elbe River flooded in May this year, Hamburg and other communities along the waterway felt reminded of the catastrophic storm flood of February 1962. I remember TV images of people clinging to rooftops that were the only portions of houses still above the water.
For the first time, the German Army was employed in relief operations, assisted by NATO units. When it was over, the floodwaters had claimed 340 lives and covered 30,000 acres of land. The disaster was caused by Atlantic storm Vincinette, pushing tall waves up the estuary of the Elbe River.
At its widest, this triangular area where river water enters the ocean measures 10 miles.
Entering this funnel, the waves grew taller and within a few hours, their enormous weight breached the levees in 60 locations. It happened in the middle of the night, and thousands of people in the low-lying sections of Hamburg woke up to a storm flood that swept many buildings away entirely.
Coming from the land instead of the sea, the 2013 flood differed from the 1962 one. This time the storms started in the Mediterranean, crossing the Alps and dumping record rainfall on southeastern Germany, Austria and the Czech Republic. Soon the Elbe was carrying excess runoff from the Czech Republic into Germany.
When flooding originates upstream in this fashion, instead of being pushed upriver from the sea like in 1962, high groundwater levels come along with it. The river surface is the visible part of the groundwater table. Invisibly, it enters the surrounding hills and saturates the bedrock. When the amount of water is as large as it was this year, it takes weeks until water tables return to normal.
Because the flood crest proceeded more slowly than the sea waves assaulting Hamburg in 1962, the death toll was limited to 25 people. But property damage was severe nonetheless. Hamburg, near the end of the Elbe River, remained relatively peaceful. But in Magdeburg, 200 miles earlier in the path of the river, 23,000 residents had to be evacuated from floodwaters topping 16 feet.
These events show that even with satellite assisted weather forecasting and flood protection dikes, there is no perfect level of safety to be achieved. The only solution for preventing deaths and property losses would be to keep from building in low-lying floodplains — a difficult proposition in areas as densely populated as Central Europe.
Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays and at gainesvilletimes.com.