View Mobile Site

Earth Sense: Changing river’s flow has drawbacks

POSTED: December 2, 2012 1:00 a.m.

In places where there are water-related problems, engineering is often touted as the solution. As an example for what happens when you tinker with natural waterways, the river Rhine in Germany, often visited by Americans, stands out.

Until the late 1700s, it was a wild stream, changing course on an almost daily basis, dividing itself into several branches and devouring entire villages overnight with frequent floods. The shifting river also hindered the establishment of clear property lines, making the tax base as well as governmental boundaries uncertain.

Mainly to address the latter problems, the world’s largest river engineering project started in 1823 with the formation of a regional Water & Roads Authority. For the next 50 years, gigantic excavations were made to provide the river with a new, straight bed on a stretch of 200 miles.

Starting at the Swiss border, the Rhine was now forced to flow in its new single channel, shored up by levees. Stone rip-rap resembling cobblestone streets was applied on both sides of the river to prevent erosion of the levees.

The effects of such massive engineering became apparent soon. Taking the water away from the many wetlands in the area caused a lowering of the groundwater table.

Most seriously though, the straightened river was now taking a shortcut through southern Germany in its new Autobahn-like bed, and stepped on the gas. Flow velocity increased, bringing floods from the Alps faster than before.
The river bed eroded, lowering groundwater tables even more. Major cities like Mannheim, Ludwigshafen, Karlsruhe, Strasbourg and Basel ran into water supply problems that continue to the present day.

To counteract the rapid flow, locks and dams were constructed, one after another, to the tune of $30-$50 million each. This resulted in accumulations of toxic sludge where the dam slowed the flow. The list goes on, and so does government spending to provide solutions through more engineering.

The latest realization has been that wetlands are actually useful. Artificial ones, so-called pocket polders, are being created, again at great cost to the taxpayer. It teaches that once you start re-engineering a river, it’s hard to stop.

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.


Contents of this site are © Copyright 2010 The Times, Gainesville, GA. All rights reserved. Privacy policy and Terms of service

Powered by
Morris Technology
Please wait ...