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CHAPTER 8 Conclusion W ater has given rise to many legends over the centuries, but none more famous than the "Sorcerer's Apprentice," the quintessential cautionary tale about unintended consequences. The story line dates back to Lucian ofSamosata (circa A.D. 120-190), but its many nineteenthcentury variants come from Goethe's poem Der Zauberlehrling (1797) and the fairy tales of the Brothers Grimm. In one popular version, a sorcerer, in possession of a magic broom, lived in a castle high above the Rhine. His apprentice, entrusted with the task ofkeeping the sorcerer's cistern full, hauled buckets ofwater each day up a steep and winding path from the river to the castle. One day, while the sorcerer was absent, the apprentice found a way to ease his burden: he invoked one of his master's spells and ordered the broom to haul the buckets for him. Relaxation turned to frenzy, however , when the apprentice belatedly realized that he only half understood the art of sorcery: he could command the broom to fill the cistern, but not to stop when the cistern was full. Soon the castle was bursting with river water. In desperation, he grabbed an ax and smashed the broom into small pieces-only to watch in horror as each ofthe splinters sprouted new arms and legs and began hauling water at an ever-faster pace. The legend has endured because it rings so true: humans are easily seduced by solutions that promise a quick fix but end up delivering results laden with unforeseen perils. French revolutionaries set out to establish an international regime that would promote free commerce and trade on a river they instinctively knew was rich in economic potential. They had no intention of undermining the river's viability as a biological habitat, even though the one-dimensionality of their course of action led in that direction . Similarly, the Vienna diplomats placed Rhineland and Westphalia in Prussian hands primarily to keep France's eastward march on the Rhine in 20 3 CONCLUSION check. They did not intend to fuel German nationalism and militarism, or spark another round of Franco-German antagonism and another century of Rhine warfare. Tulla devoted most of his professional life to devising ways to protect the Upper Rhine's villages and towns from the ravages of Alpine flooding. He did not comprehend that his project would cause longterm erosion problems and exacerbate the downstream flood danger. Successive generations ofengineers, industrialists, and urban planners set out to improve the river's navigability and thus make the riparian states more prosperous . They did not intend to kill the goose that laid the golden egg-to destroy its floodplain, pollute its water, and extirpate its oak and salmon. Collectively, they transformed the Rhine into one of the world's premier commercial streams, but at the same time turned it into a degraded biotope. Like powerful sorcerers, they put the Rhine to work for them. But like lowly apprentices, they had only half mastered the art ofhydraulic engineering. Today's engineers would not construct a navigational waterway the same way their predecessors did two hundred years ago. Ecologically based principles have come to assert themselves where techological principles once reigned supreme. Under pressure from biologists and ecologists, theyappreciate the importance of preserving a river's living spaces as they manipulate its channel. The old rules of river engineering-based on the primacy of a single straight, wide, swift channel-have largely been discredited and abandoned. Curves, islands, backwaters, deep pools, river-edge habitat, longitudinal pathways, and floodplains are now preserved as much as possible .I Past engineers thought mechanically and designed geometrically; their "ideal river" had the straight and uniform profile of a canal, their ideal channel a trapezoidal or U-shape. Today's engineers take a different approach: they even build canals with biological principles in mind. The new Rhine-Main-Danube canal (1992), for all its monstrous artificiality, meanders through the Altmiihl valley as if it were a natural river. Instead of cutting a straight line through the hills, engineers followed the contours of the valley landscape (after being forced to do so by the environmental lobby). They created river-edge habitats for aquatic and semiaquatic species, added artificial feeder streams to replicate the dynamics of a natural river, and paid attention to longitudinal pathways. As a result, the Rhine-MainDanube canal looks more natural in many stretches than the three rivers it connects-and supports a surprising amount of plant and animal...

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