Niagara Falls drained

Niagara Falls. It is an unreal picture: Where otherwise around 4 million litres of water plunge into the depths every second, only a bare rock edge now juts into the air. Engineers have drained the US part of Niagara Falls. The water is currently diverted via a tributary.

The reason for the diversion of the river is a fear of geologists: Niagara Falls could erode the rock so much over time that the Niagara River would eventually take a different path. Then the world-famous waterfalls would also be a thing of the past. Two rockfalls on the American side of the falls had already broken off tons of rock in 1931 and 1954. At the foot of Niagara Falls, the rock debris now piles up more than 30 metres high. The tourist magnet Niagara Falls is therefore in serious danger. To prevent further rockfalls, concrete is now being poured into the cracks in the rock on the American side. This is intended to strengthen the riverbed above the falls and prevent further erosion.

Soon the river will be able to resume its usual course. Let us hope that Niagara Falls will be preserved for posterity for a long time to come.

In a wooden barrel through Niagara Falls – teacher survives stunt!

It is the afternoon of 24 October 1901. 63-year-old US teacher Annie Taylor climbs an oak barrel about a mile above Niagara Falls. It is padded on the inside for her protection. She plans to plunge down Niagara Falls in this vehicle – no one has ever survived! At 4.05 p.m. she starts her daring journey. After only 18 minutes, the barrel plunges down the Canadian side of the falls. Driven down by the rapids, it is recovered at 4.40 p.m., together with its teacher. Annie Taylor is injured in the back of the head, has suffered shock and is taken to the hospital in Niagara Falls. After surviving the stunt with a lot of luck, she warns her fellow men urgently not to repeat the breakneck act.

Water in free fall

The water masses of the Salto Ángel in Venezuela fall 978 metres. The highest waterfall on earth plunges from a table mountain, partially atomises into water vapour and then collects again to form a river. After another stage, it plunges hundreds of metres again with a deafening roar. The power of water can be heard, seen and felt particularly well at a waterfall.

Most waterfalls form in places where hard rock lies above soft rock. When the water flows over these layers, it carries away the soft rock below more quickly. This happens mainly because of sand and pebbles that the water carries along. These grind away the soft rock more and more, eroding the bottom of the river more and more. Between the two layers of rock, a debris hole is created that grows larger over time. The water falls deeper and deeper at this point – this is called a waterfall.

Because the soft rock under the hard rock edge becomes more and more hollowed out, an overhang forms. When the weight of this overhang becomes too heavy, it breaks off. Its rock fragments hollow out the subsoil again. Again an overhang is formed, which finally breaks off under its own weight. The waterfall thus moves back towards the source. This movement upstream is measurable: for example, Niagara Falls on the border between the USA and Canada recedes about 70 centimetres per year.

Constant dripping wears the stone

Deep gorges in the mountains, wide sandy beaches by the sea and broad rivers meandering through meadows and fields – these are all landscapes we know well. Because they are so varied, we find them impressive and beautiful.

The sculptor of all these landscapes is the cycle of water. More than any other force, water sooner or later shapes the surface of the earth. It washes away soil after a downpour. It burrows into the subsoil and loosens parts of the rock. It carries soil and weathered rock debris down into the valley. Where the water flows away more slowly, it releases its load of silt, sand and debris. At high tide, it floods the shallow areas of a valley, the river floodplains. Here, too, it deposits fine silt. When the water finally flows into the sea, it works the coasts and forms very different landscapes, for example cliffs or long sandy beaches.

Water also shapes the landscape in the form of ice. When water freezes in rock cracks, it blasts the stone. As a glacier, it planes notch-shaped river valleys into round trough valleys. And the moraine landscape in the foothills of the Alps with its scree hills and boulders is also the result of glaciers that shaped the subsoil long ago.

From trickle to stream – flowing waters

Bubbling groundwater emerges from a spring and flows down the slope as a thin trickle or a small stream: a watercourse has been created. All flowing waters start out small. On their way towards their mouths, they merge with other watercourses and continue to grow until they have become a river or even a broad stream. At its lower end, the watercourse flows into another river, a lake or the sea.

Streams, rivers or creeks – terms that come to our lips fluidly are precisely distinguished from one another by scientists (geographers). They can be classified by their water volume, their length or their width: If the watercourse is less than half a metre wide, it is called a trickle; if it is more than 2 metres wide, it is called a stream. If the watercourse swells to a width of 10 metres, it is a river. And if it gets even wider, the river can be called a stream. The Amazon or the Nile, for example, are called rivers, but the Rhine and the Danube are also streams.

The amount of water in the flowing water increases from the source to the mouth. Nevertheless, it flows slower and slower downhill. This is because the slope down which it flows is steeper at the top than at the bottom. And because the water flows faster at the top and slower downstream, it can carry more sand and debris along the upper course than the lower. Thus, more sand and debris is removed from the upper course of a river, and more is deposited in the lower course.

Sand in sight

Germany’s best-known North Sea island is threatened with extinction. Every year, Sylt gets a little smaller. The “Blanke Hans”, as the stormy North Sea is also called, gnaws ceaselessly at the island’s west coast. To stop the shrinking of Sylt, sand is now to be pumped from the seabed onto the beach.

A hundred years ago, the island’s inhabitants were already thinking about how they could protect their coast from the raging North Sea. Long rows of wooden piles, so-called groynes, were driven into the sea at right angles to the coastline. Intended as breakwaters, they unfortunately did not bring the desired success on Sylt. Beach walls and concrete monstrosities were also built in the sand to fortify the island. Unfortunately, they were not only ugly but also useless. The masses of sand continued to be washed away and partly stranded off the coast of Amrum.

Sylt is now hoping for a new coastal protection measure: sand flushing. Dredgers dig up sand off the west coast, which is pumped onto Sylt’s beach and distributed there. When the North Sea rages again, it will initially only take the flushed-up sand with it. The original coastline is to be preserved in this way. Presumably, the flushing will have to be repeated regularly to preserve the holiday paradise in the long run. One can only hope: “Trutz Blanke Hans!”

Ballad of Detlev von Liliencron (1844-1909)

The extent to which the North Sea raged and wiped out the settlement of Rungholt and other villages in the terrible Marcellus Flood of 1362 is described by the poet Detlev von Liliencron in his ballad “Trutz Blanke Hans”, first published in 1883, which roughly translates as “Defy the stormy North Sea!”