*****The spectacular failures and successes of massive dams. Image copyright Getty Images Not far from Cairo stood a remarkable dam, the Sadd el-Kafara, more than 100m long, and 14m high, and able to store about half a million cubic metres of water.
These statistics are modest, by modern standards - but the Sadd el-Kafara is not a modern dam. It was built nearly 5,000 years ago. And it was a spectacular failure: archaeologists believe the dam burst almost immediately. Image copyright Jean-Luc Frerotte One cannot fault the ancient Egyptians for trying. Water was scarce, and rainfall uneven.
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. Where such a system is lacking, the effects can be brutal: Kenya lost more than 10 per cent of its economic output to drought in the late 1990s, followed by an even larger economic loss because of flooding. Normally submerged under 4 metres of water, an ancient packhorse bridge is revealed in County Durham as Grassholme Reservoir is drained to allow for maintenance works on the dam wall. @itvtynetees. *****Dams: I used to find this picture - and the whole concept - of a flooded valley quite haunting. Actually, I still do #RonaldLampitt (1966)
Massimo sur Twitter : "The importance of dams and civil engineering in the management of geological risks. Simple mountain spillways can be a very effective measure in reducing the impact of torrential floods [source and full video. Have you seen Birmingham's model of the Elan Valley waterworks, in Cannon Hill Park? CC @mrtimdunn.
Whaley Bridge dam: RAF Chinook brought in. The #DamUnbusters !! □ Well done #RAF #WhaleyBridge… The biggest dam removal in European History started today. Could this be the beginning of the end of big hydro? @PeterGWeather visited the dam in Normandy for us. Do dams destroy rivers? “Indeed, dams do change the world and its natural environment.
So do cities, roads, airports, chemical industries and agriculture. In general, we can say that people change their environment. The richer they are, the more change they induce. In the course of that, they often destroy species; they also create species, but that is not often measured or mentioned. “The notion that some static measure of biodiversity is good and any change is bad is not substantiated by natural history.
“So the IRN’s latest database is simply that:- a collection of data (of variable quality) with no inherent information about whether what is happening is good or bad. “What we need to take from this debate is the realisation that we now live in an anthropocene world, whose form is increasingly structured and sustained through human decision. “But that WE is not a small group of North American environmentalists and their friends. 12 dams that changed the world. Dams illustrate the brilliance and arrogance of human ingenuity.
They generate one-sixth of the world’s electricity and irrigate one-seventh of our food crops. They have flooded land areas the size of California, displaced a population the size of Germany’s, and turned freshwater into the ecosystem most threatened by species extinction. Dave Petley sur Twitter : "The enormous scale of the tailings dam collapse at #Feijão mine in #Brumadinho, Brazil is now clear. The dam was 87 m high, holding about 13 million cubic metres of #tailings. The failure appears to involve most of the waste:- h.
Dave Petley sur Twitter : "Why we need engineering geomorphology: the complex chain of events that have created a crisis on the Ituango Dam in Colombia (with an astonishing video of break-through flooding):- What future for the international agreement and the Mekong Delta. More Geography news - Leaked report warns Cambodia's biggest dam could 'literally kill' Mekong river. Europe's river life hits a barrier every 1km. And it's our fault. Imagine you’re heading out for a dinner date.
You’re hungry and left enough time to get there and not be late, but when you step outside you find that conditions aren’t quite what you expected — you run into a 30-foot wall every few steps. What would you do? If you’re anything like me, you would probably just give up — stymied, hungry, un-romanced. This is what’s happening for fish and aquatic wildlife in Europe: according to new research, there is a dam or other manmade obstruction blocking the continent’s rivers and streams every kilometer. The researchers figured this out by scraping whatever information they could find online, then went out and confirmed it for a total 1,000 kilometers.
Those researchers are launching an app that will allow people update the status of river and stream barriers as they come across them. But, ultimately, a better database doesn’t help the trapped fish (that is, unless someone does something about it). Look at the Amazon River, for example. 5 February 1852. The Bilberry reservoir in West Yorkshire collapsed, causing flooding and killing 81 people…