Posts Tagged ‘disaster’

Modelling catastrophic dam collapse and natural disasters

// June 24th, 2011 // Comments Off on Modelling catastrophic dam collapse and natural disasters // Recent Research, Science Communication

One of the biggest dams in the world, Geheyan Dam in China holds more water than five Sydney Harbour’s, a massive 3.12 billion cubic metres worth.

What would happen if it failed?

Models of Geheyan town before and after dam collapse

Australian CSIRO scientists collaborated with China’s Satellite Surveying & Mapping Application Centre (SASMAC) to model the region and apply six different dam failure scenarios.

“Our simulations show where the water would go, how fast it would reach important infrastructure such as power stations and the extent of inundation in major townships downstream,” said Dr Mahesh Prakash from CSIRO in the press release.

Dam failure is a real possibility, as many parts of China are prone to earthquakes. We’ve seen plenty of natural disasters over the past year, highlighting the need to prepare for such events.

Modelling and data visualisation can inform emergency procedure development and ensure new infrastructure is built protected areas.

“The modelling technique we developed for this work is really powerful,” Dr Prakash said. “It gives us very realistic water simulations including difficult-to-model behaviours such as wave motion, fragmentation and splashing.”

This video shows a dam failure simulation, and explains how the model was created. I enjoyed the delicious hundreds and thousands demonstration to show how water acts as a group of particles. Yummy!

The same software has been used to model other catastrophic events, including tsunamis and volcanoes. They also modeled the 1928 St Francis dam break in California. The simulation was very similar to the real event, suggesting the technique is accurate.

Dolphin safe tuna… A dolphin is worth how many fish?

// September 30th, 2010 // 2 Comments » // Unethics

Flickr Image by david.nikonvscanon

In the immortal words of Marge “I brought you a tuna sandwich. They say it’s brain food. I guess because there’s so much dolphin in it, and you know how smart they are.” Dolphin safe tuna is for some of us environmental types a no-brainer like eating free range eggs.

I was one such person, until I read this post last year.

The ecological disaster that is dolphin safe tuna by Southern Fried Science is one of my top five ever blog posts (the top prize going to the Nacho Average Cheesecake by the sadly ended Chem Blog. Read it read it read it!)

For those of us too lazy to click through, I’ll summarize the dolphin safe tuna post. Consider this cliffnotes. Hells, I’m just that kinda pirate.

To fish for tuna, ships like to locate a big school of ’em so they can nab them all at once. Finding a school of tuna is tricky.

The non-dolphin safe method is to follow some dolphins, because dolphins have their fins on the pulse and know the happy-haps of where the tuna are at. Dolphins are easy to follow because they come up to the surface for air. The downside is that the dolphins are accidentally caught with the tuna (bycatch), Southern Fried Science estimates it as 500,000 a year.

The dolphin safe method does it differently. Instead, an object is floated on the ocean. For some weird reason, floating objects attract sea life, including big ol’ schools of tuna. So you just scoop up the tuna when it comes in. Of course, this leads to bycatch of its own, including all the other sea life that came to investigate the mysterious floating object. There’s more bycatch through this method, but less of it is dolphins.

When you compare the bycatch of the dolphin safe method and the non-dolphin safe method you come up with the following.

1 dolphin saved through dolphin safe fishing costs 382 mahi-mahi, 188 wahoo, 82 yellowtail and other large fish, 27 sharks, and almost 1,200 small fish.

Food for thought. Read the original post here.






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