Grand Ethiopian Renaissance Dam

Grand Ethiopian Renaissance Dam

Ethiopia has built a giant freaking dam on the Blue Nile River just a few miles from their northern border where the Blue Nile River crosses into Sudan. Al Jazeera has a story.

With a planned installed capacity of 5.15 gigawatts, the dam will be the largest hydroelectric power plant in Africa when completed, as well as among the 20 largest in the world. - Wikipedia

They started building it in 2011 and it started generating electricity this year.

I was thinking about putting up a post about this, just because I had never heard of this project before. Seems like I should have heard something about a big deal like this, but no. A couple of days ago I started reading Maelstrom by Peter Watts and somewhere in the first few dozen pages he mentions this dam. Well, I can't ignore a coincidence like this, so this post. I've read a couple other books by Peter Watts and he's pretty great.

Looking for information, I dug up some maps.

River Nile Map

Note that the Blue Nile branches off of the main river at Khartoum. It heads southeast toward Ethiopia and just after it crosses the border is where the dam is.

Google Maps doesn't do a good job of portraying waterways. Can't say as I blame them, only a small fraction of the population gets out on the water, and the government has a whole army of people devoted to mapping water. So if you want to look at maps of rivers, search for images of maps using your regular browser.

Still, Google Maps is terrific. Here we have two views of the area being inundated by the water being held back by the dam. Both maps are about 14 miles across. First is the map view:

Map View of Blue Nile Dam area

No sign of any lake. The black line along the left hand side is the border with Sudan. Now look at the satellite view:

Satellite View of Blue Nile Dam area

Not a lot of contrast between the land and the water, but if you look carefully you might be able to pick out the shore line and see that the lake is extensive.

Update two days later.

Main Dam and Saddle Dam of GERD (Source: Hydro World, 2016)

Looking at the satellite view of the lake I noticed a large, curved line in the lower left quadrant. A little digging reveals this is a three mile long saddle dam. The water hasn't reached it yet, but it means the lake is going to get a whole lot bigger in the coming years. The saddle dam is 160 feet tall. Not giant, but still substantial.