Archive for March 8th, 2010

Some clarifications on the post of when the Guri dam will reach the critical level

March 8, 2010

(Picture of a section of the Guri dam a few days ago)

(I still have no Internet at home, rather than answering the comments, here are some clarifications on yesterday’s post)

1- What is the critical level?

Strictky speaking is 240 meters, but it is likely to be higher. Flow may have to be restricted and you have to worry about other technical problems, so a better number may be 244-245 meters, which will occur around May 10th. if it does not rain.

2.-What is the correct question to ask?

I think it is the critical level, not when is that the water stops dropping. The reason is that if it starts raining and the daily drop rate falls from 15 centimeters to 7-8 centimeters, you push the day the level gets critical 50-100 days into the future. Historically, by the end of June, the water flow has always been above 4,000 m**3/s, thus if the rains slow down the rate thirty days, the probability is extremely high that a positive equilibrium (More flow in than out) will be reached.

3.- What about the conical shape of the dam?

The shape of the dam should be or is  in the linear fit to the historical data. How fast the water drops is a function of inflows, the shape of the dam, evaporation and height. I don’t pretend or intend to model of those, I simply note that so far the fit is extremely good. I will keep monitoring it.

4.-This is not a severe drought year due to El Niño

While this is not a great year, there have been worse. The current outflow and inflows into the dam are above the worst ones historically for the same date. El Niño is a complex phenomenon, this is not the strongest one either, nor the longest running as noted in this post in January. El Niño is simply a convenient political excuse.

5.- What about the turbines?

I have not had recent information about how many turbines are online or not. This is a separate issue. My understanding is that one can not be repaired. Another has been fixed. That leaves seven off line, last time I heard.

I was a little more optimsitic when I wrote the post that I am now. It looks like assuming “240 meters” was the wrong thing to do, it seems to be higher, thsu it is going to be quite close. However, it may not last long. My worry is that if Guri is shutdown, blackouts will affect the oil industry, supplies, communications. It could be really bad for a few days. On the positive side, there have been some rains down there, inflows have moved up to 700 m**3/sec.

This slide show of Guri about ten ago days tell you the whole story.