Archive for March 11th, 2010

An update on what is happening at Guri dam

March 11, 2010

Well, I have good news and bad news. The good news, is that the model that I presented the other day is doing ok so far, it was predicting for yesterday a height of the water level at Guri dam of 253.25 meters and the reported level in the Opsis website is 253.16 meters. This is not bad, given that I used data up to February 15th., thus, after 14 days, the error is only 9 centimeters, which tracks the model quite well. Cross your fingers.

Except the bad news is that this is more complicated that it may have seemed at first sight.

First of all, it has been raining! That is definitely good news. Here is a plot of the water flow into the Guri dam:

as you can see, the flow almost doubled after February 25th. as the rain brought in more water for a few days, going from around 400 cubic meters per sec. to 800. Then the flow dropped again to around 600 m^3/sec. and on March 8th. it rained again and water inflows levels are around 700 m^3/sec.

The bad news is, that despite the fact that water inflows are higher than in all of February, the water level is still dropping, as seen below in the the plot of the Height above sea level of the water:

As can be seen, the water level keeps dropping. We have had more rain and more water, but the rate at which the level has been dropping seems to be continuing.

How come?

Easy, as the water into the dam has increased, the flow out through the turbines that produces the electricity has also been increased as can be seen in the next chart:

As you can see, as the rain has provided more water, the dam has been used more and the flow out has increased. In fact, it seems to be increasing daily as if the people running it are controlling it accordingly.

This implies, that despite the rain the daily drop in height has not slowed down, in fact, it has increased:

almost reaching 20 centimeters daily.

Thus, I am not sure why it is dropping faster, it would seem as if more water is being allowed to flow to produce more electricity, but the rate of increase in the flow out does not seem to be as large as to justify the faster drop in the height. It may be that because it is much hotter and there is a less surface area to the lake, there is much more evaporation or the shape is playing a role.

Comments are welcome, particularly by the experts, who may enlighten us on dam management!

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