Archive for April 17th, 2016

Is Drought Really Causing The Problems With Guri Dam?

April 17, 2016

The title of this post may seem strange to some, when you look, for example, at the pictures in this Reuters report, it certainly seems like there is a drought in Guri, except that if the pictures were of the bottom of the now half -dry lake that forms the dam, it is obvious that it will look dead and drought-like in the pictures.

When I was in Caracas, someone told me that they had gone fishing in one of the tributaries of the river Caroni and the water level was quite high, something that was later confirmed by another friend who went fishing in the La Paragua river and saw the water level rise by a meter in a few days.

Despite this, the dam level keeps going down, so, what gives?

Both of my friends deduced from this, that the problem was not drought, but the managing of the Guri dam.

I stored this information in the back of my mind and did not look into this for  a couple of weeks, but all of a sudden, this blog post by Roger Andrews came out. While Andrews is not an expert in this particular field, he seems to be someone that likes charts and numbers and understanding problems. What Andrews showed, and I will come back to it, is that this has not been an anomalous year in terms of rainfall in Guri and that the problem with the water level was simply overuse of the dam to generate electricity.

It is useful before we discuss this, to show you an overall map of the area of Guri:

gurimapcaroni

On the left, you can see the overall area in the Southeast of Venezuela down to Brazil and Guyana. In the blow up on the right, you can see the Caroni river and all its tributaries, which is the area that feeds the dam. What matters in the end, is what rainfall is doing there, not in Caracas or Maracaibo or even Ciudad Bolívar, far from the dam, bot in the basin of the Caroní river.

What Edwards did, was to look at the data in five rain stations in Bolivar and Amazonas and see if rain was particularly light in the last few years. Here I show two of them: Tumeremo, to the right of the dam, and Santa Elena to the South and which is in the Caroni basin:

PluviometriaAs you can see, rainfall in Tumeremo was in 2015 about the same as any other year and in the case of Santa Elena, rainfall levels were at 200 mm per month level, not exactly low given the long term record.

While I could not find a long term record for the Santa Elena Station, I did find the record for Kavanayen nearby:

KavaThis graph shows the maximum rainfall at the Kavanayen Station (black), the average (blue) and the lowest level (red) from 1969 to 1998 (Funny, there is no data after Chávez was elected)

As you can see 200 mm. is way above the lowest level ever measured.

Just to make sure, Edwards blew out the data and I will show what is seen for Santa Elena:

SantaHelena

As you can see, last year was not too different than any of the past five years, when there was no “El Niño” to blame the supposed drought on.

At this point I wished I had current data for the stations with a long term record to compare. But then, a person I follow in Tweeter (@meteovenezuela) posted the following recent rainfall map:

LLuviaembalse

This is a map of the Caroni river basin above Guri, showing the accumulated rain from March 15th. to April 13th at a number of stations. What is interesting is that we have two stations that we can compared to the long term record: Kavanyen and Uriman. At Kavanayen, the rainfall was 229.1 mm for this almost one month period. This number is way above the average rainfall for April 1st. from 1969 to 1998 in the graph above, which was of the order of 150 mm per month, and we are  talking about comparing to the average! Not to the lows…

We can do the same thing for the Uriman station, close to the dam as seen above above, where the rainfall was 151.7 mm in the same almost one month period.

Below is the long term record for this station:

Urinam

I have placed a red dot on the curve with the data for this year, as you can see, it is right on the historical average, far from being an anomalously low value, as the presence of a severe drought would require.

Despite this, the Guri dam level continues to go down…

And to increase the mystery, I found this plot of the water volume in the Caroni river tweeted by @800GWHMWH:

Caronicaudal

Clearly, the volume of the river is at levels which are historically high, not low.

I am no expert, I just enjoy looking at data and graphs, I have looked for as much new data to complement Edwards’ and I must say, everything that I have found confirms what he concludes. I do hope one or many of the readers of this blog can help me in getting more information and data and debunking the Government’s claim that this El Niño-induced drought has been anomalously strong, because it certainly does not look like it.

In closing, I show a plot of the peak power demand in Venezuela in the last few years:

peakdemand

Clearly, despite the billions that were invested in order to increase power generation, we are now back to 2007 levels, indicating that something has been going downhill in the grid and I would bet, this has to do with the overuse of Guri, to compensate the decline of the whole network.

Advertisements