Kariba Dam is 110% full
Kariba Dam as at June 2009 is 110% full !
This has apparently been allowed intentionally for a number of reasons the most important one being for the maximum generation of power. Zimbabwe is currently suffering major power outages which are impacting seriously on commerce and industry. In addition there is work being undertaken on the northern side of the dam which would be impossible if the flood gates were open.
A further reason given is that the Cabora Bassa Dam which is further downstream towards the Indian Ocean, is still pretty full with rivers still running furiously, and thus the Cabora Bassa authorities have asked for the Kariba Dam not to release water until the end of July.
When the dam first filled in the early sixties it was followed by a great deal of earthquake activity. Kariba is located on the very southern end of the Great Rift Valley which is tectonically active and many of the earthquakes measured more than 5 on the Richter scale. Kariba Dam is documented in a concerned paper prepared by the World Commission on Dams, which draws attention to many dams worldwide, with reported cases of Reservoir-induced seismicity greater than magnitude 4.0.
In the horrifying floods in Mozambique of March 2000, the US Army Corps of engineers were asked to evaluate Kariba’s safety, but an in-depth inspection was hampered by the dam authorities and several times in recent years, the flood gates have been opened in an attempt to release emergency waters from the giant dam.
There has been renewed speculation about the mighty Zambezi River recently with the building of the Mphanda Nkuwa, 60 kilometers downstream from the huge Cabora Bassa Dam in Mozambique. This new dam is expected to bring hugely destructive impacts to the lower Zambezi.
Although millions of people depend on the Zambezi River for their livelihoods, the Mozambique government – with China’s help – is proposing to build this huge new dam,in spite of huge environmental damage which will be caused by daily fluctuations in river level.
Kariba Dam has been affected by a condition that mars its concrete, known as “alkali-aggregate reaction.” as have many dams worldwide. While regional concern about the dam’s condition is widespread, little is known about the extent of the problem or its implications on dam safety.
Inspections of Kariba are carried out every five years according to the World Bank – reports are complied by an international engineering firm, but these reports are not made public. According to a Zambezi river expert who lives downstream of Kariba, there is concern about the dam’s safety, especially during large floods, because “the dam walls vibrate when several or more sluice gates are open and pass large discharges of water.”
However Kariba’s dam operators deny that there are any problems, and it is certainly in their interest to make sure the walls are stable. Meanwhile the dam wall is looking remarkable and up-stream many residents are saying they have never ever seen the dam this high so early in the season.
July 14th, 2009 03:11
The high water level has probably flooded all the coastal grazing to the detriment of the buffalo, but the fishing should be excellent.
July 14th, 2009 10:23
Dear Freedom Writer,
I am not sure where you get you data from. Please check the Zambezi River Authority website (http://www.zaraho.org.zm/lakelavel.html) and you will see that Kariba Dam is 85% full in terms of usable storage. In terms of overall capacity it is probably about 92% full
July 14th, 2009 12:09
@Water Engineer – Damn – I hope those photos are fake! ‘Cos if not, and you’re correct, Water Engineer, only a few more percent and it will be over the top!
July 14th, 2009 12:12
@water engineer
ok i also like stats, but it looks full to me…
July 15th, 2009 13:13
I Love My Home Town
July 15th, 2009 16:20
I love what you said – was thinking of camping at Mana Pools but ????????
July 16th, 2009 11:24
@Water Engineer – Freedom Writer says. Photos were taken by a knowledgeable Kariba resident who is confident of his facts.
July 17th, 2009 23:02
Conspiracy theories abound. I bet Bob is still claiming the Brits and drought have ruined the harvest?No?
July 19th, 2009 18:12
Dear Freedom Writer,
an interesting article – but why will Mphanda Nkua be so destructive? I understood it was designed as a run-of-the-river project. With little storage capacity it will simply use the water as it is released by Cahora Bassa.
July 20th, 2009 11:19
the river authority website shows the levels rising daily. is the lake level now too high to safely open the flood gates? are the gates even working?
July 20th, 2009 22:41
Mphanda Nkua – destructive. The anti dam brigade going over the top as usual. “Horrifying floods in Mozambique” does any one ever mention the huge flood reducting effect of lake Kariba, of course not, that wouldn’t suit their agenda at all! Adding another storage element downstream of Cahora Bassa will increase the flood absorbtion capacity and as you say the flows from both dams will be the same so no change to the current flow regime.
And in response to Ever – Is the intention of asking whether the gates are even working to generate some public alarm or to find out the answer? The only people who can supply the answer are the Zambesi River Authority, but I suppose that despite their having operated the dam in a perfectly responsible manner for 50 years you wouldn’t believe them if they told you that the gates were working?
Alkali/aggregate reaction – it is not the usual kind of this problem, there is a report by Coyne and Bellier who investigated the long term swelling of the concrete but the chemistry and mechanics of it are still not understood. The long term implications of the swelling are minor, to date the centre of the dam has moved upstream by 1 centimetre.
July 21st, 2009 14:40
Dear consultant2
Thank you for the information even if you have made an incorrect assumption about my intentions. Kariba is a national treasure. My enquiry was prompted by concern. According to info above and on ZRA website, the lake level is rising 2cm per day and water will not be released till next month. So how much water is flowing in per day and how much can be released per day?
July 23rd, 2009 04:46
@David Wheeler – Unfortunately you are right about the high water level impact on buffalo.
Another HUGE problem is poaching, on my last visit to Kariba in the Nyodza we were approached by the army on canoe and they said ‘there has been a lot of poaching going on and we are here to stop the poaching’. A complete fabircation as they the ones that are the poachers and the only ones with guns. Very sad case, we could visibly see a buffalo carcas in the waters (obviously culled and the meat removed) and strips of its meat hanging from trees up in the montains. The governemnt is stuffing up the very thing that make Zimbabwe unique and wonderful.
July 27th, 2009 12:23
The lake is going down again. It peaked at 486.8 on 22 June 2009.
The highest the lake ever got was 487 mt, (not sure of the exact date but around 1993 I think, stand to be corrected.)
When I last enquired the lake was 486.65 and that was on 13 July 2009
@Ever -
July 30th, 2009 16:14
I heard that the inspection tunnels on the Zambian side were blocked with concrete during the Rhodesian war years to prevent infiltration into that country.
The article I saw (cannot remember where/when), implied that that concrete cannot easily be removed and the result is that comprehensive internal inspections are not possible. This has raised concerns that there COULD be all sorts of problems that no-one is aware of.
Can anyone comment on this with any authority?
August 2nd, 2009 06:47
Obviously, independant world experts need to assess the state of the Kariba dam wall… immediately!! Regardless of what the water current levels are, or previous ‘UNDISLOSED’ reports or current political persuasions – due diligance is absolute. Anything else would be sheer neglect and lead to potential catastrophic unthinkablility!!
August 19th, 2009 11:11
I agree with the water engineers. Definitely need data. We keep an eye on the level of the dam otherwise our pumps will be submerged and it did not happen. As far as we know the dam was only at 96%. Make sure of your facts.
October 23rd, 2009 19:28
So much has been said about the possibilty of this dam being a potential danger if not properly maintained. has anybody actually said what would happen if it burst.It would probably wipe out Madagascar and send a Tsunami big enough to hit Australia. More international attention to examine this dam is urgently needed.
November 8th, 2009 11:59
Fréjus in France is this year commemorating the 50th anniversary of the breach of the Malpasset Dam, built at about the same time as the Kariba dam, by the same Engineer, André Coyne. An official description of the failure and aftermath can be found at http://barpipdf.geniecube.info/29490_malpasset_ih_gb.pdf.
March 3rd, 2010 14:32
So wondeful to see pics of Kariba! Would love to do some fishing again – it’s been 10 years!!David, any chance you went to Kariba Primary School in the 70’s?