Hidroituango: a substantial step towards reducing the immediate risk

On Sunday a significant milestone was reached in the ongoing efforts to reduce the risks at the Hidroituango dam site in Colombia.  Efforts have been ongoing to raise the crest of the dam, reducing the likelihood of it being overtopped by a wave triggered by the failure of the slopes around the lake.  The first target was to reach 410 m, at which point the spillway became operational (should it be required).  Yesterday the crest of the dam reached 415 m, providing considerable additional security.

The next target is 418 metres; the ultimate aim is to reach 435 metres.

The consequence of these improvements to the structure is that the level of warning has been reduced for a substantial part of the population living downstream from the dam.  This improved dam safety, plus the decease of inflows as the mountains upstream from the dam move out of the rainy season, has allowed 11,000 people to move back.  However, 4,000 people remain evacuated.

A recent image of the dam site at Hidroituango. Image from Caracol.com.co.

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The image above shows he current state of the dam at Hidroituango.  Note the very large volume of material tipped on the upstream face of the dam.  This appears to be the material that is being used to try to reduce the leaks in the structure.