8 June 2023
Instability in ground works at the Cóndor Cliff dam in Argentina
On a day in which a large dam is very much in the international news, I came across an interesting article that has just been published in Open Access format in the journal Natural Hazards and Earth System Sciences (Tamburini-Beliveau et al. 2023) regarding instability in ground works at the Cóndor Cliff dam in Argentina. This is a large dam that is under construction, located at [-50.214, -70.781]. The dam will be a concrete face rockfill dam (CFRD), 75 metres high and 2,780 metres long according to Wikipedia, impounding a reservoir of 14 million cubic metres and generating an installed capacity of 1,140 MW.
Tamburini-Beliveau et al. (2023) describe a site with acute geological challenges, including weak and poorly compacted bedrock, predisposition to instability and the presence of faults. Although construction started in 2015, instability at the site meant that the design had to be changed, and some of the works had to be removed.
The paper uses PSI DInSAR to examine deformation of the southern abutment of the dam, which had reported slope instability during 2018 and 2019. They point out that the deformation is visible on publicly available imagery. This is a Google Earth image from May 2020 of the site:-
In the ground works in the lower centre of the image a series of large, sub-parallel cracks can be clearly seen. These extend over a distance of about 250 m along the length of the cracks and 50 metres in width. There is a further image, probably from May 2022 (an exact date is not given in Google Earth), that also shows these cracks:-
The DInSAR work of Tamburini-Beliveau et al. (2023) indicates that instability at the Cóndor Cliff Dam started in early 2019 and was continuing in April 2021, at the end of the data series. Deformation was also recorded on the slopes around the northern abutment. Peak deformation rates of 32 mm per year were recorded.
There is little information about the ways in which these engineering challenges are being addressed that I can find. Does anyone have any information?
Tamburini-Beliveau, G., Balbarani, S., and Monserrat, O. 2023 Brief communication: Landslide activity on the Argentinian Santa Cruz River mega dam works confirmed by PSI DInSAR, Natural Hazards and Earth System Sciences, 23, 1987–1999, https://doi.org/10.5194/nhess-23-1987-2023, 2023.