Characterization and hydrological analysis of the guarumales deep-seated landslide in the tropical ecuadorian andes

Journal Article (2020)
Author(s)

A.R. Urgilez Vinueza (TU Delft - Water Resources)

Jessica Robles (Hidropaute Business Unit, Corporación Eléctrica del Ecuador (CELEC EP))

M. Bakker (TU Delft - Water Resources)

Pablo Guzman (Hidropaute Business Unit, Corporación Eléctrica del Ecuador (CELEC EP), Universidad del Azuay)

T.A. Bogaard (TU Delft - Water Resources)

Research Group
Water Resources
Copyright
© 2020 A.R. Urgilez Vinueza, Jessica Robles, M. Bakker, Pablo Guzman, T.A. Bogaard
DOI related publication
https://doi.org/10.3390/geosciences10070267
More Info
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Publication Year
2020
Language
English
Copyright
© 2020 A.R. Urgilez Vinueza, Jessica Robles, M. Bakker, Pablo Guzman, T.A. Bogaard
Research Group
Water Resources
Issue number
7
Volume number
10
Pages (from-to)
1-24
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Abstract

The high landslide risk potential along the steep hillslopes of the Eastern Andes in Ecuador provides challenges for hazard mitigation, especially in areas with hydropower dams and reservoirs. The objective of this study was to characterize, understand, and quantify the mechanisms driving the motions of the Guarumales landslide. This 1.5 km2 deep-seated, slow-moving landslide is actively moving and threatening the “Paute Integral” hydroelectric complex. Building on a long time series of measurements of surface displacement, precipitation, and groundwater level fluctuations, we analyzed the role of predisposing conditions and triggering factors on the stability of the landslide. We performed an analysis of the time series of measured groundwater levels and drainage data using transfer functions. The geological interpretation of the landslide was further revised based on twelve new drillings. This demonstrated a locally complex system of colluvium deposits overlying a schist bedrock, reaching up to 100 m. The measured displacement rates were nearly constant at ~50 mm/year over the 18 years of study. However, the measurement accuracy and time resolution were too small to identify possible acceleration or deceleration phases in response to hydro-meteorological forcing. The groundwater and slope drainage data showed a lagged response to rainfall. Finally, we developed a conceptual model of the Guarumales landslide, which we hope will improve our understanding of the many other deep-seated landslides present in the Eastern Andes.