Coca River Erosion: Impact on Ecuador's Hydroelectric Plant

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Retrogressive erosion process of the “Coca” river
and its potential impact in
the main Ecuador’s hydroelectric power plant
Dr. rer. nat. Fabián Vásconez (PhD)
Geotechnical Eng.
BACKGROUND
The waterfall “San Rafael” was formed by a blockage of
the “Coca” river by a lava flow of “Reventador” volcano
Photo: Iván Boada
Source: Jorge Sevilla - “Cascada de San Rafael Estado y Situación a cuatro meses de su desaparición”
Digital Terrain Model of “Reventador” volcano
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
BACKGROUND
On February 2, 2020, the "San Rafael" waterfall disappeared. The river
began to flow under the lava.
“San Rafael” waterfall became a kind of bridge; and a regressive erosion
process began, upstream.
Source: Jorge Sevilla in “Crónica de una Tragedia
Anunciada: La Cascada de San Rafael
Source: Antonio José Paz Cardona en https://es.mongabay.com/2020/02/cascada-san-rafael-desaparecio-en-ecuador/
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
BACKGROUND
On February 2, 2020, the collapse of the144-meter-tall “San Rafael” waterfall triggered a major
retrogressive erosion process that is being migrated upstream for the past four years; causing the
destruction of critical infrastructure (roads, bridges, oil-pipelines) and the consequently economic impact in
Ecuadors’ economy.
The hydroelectric dam, part of the Ecuador’s largest hydroelectric power central, located 19.4 km upwards
of the collapsed “San Rafael” waterfall is threatened to be destroyed by this retrogressive erosion.
On June 23, 2024; the front erosion is located 6.4 km near to this dam.
“A lava-dam collapse of this scale was previously known only in the prehistoric sense” …
“The catastrophic collapse of the Rio Coca lava-dam is unprecedented in modern history”
(USGS representative)
Over the four years since the lava dam collapsed, approximately 500 million tons of sediment has migrated
down the Rio Coca.
Source: http://lcgeography.preswex.ie/waterfall-river-landform.html
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geomorphodynamic Process
The rock mass that forms the "San Rafael" waterfall
(lava) was weakened by an erosive processes called
"Giant Marmite"; favoring the progressive
infiltration of water and internal erosion
(tubification) until the rock mass collapsed.
Photo June 2020. Credit: Jorge Sevilla.)
Source: satellite image, December 2013 (Google Earth)
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geomorphodynamic Process
SINKHOLE FORMATION (Subsidence) at
“San Rafael” waterfall was formed by two
effects.
The first effect from the upper part was a
process called “giant marmite”.
The second one, from the lower part. It
was a process of suffusion and internal
erosion of the lower layer, gradually
forming a void.
Source: https://info.igme.es/ielig/documentacion/ci/ci167/documentos/d-ci167-02.pdf
Tomado de Eduardo Aguilera
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Collapse of “San Rafael” Waterfall
The waterfall “San Rafael” was formed by a
blockage of the “Coca” river by a lava flow of
“Reventador” volcano.
Retrogressive erosion
process (upstream)
Hard Rock
(Lava Flow)
Soft Rock
(1) Undercutting
Soft Rock
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
BACKGROUND
Water dam ot the “Coca
Codo Sinclair” Major
Ecuadors’ Hydroelectric
plant (1500 MW)
Vertical erosion
Horizontal erosion
Retrogressive erosion
Modified from: https://selliliar.live/product_details/12906677.html
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
BACKGROUND
Satellite imagery taken
on February 11, 2020,
shows a process of
regressive
erosion
process towards the
Right-of-Way (ROW) of
the pipelines.
Rigth-of-way
of main
pipelines
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
BACKGROUND
On April 7, 2020, Ecuador's main oil
transport pipelines (Heavy Crude Oil
Pipeline - OCP and Trans-ecuadorian Oil
Pipeline – SOTE), as well the main polyduct,
suffered ruptures as a result of the collapse
of the Right of Way due to the effects of
the regressive erosion of the Coca River.
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Retrogressive
erosion process
threatens to
affect "Coca"
hydroelectric
power plant,
located 19,4
Km upstream
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geomorphodynamic Process
Regressive erosion process up-flow
Main Ecuador’s
Pipeline’s Right
of Way
Pipeline
rupture and
oil spill
Secondary
lateral erosion
towards roads
and pipelines
Regressive erosion
process of “Coca”
river
Photo: Andrés Novoa
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geomorphodynamic Process
Landslide Dam July 18th., 2020
Reinforcement of pipeline crossing
at “Montana” tributary river, also
affected by secondary lateral
erosion (photo: Andrés Novoa)
Photo: Andrés Novoa
Photo: Andrés Novoa
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geomorphological Processes
Sector 2: Downstream.
Narrow river channel.
Higher speed of water
flow
Geomorphological
Boundary
Sector 1: Upstream: Wide river
channels. Predominance of
sedimentation processes
Dr. Fabián Vásconez
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geomorphological Processes
Source: “Copernicus
project; Sentinel 1
Satellite, 2018.
Courtesy: Jaime Núñez.
Source: Google Earth
A macro Landslide blocked
the river flow and formed a
lagoon
Dr. Fabián Vásconez
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geomorphological Processes
A macro Landslide blocked the
river flow and formed a lagoon
Dr. Fabián Vásconez
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geomorphological Processes
Macro Landslide
Dr. Fabián Vásconez
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Civil Works to protect the Hydroelectric Dam
Source: https://radiocentro.com.ec/celec-culmina-obra-clave-para-proteger-hidroelectrica-coca-codo/
Civil Works to protect the Hydroelectric Dam
*) Mathematical and physics modelling was performed by US Army Corp
of Engineers (USACE).
https://www.celec.gob.ec/
Type:
Piles retaining wall.
Localization:
1.2 Km down-flow
of the reservoir
dam.
Quantity of Piles:
279
Type of
Installation of the
Piles:
Pre-bored.
Disposition of the
piles:
Intersected one to
the other.
Diameter of the
piles:
1.2m.
Materials:
Concrete and steel.
Depth:
24 meters.
Length of the
retainig wall:
220 m.
Start up Date:
July 2022
Finishing Date:
Sept. 2023
Cost:
USD 14,1 Mio.
Impacts in Ecuador’s
Economy
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Energy Matrix in Ecuador & Electricity Generation
Most of Ecuador’s energy supply comes from oil
and most of electricity generation form
hydropower.
Due to the fact, that retrogressive erosion of rio
“Coca” affects oil pipeline transportation and
endangers the most important hydropower
central of the country; this geomorphodymic
process has a big impact in Ecuador’s economy.
https://www.iea.org/countries/ecuador/energy-mix
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts in Ecuador’s Economy
Multiple oil-pipeline variant routes had to
be built.
Collapse of “Ventana II bridge on may 19th.
2021 (Photo credit: unknown)
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts in Ecuador’s Economy
Destroy of main access road to
oil-fields and “Amazonia” (photo
taken on March 04, 2021.
Courtesy: Andrés Novoa)
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts in Ecuador’s Economy
Photo: Andrés Novoa
Pipeline rupture
& Oil Spill
Unsuccessful efforts to stop the regressive erosion
process by placing concrete-filled containers.
Photo: Andrés Novoa
Oil Pipeline ruptures and oil spill. Around 15 K oil barrels spilled in
April 2020. 6 K oil barrels spilled in January 2022 (Photo: Andrés
Novoa)
Photo: Andrés Novoa
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts in Ecuador’s Economy
Source: https://www.primicias.ec/noticias/economia/reubicacion-obras-captacion-coca-codo-ecuador/
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts in Ecuador’s Economy
In December 2021, OCP (Heavy Oil
Pipeline) was working on the nineth
pipeline variant on the middle part of
a hillside in order to reestablish the
pumping service (photo: “El Universo”
newspaper).
Erosion
regressive
process
New Right of
Way for OCP
Pipeline
Landslide Risk
Areas
On January 28, 2022, OCP suffered a
new pipeline rupture in this sector and
an oil spill of 6.3 K barrels.
Photo: “El Universo” newspaper (Courtesy of OCP)
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts in Ecuador’s Economy
In June 2024, due to heavy
rains the erosion process
became reactivated.
Oil Pipeline
endangered due
to lateral erosion
From June 16th to 23th, the
retrogressive erosion
advanced 900m; placing the
erosion front 6.4 Km near to
the Ecuador’s main
hydroelectrical power plant.
On June, 17th the oil pipeline
operation had to be
suspended again.
On these days a new variant
of the route is being built
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts
Erosion evolution sector “San Luis” up to January 2024.
Transition form forestry coverage to eroded areas
(Source: EcoCencia, Planet)
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts in Ecuador’s Economy
 > 21 K oil barrels spilled.
 Main road to the northern Amazonia partially destroyed.
interrupted.
Connection
 Multiple pipeline route variants to keep the Trans-Ecuadorian Oil
Pipeline System (SOTE) and the Lago Agrio Quito polyduct in operation
(> USD 16.2 Mio).
 Expenses from the private sector with ten re-routes of the Heavy Crude
Oil Pipeline - OCP ( USD 70 Mio.).
 22 days of unexpected suspension in the pumping of Ecuadorian crude
oil through the Trans-Ecuadorian Oil Pipeline System (SOTE) and the
Heavy Crude Oil Pipeline (OCP). Consequently, fall in oil production,
drop in exports. Losses > USD 600 Mio.
 Import of additional $80 million in refined fuels.
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Impacts in Ecuador’s Economy
 Protecction civil works of the hydropower reservoir: USD 14,1 Mio.
 Associated costs to restart the shut-down wells. > USD 20 Mio.
 Lost of more than 500 Ha of forest between June 2020 and January
2024 (https://www.maaproject.org/2024/erosion-regresiva-ecuador/).
 Potential destruction of the water intake facility of the “Coca-Codo”
main Ecuador’ hydroelectric power and probable construction of new
water intake facilities up-flow: USD 700 Mio.
Potential Losses
>> USD 1 500 Mio.
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Could it be avoided?
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Prior Identification
Sinkhole at the
left side of the
river (red
circle)
taken on
January 28,
2020, few days
before the
waterfall
collapse.
Sinkhole was
formed as
result of an
internal
erosion and
tubing process.
Sinkhole on the
left side of the
“san Rafael”
waterfall
In yellow-color
the main oilpipeline.
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
InSAR – Interferometric
Synthetic Aperture Radar
as a remote sensing tool to
identify, and monitor
geomorphodynamic processes.
Opportune identification of
landscape changes, is the basis
for the prediction of
geotechnical and hydrotechnical
events.
InSar BACKGROUND:
Two Satellite Radar imageries of
a same area, are taken at
different times.
If a sector of the Surface has
suffered changes, a
displacement of phases occurs
and an interferogram registters
this phase differences.
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geotechnical data are automatically
collected and sent by radio
It is important to implement
real time geotechnical and
hydrotechnical monitoring in
Ecuador’s oil-pipeline systems,
in order to protect and
optimize human resources,
safeguard pipeline integrity,
save costs, and mainly to avoid
environmental impacts.
•
Geotechnical
data
are
stored,
displayed on real time and processed.
•
Dynamic
relationships
between
triggering and landslide influencing
factors
are
established
by
Geotechnical Engineers.
•
Alarm levels are set.
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Geosciences in the 21st Century – Support of Technologies
COULD HAVE BEEN AVOIDED THE EROSION REGRESSIVE
PROCESS OF THE “COCA RIVER”?
YES
It could have been avoided, if a technical service for
digitalization and analysis of multi-temporal optic satellite
imageries would have been “in place”.
The progression of the erosion process that ended in the
collapse of “San Rafael” waterfall could have been
identified opportunely, and corrective civil works could
have been implemented.
Similar kind of surveys can be implemented, as preventive
action, for others Oil & Gas Pipeline Systems.
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)
Many Thanks for
your Attention
Photo: M. Burzio
DAAD Expert Seminar “The Smarter E Europe 2024” | University of Siegen, June 24-30 2024 | Dr. Fabián Vásconez M. (PhD – Geotech. Eng.)