GHANA – Climate Change Risk Assessment for the Akosombo and Kpong Hydropower Plants

Representing COBA within the COBA/ARTELIA Consortium, specialists José Cruz Morais and Mariana Correia took part in the mission to Ghana as part of the project “Climate Change Risk Assessment for the Akosombo and Kpong Hydropower Plants”. The Stakeholder Engagement Workshop was held at the Client’s headquarters (Volta River Authority – VRA) in Accra, between 15 and 21 June 2025.

The main objective of the project is to assess the resilience of the two hydropower schemes to climate change, in line with the processes and recommendations set out in the Hydropower Sector Climate Resilience Guide, published by the International Hydropower Association (IHA).

In addition to the workshop and participation in several meetings with the VRA and the European Investment Bank, technical visits were carried out to both dams – located on the Volta River – as well as to their respective hydropower plants.

The reservoir created by the Akosombo Dam, with a surface area of approximately 8 500 km², is the largest in the world in terms of flooded area. Its total storage capacity is around 148 km³ roughly 36 times that of the Alqueva Dam reservoir.

The installed generation capacity of the Akosombo and Kpong hydropower plants is 1020 MW and 160 MW, respectively.

Lx, 24 June 2025

BRAZIL – Hydropower 3.0

The challenges associated with the modernization and repowering of Brazilian hydropower plants were the focus of a workshop organized by the World Bank and ESMAP, and led by the INTERTECHNE / COBA Portugal / PSR consortium.

The event took place on 18 June at the Ministry of Mines and Energy in Brasília and marked the culmination of a study carried out by the three companies. The aim was to identify barriers and propose solutions to unlock investment in the sector. The workshop brought together Brazilian public agencies, industry associations, and concession-holding companies.

COBA was represented by André Mendes, who led the study on behalf of the company, and António Pereira da Silva, a COBA board member, who took part in the round-table discussion “Technical Solutions for the Repowering and Optimization of Hydropower Plants”, where he shared COBA’s international experience, with particular emphasis on pumped-storage hydropower schemes.

Lx, 20 June 2025

PORTUGAL - 11th Portuguese Road and Rail Congress

The COBA Group participated in the 11th Portuguese Road and Rail Congress, organized by the Portuguese Road and Rail Centre (CRP), which was held at LNEC in Lisbon from 13 to 15 May 2025.

Alexandre Portugal contributed to the Plenary Session with a presentation on “High-Speed Rail in Portugal”.

Three technical papers were presented by COBA specialists Carla Vintém, João Pinho and Gonçalo Mateus:

“Évora Line – Southern International Corridor” (Carla Vintém);

“Structural Effects of Internal Expansive Reactions in Concrete in Standard Civil Works” (João Pinho);

“Lot 2 of the Extension of the Lisbon Metro Yellow and Green Lines | Santos – Cais do Sodré Station” (Gonçalo Mateus);

COBA also had a presence in the technical exhibition with a dedicated stand.

Lx, 20 May 2025

PORTUGAL – Strong Presence of the COBA Group at the 15th Dam World Conference 2025

The COBA Group had a prominent role at the 15th International Dam World Conference, held at LNEC in Lisbon from 13 to 17 April 2025.

As a bronze sponsor, COBA contributed actively to the event through the presentation of several technical papers, participation in training courses and parallel workshops, and with a stand in the technical exhibition.

A team of specialists from COBA – António Amador, Alexandre Duarte, Cristina Costa, Daniel Leite, Gonçalo Mateus, Joana Antunes, Lurdes Pimenta, Magda Roque, Ricardo Sardinha, Rui M. Freitas, and Virgílio Rebelo – was involved in the preparation and delivery of 12 technical papers:

“Main Failure Modes In Embankment Dams, Mappable With Drone Survey”;

“Geological and Geotechnical Studies in Dams Design. Foundation, Reservoir and Construction Materials”;

“Caculo Cabaça Hydropower Project - Evaluation of the susceptibility of aggregates for participation in expansive alkali-silica reaction”;

“River Diversion of Caculo Cabaça Hydropower Project”;

“Overall Hydraulic Model Test of Caculo Cabaça Hydropower Project”;

“Strengthening Key Water Infrastructure in Mozambique: Risk Analysis of Massingir Dam Downstream Valley”;

“Strengthening Key Water Infrastructure In Mozambique: Risk analysis of the Pequenos Libombos downstream valley”;

“A Detailed Safety and Risk Assessment of Pequenos Libombos Dam”;

“A Detailed Safety and Risk Assessment of Massingir Dam”;

“Design of Raghai Embankment Dam in a Complex Geological and Geotechnical Framework (Tunisia)”;

“Calucuve Dam – Geotechnical Conditions And Design”;

“Design, Supervision, And Technical Assistance To Construction Of The Southern Expansion Of IRCL”.

Para além das comunicações participamos em diferentes cursos e workshops:

Course 2 - “Dams affected by concrete swelling reactions: diagnosis, prediction and rehabilitation” (Maria Cristina Costa e Gonçalo Rocheta)

Course 3 - “Dam-break flood risk modelling and emergency planning” (Bruna Luís)

Workshop – “CDA Tailings Dam Breach Analysis” (André Mendes)

Lx, 21 April 2025

PORTUGAL – COBA Honoured at APPC’s 50th Anniversary Congress

The 50th Anniversary Congress of APPC (Portuguese Association of Engineering and Management Consultants) took place on March 12 at the Centro Cultural de Belém, bringing together esteemed state officials and prominent figures from the engineering sector. The event provided a platform for insightful discussions on some of today’s most pressing and complex challenges.

Beyond commemorating half a century of history and achievements in Portuguese engineering, the congress, in which COBA was represented at its highest level, served as a forward-looking forum, fostering dialogue on the sector’s future.

The event also paid tribute to APPC’s founding companies, a distinguished group in which COBA takes pride in being included, as well as to the Association’s former presidents. In this context, APPC honored Eng. Vitor Carneiro, Member of COBA’s Strategic Council and President of APPC from 2007 to 2019, along with Eng. Joaquim Caldeira Rodrigues, a founding member of COBA and President of APPC from 1990 to 1993. The latter was represented by his son, Eng. Sérgio Rodrigues, himself a former COBA collaborator.

These moments serve not only to celebrate the past but also to inspire a future filled with challenges and accomplishments.

Congratulations to APPC and to all who have contributed to its 50 years of dedication and excellence!

Lx, 25 March 2025

Did you know? - The Lezíria bridge over the Tagus river

The Lezíria Bridge crosses the Tagus River near the city of Carregado, connecting the A10 motorway to the west and the A13 motorway to the east. BRISA, the concessionaire for these motorways, launched the Design/Build tender for the construction of the bridge.

COBA led the design consortium, initiating the Detailed Design phase in 2004 and completing it in 2007 with the conclusion of the construction works. During this period, Technical Assistance was provided concurrently with both the design and construction phases.

The bridge, with a total length of 11,900 meters and a width of 30 meters, consists of three main components: the North Viaduct, the Bridge over the Tagus River, and the long South Viaduct, which spans the alluvial plain. The foundations of the viaducts consist of pier piles with a diameter of 1.5 meters, while the bridge foundations are made up of 2.2-meter-diameter piles, reaching depths of over 50 meters.

The Lezíria Bridge: Length: 11.900 m Width: 30 m

Main Structures

North Viaduct: 1.700 m

Bridge over the Tagus River: 972 m

South Viaduct: 9.230 m

The construction of the Bridge over the Tagus River was executed using the cantilever method, with a cast-in-place box girder deck and typical spans of 130 meters. The North Viaduct was primarily built with a launching girder and a deck composed of ribbed slabs, featuring typical spans of 33 meters. The South Viaduct construction involved a deck made of U-shaped beams and precast slabs, with typical spans of 36 meters.

Given the project's importance and scale, it was supported by an architectural study and a landscape integration plan, focused on creating a cohesive design for the three structures that form the crossing.

Lx, 22 January 2025