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Trojena 4.7bn NEOM reservoir project stopped, leaving partial geotechnical and hydraulic challenges

Concept rendering of the planned Trojena artificial lake and dam system, illustrating the intended high-altitude reservoir integrated within a leisure and tourism development. Source: Studio Pietrangeli

The artificial lake and dam project at Trojena, part of Saudi Arabia’s NEOM development, has reportedly been cancelled after partial construction had taken place. The decision affects a large-scale hydraulic engineering scheme planned for an arid, high-altitude environment and raises considerations regarding project planning, cost management, and the handling of incomplete infrastructure.

The project was designed as a central feature of a mountain resort and included a 1.7-mile-long artificial freshwater lake supported by multiple dam structures. The main dam, planned as a roller-compacted concrete structure, was expected to reach a height of approximately 145 m, with additional structures forming a reservoir basin. Excavation works had already removed substantial volumes of rock, some of which was intended for reuse in construction.

On-site geotechnical and engineering inspection of excavated rock slopes, highlighting stability assessments required following the suspension of construction activities. Source: Studio Pietrangeli

With construction activities halted, engineering priorities are shifting toward site stabilisation and risk management. Partially completed structures and excavated areas require monitoring and mitigation to address potential geotechnical and hydraulic risks.

Early-stage construction works at the Trojena site, showing large-scale excavation and earthworks within a mountainous desert valley prior to project suspension. Source: Studio Pietrangeli

Key technical considerations following the suspension include:

Assessment of slope stability within excavated areas, where exposed materials may be susceptible to erosion and weathering.
Monitoring of pore water pressures to identify potential seepage or subsurface instability.
Use of instrumentation, such as inclinometers, to detect ground movement in steep terrain.
Implementation of drainage and erosion control measures to manage surface runoff and reduce downstream risks.

The absence of a completed reservoir alters the risk profile of the site. Instead of operational risks associated with a functioning dam, attention is focused on surface water management, sediment movement, and long-term condition of exposed materials. Potential mitigation measures may include controlled backfilling, drainage systems, and reinforcement of partially constructed elements.

The project has also raised considerations related to large-scale infrastructure planning. The proposed lake relied on desalination and water transfer systems, which involve energy and resource requirements, particularly in regions with high evaporation rates.

The suspension of the project highlights the importance of incorporating risk management and contingency planning in large infrastructure developments, particularly in complex environmental conditions.

Future plans for the Trojena site remain subject to further evaluation, including potential stabilisation or alternative use of the existing works.

Sources: pietrangeli.com, geomechanics.io, ecoticias.com, newcivilengineer.com