KWASTT: Two tunnels, one project

Tunnels are essential for safe and efficient traffic flow. However, they can only fulfill this role if maintenance is properly managed. Commissioned by Rijkswaterstaat, SWARCO has been responsible since this summer for maintaining two key Dutch tunnels: the Koning Willem-Alexandertunnel in Maastricht and the Salland-Twentetunnel in Nijverdal. Two locations, hundreds of kilometers apart, but managed under a single framework: the KWASTT project.

Rijkswaterstaat decided to combine both tunnels into one contract because they were built according to the same national tunnel standard (LTS). This standardized approach made it possible to bundle the work efficiently. For SWARCO, this presented an excellent opportunity to further expand its expertise in tunnel management and demonstrate its reliability in this field.

The two tunnels differ in size and structure. The Koning Willem-Alexandertunnel consists of two tubes: one for the highway and one for the regional road. The Salland-Twentetunnel has a single tube and is located next to a railway tunnel. It also lacks a so-called “central tunnel channel,” requiring additional attention in emergency situations. Despite these differences, both tunnels must meet the same strict requirements for safety, availability, and maintenance.

The contract includes both fixed and variable maintenance. This means not only routine work such as inspections and periodic maintenance, but also life-extending measures. These ensure that both tunnels remain safe and reliable until the next major renovation. Examples include replacing lighting, cameras, and fire safety systems, as well as repairs to asphalt and tunnel walls—keeping the technical infrastructure in optimal condition.

The transfer of the tunnels is being carried out in phases. The Koning Willem-Alexandertunnel was officially handed over to SWARCO on June 16, followed immediately by the first maintenance nights. The Salland-Twentetunnel followed later, with its official transfer on August 29. Prior to this, SWARCO completed the necessary preparations.

The transition phase began on January 1, 2025, during which SWARCO prepared for the maintenance of the Koning Willem-Alexandertunnel. This included developing maintenance plans, coordinating with subcontractors and organizing personnel.

Following the official handover on June 16, the first maintenance activities took place during the nights of June 18 and 19. These included inspections and maintenance of ventilation systems, emergency exits and lighting. Since these installations are located inside the tunnel, temporary closures were required. To minimize disruption, the work was carried out at night, using a smart alternating approach: one night the highway tube was closed with traffic diverted via the regional road, the next night the situation was reversed. This approach ensured minimal inconvenience for road users, and the work was completed smoothly and to the satisfaction of Rijkswaterstaat.

The Salland-Twentetunnel was officially transferred to SWARCO on August 29. In the lead-up to this, SWARCO carefully managed the transition phase by conducting inspections, testing installations, and thoroughly documenting the condition of the tunnel at the time of handover. This ensured full clarity on the status of the tunnel at the moment responsibility was transferred.