Lisbon drainage tunnels and related interventions

This contract includes the construction of two tunnels, the tunnel Monsanto-Santa Apolónia (TMSA) and the tunnel Chelas-Beato (TCB), aiming at creating two independent drainage systems in Lisbon, able to respond effectively and in a structured way to the needs of stormwater drainage. 

These infrastructures will be constructed by a Tunnel-boring machine (TBM).

• The tunnel Monsanto – Santa Marta – Santa Apolónia (TMSA), with an internal diameter of 5,5 m and a length of 4,60 km, goes from Campolide to Santa Apolónia, will intercept stormwater runoff from Alcântara urban drainage basins, located at Av.  Liberdade and Av. Almirante Reis (drainage basin of 2 900 ha). The tunnel was designed for a 100-year return period and will be able to drain flows over 160 m3/s.
• The tunnel Chelas – Beato (TCB)has an internal diameter of 5,5 m and a length of 1,48 km.  Its aim is to solve flooding problems in the Xabregas area by diverting flows from Estrada de Chelas drainage system (drainage basin of 1 700 ha).

There are several works related to both tunnels, which are listed and briefly described below:

• Tunnel Monsanto-Santa Apolónia (4,60 km)

Tunnel (TMSA); Diversion work from the Alcântara Channel to the water intake work (TM1); Diversion work and intersection at Avenida da Liberdade (TM2); Diversion work and intersection at Santa Marta (TM3); Diversion work and intersection at Avenida Almirante Reis (TM4); Outlet work at Santa Apolónia (TM5); Domestic Wastewater and Stormwater drainage systems at the lowest area of Santa Apolónia drainage basin, in the surrounding area to the outlet area of TMSA (TM6).

• Tunnel Chelas-Beato (1,48 km)

Tunnel (TsCB); Diversion work from the Chelas Channel to the water intake work (does not fall under the scope of this contract); Outlet work in Doca do Poço Bispo area; Domestic Wastewater and Stormwater drainage systems intecepted by the TCB outlet work.