The main drainage tunnel will accommodate the drainage flows from the current and future drainage network in different areas in Al Wakra and Al Wukair, and transfer these flows to Al Wakra and Al Wukair Sewage Treatment Works, which will have an initial capacity of 150 million liters per day and is set to be the first project in the country to be implemented through Public-Private Partnership (PPP).
The main drainage tunnel, which will operate by gravity, will extend from Al Khuwaytim to the Birkat Al Awamer areas.
The excavation works will be carried out by two deep Tunnel Boring Machines (TBM), at a depth of about 60 metres underground. The TBMs incorporate advanced technologies since they were specifically designed to suit the geological characteristics of Qatar, to ensure the efficiency of the excavation process and provide the maximum safety standards for workers. This is in addition to guaranteeing that no damage will be caused to the services or facilities surrounding the tunnel.
The project includes the construction of eight shafts from land to the bottom of the tunnel, with depths ranging from 50 to 63 metres underground. These shafts are made to execute the deep excavation works, and carry out inspections and periodic maintenance of the tunnel.
The design life of the main drainage tunnel is about 100 years. The tunnel's innovative design adopts the best construction practices and will be implemented in accordance with international standards of health, safety, environment and sustainability management.
The project consists of two additional packages which are the Drainage Networks Branches in Al Wakra and Al Wukair, and the Treated Sewage Effluent Lines in Al Wakra and Al Wukair.