Qatar Public Works Authority 'Ashghal' announced start of excavation works for 13,3 kilometer main drainage tunnel. Tunnel have diameter of 4.5 meters. Ashghal is  responsible for the planning, design, procurement, construction, delivery, and asset management of all infrastructure projects and public buildings in Qatar.

In a new step towards implementing its plan to develop the drainage network infrastructure in Al Wakra and Al Wukair, the Public Works Authority 'Ashghal' announces the commencement of excavation works of the main drainage tunnel within the Drainage Tunnel Project in Al Wakra and Al Wukair, which will extend for over 13 km.

During a field visit to the project site, Ashghal inaugurated the operation commencement of the Tunnel Boring Machine (TBM) that will be used for the tunnel excavation. The visit was attended by Eng. Khalid Saif Al Khayareen, Drainage Networks Projects Department Manager, a number of managers and section heads from Ashghal, in addition to representatives of the project supervision consultants and contractors.

On this occasion, Eng. Khalid Saif Al Khayareen, Drainage Networks Projects Department Manager in Ashghal, stated that the main 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).

Eng. Khalid Saif Al Khayareen pointed out that the drainage tunnel in Al Wakra and Al Wukair is one of the largest drainage tunnels in Qatar so far, with a total length of about 13.3 km and a diametre of 4.5 metres. The cost of the project amounts to 859,100,000 Qatari Riyals.

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 shafts will also help in connecting the tunnel with the drainage network in nearby areas in the future.

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. That is in line with the country's vision in the sustainable infrastructure field.

In addition, 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. This integrated network provides an advanced and comprehensive wastewater management solution at low cost of operation and maintenance. The total cost of the project with its three packages amounts to more than 1.5 billion Qatari riyals.

Ashghal started the project implementation works in November 2020, and it is expected that works will be completed in the Q2 of 2024.

The project will be subject to a maintenance and operation period of 400 days after completion by its contractors PORR-HBK-MIDMAC JV. Parsons International Limited has been assigned to supervise the design, implementation and operation of the project.

Drainage Networks Branches in Al Wakra and Al Wukair

The Drainage Network Branches that are being constructed as part of the project aim to serve the commercial and residential areas in Al Wakra and Al Wukair. The total length of these small tunnels is about 15 km, with an internal diametre ranging from 400 mm to 2400 mm, and a depth ranging from 9 m to 46 m. The tunnels will be implemented using micro-tunneling techniques through 60 shafts. This package is implemented by "Qatari Group for Trading and Contracting" at a cost of QR 399,808,530.

Treated Sewage Effluent Lines in Al Wakra and Al Wukair

The Treated Sewage Effluent (TSE) transfer pipes will be developed with a total length of 29 km and a diametre ranging between 600 mm and 1400 mm. These pipes will transport treated sewage water from the receiving sewage treatment plant to different locations in the water collection areas, to be used in irrigation of areas green, among other purposes. The network has been designed to link the existing network with the projects being implemented to provide complete operational flexibility for future operations and maintenance as needed. This package is being implemented by “UCC" and “Infraroad" JV, at a cost of QR 298,090,000.

https://www.ashghal.gov.qa/en/MediaHub/News/Pages/Launch-of-Excavation-Works-of-the-Main-Drainage-Tunnel-in-Al-Wakra-and-Al-Wukair.aspx​