The first part of the project is the outfall which is constructed with a length of ten kilometres from the seashore and is one of the longest outfall tunnels in the world, which ensures the preservation of the marine environment in the country.
At a depth of fifteen metres below the seabed, excavation of the outfall tunnel is a major construction challenge due to the changing land nature, the ground pressure and the water pressure at this depth. Therefore, excavation is done using the Tunnel Boring Maching (TBM) with “Earth Pressure Balance” technique, designed to operate in a range of ground conditions in Qatar. A highly professional and specialised team carries out all marine works.
The tunnel lining is conical universal precast concrete rings with a dimeter of around four metres, and is reinforced by steel fibres to protect the tunnel. The tunnel ends on a vertical riser shaft, which pushes storm water flows to a diffuser field with an area of 14,750 square metres.
The second part of the project consists of a pumping station with 10 pumps and auxiliary facilities. The pumping station will be located at the end of Mesaimeer Tunnel south of Hamad International Airport. The pumping station will operate at a capacity of 19.7 cubic metres per second, and its function is to pump water from Mesaimeer Tunnel to the new outfall tunnel.