Tunnel boring machines (TBMs) have completed excavation work on the 10km long main tunnel of the Mesaimeer Surface and Ground Water Drainage Project in Doha, according to press reports.

The Public Works Authority (Ashghal) said the new project will discharge groundwater and storm-water into the sea, helping reduce both the pumping costs and disposal of groundwater in construction projects around the country, as well as preserving the foundations of buildings and reducing land subsidence due to rain.

According to The Peninsula, excavation work on the main tunnel required two TBMs, specially designed and developed for this project by the German manufacturing company Herrenknecht AG. The ‘moles’ excavated a tunnel 30 metres beneath the ground.

The tunnel is connected to the drainage network and will hold surface water from sub-networks over an area of about 170 sq km. The tunnel is also linked to a pumping station with a capacity of 19 cubic metres per second to discharge water through the offshore outfall.

Remaining construction work on the project includes the further excavation and construction of sub-tunnels, inspection manholes and 21 access shafts along the main tunnel to enable maintenance.

Completion of Ashghal’s Surface and Ground Water Drainage Project is expected in the first quarter of 2017.