Dubai Municipality has started exploratory groundworks for the emirate’s planned AED30bn ($8.2bn) deep tunnel sewer network.

The Dubai Strategic Sewerage Tunnels project will contain two main tunnels with a total length of 75km. The Bur Dubai deep tunnel will have a total length of 50km and the Deira tunnel with have a total length of 25km. The tunnels will be supported by about 140km of link sewers and two major pump stations. The tunnels will reach depths of up to 90m below ground level.

The municipality has revealed that it has started geotechnical studies for the scheme, of which a key part is determining existing ground parameters to design the structural integrity of tunnels, shafts and link sewers. US-based Parsons, which has been appointed consultant for the scheme, has selected a company to drill 250 boreholes along the route of the new sewerage network. The process will take 9 months, according to the Municipality.

Following completion of the field work, the results of in-situ testing and laboratory analysis will be used to provide information for selecting the appropriate construction methods for the tunnels, link sewers and shaft excavations.

MEED reported in June that the municipality had appointed Netherlands-based KPMG to advise and assist with preparation for developing the project under a PPP model. The project had originally been planned to be developed through conventional EPC packages.

The deep tunnel sewerage network and 2 major pump station will replace 11 major pump stations and more than 100 other pump stations that currently serve Dubai’ wastewater network.