Italian JV, GLF/SELI, comprising Grandi Lavori Fincosit; Società Esecuzione Lavori Idraulici; and local Philippine firm Angeles Construction Corp. has broken through on a 13km long, 4.9m diameter water diversion tunnel in Manilla.
The Umiray-Angat transbasin project (UATP) tunnel broke through in February, paving the way for the completion of the Umiray River diversion scheme in May that will help end water shortages in the Philippine capital.
The precast concrete, hexagonal, segmentally lined tunnel is believed to be the longest built by a single double shielded TBM (a Robbins machine 4.9m in diameter), operating continuously in one direction. The lack of access at the Umiray River end of the site made it impossible to create a second portal.
The project is costed at $53.2m at current exchange rates, although closer to $65m when the job started in January 1996.
About 800m litres of water a day will flow from the Umiray River through the tunnel to the Angat Reservoir in Bulacan, which supplies about 95% of Manila’s water.
This additional supply will increase total flows by 30%, boosting the number of homes with tapped water by 105 000 and ending water rationing for many others. The scheme will secure Manila’s water needs until 2007 when the Laiban dam and water supply scheme, which starts this year, is due for completion.
The Umiray-Angat project will also enable the client, the Metropolitan Waterworks and Sewerage System (MWSS), to reduce the uncontrolled abstraction of groundwater by the private sector. A full feature on the Umiray-Angat Transbasin Tunnel will appear in a forthcoming issue of T&T International.
