The new P3.29-billion tunnel that would improve the 53-year old Angat Dam’s transmission system and its overall reliability will soon be fully up and running, according to Metropolitan Waterworks and Sewerage System (MWSS).
In a statement, MWSS said the new and fourth at Angat Dam, which supplies 97 percent of Metro Manila’s water needs, is already fully commissioned after the successful completion of all the components of the Angat Water Transmission Improvement Project (AWTIP).
Metro Manila currently gets its water supply from the interconnected Angat-Ipo-La Mesa water system.
AWTIP involves the construction of a new tunnel in the system, which is 4.00 meters in diameter and 6.3 kilometers in length from Ipo to Bigte in Norzagaray, Bulacan. It seeks to augment the present three tunnels connecting the Ipo to the Bigte transmission route.
MWSS has already partially operated the Tunnel 4 last April, a development that according to MWSS Administrator Emmanuel Salamat has helped solve the usual water supply problem being experienced in Metro Manila during the summer months.
The construction of the tunnel project started in June 2016 and was expected to be fully completed in September. Thus, it was commissioned ahead of schedule.
“I am very pleased to see the completion of Tunnel 4 as it now paves the way for the rehabilitation of [Angat Dam] transmission system’s main components that are as old 75 years, in poor condition, and most likely not in compliance with current structural and seismic requirements.These factors could seriously interrupt Metro Manila’s water supply,” Salamat said in a recent statement.
“We are currently in commissioning activities and continue to work non-stop,” he added.
As part of the Tunnel 4 component of AWTIP, completed permanent works include intake structure at Ipo reservoir; new transition basin at Bigte; slope protection works at Ipo Dam; channel connecting Tunnel 4 outlet portal to existing aqueduct 5; interconnection of the new transition basin at Bigte to the existing Transition Basin No. 3; and the necessary modifications of the existing transition basin No. 3 at Bigte.
MWSS said the AWTIP is a critical component of the MWSS’ water security program as it mitigates the risk of a partial or total disruption of water supply for Metro Manila.
It will provide redundancy and enable the dam’s overall system’s full design capacity to be restored by allowing the upstream tunnels and downstream aqueducts to be sequentially closed, inspected, and rehabilitated or decommissioned.
The project was funded by Asian Development Bank (ADB), which also recently committed to fund the development of a seventh aqueduct in Angat Dam. The project is called the Bigte-Novaliches Aqueduct 7 (BNAQ7).