THE Metropolitan Waterworks and Sewerage System (MWSS) said its P3.29-billion Angat Water Transmission Improvement Project (AWTIP) has been commissioned and is ready to complement the agency’s efforts in securing water supply for Metro Manila.

In a statement Monday, the MWSS Corporate Office said that AWTIP, also known as Tunnel 4, runs for 6.3 kilometers and has a diameter of four meters. It is designed to accommodate 19 cubic meters per second of raw water from Angat Dam.

The MWSS said the construction of the tunnel began in June 2016 and was finished in June 2020, three months earlier than its original completion date of September.

The MWSS said the project reduces the risk of a partial or total disruption of water supply in Metro Manila.

“It will provide redundancy and enable the 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 MWSS said.

The MWSS said the completed permanent works include intake structure at Ipo reservoir; a new transition basin at Bigte; slope protection works at Ipo Dam; a channel connecting the Tunnel 4 outlet portal to the existing aqueduct; interconnection of the new transition basis at Bigte to the existing Transition Basin No. 3; and modifications to the existing transition basin No. 3 at Bigte.

MWSS Administrator Emmanuel B. Salamat said the completion of the tunnel project clears the way for the rehabilitation of the transmission system’s main components that are 75 years old and are in poor condition.

“These factors could seriously interrupt Metro Manila’s water supply. Minor delays due to the enhanced community quarantine (ECQ) restrictions thwarted our best efforts to place on stream the additional 19 cubic meters per second (equivalent to 1,600 million liters per day) into the delivery system,” Mr. Salamat said.

Mr. Salamat said Tunnel 4 was partially operated in April to help Metro Manila’s water supply problem during the summer months.

Tunnel 4 was built with funding from the Asian Development Bank. — Revin Mikhael D. Ochave