Angat river water is convoyed from IPO dam to Bigte through the three existing tunnels, out of which only Tunnel n.°1 is today operational. The Angat Water Transmission Improvement Project (AWTIP, the “Project”) aims to improve the reliability and security of the raw water transmission system through partial rehabilitation of the transmission system from IPO to La Mesa and the introduction of water safety, risk and asset management plans. The Project includes the following works:

• a new intake structure at Ipo reservoir
• a new tunnel n.°4 (6,4 kilometers long with an internal diameter of 4,2 m excavated for its entire length with a Tunnel Boring Machine), which connects Ipo reservoir to Bigte basin n.°3 and conveys a minimum flow rate of 19 mᶟ/S.
• a transition basin at outlet of new tunnel n.°4
• an open channel
• modification of basin n.°3
• an access roads system