Monsoon rains force Luzon dams to open spillways enablePagination: false endIndex: Metro Manila (CNN Philippines, July 26) — Three of Luzon’s major dams opened spillway gates after the southwest monsoon dumped heavy rains over the weekend. The Ambuklao Dam in Benguet province released water as the reservoir hit close to its spilling level of 752 meters early Monday morning, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration. Water discharged from the dam flows to its downstream Binga dam. Luzon’s biggest dam, the San Roque Dam in Pangasinan, serves as the catch basin for the Ambuklao-Binga dam systems. San Roque Dam’s water level on Sunday was way below its spilling level of 280 meters, enough to contain spills from the other two dams.