Geography of the Philippines Bay. Laguna de Bay, east of Manila Bay, is the largest freshwater lake in the Philippines. Several rivers have been harnessed for hydroelectric power. To protect the country's biological resources, the government has taken a first step of preparing a Biodiversity Action Plan to address conservation of threatened species. The islands are volcanic in origin, being part of the Pacific Ring of Fire, and are mostly mountainous. The highest point in the country is the peak of Mount Apo in Mindanao, which is above sea level. The second highest point can be found on Luzon at Mount Pulag, a peak
Bumbungan River from the Sierra Madre Mountains, in the highlands of Cavinti town, flowing through the town of Pagsanjan and ending in Lumban where it drains to Laguna de Bay, the largest lake in the country. Bumbungan is one of 21 major tributaries of the lake and responsible for up to 35% of the water that flows into the lake. It is regularly monitored by the Laguna Lake Development Authority(LLDA) through one of its 15 river monitoring stations. Located about southeast of Manila, the Bumbungan River is a major tourist attraction within the Pagsanjan Gorge National Park with its rapids and waterfalls.