State of water environmental issues
Enclosed Water Bodies
Lakes occupy 1,830 square kilometers (0.61 percent of total area).
There is no updated inventory of the lakes at present, but a recent study has placed the number of lakes at 72. The largest lake is the Laguna de Bay, which encompasses two regions: Metro Manila and Region IV with an area of 922 km.
56km south of Manila, occupies a huge volcanic crater and contains an island that is itself a volcano, with its own crater lake.
the largest lake in Mindanao, which is a major source of hydropower.
Source: Philippine Environment Monitor 2003
Laguna de Bay is one of the largest lakes in Southeast Asia and the largest and one of the most vital inland bodies of water in the Philippines. Pre-Hispanic Filipinos called the lake, Lawa ng Bai (pronounced as “ba-ee”), meaning Mother Lake. With Spanish colonization, the name became Laguna de Bay or Lake of Bay.
It spans some 90,000 hectares, with around 100 rivers and streams draining into it. It is cradled by a watershed area of 292,000 hectares encompassing the whole of 2 provinces and parts of Metro Manila, Batangas, Cavite and Quezon – all in all, 12 cities and 49 municipalities. This area spans 2,656 barangays, 187 of which are within lakeshore towns. It is bound by the province of Rizal to the North. It is the heart of CALABARZON (Cavite-Laguna-Batangas-Rizal-Quezon), one of the fastest growing economic zones in the country today. It answers to the competing and, often times, conflicting needs and demands of a watershed population of some 6 million (NSO 2000). It is host to some 10,000 small-, medium- and large-scale enterprises.
In August 2001, Laguna de Bay was unanimously accepted as the 18th member of the International Living Lakes Network.
Laguna de Bay is estimate to receive approximately 74,300 tons per year of BOD pollution. Domestic sources contribute 69 percent while the remaining 31 percent is from industrial and agricultural sources. Additionally, with the sedimentation rate of 0.5 centimeters per year, an estimated 66 percent of the land area in the watershed is vulnerable to erosion.
Routine monitoring of BOD in Laguna Lake shows that is meets the Class C water quality criterion (Figure 10). This indicates that BOD is not an issue, but siltation may be the main problem.
Source: “Laguna de Bay: The Living Lake” LLDA flyer