Water Quality Laguna de Bay is classified as a Class C inland water (DENR 1990), which means it is suitable for fishery. Critical levels of pollution were already detected in 1973 (SOGREAH 1974). About 5,000 tons of nitrogen were estimated to have entered the lake, 26 percent of which was domestic, 36 percent from livestock and poultry, 5 percent from industrial sources, 11 percent from fertilizers and 22 percent from the Pasig River backflow. In 1995, of about 66,305 tons/ year of BOD loading, estimates show that the main source had shifted from industrial (21 percent) to domestic (65 percent), while the contributions from agricultural sources (13 percent) and forest areas (1 percent) did not manifest significant changes. This trend continued into the next decade such that in 2000, out of 74,300 metric tons/year of BOD loading, around 69 percent came from domestic and 19 percent from industrial sources, while agriculture manifested slightly lower loading (11.5 percent) and forest areas (1 percent) the same level (LLDA-DSS 2005). In 2010, calculated 81,701 metric tons/year of BOD loading into the Laguna Lake was contributed by domestic sources (about 78 percent) ,industrial sources 11 percent, agricultural sources 10 percent and 1 percent from denuded forest (LLDA-DSS 2012; LISCOP M&E Report). On the other hand, for the same period (1995-2010) dissolved oxygen levels have consistently been much better (from 7 to more 39
than 9 mg/L) than the 5 mg/L Class C criterion. The current state of the lake is eutrophic. Several factors contributed to this present condition: population pressures, industries mostly found in the densely populated west bay area, and intensive agriculture and land-use conversion, which increased sediment loading in the lake. History of Flood Disasters Because of its location and ecological challenges, the Laguna Lake Region is among the most vulnerable to natural disasters in the country. There were historical records of flood disasters occurring in the lake region for many years. The most recent and most damaging flood events were typhoon Milenyo (September 2006), typhoon Ondoy (September 2009), typhoon Pepeng (October 2009), and typhoon Santi (October 2009). Overall, the damages and losses inflicted by these typhoons in 2006 and 2009 in the Laguna Lake Region were 1,233 dead, injured and missing, 318,055 damaged residences, PhP 2.12 billion damage to agriculture (PDNA, 2009). A 2010 synthesis report of the World Bank (WB), Asian Development Bank (ADB), and Japan International Cooperation Agency (JICA) estimates that the costs of flooding ranged from PhP 15 billion ($337 million without climate change, 1-in-10-year floods) to PhP 111 billion ($2.5 billion with climate change, 1-in-100-year floods.) These impacts
translate to roughly 3 to 24 percent of greater Metro Manila and Laguna Lake Region’s Gross Domestic Product (GDP). The report notes that flooding in Metro Manila is caused by the limited capacity of most upstream river channels draining into the Laguna Lake to confine floodwaters, the slow-flow capacity of the outlet channel from the Laguna Lake, and the declining capacity of the Laguna Lake itself to serve as a detention reservoir for floodwaters.
As LLDA celebrates 44 years of existence, it is mindful of the four decades of human activities that have changed and shaped the landscape of this region. It remains committed to restoring ecological balance to the lake, the region and its people, and transforming this all-important resource as a focal center of climate-resilient and sustainable development for the region and the country as a whole. The Ecological Footprint will play a major role in these efforts, now, and well into the future.
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