Water Pollution Control - A Guide to the Use of Water Quality Management Principles Edited by Richard Helmer and Ivanildo Hespanhol Published on behalf of the United Nations Environment Programme, the Water Supply & Sanitation Collaborative Council and the World Health Organization by E. & F. Spon © 1997 WHO/UNEP ISBN 0 419 22910 8 Case Study III* - The Pasig River, Philippines * This case study was prepared by Renato T. Cruz III.1 Country profile The Philippines is a country of 65 million people, of whom around 8 million (equivalent to 13 per cent of the total population) reside in the National Capital Region (NCR), Metropolitan Manila (Figure III.1). The population has been growing at a rate of 2.3 per cent every year over the past 10 years and urbanisation has increased from almost 40 per cent in 1985 to 43 per cent in 1990. Unemployment nationwide was 11.1 per cent in 1985 and declined to 8.6 per cent in 1989. However, the high influx of migrants from the provinces and the lack of employment opportunities in the metropolis brought the unemployment rate in the NCR to 26.1 per cent in 1985; this has since fallen to 17 per cent. The incidence of poverty has been decreasing, although it is recorded as high as 50 per cent for some provinces and at 32 per cent for the NCR. When it assumed power in 1992, the Ramos administration embarked on an ambitious programme, called "Philippines 2000", to establish the country as a newly-industrialising economy by the turn of the century. Since then the Philippines have achieved a 5.1 per cent growth in 1994 from a low of 2.4 per cent in 1993. This has earned the country the respect, albeit prematurely, of the Asian business community and the Far Eastern Economic Review referred to the country as the "most improved economy" in its Year End Review of 1994. Despite its laggard image, the Philippines remains the most politically stable country in Asia. Unlike its more economically stable neighbours which suffer from lack of succession laws, the Philippines has experienced a peaceful transfer of political power to a newly-restored democracy under Corazon Aquino, successor to the 20-year authoritarian regime of Ferdinand Marcos. This new democracy is marked by the reinstatement of democratic institutions, in particular a popularly mandated constitution, a legislature that has seen two terms since the dictatorship was overthrown, popularly elected local governments and at least three peaceful and credible elections (national and local) since 1986. By and large, the present government enjoys a relatively high level of support from the population. Its main dilemma has been sustaining the economic triumphs of the past two years while at the same time addressing the nation's advanced stage of poverty and environmental destruction. Figure III.1 Location map of the Philippines showing the national capital region of Manila III.2 Basin identification The Pasig River system runs through five cities and four municipalities (Figure III.2) and connects two large, important bodies of water; Manila Bay in the west is the country's main port of maritime trade and travel and Laguna de Bay in the east is the largest freshwater lake in the country and connects 30 suburban towns to the metropolitan centre. Before the colonial period, the Pasig River was the main point of entry for international trade into what is now the City of Manila. Advancements in land transportation have changed the landscape considerably. Traditionally, the municipalities upstream were fishing communities relying mostly on the Pasig River and Laguna de Bay, while the settlements downstream experienced rapid urbanisation with the influx of trade from other provinces and countries. Before pollution virtually extinguished aquatic life, the whole 25 km of the Pasig River between Laguna de Bay and Manila Bay served as a habitat for 25 varieties of fish and 13 different types of aquatic plant. Today, there are only six species of fish and two types of plants left that can tolerate the polluted water. The situation, however, is not irreversible. During the rainy months of June to December each year, fish from Laguna de Bay are carried by the floodwaters to the Pasig River. The flushing effect of the increased water levels in Laguna de Bay increase the dissolved oxygen content of the river to a level that increases its potential for some aquaculture activities. Unfortunately, during the dry summer months of March to May, the river is virtually dead because the water becomes stagnant with the much reduced flow. Figure III.2 Detailed map of the study area showing the Pasig River The banks of the Pasig River are lined by squatter colonies consisting of approximately 12,000 households. About 2,000 families live in houses on stilts or under the bridges, in sub-human conditions, where they present a danger to themselves and to the vessels using the river. These settlements have no sanitary facilities and their liquid and solid wastes are discharged straight into the river. The various subcultures existing in Metro Manila result in many problems that reflect the complex socio-economic characteristics of the city. With the continuous dumping of wastes, the river bed has become more and more silted with organic matter and non- biodegradable rubbish. This results in serious flooding along the river, affecting nearby communities and carrying polluted water to the households living close to the river. III.3 Pre-intervention situation A feasibility study conducted in 1991 by the Department of Environment and Natural Resources (DENR) with funding from the Danish International Development Agency (Danida) and technical assistance from the Danish consultancy company, Carl Bro International, established the levels of pollution and the overall condition of the Pasig River. The study was conducted between 1989 and 1990 and has provided the main reference point for the rehabilitation programme. III.3.1 Pollution sources Industrial pollution accounts for 45 per cent of the total pollution in the Pasig River. About 315 of the 2,000 or more factories situated in the river basin have been determined as principal polluters of the river, dumping an average of 145 t of biochemical oxygen demand (BOD) per day. This was established by determining the suspended solids in their treated and untreated waste-waters. According to records, the textile and food manufacturing industries are the greatest water polluters among those considered in the study. The pollution rate is expected to decrease by 2 per cent a year due to the limited commercial land available along the river and the increased requirements for container transport. Domestic liquid waste contributes another 45 per cent of the pollution load in the Pasig River. There were approximately 4.4 million people living in the Pasig River catchment area during the study period and only 0.6 million, or 12 per cent, were serviced by the sewerage system which treats domestic wastewaters before discharging them into Manila Bay. Untreated waste-waters from the remaining 88 per cent of the population flow through canals and esteros into viaducts leading into the Pasig River. It is estimated that 148 t d-1 of BOD is added to the Pasig River purely from the sewage outlets scattered along its banks. The Metropolitan Waterworks and Sewerage System (MWSS) (the government agency responsible for domestic liquid waste) has been hampered in its task by a lack of funds. As it is also responsible for water supply in the metropolis, it has had to give water supply a higher priority than sewage management. Solid waste contributes only 10 per cent of the pollution in the Pasig River. Although very visible, rubbish contributes only 30 t of BOD per day. However, the solid waste deposited on the surface of the water blocks the penetration of sunlight to underwater plant life and the solid waste that sinks to the river bed suffocates the existing aquatic life. Rubbish collection by the Metro Manila Authority (MMA) in the residential areas of the 367 barangays (villages) in the study varied between 70 and 100 per cent per barangay depending on the accessibility of the area to land-based collection. Inaccessible areas occur mostly along the banks of the river and hence the rubbish from these was thrown into the water. The estimated 34 t of rubbish accumulated in these riverside areas in 1990 is expected to increase to 55 t by the year 2005. III.3.2 Increasing urban migration and economic difficulties From 1988 to 1990, the rate of migration into the squatter colonies along the riverbank was estimated at 73 per cent. A steady influx of migration into the metropolis has resulted in congestion and the exploitation of land and, ultimately, the Pasig River. Increasing poverty in the rural areas has driven rural people to migrate to Metro Manila to seek better income opportunities. The river banks are the most logical areas for new settlements because many of the other squatter colonies in the metropolis are already overpopulated. The economic problems experienced by the government have prevented it from providing better housing facilities for the poor. Similarly they have been unable to address the deficient infrastructure or to introduce anti-pollution measures and this has resulted in the present state of the river and its environment. III.3.3 Lack of a strategic programme for river rehabilitation The feasibility study concluded that the pollution problems in the river have been deteriorating since the 1970s, or over the past 20 years. Previous administrations have embarked on river rehabilitation schemes but all of these, however, were short-lived because they failed to address the root of the problem.