「The State of the Laguna de Bay Environment: Management Challenges and Research Opportunities」

Adelina C. Santos-Borja (Head, International Linkages and Research Development Unit, Laguna Lake Development Authority, Philippines)

Laguna de Bay, a 900 km² lake, is the largest and most economically important lake in the Philippines. Its watershed of 2,920 km² hosts 61 cities and municipalities which belong to 5 provinces and Metro Manila. The lake is a multiple use resource, with fisheries as the dominant use. In recent years, it has become a source of raw water for drinking.

Due to its strategic location, the lake is increasingly threatened by anthropogenic activities. The economic developments in the watershed for the past 40 years have tremendously changed the landscape. Likewise, they served as a magnet for the migration of people from different regions, with some of them building their houses along the shoreland and river banks. These pressures have altered the water quality of the tributary rivers and the lake. Heavy metals, both of geogenic and anthropogenic origin, have been detected in certain areas in the lake and in the aquatic biota. Increasing eutrophication has been observed and in worst cases, have been one of the main causes of fishkills. Of equal alarm is siltation and accumulation of large volumes of solid wastes as well as biological pollution due to the invasion of non-native species which has altered the food chain and the biodiversity of the lake.

Water quantity has become a very serious concern, with the lake being the reservoir of flood waters exported from certain areas of Metro Manila since the eighties, and from the swelling of more than one hundred tributary streams and rivers during prolonged rains and typhoons. In the last five years, unprecedented floodings have been experienced by almost all of the lakeshore towns with heavy toll on human lives, properties and natural resources.

These ecological risks have compromised the environmental goods and services of the lake and diminished their economic benefits to the detriment of people, especially those who depend only on the resources of the lake for livelihood. Such challenges in the management and development of the lake basin’s resources call for a strategic assessment of the current ecological state of the lake and its watershed. The empirical data would serve as basis in the review, reformulation, or crafting of new policies on the use of the lake’s resources and on the type and magnitude of development in the watershed, the regulation of different industrial and business activities that discharge wastewater effluents, and the reforestation of critical areas in the watershed. It also calls for the development of an integrated Master Plan taking into account the National Government’s priority interventions in the lake basin.