| General Information |
| Wetland Type |
Rivers, streams - slow flowing; freshwater lake and
associated marshes |
| Province |
Rizal; Laguna; Parts of Batangas Cavite and Quezon |
| Estimated Area (has) |
91,136 |
| Coordinates |
14°11'-14°32'N; 121°03'-
121°29'E |
| Altitude |
2 masl |
|
Climate / Temperature / Relative Humidity |
Type 1 ( most of the lake); Type IV ( extreme
east). The mean annual temperature is 27°C, mean
monthly temperature range from 25°C to 29.5°C, and the extremes are
16°C and 40°C. The mean annual relative humidity is 76%. |
| Other Information |
It is the largest lake in the Philippines, with a shoreline of 220
km and a total volume of 3.2 billion cubic meters. A shallow
freshwater lake (mean annual depth , it is thought to have previously
been an extension of Manila Bay. The lake is naturally eutrophic and
highly productive. |
| Biological Diversities |
| Species Diversity |
The lake is known to support at least 23 native species of fish belonging to sixteen families and a lot of introduced species. Most common are:
Glossoqobius giurus, Clarias batrachus, phicephalus striatus, Therapon
plumbeus, Arius manilensis, Cyprinls carpio, Trichoqaster Rectoralis, Chanos
chanos, Oreochrornis nilotica, O. mossambicus
Invertibrates: Ampullaria luzonica, Corbicula manilensis,
Macrobrachium sp., Viviparara angularis. Giant golden apple snail
was introduced. Birds:
Fulica atra, Himantopus
himantopus, Ixobrychus cinnamomeus, Ardea cinerea, Sterna albifrons,
Porphyrio porphyrio, Rallus mirificust, Ixobrychus sinensis |
| Socio-Economic |
| Transboundary Human Activities |
Fishing (using fish corrals o baklad and gill net or pante), collection of snails for the local duck-raising industry. Later, fishpen culture was introduced. Other uses of the lake include irrigation of rice land, especially to the south-west, navigation and water supply for industry.
|
| Tenure |
The lake is a common resource (state owned) while surrounding areas are privately owned. |
| Threats |
| Intrinsic Source of Change |
Although the lake is eutrophic with regards to the level of
nutrients entering it, there is heavy turbidity due to wind-induced
sediment-suspension, cutting down drastically the light available for
photosynthesis. In some areas of the lake, primary production is at
critically low levels due to this inorganic turbidity. Large
blue-green algae blooms can cause heavy fish kills after calm weather.
|
| External Source of Change |
Pollution - industrial, domestic and agricultural.
About 900 industries are located in the lake basin, 90% of which are
highly polluting. Only 20% of these have any kind of wastewater
treatment facilities. The lakeshores, particularly in the north and
west are very highly populated but have no sewage treatment
facilities. In the south and and parts of the west, the lake is
contaminated by nitrates from fertilizers, and by pesticides from
ricefields. Another threat is from the closure of the NHCS. It is thought that the permanent closure of the NHCS will reduce the primary production and hence fish production. Siltation in the lake caused by the deforestation of the Sierra Madre Mountains due to kaingin and logging to the east of the lake is an extremely
a serious problem. The deforestation has likewise increased the
flooding around the lakeshore towns, especially in Metro Manila
municipalities. |
| Intervention |
| Existing National Plans |
Under the management and administration of the Laguna Lake Development Authority
(LLDA). The main plan for the lake is the possibility of using it as a
source of Manila's domestic water supply early in the next century. |
| Development Project / Research |
The NHCS was built to stop the entry of saline
water into the lake to render it suitable for human consumption.
Since
1986, extensive media campaigns have been launched to highlight the
problems of the lake and the LLDA held dialogues with NGOs, fishing
associations and other users of the lake.
It is the most extensively studied lake in the Philippines,
particularly for water quality and techniques of pen and cage culture.
Studies have been conducted by LLDA, SEAFDEC-AQD, University of the
Philippines Diliman and Los Baņos. There is a freshwater research
station at Binangonan Rizal and limnological laboratory at UP Los Baņos
and at short distance from the lake of Pasig. |
| Source of information |
Directory of Philippine Wetlands Vol I & II, PBCPP, Transboundary Diagnostic Analysis,
Philippines National Report on Wetlands |
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