Palakpakin Lake is covered by three (3) barangays, namely Brgy. San Buenaventura, San Lorenzo and Dolores, San Pablo City. It has a surface area of 479,800 sq. m. (47.98 hectares) and an average depth of 7.7 meters.

The lake’s inlet is connected with the outlet of lakes Calibato and Pandin. Palakpakin Lake is considered the shallow lake among the seven lakes of San Pablo.

As of 2008, the area occupied by aqua structures is 85,000 sq.m. (8.5 hectares) equivalent to 18 % of the total surface area of the lake.

Water Quality Monitoring Program

The Laguna Lake Development Authority (LLDA), by virtue of RA 4850, as amended, has the primary responsibility to promote the development of the Laguna de Bay region, which includes San Pablo City, while providing for environmental management and control, preservation of the quality of life and ecological systems, and the prevention of undue ecological disturbance,

deterioration and pollution.

The LLDA has been conducting regular water quality monitoring with the following objectives:

• To accurately assess the suitability of the lake for all its present and intended beneficial uses;

• To evaluate the impacts of development activities on the lake’s water quality that will serve as important criteria for environmental planning and management; and

• To provide sound technical basis for water resources management policies and programs for the lake.

Routine monitoring programs conducted by LLDA cover the Laguna de Bay and its tributaries as well as the Seven Lakes of San Pablo City and Tadlac Lake in Los Banos.

Methodology

One water quality monitoring station was established for Palakpakin Lake. During the conduct of the sampling activity, water temperature and dissolved oxygen concentration are measured at the surface and at 2, 4, and 6 meters depth. A gallon of composite water from surface to 5-meter depth is also collected for chemical analysis. The chemical parameters analyzed at  the laboratory include pH, total suspended solids (TSS), total dissolved solids (TDS), turbidity, chloride, nitrate, ammonia, inorganic phosphate, biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Zooplankton and phytoplankton samples are collected by passing five pails of surface lakewater through a 35-micron meshsized plankton net. Zooplankton sample is preserved in a 10% formalin solution. On the other hand, phytoplankton sample is preserved with Lugol’s solution. Chlorophyll sample is collected by grab method at the surface. Water transparency is likewise measured and all the physical observations including weather condition are noted and recorded.

At present, monitoring is conducted during the first (January, February, March) and last quarters (October, November and December), as well as in June and September.