Yambo Lake is shared by two municipalities: Brgy Sulsugin, Nagcarlan and Brgy. San Lorenzo, San Pablo City. It is adjacent to Pandin lake. It has a surface area of 30.5 hectares. Yambo is suitable for swimming, outings and picnics.

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, 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.

Since the 1970’s, 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.

Water quality monitoring was conducted in Yambo Lake in 1986 up to the first  quarter of 1989 on monthly basis. The monitoring was stopped in the next four years and it was in May, 1994 when the activity was again resumed. However, due to poor road condition, sampling was conducted only on an intermittent basis. It was in 2002 when road construction was completed that regular monitoring of Yambo was made.

One sampling station was established for Yambo lake. During the conduct of the sampling activity, water temperature and dissolved oxygen concentration are measured at the surface (s) and at 2,4,6,10,15, 20 and 25 meters depth. A composite water from the aforementioned depths is taken for water quality 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 lakewater through a 35-micron mesh-sized 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) and in June and September.