Lake Features
Calibato Lake is the
deepest lake among the seven lakes of San Pablo with
an average depth of 156 meters and surface area of
43 hectares. The lake has two jurisdictional areas:
Brgy. Sto. Angel in San Pablo City and Brgys. Tala
and Antipolo in Rizal, Laguna.
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 Baños.
Methodology
One
sampling station was established for Calibato lake.
During the conduct of the sampling activity, water
temperature and dissolved oxygen concentration are
measured at the surface and at 2, 4,6,10,15,20,
25,30 and 35 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 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.
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