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Earlier
classified as safe rivers or Class C waters, Tanay and Lian-Palico
Rivers in Rizal and Batangas, respectively, were found to
be risky for recreational and industrial use, and propagation
of aquatic life.
Antonio
Daño and Carmelita Villamor, researchers from the Department
of Environment and Natural Resources - Environmental Research
and Development Bureau (DENR-ERDB), further evaluated the
rivers’ water quality. They also classified the river
ecosystem of Tanay and Lian-Palico River using the landscape
approach. They determined the range of consumptive and non-consumptive
uses and identified critical parameters in assessing the ecosystem
health risk of the two rivers.
This
project of DENR-ERDB verified that the two river systems contain
very high level of coliform and organic pollutants way above
the limit for Class C waters.
The
low level of dissolved oxygen--an indication that a river
is in a very bad state--in the lower reach of Lian-Palico
river, could also trigger fish kill anytime.
The
continuous growth in human population around these rivers
increased pressure on the natural resources, which result
in environmental degradation. Such effects have spawned growing
concern on freshwater ecosystem not only due to their water
supply function but also because of its importance on the
life support system, in general.
Monitored
and evaluated by PCARRD, the project recommends that the current
system of river classification be modified to reflect its
true present condition. Specifically, the present classification
(Class A, B, C, and D) should be refined by incorporating
the water quality index system.
The
two classification systems that can be considered are as follows:
a) Incorporate the health of the river and the limitations
or problems in the rivers, and b) revise the current system
and use the health status of the river system. This means
using the classification from Very bad to Excellent condition
then indicating the major problem of the river. (Ma. Rowena
M. Baltazar, S&T Media Service)
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