For the past
decades, the Philippines has been experiencing climate variability with extreme
rainfall. Some areas, especially the southern part, are now frequented by
typhoons and heavy rains where before such phenomena were rarely experienced
resulting to disastrous run-off to a surprised populace. In reaction to series
of disasters, the government has been formulating and implementing measures to
alleviate the negative impact of these calamities. Among these are reviewing
and enforcement of policies dealing with river easement and flood control, establishment of nationwide early
warning system through improvised hydrological sonar gauges linked through SMS
and internet, acquisition of LiDar digital elevation maps for flood modeling
and flood forecasting, and production of hazard maps as guides for land use
planning, and formulation and revision of master plans and feasibility studies for flood management in prioritized
river basins. At this stage in a changing environment, accuracy and reliability
of each measure is still rudimentary.
While the
country is developing flood disaster management, there are still many issues to
resolve. At present flood plain management is governed by the current policy on
river easement. It is enforced hardly as
there are many encroachments legally and illegally in the waterways. At the
same time, river boundaries are not clearly established even in urbanized areas
and especially where river shifting is experienced. Another issue is the
watershed where settlers are uncontrollably falling down trees and bushes for
agricultural purpose, for firewood and as means of livelihood.
It is indeed
a big challenge to clear the high risk areas in flood plain and watershed areas
where more often available budget for relocation and political interest are big
stumbling blocks. These could be one of the foreseeable reasons for poor implementation
of land use and watershed management.
On modeling, flood
hazard mapping, flood forecasting, warning, and planning, the country has spatially
sparse hydrological data plus the changing norms due to climate change. Also, data
sharing even among government agencies is not cohesive. Dissemination of warning
information becomes confusing also, because many players are now involved in
processing and in media release. It is also found out that there are discrepancies
between the actual and the acquired data. As there are few local experts on
modeling, calibration to get more efficient results may take some time.
Lastly, due
to limitation of budget, flood management implementation in different river
basins is prioritized according to risk and necessity. At the rate of
occurrence of disasters on nationwide scale, priority ranking will be revised
soon.
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