Geoinformation for Disaster and Risk Management - ISPRS

Accomplishments and limitations
The Binahaan River LFEWS has been operating since
2007 and largely without flaws (see also
http://www.leyte.org.ph/binahaan/). This means it
did not miss a single flooding event and it did not
issue a false alarm. It was activated 13 times, giving
residents between 3 and 10 hours to move
possessions and evacuate. This also includes
warnings at Level 1 that do not always lead to a Level
2 situation. A survey revealed that the majority of
inhabitants of the flood-prone area are satisfied with
the LFEWS, and that flood damage has been reduced.
The data currently available for the hydrology and
characteristics of the watershed (e.g. slope map) are
not sufficiently precise to run actual computer flood
models. This is a constraint, especially when it comes
to rare but very high floods not experienced by the
generation of people currently living in the river
basin. It was also observed that data gathering by
community volunteers is at times erratic and does
not provide enough reliability for basing the whole
system on volunteer contributions.
The LFEWS introduced here is an effective tool to
issue early warnings and thus increase preparedness
and reduce damage. However, disaster risk
management (DRM) is a comprehensive strategy
that should also include other aspects of risk
reduction, such as careful urban and regional
planning (e.g. prohibiting settlements in highly
flood-prone areas), or flood hazard reduction via
afforestation in the watershed (Smith, 2004; Wisner
et al., 2003). Geoinformatics has been shown to be
highly useful for all aspects of DRM and virtually all
natural hazard types (Ebert et al., 2009; Kerle et al.,
2008; Zhang and Kerle, 2008), but a real effort is
needed to set up and maintain such systems,
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which includes building and retaining the required
human and technical capacity to lead to a lasting
increase in capacity to face environmental hazards
(Smit and Pilifosova, 2003). The Binahaan system
demonstrates how low-cost solutions can be as
effective as expensive monitoring installations,
provided they have appropriate political support as
well as that of the affected people, i.e. they have a
sense of ownership.