Expert offers technology to control flood
Expert offers technology to control flood
Sri Wahyuni, The Jakarta Post, Yogyakarta
Eco-hydraulic researcher Agus Maryono from the School of
Engineering at Gadjah Mada University criticized on Friday the
conventional method of controlling the annual floods by building
dams, raising riverbanks or straightening rivers, arguing that it
had instead decreased the rivers' capacity to hold the
floodwaters.
"Both the government and the community seem confused in
choosing programs to cope with the problems. The choices are
often unrealistic and ineffective," Agus said in response to the
recurring floods in many regions across the country.
Instead of building more dams or riverbanks, according to
Agus, the best and most effective way to control the floods was
to increase the capacity of rivers by developing infrastructure
to distribute the floodwaters among the many rivers in the
affected areas.
"It's okay if a river overflows a little bit along the way as
it flows downstream, because it needs to maintain its existence.
It is also useful to improve water conservation in both upstream
areas and the river itself," he said.
To help a river boost its capacity to contain a flood,
riversides should be turned into structures, or "parking areas",
which can hold excess water and runoffs as the river flows
downstream. A study, therefore, was needed to locate ideal sites
to be developed into natural polders to temporarily intercept and
retain the floodwater, Agus said.
"The more parking areas there are, the more significant
they will be in preventing floods," he said.
Agus, who is also a member of the central appraisal team of
Amdal, or the Environmental Impacts Analysis, criticized the use
of other conventional drainage principles, which aimed to channel
rainwater to the rivers as quickly as possible.
"It's time to abandon these principles, because controlling a
flood is not the same as draining an area," he said.
Instead of draining, various areas allocated for farms,
housing estates, industrial complexes or office buildings must be
equipped with conservation pools to intercept and retain
rainwater before it reached the rivers, he said. The pools would
also function to absorb rainwater and conserve the water
underground.
"Conservation pools will significantly prevent the downstream
area from flooding, especially because of their capability to
absorb and temporarily hold the rainwater," Agus said.
Mass reforestation along the riverbank was another preventive
solution for the annual floods, the cause of which has often been
linked to the widespread deforestation in forest preserves and
concessions from illegal logging and poor management.
"Reforestation can no longer be postponed, because the
decreasing size of forests in various places in the country are
no longer tolerable," said Agus.
He also suggested that logging activities be halted and a
nationwide reforestation campaign be raised as soon as possible.
"Otherwise, the drought during the dry season and the floods
and landslides during the rainy season will worsen and spread
everywhere in the country. The three disasters actually stem from
the damaged ecology of riverside areas," he said.
He added that developing a "water culture" at the community
level would help in the effort to prevent floods. The campaign
for the culture would improve people's readiness to rescue their
lives and belongings in the event of flood.
"Experience shows that the efforts can curb the losses
resulting from flood up to 25 percent," Agus said.