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.