Cirebon is vulnerable to flooding ahead of the rainy season because environmental degradation has altered river deltas, a conservationist said recently.
"The damage is caused by severe silt buildup in the rivers. They can't retain water during the wet season so runoff overflows and floods surrounding areas," said Yoyon Suharyono, an activist at the Labor and Environment Foundation, after taking part in a regreening initiative which planted 6,000 saplings in Cirebon regency Tuesday.
He said upstream forest destruction had triggered the excessive sedimentation. Nearly all rivers which empty along Cirebon's north coast begin on Mount Ciremai, the highest mountain in West Java.
Forested areas on Ciremai's slopes face chronic degradation, and regularly fail to function as catchment areas.
"Destruction in the upper courses has worsened erosion and accelerated the silting-up of these rivers," said Yoyon.
He said at least 20 of the 56 rivers and tributaries which empty along the regency's north coast were badly silted up.
The worst-affected areas are in Gunung Jati, Gebang, Kapetakan, Losari and Mundu districts.
"Sedimentation is caused by soil getting swept into runoff which flows into the rivers and ends up deposited in the rivers' deltas," said Yoyon.
Yoyon added forest destruction around Mount Ciremai was mainly caused by illegal logging, sand mining and forest fires. He said the extent of damage in the area has reached 2,000 hectares.
"These factors have contributed to the rapid sedimentation rate in the rivers," he said.
Other causes for excessive river silting are the piling up of solid waste in the rivers and heavy rainfalls which accelerate sedimentation.
"Many people are still unaware of the environment's importance so they continue to dump garbage into the rivers," Yoyon said.
Flood-prone areas in Cirebon regency include thousands of hectares of rice fields in the five worst-affected districts. Besides devastating farmland, floods often ravage residential areas in those districts.
Last year, damaged farmland amounted to 2,500 hectares and cost Rp 3.5 billion (US$304,000).
