Jakarta (Greeners) – Following recent flash floods in Sentani of Papua which have claimed lives, government agencies have split opinions about the cause of the disaster.
Ministry of Environment and Forestry ruled the flash floods were triggered by heavy rainfalls. Meanwhile, National Mitigation Disaster Agency or BNPB declared the disaster was a combination of nature and human factors.
IB Putera Parthama, director general of river catchment areas and protected forest management at the ministry, said that extreme rainfalls and high intensity rain, along with peak floods above water catchment levels are what causing the floods in Sentani.
Parthama said forest cover in Sentani river water catchment area is in good condition which makes up 55 percent of the total area. He cited logs felled with its roots, landslides on the upstream areas as the proof.
Furthermore, he said that flash floods hit Sentani after torrential rains occurred from 7pm to 11.30pm local time.
Data shows water discharge in Sentani that night was above normal condition, reached up to 193.21 m3/seconds. Meanwhile, water discharge on the banks was relatively low with 91.38 m3/seconds.
“Other factors causing flash floods in Sentani are the unstable condition of the upstream of water catchment areas. The upstream has waterproof rock contour so it would form a natural dam prone to collapse if heavy rains. The city and housing development in the downstream (affected areas) give significant impacts,” he said in Jakarta, Tuesday (19/03/2019).
He added that there were no illegal logging at the site near flash floods as no logged woods were carried out by water.
“The trees were intact with branches and roots. It showed that the logs were not from illegal logging causing flash floods,” he said.
He said water from Sereh/Tahara river and Kemiri river flooded Sentani water catchment areas which located at Cycloop Mountains Nature Reserve.
Based on the 2017 Map of Forest Covers, the reserve is 31,479.89 hectares with 2,145 hectares open areas for traditional farming, housing and non-forested areas.
He said that Sentani water catchment land cover in 1990ish was 52,226 hectares in 1996, then declined to 52,305 hectares in 2000. It kept on declining to 48,073 hectares in 2017 and 47,716 hectares in 2018.
Based on the data, land cover has been declining for five percent between 1996 and 2018.
Meanwhile, Sutopo Purwo Nugroho, head of data and information of BNPB, said the cause of flash floods, besides nature, is 43,030 people or 735 families encroaching the Cycloop Nature Reserve since 2003.
“In addition, there are land settlements and dry farming on the water catchment areas of a total of 2,415 hectares, trees logged for land clearing, housing and wood supplies, and mining,” said Sutopo at a press conference on Monday (18/03/2019).
Kadarsah, chief of climate change at Indonesia’s Climatology Agency, BMKG, said environmental destructions will turn into disasters when nature starts to work (meteorological factor). Extreme rainfalls and deforested nature reserves will cause floods.
“Climate change will lead to extreme events, including extreme rainfalls, which will frequently happen. Hence, high alert and anticipation in the future, don’t mountains go barren, better drainage. If blaming high rainfalls, this is an issue argued by people that are doing the damages or causing environmental destructions not to get the blame,” said Kadarsah.
On current development, 104 people died, — 97 in Jayapura district and 7 in Jayapura city –, because of the flash flood.
At least 40 victims were unidentified. Jayapura governor had announced mass burial on Thursday (21/3/2019).
Reports by Dewi Purningsih