YOGYAKARTA- It is assumed that the rainy season in 2011 is influenced by La Nina, a natural phenomenon of sea surface temperature deviation in the western Pacific Ocean region, where sea surface temperature in Indonesia will be hotter, which will form rain clouds and cause rain with high intensity. Consequently, the rainy season will last longer and wetter. As a consequence, the potential for floods in this rainy season will be greater, too.
This was delivered by researcher from Centre for Disaster Studies of Universitas Gadjah Mada (UGM), Prof. Dr. Sudibyakto, at a roundtable discussion, Climate Change and Disaster Management with the theme of Anticipation of Merapi Lava Flood Based on Rain Characteristics Analysis in Rainy Season Year 2011 at the office of the Center on Friday (30/9).
On that occasion Sudibyakto also explained about the Government Regulation of Indonesia No. 38 Year 2011 about Rivers. With the regulation, the concept of handling rivers that disgorge at Merapi is needed as a single entity of River Management.
"The concept that should be thought by the Central Government and Regional Government should be finished before the rainy season this year, because the concept is very helpful and very necessary in the arrangement of permanent occupancy of the victims of Merapi eruption in 2010 who still reach more than 2000 families," Sudibyakto said.
Furthermore, Sudibyakto said in the management of rivers that disgorge at Merapi should be done gradually, among others by preparation of programs and activities, implementation of activities and strict monitoring and evaluation. Mining of mineral stones, sand andothers should be done in a more disciplined manner, because the threat of Merapi lava flood is still very great.
Therefore, Sudibyakto added, the government should provide firmer boundaries that include areas where the riverbeds are, which includes the border river. Borderline cases should be cleared by considering the possibility of potentially destructive lava flows. Determining the demarcation line of the river should take into consideration the characteristics of river geomorphology, social and cultural conditions, as well as accessibility for further management of the river areas.
Another researcher of the Center, Dr. Danang Sri Hadmoko, S.Si., M. Sc, in the discussion explained about the research they conducted on the frequency of cold lava flood from Mount Merapi. As high as 54% cold lava flood lead to the southwest 21% to Kali Putih, 10% Kali Boyong, 28% to the south, 10% to Kali Code, and 18% to the southeast.
"This is seen from the frequency or level of frequency of flood occurrence, not from its volume," Danang said.
Previously, Head of Data and Information of Meteorology and Geophysics Agency of Yogyakarta, Toni Wijaya, predicted rains around Merapi, Sleman and Magelang to fall on the twentieth day of October. The nature of rainfall, Toni said, is expected to be normal as the previous year.
"Even in Sleman, actually, the rainfall is below normal. Unlike Magelang, it is relatively higher," Toni said.