Analysis and Flood Prevention Strategy
Flooding again hit several regions in Indonesia. Usually flood occurred in January or February, but during the rainy season this time the great flood occurred late December 2007. In fact, at the beginning of the rainy season has been widespread flooding in North Sumatra, West Java, Central Java, East Java, and Jakarta.
Flooding in the Watershed (DAS) Solo, Central Java and East Java is very surprising because luapannya vast flooded several districts, ranging from Karanganyar, Solo, Bojonegoro, Tuban, Lamongan, and Gresik. In addition to the Solo river basin flooding, flood basin Wulan and Juwana also flooded rice fields and settlements in Pati, Kudus and Demak. These floods destroying thousands of homes, destroyed the field population, and claimed lives. When combined with the total population by landslides that killed more than 60 people. This is very alarming and must be a special concern of government.
Floods in Jakarta on Wednesday and Thursday 2-3/1/2008 only caused by rain on Tuesday, which curahnya only 92 mm for 24 hours. Rain with precipitation 92 mm / day in the rain which pertained Ciliwung normal intensity. Although rain was still normal, even below the average maximum daily rainfall with return period of two years, but what resulted was a big flood. Several villages in Kampung Melayu and Cawang flooding that reached two meters deep. Similar things occur in the watershed Solo (Central Java and East Java), DAS Wulan, and Juwana (Central Java).As stated above, the rainfall was not especially biasadan in the normal category. If the condition of watersheds in the region well beyond the actual flood plain will not happen. However, the reality is a big flood. All these circumstances indicate that land degradation has occurred in the watershed. This is in line with data published by the Director General RLPS, Ministry of Forestry that the number of critical and very critical land in Indonesia has reached 30 million hectares. When combined with the land rather critical, the number reached 70 million ha. The number of degraded forests in Indonesia has reached 59 million ha. Land degradation resulted in the destruction of watershed hydrological functions. DAS decreased infiltration capacity and runoff coefficient increases. Based on the analysis in 2005, eventhough the surface flow coefficient on the average has reached 0.54 and now it may already exceed that number. Based on data published by the Director General RLPS, the number belonging to Priority Watershed I reach 60, are classified as Priority II reached 228.