ESTIMATION OF COASTAL FLOODING CONTAMINATED BY MUD-VULCANO ON FISHPONDS AND MANGROVE AREA AT SIDOARJO DISTRICT, INDONESIA

摘要

Mud-vulcano disaster at Sidoarjo District, East Java Province, Indonesia has greatly impacted the environment especially at the Jabon Sub-District. Mangrove ecosystem and fishponds in Porong Delta estuary are at risk for experiencing pollution brought by the flooding caused by the disposal Sidoarjo mud-vulcano to Porong River. This study is aimed to estimate coastal flooding of contaminated Sidoarjo mud-vulcano around the area of the Porong River and the effect on fishponds and mangrove areas. Flood model was applied to estimate flood inundation using an elevation data derived from the topographic map and the highest tide information obtained from the community who lives around the area. On-screen digitizing on Landsat and Geoeye images was extracted to get land cover information. Some interviews with the community were carried out to gather the information to estimate the effect on the product of aquaculture, especially shrimp and milkfish commodities. The results based on the model showed a decrease of productive fish-pond from 5,011 ha to 4,473 ha (60 cm inundation scenario) and 1,631 ha (80 cm inundation scenario). The effect will decrease the product of shrimp from 250 kg/ha/year to 75 kg/ha/year, but there are no significant effect on the product of milkfish. On the contrary the mangrove area have increased from 375 ha to 571 ha based on the interpretation of land cover.