Analysis of Lahar Flood Impact on Agricultural Land in Telagawaja Watershed, Bali, Indonesia

Following the eruption of Agung Volcano in 2017, erosion from material deposits in the recharge area of the river can cause lahar flooding in the downstream areas. Lahar flood which triggered by high rainfall intensity will impact the environmental, one of it is agricultural land especially ricefields. This research is carried out to analyse the impact of Agung Volcano's lahar to rice fields in Telaga Waja Watershed, one of the watershed with high potential of lahar flood. Calculation on the impact of lahar flood to rice fields is calculated using the value of rice productivity. The lahar flood hazard areas are modelled based on 1 million m 3 , 5 million m 3 and 10 million m 3 of lahar volume. The impact of lahar flood to rice fields from 1 million m 3 lahar flood scenario shows that total 30,45 ha areas are affected with total productivity reached 194.89 ton and total value of IDR 2,338,680,000.00. 5 million m 3 lahar flood scenario shows total 68.26 ha areas of rice fields are affected by lahar flood with total productivity reached 436.89 ton with total value of IDR 5,242,680,000.00. Meanwhile 10 million m 3 lahar flood scenario analysis shows that total 74.08 ha areas of rice fields are affected by lahar flood with total productivity reached 474.1 ton with total value of IDR 5,689,200,000.00.