PROCEEDING ICoSTH 2019
INTERNATIONAL CONFERENCE OF SCIENCE, TECHNOLOGY AND HUMANITIES
Chair
Ni Nyoman Pujianiki General Secretary Agoes Ganesha Rahyuda
Putu Yadnya TPC Chair Gusti Ayu Made Suartika
I Nyoman Udayana Treasury I Wayan Sariasih
Conference Management System Nyoman Putra Sastra
Duman Care Khrisne Program Chair
Ngakan Ketut Acwin Dwijendra Publications/Proceeding Ni Made Ary Esta Dewi Wirastuti
Komang Oka Saputra Nyoman Pramaita Widyadi Setiawan IGAK Diafari Djuni Hartawan I Wayan Nico Fajar Gunawan
I Made Budi Arsika
LEMBAGA PENELITIAN DAN PENGABDIAN KEPADA MASYARAKAT UNIVERSITAS UDAYANA
2019
ISBN : 978-602-294-388-4
Proceedings of the International Conference on Science, Technology and Humanities Bali, Indonesia, 14-15 November 2019
Overview of Manganese Superoxide Dismutase (MnSOD) Enzyme Level in Population with Coronary Heart Diseases Risk Factors in Denpasar
054-1 – 054-4
Nila Wahyuni, I Made Krisna Dinata, I Putu Adiartha Griadhi
Utilization Of Fly Ash Waste From PLTU Tarahan Lampung For High Quality Concrete With Glass Powder as Filler
055-1 – 055-4
Siska Apriwelni, Nugraha Bintang Wirawan, Anggi Utama Purba
Analysis of Lahar Flood Impact on Agricultural Land in Telaga Waja Watershed, Bali, Indonesia
056-1 – 056-4
I Wayan Diara, R. Suyarto, Tati Budi Kusmiyarti, Putu Perdana Kusuma Wiguna Total Cholesterol And Triglycerides Of Weaning Bali Cattle Fed Varying Protein Energy Levels
057-1 – 057-3
Nyoman Sadra Dharmawan, I Gede Mahardika, Ni Nyoman Suryani
Abstract Document Clustering using Bisecting K-means Algorithm 058-1 – 058-4 Nyoman Putra Sastra, I Putu Gede Hendra Suputra
The Effect of Production and E-Commerce Factors on the Income of Alpaka Jewelry Craftsmen in Gianyar Regency
059-1 – 059-5
I Ketut Sudiana, I Gede Wardana, I Gde Ketut Warmika
The Effect Of Proactive Cognitive Game Method Toward Knowledge Of Adolescents Reproductive Health
060-1 – 060-5
Anak Agung Istri Mas Padmiswari, S.Si., M.Si, Putu Indrayoni, S.Farm., M.Farm., Apt.
Modelling Microservices Architecture For Integrated Information Systems
061-1 – 061-4
Dewa Made Wiharta, Nyoman Putra Sastra, Linawati, I Wayan Adi Juliawan Pawana, I Gusti Ayu Garnita Darma Putri
The Provision Of Campus Bus Through A Use Of PTVVisum (Case Study:
InstitutTeknologi Sumatera)
062-1 – 062-6
Siti Rahma, Reza Asriandi Eka Putra
Characteristics Of Turmeric And Tamarind Leaf Extract Cream In Hydrophile-Lipophile Balance And Perfume Type Variation
063-1 – 063-5
Sri Mulyani, Bambang Admadi Harsojuwono and I Ketut Satriawan
EFFECT OF ETHANOL EXTRACTS OF MUSTARD GREEN ( Brassica rapa L) CAUSEON LOWER MALONDIALDEHYDE (MDA) IN STREPTOSOTOZIN INDUCED DIABETIC RATS WISTAR
064-1 – 064-5
Sri Wahjuni, Ni Wayan Bogoriani
Proceedings of the International Conference on Science, Technology and Humanities Bali, Indonesia, 14-15 November 2019 Paper No. 056
056-1
Analysis of Lahar Flood Impact on Agricultural Land in
Telaga Waja Watershed, Bali, Indonesia
1I Wayan Diara
Faculty of Agriculture Udayana University
Bali, Indonesia [email protected]
2R. Suyarto, 3Tati Budi Kusmiyarti, 4Putu Perdana Kusuma Wiguna 2Faculty of Agriculture
Udayana University Bali, Indonesia [email protected]
3Faculty of Agriculture Udayana University
Bali, Indonesia [email protected]
4Faculty of Agriculture Udayana University
Bali, Indonesia [email protected]
Abstract—
F
ollowing 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 m3, 5 million m3 and 10 million m3 of lahar volume. The impact of lahar flood to rice fields from 1 million m3 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 m3 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 m3 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.Keywords—lahar, impact, agriculture.
I. INTRODUCTION
Indonesia is one of the countries with the most volcanoes. Indonesia has 129 active volcanoes [1]. Volcanoes that are still active and has residential on the surroundings should be aware of the potential for volcanic eruptions.
Potential for volcanic eruptions without population preparedness will increase the risk of being affected by eruptions.
One of the volcanoes that experienced an eruption was Agung Volcano in Bali Province at the end of 2017.
Agung Volcano is a stratovolcano. The main hazards produced by this type of volcano are explosive eruptions, pyroclastic flows, lahars and slow-moving lava flows. Typically the pyroclastic flows and lahars cause the majority of the damage, with the ash generated by explosions creating the greatest disruption and discomfort to communities [2].
After 53 years of quiescence, Mount Agung start to awoke in August 2017, with intense seismicity, measurable ground deformation, and thermal anomalies in the summit crater. Although the seismic unrest peaked in late September and early October, the volcano did not start erupting until 21 November. The most intense explosive eruptions with accompanying rapid lava efusion occurred between 25 and 29 November. Smaller infrequent explosions and extrusions continue through the present (June 2019). The delay between intense unrest and eruption caused considerable challenges to emergency responders, local and national governmental agencies, and the population of Bali near the volcano, including over 140,000 evacuees [3].
After the latest eruption of Agung Volcano in December 2017, erosion from material deposits off the volcano in the upstream area can cause lahar flooding and high levels of sedimentation in the downstream areas of the river.
Lahar flood resulting from the sediment discharges triggered by high rainfall intensity can cause losses and damage to the rice fields. Entering the rainy season, lahar floods hazard is increasing so there’s an urgency to estimate the impact by lahar floods, especially on rice fields.
II. METHODOLOGY A. Research Location
This research was carried out in Telaga Waja Watershed. Geographically, Telaga Waja Watershed is located between 08o16'49,481" - 08o30'29,371" S and 115o23'30.81 "- 115o30 '17,745" E. Administratively, Telaga Waja Watershed is located in Bangli, Karangasem and Klungkung Regencies of Bali Province with an area of 11,864 Ha.
B. Data Collection
Data collection on this research including actual extent of agricultural land especially rice fields, extent of rice fields affected by lahar floods and analysis of impact of lahar to rice fields. Calculation on the impact of lahar flood to rice fields is calculated using the value of rice productivity from Statistical Bureau of Bali Province and Statistical Bureau of Karanasem Regency [4][5]. Table 1 shows the data collection for this research.
TABLE 1.
DATA COLLECTION PROCESS
No. Data Collection Process
1 The actual extent of rice fields Digitation on Quickbird image, 2017 2 Extent of rice fields affected by lava floods Overlay process with lahar extent model [6]
3 Analysis of impact of lahar to rice fields Survey and Interviews 4 RBI maps of Bali Province and Quickbird
Satellite Image (2017)
Geospatial Information Agency (BIG) of Republic of Indonesia
C. Methodology
Estimation of the extent of rice fields affected by the lahar flood hazard is carried out using satellite image interpretation and digitation. The objects examined in this work are agricultural land especially rice fields along the Telaga Waja River. The image for this research is the high resolution satellite image from Geospatial Information Agency (BIG) assisted by Google Satellite imagery.
The method of analysis of the lahar flood hazard model in the study, focused on the results of the lahar flood model using LAHARZ software. LAHARZ software is a tool to estimate the upcoming lahar events. LAHARZ using DEM (Digital Elevation Model) and several scenarios of lahar volumes as input to create delineations of areas with potential lahar inundation from selected scenarios [6] [7].
The lahar flood hazard areas are modelled based on 1 million m3, 5 million m3 and 10 million m3 of lahar volume [8]. Then, the agricultural land impacted from lahar flood are carried out by overlay of lahar model extent and extent of rice fields. Interview, survey and questionnaire methods were then carried out to determine community’s perceptions related to impact of lahar floods to rice fields.
The approach of community perception in the context of this study uses the knowledge and experience of farmers through interviews related to the value of rice field’s production. The method of determining the sample of respondents used is purposive sampling, which is addressed to the owners of rice fields.
056-3
III. RESULT AND DISCUSSIONS
Based on the modelling using Laharz software and lahar volume scenarios of 1 million m3 (1st scenario), 5 million m3 (2nd scenario) and 10 million m3 (3rd scenario), the area affected by lahar floods is 162.63 Ha for 1st scenario, 376.63 ha for 2nd scenario and 403.23 ha for 3rd scenario [6].
The agricultural rife field impacted from lahar flood from 1 million m3 lahar flood scenario shows that total 30,45 ha areas are affected. From 5 million m3 lahar flood scenario shows total 68.26 ha areas of rife field are affected by lahar flood and from 10 million m3 lahar flood scenario analysis shows that total 74.08 ha areas of rice fields are affected by lahar flood.
Total productivity of rice fields in Karangasem Regency shows that as much as 6.4 ton are produced per ha of area [5]. The calculation with total area affected by lahar flood shows that from 1 million m3 lahar flood scenario shows that total productivity which affected by lahar flood reached 194.88 ton. From 5 million m3 lahar flood scenario shows total productivity which affected by lahar flood reached 436.86 ton and from 10 million m3 lahar flood scenario analysis shows total productivity which affected by lahar flood reached 474.11 ton. Table 2 shows the productivity of rice fields which affected by lahar flood. Fig. 2 shows area of the rice fields that affected by lahar flood.
TABLE 2.
THE PRODUCTIVITY OF RICEFIELDS WHICH AFFECTED BY LAHAR FLOOD Lahar
Scenario
Volume Affected Rice fields (ha)
Productivity (ton/ ha)
Total
Productivity (ton)
I 1 mil. m3 30.45 6.4 194.88
II 5 mil. m3 68.26 6.4 436.86
III 10 mil. m3 74.08 6.4 474.11
Source: Data Analysis
Fig. 3 Area of rice fields that affected by lahar flood, 1 mil. m3 scenario, 5 mil. m3 Scenario and 10 mil. m3 Scenario Source: Data Analysis
Loss from the lahar flood are calculated based on average rice price on the market and interviews with the farmers. With average rice price per kilogram is IDR 12,000.00, then the loss for onetime harvest from 1 million m3 lahar flood scenario reach total value of IDR 2.338.680.000,00 (USD 165.418,86). Loss for onetime harvest from 5 million m3 lahar flood scenario reach value of IDR 5,242,680,000.00 (USD 370,823.77). Meanwhile loss for onetime harvest from 10 million m3 lahar flood reach total value of IDR 5,689,200,000.00 (USD 402,406.90).
IV. CONCLUSION
The impact of lahar flood to rice fields from 1 million m3 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 m3 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 m3 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.
ACKNOWLEDGEMENTS
Writers would like to thank the Rector of Universitas Udayana, Dean of Agriculture Faculty of Universitas Udayana, Head of Center for Spatial Data Infrastructure Development (PPIDS) Universitas Udayana, fellow staff, researchers and professors at Universitas Udayana for all the support.
REFERENCES
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