Shoreline Sensitivity Index to Oil Spills in Nusa Penida Marine Protected Area (Mpa), Bali
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Shoreline Sensitivity Index to Oil Spills… [IPG Eka Handrayana Putra, dkk] SHORELINE SENSITIVITY INDEX TO OIL SPILLS IN NUSA PENIDA MARINE PROTECTED AREA (MPA), BALI IPG Eka Handrayana Putra1*), Takahiro Osawa2,3), I Wayan Gede Astawa Karang4) 1)Master Program of Environmental Science, Udayana University 2)Centre for Remote Sensing and Ocean Science (CReSOS), Udayana University 3)Centre for Research and Application of Satellite Remote Sensing (YUCARS) Yamaguchi University, Japan 4)Faculty of Marine Science and Fisheries, Udayana University *Email: [email protected] ABSTRACT The Shoreline Sensitivity Index(SSI) is one crucial aspect to know in protecting the coast from all threats, including oil spills. This study aims to determine the shoreline's sensitivity for oil spills based on several oceanographic parameters: shoreline type, tidal range, slope, and wave high in Nusa Penida, Map Protection Area (MPA). The weight overlay method was employed to apply the geographic information system (GIS). Each parameter component was scored as five categories before the weighted overlay. The shoreline sensitivity level of Nusa Penida island is divided into five categories: very low sensitive, low sensitive, medium sensitive, high sensitive, and very high sensitive. As the results, the SSI was categorized during the east monsoons (from June to August) and during the west monsoons (from December to February) is at a low sensitivity level to very high sensitivity. SSI during east monsoons there is about 60.05% (627.33 ha) in the medium, 9.39% (98.11 ha) in the high, and 2.39% (24.99 ha) in the very high sensitive. The SSI during the west season is about 78.16% (816.95 ha) with the medium, 19.43% (203.11 ha) with the high, and 2.39% (24.99 ha) with the very high sensitive. The difference in wave height during east and west monsoons greatly affects the sensitivity level of the Nusa Penida coastal area. However, sensitivity level in Jungutbatu and Lembongan Villages are not affected by the east or west monsoons. Keywords: Shoreline Sensitivity; GIS; Nusa Penida; Oil Spill. triangle so that it has fertile ecological 1. INTRODUCTION conditions. Darma et al. (2010); Pemkab Nusa Penida Sub-district is located in Klungkung (2012); Dermawan et al. Klungkung Regency, Bali Province. The (2014) stated that Nusa Penida MPA has a only archipelago district in Bali Province complex resources. Turak and Lyndon has three main islands: Nusa Penida, Nusa (2011) stated that Nusa Penida waters Lembongan, and Nusa Ceningan. These have high biodiversity, there is three islands are included in the Nusa approximately 149 Ha of coral reefs with Penida Marine Protected Area (MPA) 296 species of coral. Sanjaya (2009), because these land and water areas have noted that Nusa Penida has 149 Ha of very high resources. According to Tania et coral reef, 230 Ha of mangrove forest, and al. (2011), Nusa Penida has high resources 108 Ha of seagrass. Dermawan et al. because it is included in the world's coral (2014) add that this island also has 576 species of fish. ECOTROPHIC • 15 (1) :47-60 p-ISSN:1907-5626,e-ISSN: 2503-3395 47 ECOTROPHIC • VOLUME 15 NOMOR 1 TAHUN 2021 p-ISSN:1907-5626,e-ISSN: 2503-3395 Nusa Penida borders directly with the show the level of sensitivity of the Nusa Badung Strait in the North and West, the Penida coastline simply by using only a few Indian Ocean in the South, and Lombok physical parameters that have been Strait in the East (BPS, 2020; Widyarsana mentioned earlier. and Agustina, 2020). Ship traffic activity in these bays is very high, both locally, 2. METHODOLOGY regionally, and internationally. The high activity of ships in the Badung Strait and 2.1 Research Location the Lombok Strait can cause Nusa Penida Nusa Penida MPA is located in MPA exposed to the threat of oil spills. Klungkung Regency, Bali Province. Dewanto and Faturachman (2018) stated Nusa Penida archipelago has a beach that there are frequent ship accidents in length of around 83.5 km. The Nusa Indonesian waters. At least 349 ship Penida MPA covers an area of 20.057 ha accidents were recorded from 2003-2013. with an outer border of 1 mile (1.8 km) About 80-85% of accidents that occur are from the coastline, marked by caused by human error. Therefore, it is coordinates at six locations namely: necessary to prepare to anticipate greater Batununggul (115°34'37.10" E - losses in the event of an oil spill. Mapping shoreline sensitivity to oil 8°39'14.43" S), Batu Abah pollution is an essential step in the (115°39'41.36" E - 8°46'25.54" S), preparedness, response, and collaborative Sekartaji (115°35'32.77" E - efforts to overcome oil pollution. 8°52'39.59"S), Sakti (115°24'13.28" E - IPIECA/IMO/OGP (2012) and UNEP- 8°45'46.33" S), Lembongan WCMC (2019) states that maps are tools (115°24'13.28" E - 8°41'5.82" S), and that responders can use more quickly and Jungutbatu (115°26'45.52" E - 8° accurately for decision-makers to prevent 38'34.63" S). oil-spread spills. NOAA (2019) states that 2.2 Shoreline Type Classification and shoreline sensitivity mapping will play an Ranking essential role for planners or responders to Field observation of shoreline identify vulnerable locations, set protection conducted in the MPA Nusa Penida in priorities, and identify cleaning strategies. August and September 2020. The This study aims to spatially analyze the shoreline classification refers to the level of shoreline sensitivity based solely on guidelines published by NOAA (2019), coastal physical parameters such as the type which can be accessed at of coastline, wave height, bathymetric slope, https://response.restoration.noaa.gov. and tidal range. whereas biological and Each type of shoreline was contained in socio-economic parameters are not terms of which can be seen in Table 1. considered. The results of this study will Table 1. Shoreline Type Sensitivity Ranking No Shoreline Type Score Sensitivity 1. Code 1 and 2 (Man-Made Structure, Rocky 1 Very Low Sensitive Cliffs) 2. Code 3, 4, 5 and 6 (Sand) 2 Low Sensitive 3. Code 7 (Gravel) 3 Medium Sensitive 4. Code 8 (Sheltered area) 4 High Sensitive 5. Code 9 and 10 (Mangrove/mud) 5 Very High Sensitive 48 Shoreline Sensitivity Index to Oil Spills… [IPG Eka Handrayana Putra, dkk] 2.3 Tide Classification and Ranking (1) Where : Daily tide data from January 2019 to TR = Tidal Range August 2020 were employed. The data is HWL = Highest Water Level supplied from the Automatic Weather LWL = Lowest Water Level Station (AWS) Maritime Benoa Bali, owned by Meteorology, Climatology, The tidal range sensitivity level Geophysics Agency (BMKG) of category were developed from the criteria Indonesia. The Admiralty method was made by Utantyo et al. (2003) by applied to analyze the tidal data. The displaying the tidal range sensitivity level method calculated an average tide value into five categories. The sensitivity value from the average difference between the is assessed based on the following highest and lowest during that period. The conditions in Table 2. formula (1) for measuring the tides is as follows. Table 2. Tydal Range Sensitivity Ranking No Tide Range Score Sensitivity 1. >4 m 1 Very Low Sensitive 2. 3.1 - 4.0 m 2 Low Sensitive 3. 2.1 - 3.0 m 3 Medium Sensitive 4. 1.1 - 2.0 m 4 High Sensitive 5. <1 m 5 Very High Sensitive 2.3 Bathymetric Slope Classification https://tanahair.indonesia.gi.id. The and Ranking bathymetry data has a resolution of 6 The Nusa Penida bathymetric slope arc-second (180 m). Based on data were obtained from BATNAS BIG Husnayen et al. (2011) bathymetric (National Bathymetry, Geospatial slope sensitivity was classified Information Agency) of Indonesia in according to the following conditions in 2018 that was accessed in Table 3. Table 3. Slope Bathymetry Sensitivity Ranking No Slope Score Sensitivity 1. >1,2% 1 Very Low Sensitive 2. 0.9-1.2% 2 Low Sensitive 3. 0.6-0.9% 3 Medium Sensitive 4. 0.3-0.6% 4 High Sensitive 5. <0.3% 5 Very High Sensitive 2.4 Wave High Classification and Bali Province. This wave height Ranking information was categorized into two The Nusa Penida wave height data seasons: the east monsoon wave height were obtained from the wave simulation during June, July, August and the west modeling results on the MIKE21 monsoon wave height during December, Spectral Wave FM Module in 2018 from January and February. Wave height the Marine and Fisheries Department of sensitivity level classification were developed from the criteria made by 49 ECOTROPHIC • VOLUME 15 NOMOR 1 TAHUN 2021 p-ISSN:1907-5626,e-ISSN: 2503-3395 Utantyo et al. (2003) by displaying the also classified as a sensitivity level with wave height sensitivity level into five the following Table 4. categories. The wave height value was Table 4. Wave High Sensitivity Ranking No Wave High Score Sensitivity 1. >2 m 1 Very Low Sensitive 2. 1.6 –2 m 2 Low Sensitive 3. 1.1 – 1.5 m 3 Medium Sensitive 4. 0.6 – 1 m 4 High Sensitive 5. <0.5 m 5 Very High Sensitive 2.5 Shoreline Sensitivity Analysis SI = Shoreline Index SCj = Shoreline Parameters Score Tidal range, slope, and wave high Based on Agustina and Sunarto (2016), parameters were classified and weighted shoreline sensitivity level was classified after the shoreline type was detected. In into five category by the equation (3): this study, Shoreline Sensitivity Index (3) was defined 100 m from the coastline to the sea. This area is assumed to be the From formula (3) it can be known that mean of the intertidal zone of the Nusa Shoreline Sensitivity Index criteria are Penida coastal area.