Analisis Sebaran Spasial Area Banjir Dengan InSAR Coherence Dan Backscatter Citra SAR Sentinel-1 (Studi Kasus: Kabupaten Gresik, Jawa Timur)

Taslyanto, Chelsea Alfarelia Putri (2025) Analisis Sebaran Spasial Area Banjir Dengan InSAR Coherence Dan Backscatter Citra SAR Sentinel-1 (Studi Kasus: Kabupaten Gresik, Jawa Timur). Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Indonesia merupakan salah satu negara dengan tingkat kerawanan bencana alam yang tinggi. Berdasarkan data dari Badan Nasional Penanggulangan Bencana (BNPB) tercatat sebanyak 1.478 kejadian bencana alam di seluruh wilayah Indonesia. Pada tahun 2024, bencana alam banjir memiliki jumlah frekuensi sebanyak 814 kejadian atau 55% dari keseluruhan kejadian bencana. Kabupaten Gresik merupakan wilayah dengan frekuensi banjir yang cukup tinggi. Berdasarkan data Badan Nasional Penanggulangan Bencana (BNPB), pada tahun 2019 banjir terjadi sebanyak 17 kali, kemudian menurun menjadi 13 kejadian pada tahun 2020, meningkat menjadi 19 kejadian pada tahun 2021, dan mencapai 33 kejadian pada tahun 2022. Pada bulan Februari tahun 2024 terdapat hujan dengan intensitas tinggi melanda Kabupaten Gresik hingga menyebabkan meluapnya Kali Lamong dan menggenangi daratan. Oleh karena itu, dibutuhkan identifikasi dan estimasi luasan wilayah tergenang. Salah satu metode pemantauan adalah dengan mengidentifikasi wilayah banjir menggunakan citra Sentinel-1 SAR (Synthetic Aperture Radar). Citra Sentinel-1 dipilih karena memiliki resolusi spasial dan temporal tinggi serta dapat menghasilkan data tanpa gangguan awan. Penelitian ini memanfaatkan metode backscatter untuk pemetaan banjir di wilayah non-urban dan metode InSAR Coherence untuk pemetaan banjir di wilayah urban. Penggunaan dua jenis data dan dua jenis metode yang berbeda diharapkan mampu mengidentifikasi area banjir secara menyeluruh. Hasil dari metode InSAR Coherence menunjukkan Kecamatan Dukun, Benjeng, Manyar, dan Balongpanggang memiliki sebaran banjir terbesar. Hasil dari metode InSAR Coherence didapatkan sebaran banjir terbesar ada pada Kecamatan Dukun sebesar 4,98 km2, Benjeng 5,61 km2, dan Balongpanggang sebesar 4,26 km2. Hasil dari metode backscatter menunjukkan bahwa sebaran banjir terbesar ada pada Kecamatan Benjeng sebesar 5,17 km2, diikuti oleh Kecamatan Ujungpangkah 5,01 km2, dan Kecamatan Manyar sebesar 4,32 km2. Sebaran banjir dari metode InSAR Coherence didominasi oleh kelas urban dengan persentase 56% pada operasi diferensial dan 42% pada operasi rasio. Sedangkan hasil sebaran banjir metode backscatter didominasi oleh kelas non-urban dengan persentase 85.5%.
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Indonesia is among the countries with a high susceptibility to natural disasters. According to data from the National Disaster Management Agency (BNPB), a total of 1,478 natural disasters were recorded across Indonesia. In 2024, flood events accounted for 814 incidents, or 55% of all natural disasters. Gresik Regency is one of the regions with a significant frequency of flooding. BNPB data indicate that floods occurred 17 times in Gresik in 2019, decreased to 13 incidents in 2020, rose to 19 incidents in 2021, and reached 33 incidents in 2022. In February 2024, heavy rainfall hit Gresik Regency, causing the Lamong River to overflow and inundate surrounding areas. Consequently, there is a critical need to identify and estimate the extent of the inundated areas. One effective approach to flood monitoring is the use of Sentinel-1 SAR (Synthetic Aperture Radar) imagery. Sentinel-1 SAR imagery offers high spatial and temporal resolution, making it highly effective for monitoring dynamic flood events. The Sentinel-1 imagery is particularly advantageous due to the SAR radar technology's ability to transmit and receive microwave signals, allowing data acquisition even under cloudy conditions. This study employs the backscatter method for flood mapping in non-urban areas and the InSAR Coherence method for flood mapping in urban areas. The use of two different types of data and two different types of methods is expected to be able to identify flood areas thoroughly. The results of the InSAR Coherence method found that the largest flood distribution was in Dukun District by 4.98 km2, Benjeng 5.61 km2, and Balongpanggang by 4.26 km2. The results of the backscatter method show that the largest flood distribution is in Benjeng sub-district of 5.17 km2, followed by Ujungpangkah sub-district of 5.01 km2, and Manyar sub-district of 4.32 km2. Flood distribution from the InSAR Coherence method is dominated by the urban class with a percentage of 56% in differential operations and 42% in ratio operations. While the flood distribution results of the backscatter method are dominated by the non-urban class with a percentage of 85.5%.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Banjir, Sentinel-1, Synthetic Aperture Radar, InSAR Coherence, Backscatter, Flood, Sentinel-1, Synthetic Aperture Radar, InSAR Coherence, Backscatter
Subjects:	G Geography. Anthropology. Recreation > GA Mathematical geography. Cartography > GA102.4.R44 Cartography--Remote sensing
Divisions:	Faculty of Civil Engineering and Planning > Geomatics Engineering > 29101-(S2) Master Thesis
Depositing User:	Chelsea Alfarelia Putri Taslyanto
Date Deposited:	29 Jul 2025 06:45
Last Modified:	29 Jul 2025 06:45
URI:	http://repository.its.ac.id/id/eprint/122680

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