Analisis Perubahan dan Prediksi Garis Pantai Muara Gede di Kabupaten Lumajang Menggunakan QGIS dan DSAS

Perubahan garis pantai merupakan proses dinamis yang dipengaruhi oleh interaksi faktor oseanografi dan aktivitas manusia, serta berdampak pada lingkungan, ekosistem, dan aktivitas masyarakat pesisir. Skripsi ini bertujuan menganalisis dan memprediksi perubahan garis pantai di Pantai Muara Gede, Kabupaten Lumajang, menggunakan perangkat lunak QGIS, metode Digital Shoreline Analysis System (DSAS), dan plugin QSCAT.Data yang digunakan berupa citra satelit multitemporal Landsat 8–9 OLI/TIRS Collection 2 Level-2 tahun 2020–2025. Garis pantai diekstraksi menggunakan Normalized Difference Water Index (NDWI), kemudian dianalisis pada 88 transek berjarak 20 meter berdasarkan parameter EPR, LRR, NSM, SCE, dan WLR, dengan nilai ketidakpastian citra 33,95–36,35 meter dan RMSE 4,890–9,402 meter.Hasil analisis menunjukkan bahwa Pantai Muara Gede didominasi proses abrasi, dengan nilai rata-rata EPR −4,07 m/tahun dan NSM −20,74 meter, serta 56 dari 88 transek (63,64%) tergolong abrasi dengan kemunduran terbesar mencapai −58,61 meter. Nilai SCE rata-rata 29,46 meter menunjukkan dinamika perubahan yang tidak seragam antarsegmen. Hasil prediksi menggunakan QSCAT menunjukkan bahwa pada tahun 2045 garis pantai diperkirakan masih mengikuti kecenderungan historis, yaitu dominasi abrasi pada sebagian besar segmen pantai. Skripsi ini diharapkan dapat menjadi dasar ilmiah bagi perencanaan pengelolaan wilayah pesisir serta mitigasi dampak abrasi di Kabupaten Lumajang secara adaptif dan berkelanjutan.

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Shoreline change is a dynamic process influenced by the interaction of oceanographic factors and human activities, with significant impacts on the environment, ecosystems, and the livelihoods of coastal communities. This study aimed to analyze and predict shoreline changes at Muara Gede Beach, Lumajang Regency, using QGIS, the Digital Shoreline Analysis System (DSAS), and the QSCAT plugin. The study utilized multi-temporal Landsat 8–9 OLI/TIRS Collection 2 Level-2 satellite imagery acquired between 2020 and 2025. Shorelines were extracted using the Normalized Difference Water Index (NDWI) and subsequently analyzed along 88 transects spaced 20 meters apart using the End Point Rate (EPR), Linear Regression Rate (LRR), Net Shoreline Movement (NSM), Shoreline Change Envelope (SCE), and Weighted Linear Regression (WLR) parameters. The image uncertainty ranged from 33.95 to 36.35 meters, while the Root Mean Square Error (RMSE) ranged from 4.890 to 9.402 meters. The analysis revealed that Muara Gede Beach was predominantly affected by coastal erosion, with an average EPR of −4.07 m/year and an average NSM of −20.74 meters. Of the 88 transects, 56 (63.64%) were classified as experiencing erosion, with the maximum shoreline retreat reaching −58.61 meters. The average SCE value of 29.46 meters indicates that shoreline change varied considerably among different coastal segments. Predictions generated using the QSCAT plugin indicate that by 2045, the shoreline is expected to continue following its historical trend, with coastal erosion remaining the dominant process along most segments of the coastline. The findings of this study are expected to provide a scientific basis for adaptive and sustainable coastal zone management planning and the mitigation of coastal erosion impacts in Lumajang Regency.