Peran Mitigasi Abrasi terhadap Perubahan Garis Pantai di Kabupaten Bantul dan Kulon Progo

Kadziya Keisha Hanugh, Atrida Hadianti, S.T., M.Sc., Ph.D.

2025 | Skripsi | PERENCANAAN WILAYAH DAN KOTA

Pesisir selatan Daerah Istimewa Yogyakarta, khususnya di Kabupaten Bantul dan Kulon Progo, mengalami tekanan abrasi yang signifikan akibat dinamika oseanografi dan aktivitas manusia. Penelitian ini bertujuan untuk menganalisis perubahan garis pantai selama periode 1989, 2006, dan 2023, mengevaluasi intervensi pesisir atau mitigasi abrasi yang telah dilakukan, serta mengidentifikasi hubungan spasial antara intervensi dan perubahan garis pantai. Metode yang digunakan meliputi analisis spasial garis pantai berbasis citra Landsat dan Sentinel-2, delineasi garis pantai menggunakan indeks Normalized Difference Water Index (NDWI), serta perhitungan perubahan garis pantai menggunakan metode Shoreline Change Envelope (SCE), Net Shoreline Movement (NSM), End-Point Rate (EPR), dan Linear Regression Rate (LRR). Sebanyak 4.295 transek dihasilkan dengan jarak 10 meter untuk mendeteksi perubahan garis pantai secara spasial. Mitigasi yang dianalisis meliputi vegetasi cemara laut, mangrove, gumuk pasir, serta struktur keras berupa jetty. Hasil penelitian menunjukkan bahwa intervensi memberikan pengaruh yang bervariasi terhadap dinamika garis pantai. Korelasi antara lokasi intervensi dan nilai perubahan garis pantai dianalisis menggunakan pendekatan visualisasi heatmap dan box plot. Penelitian ini diharapkan memberikan kontribusi terhadap pemahaman efektivitas spasial mitigasi abrasi dan dapat menjadi acuan dalam pengelolaan pesisir berbasis bukti di wilayah terdampak abrasi.

The southern coast of the Special Region of Yogyakarta, particularly in Bantul and Kulon Progo Regencies, is experiencing significant erosion pressure due to oceanographic dynamics and human activities. This study aims to analyze shoreline changes over the periods of 1989, 2006, and 2023, evaluate erosion mitigation interventions that have been implemented, and identify the spatial relationship between interventions and shoreline changes. The methods used include spatial analysis of the shoreline based on Landsat and Sentinel-2 imagery, shoreline delineation using the Normalized Difference Water Index (NDWI), and shoreline change calculation using the Shoreline Change Envelope (SCE), Net Shoreline Movement (NSM), End-Point Rate (EPR), and Linear Regression Rate (LRR). A total of 4,295 transects spaced at 10-meter intervals were generated to detect shoreline changes spatially. The analyzed mitigation interventions include coastal vegetation such as pine trees (Casuarina equisetifolia), mangroves, sand dunes, and hard structures such as jetties. The results show that the interventions have varying degrees of influence on shoreline dynamics. Correlation between intervention locations and shoreline change values was analyzed using heatmap and box plot visualizations. This study is expected to contribute to a better understanding of the spatial effectiveness of coastal mitigation and serve as a reference for evidence-based coastal management in erosion-affected areas.

Kata Kunci : perubahan garis pantai, abrasi, mitigasi abrasi, intervensi pesisir, Kulon Progo, Bantul