Kajian Perubahan Morfologi Pantai Seminyak Berdasarkan Kondisi Eksisting dan Skenario Rencana Menggunakan Pemodelan Numerik

Alfahreza, Dafa Hanif (2026) Kajian Perubahan Morfologi Pantai Seminyak Berdasarkan Kondisi Eksisting dan Skenario Rencana Menggunakan Pemodelan Numerik. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pantai Seminyak, Bali, mengalami dinamika perubahan morfologi signifikan berupa akresi alami akibat suplai sedimen melimpah dan arus susur pantai dominan dari arah Selatan. Sebagai pusat pariwisata bernilai ekonomi tinggi yang terintegrasi dalam Bali Beach Conservation Project Phase II (BBCP-2), prediksi perubahan garis pantai jangka panjang menjadi krusial untuk mengevaluasi keberlanjutan konservasi pesisir. Penelitian ini menganalisis karakteristik hidrodinamika eksisting dan mengidentifikasi batas maksimum stabilitas pantai pada kondisi eksisting dan skenario rencana pemajuan garis pantai. Metodologi menggunakan pemodelan numerik MIKE 21 mengintegrasikan modul hydrodynamic, spectral wave, dan sand transport. Data input meliputi angin 10 tahun (ERA5 Copernicus), pasang surut (metode Admiralty), gelombang hasil hindcasting (metode SPM), dan batimetri terkoreksi. Simulasi proyeksi 25 tahun dengan speed-up factor 5. Hasil menunjukkan kondisi eksisting Pantai Seminyak mengalami akresi konsisten 0,88 m/tahun rata-rata, didorong gelombang Hs = 2,45 m dari Selatan, arus rata-rata 0,048 m/s, dan pasang surut tipe campuran semi-diurnal. Pada skenario rencana pemajuan garis pantai, beberapa lokasi mengalami akresi (maksimal 0,90 m/tahun), sementara lain mengalami erosi lokal (maksimal 0,33 m/tahun) akibat penyesuaian profil pantai. Analisis cross-section menunjukkan erosi bersifat lokal di beach face yang dimajukan, dengan sedimen terendapkan di nearshore untuk profil seimbang jangka panjang. Pada skenario pemajuan garis pantai, simulasi menunjukkan laju sedimentasi positif di sebagian besar pantai selama 25 tahun, namun beberapa lokasi mengalami erosi lokal sebagai hasil penyesuaian profil pantai. Hasil ini menunjukkan bahwa pemajuan garis pantai memerlukan pemantauan berkelanjutan di zona berisiko tinggi dan pengelolaan adaptif untuk mengantisipasi perubahan iklim jangka panjang.
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Seminyak Beach, Bali, experiences significant morphological dynamics characterized by natural accretion driven by abundant sediment supply and dominant southward longshore currents. As a high-value tourism destination integrated into Bali Beach Conservation Project Phase II (BBCP-2), long-term shoreline change prediction is essential for evaluating coastal conservation sustainability. This research analyzes existing hydrodynamic characteristics and identifies maximum stability boundaries under existing conditions and planned shoreline advancement scenarios. The methodology employs MIKE 21 numerical modeling integrating hydrodynamic, spectral wave, and sand transport modules. Data includes 10-year wind records (ERA5 Copernicus), tidal data (Admiralty method), hindcasted waves (SPM method), and corrected bathymetry. Simulations project 25 years with speed-up factor 5. Results demonstrate existing Seminyak Beach undergoes consistent accretion averaging 0.88 m/year, driven by significant wave height Hs = 2.45 m from the South, mean current 0.048 m/s, and mixed semidiurnal tides. Under planned shoreline advancement, some locations experience residual accretion (maximum 0.90 m/year), while others undergo localized erosion (maximum 0.33 m/year) due to beach profile adjustment. Cross-sectional analysis reveals erosion is confined to the advanced beach face, with sediment redistribution in the nearshore zone establishing long-term equilibrium. Under the shoreline advancement scenario, numerical simulation results indicate positive sedimentation rates across most of the beach over a 25-year projection period; however, localized erosion occurs at certain locations as a result of beach profile readjustment. These findings suggest that shoreline advancement requires continuous monitoring in high-risk erosion zones and adaptive management strategies to account for long-term climate change impacts.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	morfologi pantai, akresi, pemodelan MIKE 21, Pantai Seminyak,coastal morphology, accretion, MIKE 21 modeling, Seminyak Beach
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC203.5 Coastal engineering
Divisions:	Faculty of Vocational > 22301-Civil Infrastructure Engineering (D4)
Depositing User:	Dafa Hanif Alfahreza
Date Deposited:	04 Aug 2026 04:45
Last Modified:	04 Aug 2026 06:13
URI:	http://repository.its.ac.id/id/eprint/142699

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