Firdaus, Muhammad Miftakhul (2026) Sand Nourishment Strategy For Coastal Protection Of Padang Galak Beach, Sanur, Bali: A Case Study Of The Sand Engine. Masters thesis, Institut Teknologi Sepuluh Nopember.
![[thumbnail of 6012251065-Master_Thesis.pdf]](http://repository.its.ac.id/style/images/fileicons/text.png) |
Text
6012251065-Master_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (29MB) | Request a copy |
Abstract
Pantai Padang Galak, Bali, mengalami erosi pantai yang terus meningkat akibat proses hidrodinamika alami dan pembangunan Pelabuhan Sanur yang mengubah pola gelombang, arus, serta sistem transpor sedimen alami. Keberadaan breakwater pelabuhan menghambat pergerakan sedimen sejajar pantai sehingga menyebabkan akumulasi sedimen di sekitar pelabuhan dan meningkatkan erosi pada wilayah pantai di sisi hilir (downdrift). Kondisi ini menunjukkan perlunya strategi perlindungan pantai yang efektif, berkelanjutan, dan berbasis proses alami. Penelitian ini bertujuan untuk menganalisis pola gelombang dan arus, mengevaluasi distribusi transpor sedimen serta perubahan garis pantai akibat pembangunan Pelabuhan Sanur, menentukan desain dan lokasi sand nourishment yang paling optimal, serta menilai perubahan garis pantai selama periode simulasi 10 tahun setelah penerapan sand nourishment. Metode penelitian mengintegrasikan pemodelan hidrodinamika dan morfodinamika menggunakan Delft3D, analisis debit dan hasil sedimen DAS menggunakan HEC-HMS dengan metode Modified Universal Soil Loss Equation (MUSLE), validasi perubahan garis pantai menggunakan CoastSat, serta prediksi perubahan garis pantai jangka panjang menggunakan ShorelineS. Analisis dilakukan pada dua lokasi skenario dengan dua standar volume sand nourishment, yaitu konsep mega nourishment dengan volume besar dan konsep sediment recycling yang memanfaatkan material hasil pengerukan di sekitar Pelabuhan Sanur. Setiap skenario terdiri atas tiga alternatif bentuk desain yang dievaluasi menggunakan metode Multi-Criteria Decision Making (MCDM) berdasarkan kriteria volume, retensi sedimen, kemudahan konstruksi, stabilitas, dan ketahanan. Hasil penelitian menunjukkan bahwa pembangunan Pelabuhan Sanur mengubah sistem hidrodinamika secara signifikan dengan menyebabkan akumulasi sedimen lebih dari +3,55 m di dalam pelabuhan dan gerusan hingga −4,0 m pada wilayah sekitarnya. Analisis penampang melintang menunjukkan tambahan erosi dasar pantai hingga 1,5 m pada zona yang mengalami kekurangan sedimen. Desain mega nourishment terpilih memperoleh skor efektivitas 88% dengan efisiensi retensi sedimen 91,2%, sedangkan desain sediment recycling memperoleh skor efektivitas 84%, menghasilkan akresi bersih sebesar +3.954,0 m³, serta mempertahankan efisiensi retensi 81,5% setelah lima tahun. Simulasi ShorelineS selama 10 tahun menunjukkan bahwa penerapan sand nourishment mampu meningkatkan kestabilan pantai dengan 39,3% segmen garis pantai mengalami akresi dan 46,1% mengalami erosi terkendali, sehingga membentuk sistem pantai yang lebih seimbang dan berkelanjutan
====================================================================================================================================
Padang Galak Beach, Bali, has experienced continuous coastal erosion due to natural coastal processes and the construction of Sanur Port, which has altered hydrodynamic conditions and disrupted the natural sediment transport system. The port breakwater interrupts longshore sediment movement, causing sediment accumulation near the harbor while increasing erosion along the downdrift coastline. These changes highlight the need for an effective and sustainable coastal protection strategy. This study aims to analyze wave and current patterns, evaluate sediment transport and shoreline changes caused by the construction of Sanur Port, determine the optimal sand nourishment design and implementation site, and assess shoreline changes over a 10-year period after nourishment. The study combines hydrodynamic and morphodynamic modeling using Delft3D, sediment yield analysis using HEC-HMS with the Modified Universal Soil Loss Equation (MUSLE), shoreline validation using CoastSat, and long-term shoreline prediction using ShorelineS. Two nourishment scenario locations with two different nourishment volume standards were evaluated. The first scenario applied a larger-volume mega-nourishment concept, while the second used a smaller sediment recycling volume sourced from dredged material near Sanur Port. Each scenario included three alternative layout geometries that were evaluated using a Multi-Criteria Decision Making (MCDM) approach based on volumetric performance, sediment retention, constructability, stability, and resilience. The results show that Sanur Port significantly modified the coastal hydrodynamic system. Sediment trapping inside the harbor produced bed level changes exceeding +3.55 m, while scour reached −4.0 m in surrounding areas. Cross-sectional analysis identified up to 1.5 m of additional bed erosion in sediment-starved zones. The selected mega-nourishment design achieved an effectiveness score of 88% with a sediment retention efficiency of 91.2%, while the selected sediment recycling design achieved an effectiveness score of 84%, generated +3,954.0 m³ of net accretion, and maintained a long-term retention efficiency of 81.5% after five years. The 10-year shoreline simulation indicates improved coastal stability, with 39.3% of shoreline segments experiencing accretion and 46.1% showing controlled erosion, demonstrating that the proposed sand nourishment strategy can restore a more balanced and resilient coastal system.
Actions (login required)
 |
View Item |