Evaluasi Kinerja Breakwater Terhadap Gelombang di Pantai Tanjung Medang Kecamatan Rangsang Kabupaten Kepulauan Meranti: Evaluation of Breakwater Performance Against Waves At Tanjung Medang Beach, Rangsang District, Meranti Islands Regency - Azima, Fauzan; Harmiyati; Agus, Firdaus; Zaenal Muttaqin, Muchammad (JURNAL SAINTIS, 2023)
[IN] Pantai Tanjung Medang di Kabupaten Kepulauan Meranti mengalami abrasi dan kerusakan akibat gelombang besar, mengancam pemukiman dan pelabuhan. Untuk mengatasinya, dibangun pemecah ombak (breakwater). Namun, seiring waktu dan kenaikan muka air laut, kinerja breakwater dinilai tidak lagi maksimal, terutama saat pasang besar. Penelitian ini bertujuan mengevaluasi kinerja breakwater eksisting dengan menganalisis karakteristik gelombang. Metode yang digunakan adalah hindcasting gelombang berdasarkan data angin 10 tahun dari BMKG Tanjung Balai Karimun untuk mendapatkan tinggi, periode, dan transformasi gelombang. Analisis dilanjutkan dengan penentuan elevasi muka air laut menggunakan metode Admiralty, serta analisis run-up dan overtopping gelombang. Hasil analisis menunjukkan bahwa gelombang dominan berasal dari arah timur laut dengan ketinggian di atas 1 m, menjadikannya gelombang destruktif. Pada kondisi muka air tertinggi (HHWL), breakwater setinggi 3 m mengalami overtopping dari berbagai arah (nilai run-up tertinggi 2,25 m dari utara), sehingga tidak sepenuhnya aman meskipun masih efektif memecah gelombang. Sementara itu, breakwater setinggi 1,6 m sudah tidak efektif dalam mereduksi energi gelombang yang datang. [EN] Tanjung Medang Beach in Meranti Islands Regency has experienced abrasion and damage from large waves, threatening settlements and the local port. A breakwater was built to mitigate this issue. However, over time, due to changing natural conditions and rising sea levels, its performance is considered suboptimal, especially during high tides. This study evaluates the existing breakwater's performance by analyzing wave characteristics. The method involves wave hindcasting based on 10 years of wind data from BMKG Tanjung Balai Karimun to determine wave height, period, and transformation. The analysis is supplemented by determining the sea level elevation using the Admiralty method, followed by a run-up and overtopping analysis. The results indicate that the dominant waves come from the northeast with heights exceeding 1 m, classifying them as destructive waves. At the highest water level (HHWL), the 3 m high breakwater experiences overtopping from various directions (with the highest run-up value of 2.25 m from the north), rendering it not entirely safe, although it remains effective at breaking incoming waves. Meanwhile, the 1.6 m high breakwater is no longer effective in reducing wave energy.