Pemodelan Perubahan Garis Pantai Setelah Pembangunan Bangunan Groin di Pantai Logending, Kabupaten Kebumen, Jawa Tengah

Firdaus, Debrina Cikitha (2020) Pemodelan Perubahan Garis Pantai Setelah Pembangunan Bangunan Groin di Pantai Logending, Kabupaten Kebumen, Jawa Tengah. Undergraduate thesis, InstitutTeknologi Sepuluh Nopember.

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Abstract

Pada tahun 2019, Kontraktor WIKA - Bahagia Bangunnusa, KSO hampir menyelesaikan pelaksanaan pembangunan Groin di Pantai Logending-Jetis, Perbatasan Kebumen dan Cilacap, Jawa Tengah. Pembangunan Groin tersebut bertujuan untuk menanggulangi pendangkalan sedimen akibat adanya penutupan mulut muara akibat dari sedimentasi laut yang menyebabkan sistem pengendali banjir terganggu alirannya menuju ke laut dan sebagai pemecah ombak gelombang besar untuk mereduksi besaran gelombang ombak yang datang menuju pantai di wilayah Pantai Selatan Jawa. Setelah pembangunan Groin selesai, kemungkinan akan menimbulkan masalah yang berdampak pada perubahan alam seperti aktivitas gelombang, angin, pasang surut, dan sedimentasi daerah Muara Sungai Ijo yang akan terjadi endapan erosi atau abrasi. Sehingga dengan kondisi tersebut, akan terjadi adanya perubahan garis pantai sepanjang tahun ke depan yang dapat mengganggu di lingkungan sekitar Pantai Logending – Jetis, sehingga diperlukan analisa pemodelan garis pantai untuk memprediksi besarnya perubahan garis pantai tersebut. Dengan menganalisa pasang surut, angin, transfomasi gelombang, sedimentasi sejajar pantai dan model perubahan garis pantai didapatkan Ho= 2,6 dan To= 9 s C= 4,35 m/s, tinggi gelombang H= 2,32 m. Berdasarkan hasil iterasi menujukkan dengan terjadinya gelombang mulai pecah pada elevasi d= -2 m, tepat pecah d= -2 m dan berangsur sampai d= -1m. Analisis sedimen sejajar pantai / Long Shore Current yang terjadi di sepanjang Pantai Logending-Jetis dengan meninjau 11 titik yang selisih jarak 200 m tiap titik. Pada area A di titik 1-6 berada di groin sisi kanan memiliki volume total sebesar 20.238,97 m3/tahun dengan membentuk kondisi sedimentasi. Pada area B di titk 7-9 berada di groin sisi kiri memiliki volume total sebesar -720,75 m3/tahun dengan membentuk kondisi sedimentasi. Dan pada area C di titik 10-12 berada di dekat Muara Sungai Ijo memiliki volume total sebesar 182.697,31 m3/tahun dengan membentuk kondisi sedimentasi. Hasil analisa dari perubahan garis pantai dengan kondisi eksisting setelah dibangun groin baru pada kurun waktu 2, 5, 10, 15, dan 20 tahun. Perubahan garis pantai pada kondisi tersebut mengalami kemajuan dan kemunduran secara signifikan. ================================================================================================================== In 2019, the WIKA Contractor - Bahagia Bangunnusa, KSO almost completed the implementation of the Groin construction at Logending-Jetis Beach, Kebumen and Cilacap Border, Central Java. The development of the Groin aims to overcome sediment silting due to the closure of the mouth of the estuary as a result of sea sedimentation which causes the flood control system to disrupt its flow to the sea and as a breakwater of large waves to reduce the magnitude of waves coming towards the coast in the South Coast of Java. After the Groin construction is completed, it is likely that it will cause problems that have an impact on natural changes such as wave activity, wind, tides, and sedimentation in the Ijo River Estuary area which will result in sediment erosion or abrasion. So that with these conditions, there will be changes in the coastline throughout the next year which can disturb the environment around Logending Beach - Jetis, so it is necessary to analyze the shoreline modeling to predict the magnitude of the change in the coastline. By analyzing tides, wind, wave transformation, longshore sedimentation and shoreline change models, it is found that Ho = 2,6 and To = 9 s C = 4,35 m / s, wave height H = 2,32 m. Based on the results of the iteration, it shows that the wave begins to break at an elevation of d = -2 m, breaks right at d = -2 m and gradually breaks up to d = -1m. Long Shore Current sediment analysis along the Logending-Jetis coast by observing 11 points with a difference of 200 m per point. In area A at points 1-6 located on the right side groyne has a total volume of 20,238.97 m3 / year by forming sedimentation conditions. In area B at points 7-9 in the left side groyne has a total volume of -720.75 m3 / year by forming sedimentation conditions. And in area C at points 10-12 near the mouth of the Ijo River, it has a total volume of 182,697.31 m3 / year by forming sedimentation conditions. The results of the analysis of changes in the shoreline with existing conditions after the construction of new groynes over a period of 2, 5, 10, 15, and 20 years. Changes in the coastline under these conditions have progressed and retreated significantly.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: Groin, Perubahan Garis Pantai, Transport Sedimen, Groynes, Shoreline Changes, Sediment Transport
Subjects: T Technology > TC Hydraulic engineering. Ocean engineering > TC147 Ocean wave power.
T Technology > TC Hydraulic engineering. Ocean engineering > TC175.2 Sediment transport
T Technology > TC Hydraulic engineering. Ocean engineering > TC333 Breakwaters
Divisions: Faculty of Vocational > Civil Infrastructure Engineering (D3)
Depositing User: Debrina Cikitha Firdaus
Date Deposited: 27 Aug 2020 02:41
Last Modified: 27 Aug 2020 02:41
URI: https://repository.its.ac.id/id/eprint/81424

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