Analisis Fungsi Groundsill 7 Terhadap Stabilitas Morfologi Sungai Cipamingkis Menggunakan HEC-RAS 2D

Octaviani, Aisyah (2026) Analisis Fungsi Groundsill 7 Terhadap Stabilitas Morfologi Sungai Cipamingkis Menggunakan HEC-RAS 2D. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Sungai Cipamingkis yang terletak di Kabupaten Bogor, Jawa Barat, merupakan anak Sungai Citarum yang memiliki peran penting sebagai penyangga keseimbangan lingkungan. Dinamika debit banjir rencana, proses transportasi sedimen yang masif, serta morfologi sungai yang curam telah memicu erosi dasar (degradasi) sungai yang sangat parah. Analisis menunjukkan bahwa tanpa adanya struktur pengendali (Kondisi Awal), dasar sungai mengalami pengikisan yang sangat lebar dan dalam di sepanjang alur utama akibat tingginya debit sedimen dan daya rusak arus. Pembangunan Groundsill 7 pada Kondisi Eksisting berhasil menstabilkan elevasi dasar saluran di area hulu melalui proses pengendapan sedimen (agradasi), namun karakteristik aliran tunggalnya memicu fenomena gerusan lokal (local scouring) sekunder yang sangat tajam dan ekstrem tepat di hilir struktur akibat efek hantaman terjunan air. Penelitian ini bertujuan menganalisis efektivitas Groundsill 7 serta merumuskan rekomendasi penanganan lanjutan yang optimal untuk menjaga stabilitas morfologi sungai menggunakan perangkat lunak HEC-RAS 2D. Sebagai solusi, dirumuskan alternatif penanganan lanjutan berupa sistem terjunan bertingkat menggunakan kombinasi Groundsill dengan Dam Utama setinggi 3 meter. Hasil simulasi numerik 2D membuktikan bahwa skenario usulan ini sangat efektif meredam energi kinetik banjir dan mengalihkan titik jatuh pusaran air ke atas lantai pelindung. Rekayasa penanganan bertingkat ini terbukti mampu menurunkan tegangan geser dasar puncak dan memotong debit sedimen maksimum secara signifikan, sehingga sukses meredam lubang gerusan lokal ekstrem menjadi hanya gerusan minor yang dangkal serta menjaga elevasi dasar saluran utama tetap aman dan stabil. Hasil ini diharapkan dapat menjadi dasar perencanaan teknis pengendalian erosi yang aman, efektif, dan berkelanjutan pada Sungai Cipamingkis serta mendukung pengelolaan sungai yang lebih adaptif terhadap perubahan morfologi di masa mendatang.
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The Cipamingkis River, located in Bogor Regency, West Java, is a tributary of the Citarum River that plays an important role in maintaining environmental balance. The combination of design flood discharge, intensive sediment transport, and the river's steep morphology has resulted in severe riverbed degradation. The analysis indicates that, in the absence of a control structure (Initial Condition), the riverbed experiences extensive and deep erosion along the main channel due to the high sediment discharge and strong erosive flow. The construction of Groundsill 7 under the Existing Condition successfully stabilizes the upstream riverbed elevation through sediment deposition (aggradation). However, its single-drop configuration induces severe secondary local scouring immediately downstream of the structure due to the impact of plunging flow. This study aims to evaluate the effectiveness of Groundsill 7 and develop an optimal mitigation alternative to maintain river morphological stability using HEC-RAS 2D. As a solution, a stepped energy dissipation system consisting of an additional groundsill with a 3-meter-high main dam is proposed. The two-dimensional numerical simulation demonstrates that the proposed scenario effectively dissipates flood flow kinetic energy and shifts the vortex impact zone onto the apron. This stepped mitigation measure significantly reduces the maximum bed shear stress and sediment discharge, thereby minimizing extreme local scouring into shallow minor erosion while maintaining a stable and safe riverbed elevation. These findings are expected to provide a technical basis for safe, effective, and sustainable river erosion control and support more adaptive river management in response to future morphological changes.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Groundsill, HEC-RAS 2D, morfologi sungai, erosi dasar, sedimentasi, Sungai Cipamingkis. Groundsill, HEC-RAS 2D, river morphology, bed erosion, sedimentation, Cipamingkis River.
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC175.2 Sediment transport
Divisions:	Faculty of Vocational > 22301-Civil Infrastructure Engineering (D4)
Depositing User:	Aisyah Octaviani
Date Deposited:	03 Aug 2026 04:24
Last Modified:	03 Aug 2026 04:24
URI:	http://repository.its.ac.id/id/eprint/142329

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