Perencanaan Bangunan Groundsill Sebagai Pengendali Sedimen Pada Sungai Kolokoso Kota Kediri

Trifirmansa, Ramadani (2026) Perencanaan Bangunan Groundsill Sebagai Pengendali Sedimen Pada Sungai Kolokoso Kota Kediri. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Sungai Kolokoso di Kabupaten Kediri menghadapi masalah serius akibat sedimentasi yang mengurangi kapasitas tampung sungai dan meningkatkan risiko banjir tahunan. Kondisi topografi yang terjal di wilayah hulu dan datar di wilayah tengah hingga hilir, serta perubahan tata guna lahan yang intensif, memperburuk situasi ini. Akumulasi sedimen yang berlebihan menyebabkan penyempitan sungai, menghambat aliran, dan merusak infrastruktur serta fasilitas umum di Kecamatan Grogol, Kecamatan Banyakan, dan Kecamatan Tarokan. Pada proyek akhir ini untuk solusi penanganan yang direncanakan menggunakan bangunan groundsill. Pembangunan groundsill dengan debit banjir rencanan 50 tahun diharapkan dapat mengendalikan sedimen yang terjadi di Sungai Kolokoso. Analisi debit banjir rencana menggunakan metode Nakayasu sesuai dengan karakteristik Sungai Kolokoso. Selanjutnya dilakukan analisis hidraulika sungai untuk melihat kondisi penampang Sungai apakah mampu menampung debit banjir yang direncanakan. Selanjutnya dilakukan analisis letak groundsill di Sungai Kolokoso untuk mencari reduksi kecepatan aliran yang terjadi setelah peletakan groundsill. Mercu groundsill dianalisis menggunakan tiga tipe mercu yaitu mercu ambang datar, bulat, dan ogee lalu dipilih muka air diatas mercu yang terendah. Selanjutnya dianalisis pengaruh groundsill terhadap backwater. Desain mercu groundsill perlu dilakukan kontrol Factor of Safety (FS) terhadap guling, geser, daya dukung tanah Pondasi, dan rembesan. Berdasarkan hasil analisis, groundsill direncanakan ditempatkan pada STA 0+130 dengan tinggi 0,8 m dan lebar mercu 21,5 m, serta dilengkapi kolam olak tipe USBR III dengan panjang 10 m. Analisis stabilitas menunjukkan bahwa groundsill memenuhi kriteria keamanan, ditinjau dari stabilitas guling dengan faktor keamanan sebesar 1,26 (> 1,2), stabilitas geser sebesar 7,25 (> 1,2), serta daya dukung tanah pondasi yang masih berada di bawah nilai izin, yaitu Q₁ = 23,095 t/m² dan Q₂ = 10,763 t/m² terhadap daya dukung izin sebesar 87,613 t/m². Selain itu, hasil analisis rembesan menunjukkan debit rembesan sebesar 0,000016 m³/det yang lebih kecil dibandingkan debit rembesan izin sebesar 4,15 m³/det. Dengan demikian, dapat disimpulkan bahwa groundsill yang direncanakan berada dalam kondisi stabil dan aman terhadap guling, geser, daya dukung tanah pondasi, serta rembesan, baik pada kondisi muka air normal maupun kondisi banjir.
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The Kolokoso River in Kediri Regency faces serious problems due to sedimentation, which reduces the river’s capacity and increases the risk of annual flooding. The steep topography in the upstream area and flat terrain in the middle to downstream segments, combined with intensive land use changes, have exacerbated the situation. Excessive sediment accumulation has led to channel narrowing, flow obstruction, and damage to public infrastructure and facilities in Grogol, Banyakan, and Tarokan Subdistricts. In this final project, the proposed solution involves the construction of a groundsill structure. The groundsill is designed based on a 50-year return period flood discharge and is expected to control sediment movement in the Kolokoso River. The flood discharge analysis uses the Nakayasu method, which is suitable for the characteristics of the Kolokoso River Basin. A hydraulic analysis was then conducted to assess whether the river's existing cross-section is capable of accommodating the design flood. The optimal placement of the groundsill was determined to achieve maximum reduction in flow velocity after installation. The crest of the groundsill was analyzed using three types of shapes: flat, rounded, and ogee, with the selection based on the lowest resulting upstream water level. The influence of the groundsill on backwater conditions was also evaluated. Furthermore, the structural design includes safety checks for Factor of Safety (FS) against overturning, sliding, bearing capacity of the foundation soil, and seepage. Based on the analysis results, the groundsill is planned to be located at STA 0+130 with a height of 0.8 m and a crest width of 21.5 m, and is equipped with a USBR Type III stilling basin with a length of 10 m. The stability analysis indicates that the groundsill satisfies the required safety criteria, as evidenced by a factor of safety against overturning of 1.26 (> 1.2), a factor of safety against sliding of 7.25 (> 1.2), and foundation bearing pressures that remain below the allowable bearing capacity, with Q₁ = 23.095 t/m² and Q₂ = 10.763 t/m² compared to an allowable value of 87.613 t/m². In addition, the seepage analysis shows a seepage discharge of 0.000016 m³/s, which is smaller than the allowable seepage discharge of 4.15 m³/s. Therefore, it can be concluded that the proposed groundsill is stable and safe against overturning, sliding, foundation bearing capacity failure, and seepage under both normal water level and flood conditions.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Kolokoso River, Sedimentation, Flooding, Groundsill, Sungai Kolokoso, Sedimentasi, Banjir, Groundsill.
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TC Hydraulic engineering. Ocean engineering > TC175.2 Sediment transport
Divisions:	Faculty of Vocational > Civil Infrastructure Engineering (D4)
Depositing User:	Ramadani Trifirmansa
Date Deposited:	30 Jan 2026 07:41
Last Modified:	30 Jan 2026 07:41
URI:	http://repository.its.ac.id/id/eprint/131241

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