Analisis Prediksi Pola Distribusi Sedimentasi dan Estimasi Umur Guna Waduk Cabean Berdasarkan Prediksi Perubahan Tata Guna Lahan

Hakim, Muhammad Taufiqul (2026) Analisis Prediksi Pola Distribusi Sedimentasi dan Estimasi Umur Guna Waduk Cabean Berdasarkan Prediksi Perubahan Tata Guna Lahan. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Bendungan Cabean dibangun untuk membendung Sungai Galuk di Desa Karanganyar, Kecamatan Todanan, Kabupaten Blora. Bendungan ini berfungsi sebagai pengendali banjir, penyedia air irigasi, serta penyedia air baku bagi Kabupaten Blora dan Kabupaten Pati. Seperti halnya waduk pada umumnya, kapasitas tampungan Bendungan Cabean berpotensi menurun akibat sedimentasi yang berasal dari proses erosi di daerah tangkapan air, sehingga diperlukan kajian untuk memprediksi pola distribusi sedimen guna menentukan umur guna waduk dan strategi penanganan sedimen yang tepat. Metode yang digunakan dalam penelitian ini meliputi analisis hidrologi dengan metode FJ Mock untuk menentukan debit aliran, perhitungan laju erosi dengan metode USLE, perhitungan angkutan sedimen, serta pemodelan pola sebaran sedimen menggunakan perangkat lunak MIKE 21. Analisis dilakukan secara terpisah pada enam Sub-DAS Kali Galuk, dengan mempertimbangkan data historis dan prediksi perubahan tata guna lahan. Pemodelan spasial dilakukan dengan skenario simulasi pertahun selama periode 2026-2066. Hasil penelitian menunjukkan debit inflow rata-rata tahunan total sebesar ±8,07 juta m³/tahun dari keenam Sub-DAS, dengan kontribusi terbesar dari Sub-DAS 2 dan terkecil dari Sub-DAS 5. Sedimen yang masuk didominasi oleh material pasir, dengan diameter median (d50) bervariasi antar Sub-DAS antara 0,24 mm hingga 1,76 mm, dan total muatan sedimen tahunan sebesar 8917,638 m³/tahun. Berdasarkan perbandingan dengan kapasitas tampungan mati waduk sebesar 432000 m³ dengan metode USLE ataupun angkutan sedimen, diperoleh estimasi umur guna waduk berkisar antara 46-48 tahun. Hasil pemodelan menggunakan MIKE 21 menunjukkan sedimentasi terkonsentrasi di bagian hulu waduk (sekitar inlet), dengan kapasitas tampungan pada elevasi yang sama menyusut dari 4,573 juta m³ (kondisi eksisting 2026) menjadi 2,428 juta m³ (2066), atau berkurang sekitar 47%. Umur guna waduk berdasarkan hasil simulasi diperkirakan sekitar 40 tahun. Penanganan sedimen dengan metode dredging di area inlet yang dikombinasikan dengan konservasi DAS di hulu diusulkan untuk memperpanjang umur layan waduk.
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Cabean Dam was constructed across the Galuk River in Karanganyar Village, Todanan District, Blora Regency. The dam functions as a flood control structure, an irrigation water supply, and a raw water source for Blora and Pati Regencies. Like most reservoirs, the storage capacity of Cabean Dam is susceptible to reduction due to sedimentation resulting from erosion processes within the catchment area. Therefore, a study is required to predict sediment distribution patterns in order to estimate the reservoir's service life and determine appropriate sediment management strategies. The methods employed in this study include hydrological analysis using the F.J. Mock method to estimate streamflow, soil erosion estimation using the Universal Soil Loss Equation (USLE), sediment transport analysis, and sediment distribution modeling using MIKE 21 software. The analyses were conducted separately for the six sub-watersheds of the Galuk River by considering historical land-use data and projected land-use changes. Spatial simulations were performed annually for the period of 2026-2066. The results indicate that the average annual inflow from the six sub-watersheds is approximately 8,07 million m³/year, with the largest contribution originating from Sub-watershed 2 and the smallest from Sub-watershed 5. The incoming sediment is predominantly composed of sand, with median grain size (d50) ranging from 0,24 mm to 1,76 mm, and an estimated annual sediment load of 8917,638 m³/year. Based on comparisons between the annual sediment volume estimated using the USLE and sediment transport methods and the reservoir dead storage capacity of 432000 m³, the reservoir service life is estimated to range between 46 and 48 years. MIKE 21 simulation results show that sediment deposition is concentrated in the upstream reservoir area (near the inlet), reducing the storage capacity at the same elevation from 4,573 million m³ (existing condition in 2026) to 2,428 million m³ (2066), representing a reduction of approximately 47%. The reservoir service life based on the simulation is estimated to be approximately 40 years. Sediment management through dredging in the inlet area, combined with upstream watershed conservation measures, is proposed to extend the reservoir's service life.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Sedimentation, Universal Soil Loss Equation (USLE), Erosion, Dam, Reservoir Service Life, MIKE 21, Land Use, Sedimentasi, Erosi, Bendungan, Umur guna waduk, MIKE 21, Tata guna lahan
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TC Hydraulic engineering. Ocean engineering > TC167 Dams, reservoirs T Technology > TC Hydraulic engineering. Ocean engineering > TC175.2 Sediment transport
Divisions:	Faculty of Vocational > 22301-Civil Infrastructure Engineering (D4)
Depositing User:	Muhammad Taufiqul Hakim
Date Deposited:	04 Aug 2026 10:17
Last Modified:	04 Aug 2026 10:17
URI:	http://repository.its.ac.id/id/eprint/143517

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