Pambudi, Yan Ahmad Christy (2018) Studi Perencanaan Konsolidasi Dam di Sungai Mujur Desa Pasrujambe Kecamatan Pasrujambe Kabupaten Lumajang. Sarjana thesis, Universitas Brawijaya.
Abstract
DAS Mujur merupakan salah satu DAS yang sungai utamanya berhulu di Gunung Semeru yang terletak di Kabupaten Lumajang, lebih tepatnya diantara 08°01'28"-08°09'25" LS dan 112°54'43"-113°03'50" BT. DAS Mujur mempunyai luas DAS 44,904 km2 dengan panjang sungai utama mencapai 16,95 km. Sungai Mujur merupakan sungai yang berada di DAS Mujur yang seringkali membawa material hasil letusan dari puncak Gunung Semeru. Material hasil letusan dapat berupa batu-batuan, kerikil dan pasir yang bercampur menjadi satu dengan aliran banjir. Kondisi alur sungai di bagian hulu mempunyai kemiringan dasar sungai yang cukup curam untuk menyebabkan terjadinya mass movement. Oleh sebab itu diperlukan penanganan yang disesuaikan dengan slope sungai dan jenis aliran sedimen yang terjadi di Sungai Mujur agar fungsi bangunan yang direncanakan berfungsi optimal. Selain masalah banjir aliran mass movement yang dapat terjadi saat hujan dengan intensitas tinggi, terdapat tikungan sungai di bagian Sungai Mujur yang mengakibatkan proses agradasi dan degradasi tidak seimbang. Akibatnya kedalaman aliran sungai menjadi tidak seragam di bagian sungai. Selain itu tebing sungai di sisi luar belokan akan tergerus secara terus menerus saat terjadi banjir jika aliran di tikungan sungai tidak dikendalikan. Untuk itu perlu dilakukan perencanaan bangunan konsolidasi dam yang bertujuan untuk mengatur alur dan dasar sungai serta dapat mengarahkan aliran saat terjadi banjir aliran mass movement. Keberadaan bangunan konsolidasi dam diharapkan mampu untuk mengatur proses agradasi-degradasi sungai sehingga Sungai Mujur dapat berfungsi dengan optimal jika suatu saat terjadi banjir aliran mass movement. Berdasarkan analisa perhitungan yang telah dilakukan, yaitu analisa hidrologi, analisa hidrolika, analisa jenis angkutan sedimen, perencanaan dimensi konsolidasi dam, kontrol stabilitas main dam dan sub dam maka bangunan konsolidasi dam akan direncanakan dengan jarak ±215 m sebelah hilir tikungan sungai. Analisa debit banjir rancangan kala ulang 25 tahun menggunakan metode Hidrograf Satuan Sintetis Nakayasu sebesar 155,367 m3/dt, sedangkan debit desain untuk bangunan konsolidasi dam dengan mempertimbangkan konsentrasi aliran sedimen sebesar 204,424 m3/dt. Volume sedimen sekali banjir dengan kala ulang 25 tahun sebesar 199.918,30 m3. Detail dimensi bangunan konsolidasi dam yaitu tinggi main dam 3 m, lebar pelimpah 100 m, tebal mercu main dam 2,5 m, kedalaman pondasi 2 m, tinggi sub dam 0,75 m dan tebal mercu sub dam 2,5 m.
English Abstract
Mujur watershed is one of the main river basins in Mount Semeru located at Lumajang Regency, more precisely between 08°01'28"-08°09'25" LS and 112°54'43"-113° 03'50" BT. Mujur watershed has a 44,904 km2 watershed with a main river length of 16,95 km. Mujur River is a river that is in the Mujur watershed that often bring material from the eruption of Mount Semeru. Eruption material can be rock, gravel and sand mixed together with flood stream. The condition of the river channel in the upstream has a steep slope of the river bottom to cause mass movement. Therefore it is necessary to adjust the handling of the river slope and the type of sediment flow that occurs in the River Mujur for the function of the planned building to function optimally. In addition to the problem of flooding mass movement can occur when rain with high intensity, there is a bend of the river in the Mujur River which resulted in the process of agradation and degradation is not balanced. As a result the depth of the river flow becomes uniform in the river. In addition, river cliffs on the outer side of the bend will be eroded continuously during flooding if flow in the bend of the river is not controlled. For that reason, it is necessary to do the planning of the consolidation dam building which aimed to regulate the flow and the bottom of the river and can direct the flow during the mass movement flood. The existence of the consolidation dam is expected to be able to manage the process of agradasi-degradation of the river so that the Mujur River can function optimally if one day there is a flood of mass movement. Based on the calculation analysis, hydrology analysis, hydrolic analysis, sediment transport type analysis, dimension of consolidation dam planning, stability control of main dam and sub dam, a consolidation dam will be planned with ± 215 meters distance downstream from the bend of the river. Also, the flood discharge analysis of 25-year return period design used the Nakayasu Synthetic Unit Hydrograph method is 155.367 m3/dt, while the design debit for consolidation of dam by considering the effect of sediment concentration is amounted to 204,424 m3/dt. The onetime flooded sediment volume with a 25-year return period is 199,918.30 m3. Moreover, the detailed dimension of the consolidation dam building are the height of the main dam is 3 m, the width of the main dam weir is 100 m, the thickness of the main dam is 2,5 m, footing depth is 2 m, the height of the sub dam is 0,75 m and the thickness of the sub dam is 2.5 m.
| Item Type: | Thesis (Sarjana) |
|---|---|
| Identification Number: | SKR/FT/2018/897/051809130 |
| Uncontrolled Keywords: | konsolidasi dam, mass movement, tikungan sungai consolidation dam, mass movement, river bend |
| Subjects: | 600 Technology (Applied sciences) > 627 Hydraulic engineering > 627.8 Dams and reservoirs |
| Divisions: | Fakultas Teknik > Teknik Pengairan |
| Depositing User: | Budi Wahyono Wahyono |
| Date Deposited: | 10 Oct 2018 01:45 |
| Last Modified: | 10 Oct 2018 01:45 |
| URI: | http://repository.ub.ac.id/id/eprint/12492 |
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