Alternatif Desain Penanganan Banjir pada DAS Serang, Kulon Progo, Daerah Istimewa Yogyakarta

Nurdianto, Wicaq (2024) Alternatif Desain Penanganan Banjir pada DAS Serang, Kulon Progo, Daerah Istimewa Yogyakarta. Diploma thesis, Institut Teknologi Sepuluh Nopember.

Text 2036201074-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only until 1 October 2026. Download (13MB) | Request a copy

Abstract

Dalam suatu DAS terdapat beberapa permasalahan, salah satunya adalah permasalahan banjir. Daerah Istimewa Yogyakarta merupakan salah satu daerah di Indonesia yang mengalami banjir, khususnya pada desa Glagah. Desa Glagah berada di Kecamatan Temon, Kabupaten Kulon Progo, Daerah Istimewa Yogyakarta. Desa Glagah termasuk dalam luasan area DAS Serang. Dalam sistem DAS serang, terdapat 12 sungai yang bermuara di sungai serang. Beberapa sungai tersebut adalah sungai turi, sungai seling, sungai dengen, sungai gandri, sungai kaligintung, sungai sidatan, sungai sikebo, sungai plumbon, sungai banjaran, sungai carik timur, sungai ledeng, dan sungai jelantoro. Banjir pada DAS serang terjadi akibat penampang sungai yang tidak mampu lagi menampung dan mengalirkan air menuju hilir, dan terdapat pengaruh dari air pasang laut yang menghambat laju air di hilir. Hasil dari analisis eksisting sungai didapatkan bahwa terdapat luapan di semua sungai yang berpotensi merendam area pemukiman. Selain area pemukiman, jalan akses bandara Yogyakarta International sisi barat laut juga berpotensi terdampak banjir karena luapan dari sungai turi. Dari permasalahan tersebut, direncanakan alternatif desain penanganan banjir yang efektif melalui pendekatan teknis. Penelitian ini dilaksanakan dengan mengkombinasikan normalisasi sungai dan pintu air dengan debit rencana Q10 dan pasang air laut setinggi 1.074 m. Hasil dari penelitian ini adalah pada beberapa sungai mengalami luapan dengan kondisi Q10 dan pasang setinggi 1,074. Pada sungai sidatan bagian hulu, diberi tanggul untuk menambah kapasitas tampungan sungai tanpa dilakukan pelebaran, dan sungai lainnya dilakukan normalisasi berupa pelebaran sungai. Hasil normalisasi sungai diharapkan dapat mengendalikan banjir. Untuk mencegah air pasang masuk menuju sistem, telah dibangun kolam retensi karangwuni untuk menampung air sementara selama pasang. Selain itu, dibuat pintu air dengan lebar pintu diasumsikan 5 meter, dan tinggi pintu 9 meter. Bukaan pintu maksimum yang direncanakan adalah tidak lebih dari 0,6 meter dengan kondisi h air sungai (hulu pintu) setinggi 8,75 m dari dasar dan h air pasang (hilir pintu) setinggi 8,25 m dari dasar. Karena berpotensi air pasang masuk kedalam sistem sungai apabila bukaan melebihi 0,6 meter. Stabilitas terhadap longsoran dari struktur rencana mendapatkan hasil yang memenuhi syarat FS yaitu pada kondisi normal FS minimal 1,5 dan kondisi gempa 1,3. Stabilitas terhadap gulung pada tanggul mendapatkan nilai FS 2,3 dengan batas minimal FS 1,5, namun stabilitas terhadap geser mendapatkan nilai FS 0,89 dengan batas minimal FS 1,5 sehingga perlu adanya diperbaiki daya dukung tanah. Biaya yang dibutuhkan dalam pembangunan adalah Rp189,580,009,058 mencakup biaya galian dan timbunan tanah, pekerjaan pasangan batu, plesteran, siaran, dan pintu air.
=================================================================================================================================
In a watershed area, one of the problems is flooding. The Special Region of Yogyakarta is one of the areas in Indonesia experiencing flooding, particularly in the village of Glagah. Glagah village is located in Temon District, Kulon Progo Regency, Special Region of Yogyakarta. Glagah village is part of the Serang watershed area. In the Serang watershed system, there are 12 rivers that flow into the Serang River. Some of these rivers are Turi River, Seling River, Dengen River, Gandri River, Kaligintung River, Sidatan River, Sikebo River, Plumbon River, Banjaran River, Carik Timur River, Ledeng River, and Jelantoro River. Flooding in the Serang watershed occurs because the river cross-sections can no longer accommodate and channel water downstream, and there is an influence from seawater tides that hinder the flow of water downstream. The results of the existing river analysis show that there is an overflow in all rivers that potentially inundate residential areas. In addition to residential areas, the access road to Yogyakarta International Airport on the northwest side is also at risk of flooding due to overflow from the Turi River. To address these issues, an alternative flood management design is planned using a technical approach. This research was conducted by combining river normalization and floodgates with a planned discharge of Q10 and seawater tides of 1.074 m. The results of this study show that some rivers overflow with Q10 conditions and tides of 1.074 m. In the upstream part of the Sidatan River, embankments are added to increase the river's holding capacity without widening it, while other rivers are normalized by widening. The river normalization results are expected to control flooding. To prevent tidal water from entering the system, a retention pond was built in Karangwuni to temporarily hold water during tides. Additionally, a floodgate was constructed with a door width assumed to be 5 meters and a door height of 9 meters. The maximum planned door opening is no more than 0.6 meters with the river water level (upstream of the gate) at 8.75 m from the base and the tidal water level (downstream of the gate) at 8.25 m from the base. Opening the gate beyond 0.6 meters may allow tidal water to enter the river system. The stability of the planned structure against sliding meets the FS requirement, with a minimum FS of 1.5 under normal conditions and 1.3 during earthquakes. The embankment stability against rolling achieved an FS value of 2.3 with a minimum FS of 1.5, but the stability against shearing achieved an FS value of 0.89 with a minimum FS of 1.5, indicating that the soil bearing capacity needs improvement. The total construction cost is estimated at IDR 189,580,009,058, covering the costs of excavation and filling, stone masonry work, plastering, and floodgate installation.

Item Type:	Thesis (Diploma)
Uncontrolled Keywords:	DAS, Penanganan Banjir, Sungai, Normalisasi, Pntu air, Watershed, Flood Management, River, Normalization, Floodgate
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA749 Soil stabilization T Technology > TC Hydraulic engineering. Ocean engineering > TC424 Water levels T Technology > TC Hydraulic engineering. Ocean engineering > TC530 Flood control
Divisions:	Faculty of Vocational > Civil Infrastructure Engineering (D4)
Depositing User:	Wicaq Nurdianto
Date Deposited:	29 Aug 2024 02:54
Last Modified:	29 Aug 2024 02:54
URI:	http://repository.its.ac.id/id/eprint/113825

Actions (login required)

View Item