UJI MODEL FISIK PENGENDALIAN ELEVASI DASAR SUNGAI DI SEKITAR INTAKE POLDER ALABIO, KABUPATEN HULU SUNGAI UTARA, PROPINSI KALIMANTAN TIMUR DENGAN MENGGUNAKAN VANE - Joko Nugroho; Febry Asthia Miranti; Yiniarti Eka Kumala; Dhemi Harlan (Jurnal Teknik Sipil, 2021)
Abstrak Pada makalah ini disampaikan hasil penelitian terhadap pengendalian elevasi dasar sungai di depan intake dengan menggunakan vane, pada kasus intake Irigasi Polder Alabio, Kabupaten Hulu Sungai Utara, Provinsi Kalimantan Selatan, dengan menggunakan model fisik. Intake dari daerah irigasi ini berada di Sungai Negara.  Lahan pada DAS Sungai Negara semakin kritis sehingga terjadi pendangkalan dasar sungai, sehingga hal ini dapat mengganggu kinerja operasional intake irigasi teknis. Pemodelan fisik di laboratorium dilakukan dengan menggunakan skala geometri 1:40, dengan kala kecepatan dan debit ditentukan berdasarkan keserupaan aliran berdasarkan bilangan Froude. Model vane yang digunakan di laboratorium berukuran panjang 10 cm, tebal 1 cm, tinggi 3 cm. Pengujian dilakukan dengan debit prototip 263,17 m3/s dan 65,53 m3/s. Berdasarkan hasil percobaan didapatkan bahwa pemasangan vane dapat menurunkan elevasi dasar sungai di depan intake. Kemapuan vane dalam menurunkan elevasi dasar sungai dipengaruhi oleh jarak terhadap intake dalam arah lateral maupun longitudinal. Dari simulasi pada model fisik, perbandingan volume sedimen yang masuk akibat vane terhadap volume sedimen eksisting dapat diturunkan hingga 44%. Kata kunci: Vane, intake, gerusan, sedimentasi. Abstract This paper presents the results of research through a physical model on controlling the elevation of the riverbed in front of the intake using a vane, in the case of the Alabio Polder Irrigation intake, North Hulu Sungai Regency, South Kalimantan Province. The intake of this irrigated area is located at Sungai Negara. The land in the Sungai Negara watershed is increasingly critical in terms of land cover, resulting in silting of the riverbed, so that this can interfere with the operational performance of irrigation intake. Physical modeling in the laboratory was carried out using a geometric scale of 1:40, with the velocity and discharge at the model are determined based on the similarity based on the Froude number.  The vane model used in the laboratory was 10 cm long, 1 cm thick, and 3 cm high. The test was carried out with prototype discharges of 263.17 m3/s and 65.53 m3/s. Based on the experimental results, it was found that the installation of vanes can reduce the elevation of the riverbed in front of the intake. The vane's ability to reduce the riverbed elevation is affected by the distance to the intake in both lateral and longitudinal directions. From the simulation on the physical model, the ratio of the incoming sediment volume due to the vane to the existing sediment volume can be reduced to 44%. Kata kunci: Vane, intake, scour, sedimentation. Abstrak Pada makalah ini disampaikan hasil penelitian terhadap pengendalian elevasi dasar sungai di depan intake dengan menggunakan vane, pada kasus intake Irigasi Polder Alabio, Kabupaten Hulu Sungai Utara, Provinsi Kalimantan Selatan, dengan menggunakan model fisik. Intake dari daerah irigasi ini berada di Sungai Negara.  Lahan pada DAS Sungai Negara semakin kritis sehingga terjadi pendangkalan dasar sungai, sehingga hal ini dapat mengganggu kinerja operasional intake irigasi teknis. Pemodelan fisik di laboratorium dilakukan dengan menggunakan skala geometri 1:40, dengan kala kecepatan dan debit ditentukan berdasarkan keserupaan aliran berdasarkan bilangan Froude. Model vane yang digunakan di laboratorium berukuran panjang 10 cm, tebal 1 cm, tinggi 3 cm. Pengujian dilakukan dengan debit prototip 263,17 m3/s dan 65,53 m3/s. Berdasarkan hasil percobaan didapatkan bahwa pemasangan vane dapat menurunkan elevasi dasar sungai di depan intake. Kemapuan vane dalam menurunkan elevasi dasar sungai dipengaruhi oleh jarak terhadap intake dalam arah lateral maupun longitudinal. Dari simulasi pada model fisik, perbandingan volume sedimen yang masuk akibat vane terhadap volume sedimen eksisting dapat diturunkan hingga 44%. Kata kunci: Vane, intake, gerusan, sedimentasi. Abstract This paper presents the results of research through a physical model on controlling the elevation of the riverbed in front of the intake using a vane, in the case of the Alabio Polder Irrigation intake, North Hulu Sungai Regency, South Kalimantan Province. The intake of this irrigated area is located at Sungai Negara. The land in the Sungai Negara watershed is increasingly critical in terms of land cover, resulting in silting of the riverbed, so that this can interfere with the operational performance of irrigation intake. Physical modeling in the laboratory was carried out using a geometric scale of 1:40, with the velocity and discharge at the model are determined based on the similarity based on the Froude number.  The vane model used in the laboratory was 10 cm long, 1 cm thick, and 3 cm high. The test was carried out with prototype discharges of 263.17 m3/s and 65.53 m3/s. Based on the experimental results, it was found that the installation of vanes can reduce the elevation of the riverbed in front of the intake. The vane's ability to reduce the riverbed elevation is affected by the distance to the intake in both lateral and longitudinal directions. From the simulation on the physical model, the ratio of the incoming sediment volume due to the vane to the existing sediment volume can be reduced to 44%. Kata kunci: Vane, intake, scour, sedimentation.