Pemodelan Hidrolik Sistem Kanal Larona akibat Perbaikan Dasar Saluran Menggunakan Aplikasi HEC-RAS

Khoiruddin, Muhammad Fahmi (2020) Pemodelan Hidrolik Sistem Kanal Larona akibat Perbaikan Dasar Saluran Menggunakan Aplikasi HEC-RAS. Sarjana thesis, Universitas Brawijaya.

Abstract

Keretakan sambungan panel kanal bermaterial beton berakibat pada penghentian operasional Pembangkit Listrik Tenaga Air (PLTA) Larona untuk proses pelapisan dasar saluran. Pelapisan dasar saluran menggunakan material geomembrane menyebabkan perubahan kinerja akibat peningkatan kapasitas pengaliran air menuju kolam penenang (headpond). Studi ini akan memodelkan dan mengkaji kinerja hidrolik sistem kanal air kondisi eksisting, sehingga dapat memberikan usulan bukaan pintu pada bagian pengambilan (intake) agar debit yang dialirkan melalui kanal menjadi optimal. Pemodelan hidrolik sistem kanal air Larona menggunakan aplikasi HEC-RAS versi 5.0.7 dengan 2 alternatif pendekatan. Panel kanal air dimodelkan menyerupai cross section dengan jumlah 469 buah. Penentuan syarat batas berdasarkan pada operasi debit melalui kanal, elevasi muka air waduk, dan elevasi minimum pada kolam penenang. Proses kalibrasi menggunakan estimasi nilai Manning dengan pencocokan data pengukuran parameter kecepatan dan kedalaman aliran. Evaluasi kinerja menggunakan hasil pemodelan dengan melihat elevasi air di kolam penenang (headpond) kemudian memberikan usulan bukaan pintu di pengambilan (intake). Model hidrolik menunjukkan hasil kalibrasi cukup baik menggunakan pendekatan alternatif 1. Diperoleh nilai Manning 0.016 untuk kondisi kanal sebelum lining dan 0.013 kondisi setelah lining, dengan kesalahan relatif rerata terkecil yaitu 4,39 %. Usulan bukaan pintu pengambilan mengacu pada pengaliran debit dengan waktu tempuh yang sama sebelum dan sesudah lining sehingga memberikan waktu pengisian yang sama saat aliran menuju headpond. Untuk operasional maksimum maka perlu pengusulan debit masuk dari intake 131.98 m3/detik, sedangkan untuk operasional normal perlu pengusulan debit masuk intake 103.80 m3/detik. Usulan debit yang masuk intake menghasilkan bukaan pintu yang lebih rendah daripada bukaan pintu eksisting. Hasil evaluasi kinerja peluap samping (sideweir) menunjukkan bahwa operasional debit maksimum yang tidak optimal dengan bukaan pintu eksisting. Hasil komputasi hidrolik menunjukkan debit melimpas sebesar 5.15 m3/detik di atas peluap samping. Usulan bukaan pintu menunjukkan pengoperasian optimal, diketahui dari elevasi muka air hasil running program tidak ada yang lebih tinggi dari elevasi puncak peluap samping (side-weir).

English Abstract

The crack of joint of the canal panel with the concrete material caused the operational shutdown of the Larona Hydroelectric Power (PLTA) in the process lining of the bottom channel. The lining of the bottom canal on the Larona Hydropower Plant using geomembrane material caused a change of performance due to increased water flow capacity to the headpond. This study will be modeling and examine the hydraulic performance of the existing water canal system so that it can present the proposed opening gates at the canal intake to pass the operating discharge optimally. The hydraulic modeling of the Larona water canal system uses HEC-RAS software version 5.0.7 with 2 alternative approaches. The canal panels are modeled as a cross-section as many as 469 pieces. Determination of the boundary conditions is based on the operation of the discharge through the channel, the elevation of the reservoir water level, and the minimum elevation in the headpond. The calibration uses the estimated Manning value with matching measurement data of velocity and flow depth. Performance evaluation uses modeling results by checking at the elevation of the headpond and then giving the proposed opening gates at intake. The hydraulic model shows calibration results using alternative approach 1 were quite good. Acquired the value of Manning 0.016 for canal conditions before lining and 0.013 conditions after lining, with the smallest average error of 4.39%. The proposed opening gates at intake refers to the same stream time as the flow of the discharge before and after the lining, thus giving the same charging time as the stream to the headpond. For maximum operation, it is necessary to propose incoming discharge from intake 131.98 m3/sec, while for normal operation need to be the discharge of incoming intake of 103.80 m3/sec. The proposed discharge that enters the intake results in lower opening gates than the existing opening gates. The results of the side weir performance evaluation showed optimal on maximum discharge operational results using existing opening gates. Hydraulic computing results show a spill discharge over a side weir of 5.15 m3/sec. Proposed opening gates indicate optimal operation, known from the elevation of water in the results running program does not exist higher than the crest elevation of the side weir.

Other obstract

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Item Type: Thesis (Sarjana)
Identification Number: 0520070133
Uncontrolled Keywords: model hidrolik, kalibrasi model, bukaan pintu, kinerja sistem kanal, HEC-RAS , hydraulic model, model calibration, opening gate, canal system performance, HEC-RAS
Subjects: 600 Technology (Applied sciences) > 620 Engineering and allied operations > 620.1 Engineering mechanics and materials
Divisions: Fakultas Teknik > Teknik Pengairan
Depositing User: Bambang Septiawan
Date Deposited: 21 Feb 2021 22:27
Last Modified: 21 Feb 2021 22:27
URI: http://repository.ub.ac.id/id/eprint/182611
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