Analisis Skenario Bahaya Banjir Berbasis Model Hidrodinamika 2D pada Kawasan Banyakan, Kabupaten Kediri

Rahmantyas, Srie Harnanda Bagus (2026) Analisis Skenario Bahaya Banjir Berbasis Model Hidrodinamika 2D pada Kawasan Banyakan, Kabupaten Kediri. Masters thesis, Institut Teknologi Sepuluh Nopember.

Text 6012221112-Master_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (36MB) | Request a copy

Abstract

Kawasan Banyakan dan Grogol, Kabupaten Kediri, berulang kali dilanda banjir luapan Sungai Bendo Krosok dan Bondo Mongal yang merendam permukiman serta koridor jalan arteri Kediri–Nganjuk. Kedua DAS tidak memiliki stasiun ukur debit, sehingga penilaian bahaya banjir bergantung sepenuhnya pada pemodelan. Penelitian ini bertujuan menganalisis karakteristik hidrologi dan hidraulika banjir pada daerah penelitian, mengevaluasi tingkat keandalan model dalam menyimulasikan kejadian banjir berdasarkan data historis, menganalisis karakteristik genangan banjir pada berbagai kala ulang, serta menyusun peta zonasi bahaya banjir berdasarkan karakteristik kedalaman dan kecepatan aliran. Pemodelan menggunakan skema hibrida Hydrology–Rain-on-Grid (H-RoG). Limpasan Sub-DAS hulu dihitung pada HEC-HMS menggunakan metode SCS Curve Number, hidrograf satuan SCS, dan Lag Routing, lalu dimasukkan sebagai hidrograf ke model HEC-RAS 2D bersolver Diffusion Wave, sedangkan hujan langsung diterapkan pada kawasan hilir. Skema Rain-on-Grid penuh dijalankan sebagai pembanding dengan parameter fisik yang dikunci identik. Geometri model dibangun dari FABDEM yang digabungkan dengan survei topobatimetri. Kalibrasi dilakukan terhadap koefisien Manning bangunan dan divalidasi pada delapan titik observasi kejadian banjir 23–24 Desember 2024. Validasi pada tujuh titik menghasilkan RMSE 0,0176 m dan NSE 0,9854, dengan H-RoG unggul pada seluruh indikator sekaligus menghemat 42,0% sel komputasi. Simulasi kala ulang 20, 50, dan 100 tahun memperlihatkan respons yang teredam, yaitu debit puncak gabungan naik 40,7% sementara luas genangan hanya bertambah 21,90%. Luas area bahaya menurut AIDR Guideline 7-3 meningkat dari 1.199,31 ha menjadi 1.338,53 ha, dengan pertumbuhan terbesar pada kelas bahaya menengah. Ancaman utama pada kala ulang ekstrem karena itu bukan perluasan wilayah terdampak, melainkan intensifikasi genangan pada area yang telah terdampak.
===================================================================================================================================
The Banyakan and Grogol areas of Kediri Regency are repeatedly inundated by overbank flow from the Bendo Krosok and Bondo Mongal rivers, affecting settlements and the Kediri–Nganjuk arterial road corridor. Neither catchment is gauged, so flood hazard assessment depends entirely on modelling. This study aims to characterise the hydrological and hydraulic behaviour of flooding in the study area, evaluate model reliability in reproducing a historical flood event, characterise inundation across return periods, and develop a flood hazard zonation map based on inundation depth and flow velocity. A hybrid Hydrology–Rain-on-Grid (H-RoG) scheme was applied. Upstream sub-catchment runoff was computed in HEC-HMS using the SCS Curve Number loss method, the SCS unit hydrograph, and Lag Routing, then introduced as an inflow hydrograph to a HEC-RAS 2D model running the Diffusion Wave solver, while direct rainfall was applied over the downstream area. A full Rain-on-Grid scheme was run as a benchmark with physical parameters held identical. Model geometry combined FABDEM terrain with a topobathymetric survey. Calibration targeted the building roughness coefficient and was validated against eight observation points from the 23–24 December 2024 flood event. Validation at seven points yielded an RMSE of 0.0176 m and an NSE of 0.9854, with H-RoG outperforming on every indicator while requiring 42.0% fewer computational cells. Simulations for the 20, 50, and 100-year return periods revealed a damped response: peak combined discharge increased by 40.7% whereas inundation area grew by only 21.90%. Hazardous area classified under AIDR Guideline 7-3 expanded from 1,199.31 ha to 1,338.53 ha, with the sharpest growth occurring in the intermediate hazard classes. Under extreme return periods the dominant threat is therefore not the spatial expansion of flooding but its intensification within areas already affected.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Hydrology–Rain-on-Grid, HEC-RAS 2D, Diffusion Wave, Ungauged Catchment, Zonasi Bahaya Banjir, Hydrology–Rain-on-Grid, HEC-RAS 2D, Diffusion Wave, Ungauged Catchment, Flood Hazard Zonation
Subjects:	T Technology > T Technology (General) > T174.5 Technology--Risk assessment. T Technology > TA Engineering (General). Civil engineering (General) T Technology > TA Engineering (General). Civil engineering (General) > TA590 Topographical surveying T Technology > TC Hydraulic engineering. Ocean engineering T Technology > TC Hydraulic engineering. Ocean engineering > TC530 Flood control
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	Srie Harnanda Bagus Rahmantyas
Date Deposited:	12 Aug 2026 00:35
Last Modified:	12 Aug 2026 00:35
URI:	http://repository.its.ac.id/id/eprint/144319

Actions (login required)

View Item