MODIFIKASI KOEFISIEN PENGALIRAN PADA METODE RASIONAL BERDASARKAN DATA TIME SERIES (STUDI KASUS SUB DAS PANDANTOYO DAN SUB DAS NGADIREJO)

Kencanawati, Martheana (2024) MODIFIKASI KOEFISIEN PENGALIRAN PADA METODE RASIONAL BERDASARKAN DATA TIME SERIES (STUDI KASUS SUB DAS PANDANTOYO DAN SUB DAS NGADIREJO). Doctoral thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Metode Rasional untuk menghitung peak flow telah diturunkan persamaannya sejak tahun 1880. Salah satu parameter utama dalam metode rasional adalah koefisien runoff. Tujuan dalam penelitian lapangan ini terbagi menjadi dua hal utama yaitu memodifikasi koefisien pengaliran pada metode rasional berdasarkan data time series dan membandingkan model numerik hujan rainfall runoff modeling.
Metode penelitian yang diterapkan dalam penelitian ini adalah Horton method, analisis rating curve dengan menggunakan data dari pengamatan dengan automatic water level logger (AWLL), penentuan intensitas curah hujan rata-rata maksimum berdasarkan metode Poligon Thiessen. Estimasi curve number menggunakan metode Natural Resources Conservation Soil SCS-CN kemudian dilanjutkan pada pemodelan, data analitik dan ditahap akhir uji model SPSS.
Dari analisis data didapatkan nilai laju infiltrasi Sub DAS Ngadirejo adalah 27 mm/jam kategori sedang sedangkan di Sub DAS Pandantoyo adalah 90 mm/jam yaitu kategori agak cepat. Sehingga sensitivity curve pada model yang didapatkan, dengan range berbeda di antara Sub DAS Pandantoyo (CN 49-53) dan Sub DAS Ngadirejo (CN 53-55). Modifikasi kisaran nilai koefisien runoff (dimensionless) yang didapatkan, Modifikasi kisaran nilai koefisien runoff (dimensionless) yang didapatkan C pandantoyo : C Ngadirejo adalah fungsi = f (R24,Sm),LU Dapat disimpulkan bahwa, modifikasi rumusan metode rasional adalah fungsi C modifikasi yang merupakan fungsi Q rational
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The determination of peak flow using the rational method was introduced in the 1880s. One of the main parameters in the rational method formula is the runoff coefficient. The rational method could be the basic procedure for determining the peak flow derived from surface runoff flow. This research aims to modify a rational method formulation based on fieldwork and compare numerical rainfall modeling with the relationship model for hydrological conditions based on simulation parameters: rainfall, infiltration, land use, and flow.
In this study, we applied the Horton method, Rating curve analysis, Thiessen Polygon, NRCS-CN, rainfall-runoff modeling, analytical data, and SPSS models.
From the analysis, it was found that the infiltration rate value of Ngadirejo village was 27 mm/hour in the medium category, and that of Pandantoyo village was 90 mm/hour. The differences in curve number modeling at the Pandantoyo subbasin and Ngadirejo subbasin. The sensitivity curve number was obtained in the range of 49–57. For the result, different sensitivity curve numbers were obtained between the Pandantoyo subbasin (CN 49–53) and the Ngadirejo subbasin (CN 53–55). Modification runoff coefficient values (dimensionless) for an ungauged catchment can be obtained Modification runoff coefficient values (dimensionless) for an ungauged catchment can be obtained function of f (R24,Sm),LU. It can be concluded that the modification of the rational method formulation is in the modified C function which is the Q rational function

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	koefisien runoff, laju infiltrasi, surface runoff, metode rational, presipitasi, tutupan lahan curve number, infiltration rate, rational methods, rating curve, runoff coefficients
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC424 Water levels
Divisions:	Faculty of Civil Engineering and Planning > Civil Engineering > 22001-(S3) PhD Thesis
Depositing User:	Martheana Kencanawati
Date Deposited:	08 Aug 2024 03:07
Last Modified:	08 Aug 2024 03:07
URI:	http://repository.its.ac.id/id/eprint/113621

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