Model hidrograf satuan sintesis beberapa sungai di Wilayah Indonesia

Nizarsyah, Faishal (2005) Model hidrograf satuan sintesis beberapa sungai di Wilayah Indonesia. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Ketidaklengkapan data aliran sungai seperti data debit dan tersedianya data hujan yang memadai menjadikan metode Hidrograf Satuan Sintetis (HSS) dipilih sebagai alternatif utama untuk memperkirakan besarnya debit banjir. Walaupun telah ada beberapa model HSS yang siap pakai, perlu diketahui bahwa kondisi hidrologi di Indonesia (dan di mana pun) adalah khas, sehingga tidak semua cara dan semua konsep dapat digunakan untuk memecahkan masalah hidrologi di Indonesia. Dalam penelitian ini, penulis mencoba memformulasikan model HSS yang sederhana dan memadai untuk beberapa sungai di Indonesia.
Proses pemodelan didekati secara statistik dengan metode regresi. Penelitian dilakukan terhadap faktor fisik DAS berupa luas DAS (A), panjang sungai utama (L), kemiringan rerata sungai (S), koefisien kekasaran DAS rerata (n), kemiringan rerata DAS (Ic), dan koefisien jenis tanah (Sc) yang diyakini berpengaruh terhadap bentuk hidrograf. Perumusan model kurva hidrograf didekati dengan gradien persamaan garis. Kriteria pemilihan model terbaik didasarkan pada besaran-besaran statistik yang telah ditetapkan.
Setelah dilakukan kalibrasi berdasarkan kriteria NASH diperoleh: Waktu Puncak (Tp) = 99,65%; Debit Puncak (Qp) = 99,94%; dan Waktu Dasar (Tb) = 99,99%. Rumus kurva naik hidrograf yang mengacu kriteria Q_n=Q_p (t/T_p )^(m_1 )dan rumus kurva turun hidrograf Q_t=Q_p e^(-(t-T_p)/m_2 ), di mana m_1dan m_2merupakan fungsi dari parameter fisik DAS.
Dari hasil uji keandalan model HSS, ternyata model HSS ini memberikan simpangan yang sangat kecil terhadap HSO dibandingkan dengan HSS lainnya, dengan rata-rata penyimpangan sebesar 3%.
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The insufficient river streamflow data, such as discharge data, along with the availability of adequate rainfall data, makes the Synthetic Unit Hydrograph (SUH) method the main alternative for predicting flood discharge. Although several SUH models are readily available, it is important to recognize that hydrological conditions in Indonesia (and elsewhere) are unique. Therefore, not all methods and concepts can be applied to solve hydrological problems in Indonesia. In this research, the author attempts to formulate a simple and adequate SUH model for several rivers in Indonesia.
The modeling process was approached statistically using regression methods. The study investigated the physical factors of the watershed, including watershed area (A), main river length (L), average river slope (S), average watershed roughness coefficient (n), average watershed slope (Ic), and soil type coefficient (Sc), which are believed to influence the shape of the hydrograph. The formulation of the hydrograph curve model was approached using the gradient of a linear equation. The criteria for selecting the best model were based on predetermined statistical parameters.
After calibration based on the NASH criteria, the results obtained were: Peak Time (Tp) = 99.65%, Peak Discharge (Qp) = 99.94%, and Base Time (Tb) = 99.99%. The formula for the ascending hydrograph curve that meets the criteria is Q_n=Q_p (t/T_p )^(m_1 ), while the descending hydrograph curve is Q_t=Q_p e^(-(t-T_p)/m_2 ), where m_1and m_2are functions of the physical parameters of the watershed.
Based on the results of the reliability test of the SUH model, this model produced a smaller standard error compared with other SUH models, with an average standard error of 3%.

Item Type:	Thesis (Other)
Additional Information:	551 46 Niz m
Uncontrolled Keywords:	HSS. Fak1or ftsik DAS, SUH. physical factor of Watershed.
Subjects:	T Technology > TN Mining engineering. Metallurgy > TN688 Hydrometallurgy
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	magang .
Date Deposited:	06 Oct 2026 08:48
Last Modified:	06 Oct 2026 08:48
URI:	http://repository.its.ac.id/id/eprint/145351

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