Estimasi Fluks Sedimen Tersuspensi Berdasarkan Pengukuran ADCP dan Multi-frekuensi Multibeam Echosounder

Hariyanto, Irena Hana (2021) Estimasi Fluks Sedimen Tersuspensi Berdasarkan Pengukuran ADCP dan Multi-frekuensi Multibeam Echosounder. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Akuisi data dalam studi dinamika sedimen tersuspensi umumnya menggunakan sampel sedimen tersuspensi dan pengamatan arus. Metode tersebut memiliki keterbatasan dalam merepresentasikan dinamika sedimen tersuspensi secara menyeluruh karena akuisisi data dilakukan di satu titik pada waktu tertentu. Pada penelitian ini, multi-frekuensi multibeam echosounder (MBES) R2Sonic 2024 digunakan sebagai metode alternatif untuk studi dinamika sedimen tersuspensi. Multi-frekuensi MBES menggunakan beberapa frekuensi gelombang suara yang dipancarkan sekaligus dalam satu waktu. Dengan demikian data yang diperoleh dapat merepresentasikan kondisi dinamika sedimen di lokasi penelitian secara lebih menyeluruh. Lokasi penelitian berada di Sungai Colorado, Arizona, Amerika Serikat sebagai salah satu sungai dengan tingkat sedimentasi yang tinggi. Penelitian ini memiliki fokus di area sepanjang 330 m dengan lebar sekitar 58 m. Parameter dinamika sedimen yang digunakan pada penelitian ini meliputi konsentrasi dan fluks sedimen tersuspensi.
Frekuensi MBES yang digunakan pada akuisisi data adalah 170, 330, 450, dan 700 kHz. Proses validasi data water column multi-frekuensi MBES dilakukan dengan mengunakan data sampel sedimen in-situ. Berdasarkan data hasil akuisisi ADCP, diketahui bahwa arus sungai di area penelitian bertipe unidirectional dengan arah sekitar 250° dan nilai kecepatan arus rata-rata sebesar 0,94 m/s. Estimasi nilai konsentrasi sedimen tersuspensi berdasarkan data sampel sedimen in-situ dengan data water column berkisar antara 370 hingga 430 mg/L. Dengan mengintegrasikan data arus ADCP dan hasil estimasi konsentrasi sedimen tersuspensi, dapat diprediksi besar fluks sedimen tersuspensi di area penelitian memiliki nilai sekitar 5 × 10⁶ ton/tahun. Analisi fluks sedimen tersuspensi antar transect di sepanjang area penelitian memiliki nilai yang berbeda-beda. Perbedaan nilai tersebut dipengaruhi oleh variasi debit sungai, tutupan lahan di bantaran sungai, dan curah hujan yang pada akhirnya mempengaruhi suspended budget di sepanjang area penelitian.
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Data acquisition in the study of suspended sediment dynamics generally uses suspended sediment samples and current observations. This method has limitations in representing the dynamics of suspended sediment because data acquisition is acquired at one point at a time. In this study, multi-frequency multibeam echosounder (MBES) R2Sonic 2024 was utilized as an alternative method for the study of suspended sediment dynamics. Multi-frequency MBES uses multiple frequencies of acoustic waves to be transmitted at once. Thus the data achieved can represent the dynamics of the sediment conditions at the research site continuously. The research location is in the Colorado River, Arizona, United States as one of the rivers with a high sedimentation rate. This study focuses on an area of 330 m long and 58 m wide. The parameters of sediment dynamics used in this study include the concentration and flux of suspended sediment.
The MBES frequencies that used in the data acquisition are 170, 330, 450, and 700 kHz. The multi-frequency MBES water column data was validated using in-situ sediment sample data. Based on the data collected from ADCP, the river current in the research area is unidirectional type with directions approximately 250° and the average of the flow is 0.94 m/s. Based on the analysis of in-situ sediment sample data and MBES water column data, the suspended sediment concentration estimation ranges from 370 to 430 mg/L. By integrating the ADCP current data with the estimated suspended sediment concentration, the suspended sediment flux can be predicted which is about 5 × 10⁶ tons/year. The analysis of suspended sediment flux among the transects along the study area has different magnitudes. This occurs because of the variations in river discharge, land cover along the riverbank, and rainfall which ultimately affects the suspended budget throughout the study area.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Water Column, Multibeam Echosounder, Acoustic Current Doppler Profiler, Dinamika Sedimen Tersuspensi, Water Column, Multibeam Echosounder, Acoustic Doppler Current Profiler, Suspended Sediment Dynamics.
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences Q Science > QE Geology T Technology > T Technology (General)
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29101-(S2) Master Thesis
Depositing User:	Irena Hana Hariyanto
Date Deposited:	19 Aug 2021 06:35
Last Modified:	19 Aug 2021 06:35
URI:	http://repository.its.ac.id/id/eprint/88150

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