Pengaruh Tanaman Pada Dataran Banjir Terhadap Kekasaran Hidrolik Sungai Barabai

Fitriani Hayati, Mohammad Yanuar Jarwadi Purwanto, Hidayat Pawitan, Suria Darma Tarigan, Latief Mahir Rachman


Hydraulic roughness value is a value that describes the estimation of retention towards water flow due to energy loss caused by friction between channel and water. The type, density and height of vegetation cause variations in the hydraulic roughness value. The hydraulic roughness value can be observed by using a physical model representing the real condition. The objective of this research is to figure out the
effect of plants planted in floodplain by conducting a research using physical model in a laboratory. This research was conducted by carrying out experiments and observations in a laboratory on a physical model that represents the condition of the cross section of Barabai River in South Kalimantan. The model was designed with a scale of 1:110, and in the floodplain were planted bamboo plants with a space of 1.82 by 1.82 cm. The plants’ diameter and length were 0.1 cm and 8 cm, respectively. The model was made in two types, namely a model with monocrops and another model with clump. The model is combined with an open channel along with its device. The research results show that there was an effect of plants on the hydraulic roughness value. This value was indicated by n4 value which increased by 65.13% if the plants were changed from monocrops into clump. This increase was caused by the increase of plants density. Besides, it was also discovered that the flow velocity decreased by 33.83% if the plants were changed from monocrops into clump.

Nilai kekasaran hidrolik adalah nilai yang menggambarkan perkiraan retensi terhadap aliran karena kehilangan energi yang disebabkan oleh gesekan antara saluran dan air. Jenis, kerapatan, ketinggian vegetasi menyebabkan variasi nilai kekasaran hidrolik. Nilai kekasaran hidrolik dapat diamati dengan menggunakan sebuah model fisik yang mewakili kondisi sesungguhnya. Penelitian ini bertujuan mengetahui
pengaruh tanaman yang ditanam pada dataran banjir dengan melakukan percobaan dengan model fisik di laboratorium. Penelitian dilakukan dengan melakukan percobaan dan pengamatan di laboratorium pada sebuah model fisik yang mewakili kondisi penampang pada Sungai Barabai di Kalimantan Selatan. Model dirancang dengan skala 1:110, pada dataran banjirnya ditanam tanaman bambu dengan jarak 1.82
x 1.82 cm. Diameter tanaman 0.1 dan panjang 8 cm. Model dibuat dalam dua jenis yaitu model dengan tanaman tunggal dan model dengan tanaman rumpun. Model dipadukan dengan saluran terbuka beserta perangkatnya. Hasil penelitian menunjukan adanya pengaruh tanaman terhadap nilai kekasaran hidrolik. Nilai ini ditunjukkan oleh nilai n4 yang meningkat sebesar 69 – 70% apabila tanaman diubah dari tanaman tunggal menjadi tanaman rumpun. Peningkatan ini disebabkan meningkatnya kerapatan tanaman. Selain itu diketahui kecepatan aliran menurun sebesar 2.3 – 1.7% apabila tanaman diubah dari tanaman tunggal
menjadi tanaman rumpun.


hydraulic roughness, plants, floodplain.

Full Text:



Arcement, G.J.J. and V.R.S., 1989. Guide for Selecting Manning â€TM s Roughness Coefficients for Natural Channels and Flood Plains United States Geological Survey Watersupply Paper 2339. Area, 2339(2339), p.39.

Barnes Jr., H.H., 1967. Verified Roughness Characteristics of Natural Channels. , p.96. Buffington, J.M., 1995. Effects of hydraulic roughness and sediment supply on surface

textures of gravel-bedded rivers. Department of

Geological Sciences, 35(11), p.184.

Chow, V.T., 1959. Open Channel Hydraulics. McGraw-Hill Book Company, p.728. Fathi-Maghadam, M. et al., 2011. Determination of friction factor for rivers with non-submerged vegetation in banks and floodplains. Scientific

Research and Essays, 6(22), pp.4714–4719.

Fischenich, C., 1997. Hydraulic Impacts of Riparian Vegetation; Summary of the Literature. , (May). Fischenich, C., 2000. Value as a Design Tool Cost Resistance Due to Vegetation. , pp.1–9.

Freeman, G.E., Rahmeyer, W.J. & Copeland, R.R., 2000. Determination of Resistance Due to Shrubs and Woody Vegetation Coastal and Hydraulics Laboratory. , (October), p.62.

Huthoff, F. et al., 2013. Evaluation of a Simple Hydraulic Resistance Model Using Flow Measurements Collected in Vegetated Waterways. , 2013(January), pp.28–37.

Järvelä, J., 2002. Determination of flow resistance of vegetated channel banks and floodplains. River flow, (1991), pp.311–318. Available at: VegetationReferences/12 Determination of flow resistance of vegetated channel banks and floodplains.pdf.

Järvelä, J., 2004. Determination of flow resistance caused by non‐submerged woody vegetation. International Journal of River Basin Management, 2(1), pp.61–70.

Mckay, K. & Fischenich, C., 2011. Robust Prediction of Hydraulic Roughness. , (March), pp.1–19. Nitsche, M. et al., 2012. Macroroughness and variations in reach-averaged flow resistance in steep mountain streams. Water Resources Research, 48(12).

Sterman, J.D., 2002. System Dynamics: Systems Thinking And Modeling For A Complex World. , p.31.

Wilson, C.A.M.E. & Horritt, M.S., 2002. Measuring

the flow resistance of submerged grass. Hydrological Processes, 16(13), pp.2589–2598.

Copyright (c) 2017 Jurnal Keteknikan Pertanian

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Alamat Redaksi: 
Jurnal Keteknikan Pertanian, Departemen Teknik Mesin dan Biosistem, Institut Pertanian Bogor, Kampus IPB Darmaga, Bogor 16680. Telp. 0251-8623026; Fax: 0251-8623026; Email:  website: 


This journal is published under the terms of Creative Commons Attribution 4.0 International License.