GRD Journals- Global Research and Development Journal for Engineering | Volume 4 | Issue 6 | May 2019 ISSN: 2455-5703
Bed Load Transport Analysis for Gravel Bed River Shashikant V Singh P.G. Student Department of Civil Engineering GEC, Surat, Gujarat, India
S. I. Waikhom Associate Professor Department of Civil Engineering Government Engineering College, Surat, Gujarat, India
Abstract Prediction of bed load transport is important in many river engineering projects, including hydraulic structures like piers, reservoir life of dams, etc. The maximum bed load transport per unit width that a particular discharge can transport at a certain slope is defined as bed load transport rate. In the present study, analysis of steep slope river data is carried out using bed load functions of Parker (1979) Parker et.al (1982), Parker (1990),Graf (1998) and Wong and Parker (2006b).The computed dimensionless bed load transport rate are compared for analysing the prediction by selected equations. The predicted bed load transport rate is compared with the actual measured values for all data set to identify the equation which gives best prediction of bed load transport rate. Keywords- Alluvial Channel, Steep slope, Bed load transport
I. INTRODUCTION Water is the most precious natural asset of any civilization and is very important for physiological processes. The processes of erosion of land surfaces, transportation of eroded material, deposition of this material in river and streams and such other processes depend upon flow and hydrological parameters. These factors can be classified into following categories: Characteristics of sediment, Characteristics of the fluid, Characteristics of the flow and Characteristics of the channel. Among the different categories stated above, sediment characteristics such as shape, size, density and fall velocity plays a decisive role in different stages of the phenomenon of sediment transport and these properties are governed to a large extent by the origin of sediment and process of its formation. When flow conditions exceed the criterion for incipient motion, sediment particles along an alluvial bed start to move. If the motion of sediment particles is rolling, sliding, or occasional jumping along the bed, it is called as bed load transport. Prediction of bed load transport is important for river engineering projects. River characteristic can be understood well by studying the bed load composition and movement of various size particles to evaluate the vertical sorting and refining processes along the bed. For some cases engineers use field measurements to calibrate a sediment curve, but in most cases measured data does not exist because measurement of bed load in the field is difficult, expensive, and time-consuming task. This is why engineers employ computational methods, often established with flume experiments (Recking, 2013). Results obtained from different approaches often differ drastically from each other and from observations in the field. The present study tested the accuracy of applicability of bed load transport models suggested for gravel bed River using published field data of steep slope river.
II. DATA COLLECTION For the present research river data is used for comparative analysis of bed load models. River data of United States - East St. Louis Creek, St. Louis River site-1 and site-2 and Fall creek, are collected from Hinton, D., Hotchkiss, R., Ames, D.P. (2016) for analysis. St. Louis River is the largest tributary of Lake Superior and carries a heavy bed load from non-point sources. The river also has a number of sites known to contain contaminated sediments. Fall Creek is the tributary of white river in the U.S. state of Indiana. It begins near the town of honey creek, Indiana. The selected river data has high slope (Table 1). For fair comparison, Parker’s original bed load transport model and modified bed load transport models and Wong and Parker (2006,b) bed load transport model are selected for present study. The range of hydraulic parameters collected is given in Table 1. Sr.No
Name River
1 2 3
East St. Louis Creek Fall Creek St. Louis Creek Site 1
Depth (m) 0.12- 0.4 0.07-0.22 0.16-0.62
Table 1: Range of Hydraulic Parameter width Velocity Discharge Observed Bed load transport (m) (m/s) (m^3/s) (kg/s) 2.84-3.03 0.264-1.32 0.09-1.24 0-0.06244 1.68-2.11 0.15-1.16 0.04-0.5 0-0.03085 6.4-7.25 0.38-1.77 0.39-6.95 0.0002-0.44706
Slope m/m 0.051-0.0617 0.052-0.056 0.01-0.0280
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Bed Load Transport Analysis for Gravel Bed River (GRDJE/ Volume 4 / Issue 6 / 001)
As per the classification of natural rivers by David L. Rosgen S (1990), slope in the range of .04 to 0.10 is classified as steep slope and range for moderate slope is 0.02 to 0.039. Accordingly, the selected rivers are considered having steep slope.
III. METHODOLOGY The concept of bed shear stress or tractive force to study sediment transport and develop a model of sliding layers for the description of the movement of uniform bed load particles was first introduced by Du Boys (1879) . Since the pioneering work of Du Boys, bed-load transport has been the subject of extensive research (Garde and Ranga Raju 1985). Inconsistency in prediction is obtained when Meyer-Peter and Müller (1948), Einstein (1950), Parker (1979) and Parker et al. (1982) bed load transport equations are verified with174 data value of three natural gravel bed streams, Almedeij and Diplas (2003), Bravo-Espinosa et al. (2003) agreed that Parker et al. (1982) and Meyer-Peter and Müller (1948) predicted bedload transport to fair degree of accuracy for flume data. For the present study, bed load transport models suggested for gravel bed river such as Parker (1979), Parker et al. (1982), Parker (1990), Graft (1998), and Wong and Parker (2006a.b) are considered. The bed load transport models are given in Table 2. Sr. No 1 2
Table 2: Bed Load Transport Models used in present study Bed Load Transport Model Equation ⁄ Parker (1979) = 11.2( ⁄ = 11.2 for = 0.0025 for Parker et.al (1982) for
)
,
(
)
= 0 for 3
Parker (1990)
4 5
Graf (1998) Wong and Parker (2006 b)
⁄
= 13.69*
Where is the dimensionless bed load transport rate, is shear velocity, width (Kg/ms), is the volumetric bed load transport rate per unit width (m2/sec). , represents Shield’s parameter as
for
is the bed load transport rate per unit
(1) (2) (3) = Specific weight of sediment, = Specific weight of fluid, critical shear stress, is Shield’s dimensionless critical shear stress.
is the average bed shear stress,
is the Shield’s
IV. RESULTS The range of dimensionless bed load transport rate predicted by selected bed load transport models is given in Table 3. Data set name East St. Louis Creek Fool Creek St. Louis Creek Site 1
Table 3: Range of Dimensionless bed load transport rate, Data Range Parker (1979) Parker (1982) Parker (1990) Graf (1998) Min 2.856 3.68 6.60 0.20 Max 10.178 9.14 9.83 11.079 Min 0.270 1.32 0.717 0.1025 Max 3.36 7.51 5.83 2.160 Min 0.0094 0.162 1.34E-06 0.0156 Max 1.605 7.202 5.42 1,693
Wong and Parker (2006 b) 1.13 4.23 0.058 4.236 0.114 1.119
From Table 3 it is observed that the minimum and maximum dimensionless bed load transport predicted by Parker (1979) gives near equal value with Parker (1982) for East St. Louis Creek river data. It is also observed that Parker (1979) and Graf (1998) gives similar range of maximum value of dimensionless bed load transport rate for all the selected river data. To precisely see the trend of prediction, graphical plot of predicted dimensionless bed load transport rate for the study river data are shown in Fig.1.
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Bed Load Transport Analysis for Gravel Bed River (GRDJE/ Volume 4 / Issue 6 / 001)
Fig. 1: Prediction of Dimensionless bed load transport rate a. Parker (1979), b. Parker et.al (1982), c. Parker (1990), d. Graf (1998), e. Wong and Parker (2006,b)
From Fig.1.a, c and e, it is observed that Parker (1979), Parker (1990) and Wong and Parker (2006,b) predicts higher value for East Louis creek river data. Parker et al. (1982), Parker (1990), Graf (1998), Wong and Parker (2006,b) predict with similar trend for all the three rivers as observed in Fig. 1. b, c, d and e. It is also found that Parker et.al. (1982) predicts dimensionless bed load transport rate for Saint Louis Creek Site-1 and East Louis Creek river data with minimum variation. Overall, it can be said that consistency in prediction is obtained for all the river data of different hydraulic parameters. Predictability range for all the five bed load transport model for each river is compared. The graphical comparison of predictability for each river is shown in Fig 2, 3 and 4. All rights reserved by www.grdjournals.com
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Bed Load Transport Analysis for Gravel Bed River (GRDJE/ Volume 4 / Issue 6 / 001)
Fig. 2: Comparison of predicted dimensionless bed load transport for East St. Louis Creek River data
From Fig. 2, it is observed that the trend of prediction of bed load by Parker et al. (1982), Parker (1979) and Wong and Parker (1999) is similar with minimum variation in value. Similar trend of prediction is obtained for Graf (1998) and Parker (1990).
Fig. 3: Comparison of predicted dimensionless bed load transport for Fool Creek River data
From Fig. 3, it is observed that similar trend of prediction is obtained for Parker et al. (1982), Parker (1979) and Wong and Parker (2006,b). It is also observed that Parker (1979) and Wong and Parker (2006,b) predicts equally well for Fool creek River data. Similar trend of prediction is obtained for Graf (1998) and Parker (1990).
Fig. 4: Comparison of predicted dimensionless bed load transport for St. Louis Creek Site 1
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Bed Load Transport Analysis for Gravel Bed River (GRDJE/ Volume 4 / Issue 6 / 001)
From Fig. 4, variation in the trend of prediction is seen for Parker (1990), Parker et al. (1982), Parker (1979) and Wong and Parker (2006, b) for St. Louis Creek Site 1 river data. However Graf (1998) gives a consistent lower value for all the three river data. The predicted bed load transport rate using different bed load transport models are compared with the measured bed load transport rate as given in Table 4. Data set name East St. Louis Creek Fool Creek St. Louis Creek Site 1
Data Range Min Max Min Max Min Max
Table 4 Summary of range of Predicted and Bed Load transport Rate (Kg/ms), Parker Parker Graf Wong and Parker Parker (1979) (1982) (1990) (1998) (2006 b) 45.136 6.104 49.28 3.55 17.88 160.85 150.08 73.31 175.08 66.94 4.78 1.300 5.98 1.81 1.3751 59.37 51.71 48.59 38.15 23.600 0.0019 .0725 1.49E-05 0.3680 0.2275 0.3382 57.27 60.46 40.008 26.44
Measured Bed load Transport Rate 1.70E-05 0.0212 0.00008 0.0146 3.076E-05 0.06574
From Table 4, it is found that the predicted bed load transport rate is over predicted for all the selected river data when compared with the measured bed load transport rate.
V. CONCLUSION Following are the findings of the present study: The modified parkers bed load transport models - Parker et.al (1982), Parker (1990) and Wong and Parker (2006,b) gives similar trend of prediction for East Louis Creek and Fool creek river data having similar slope range of 0.051-0.0617. Variation in the trend of prediction is seen for Parker (1990), Parker et.al (1982), Parker (1979) and Wong and Parker (2006,b) for St. Louis Creek Site 1 river data. However Graf (1998) gives a consistent lower value for all the three river data. It can be said that all the selected bed load transport models predict poorly for all the river data. However consistency in prediction is obtained for Parker (1979) and Parker (1990) for East Louis Creek river data and Fool creek River data. Parker (1979) predicts bed load transport values nearly equal to the measured values for St. Louis Creek Site 1 river data.
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Du Boys M. P., (1879), Le Rhone et les Rivieres a Lit affouillable. Mem. Doc., Ann. Pont et Chaussees, ser. 5, 18. Meyer-Peter, E., and Müller, R. (1948). “Formulas for Bed-Load Transport.” Proceedings of the 2nd Meeting of the International Association of Hydraulic Research, 39–64. [3] Parker G., (1979), Hydraulic geometry of active gravel rivers. Journal of Hydraulic Engineering, 105, 9, 1185–1201. [4] Parker G., Klingeman P. C., Mclean, D. G., (1982), “Bedload and size distribution in paved gravel-bed streams”. Journal of Hydraulic Division, 108, 544– 571. [5] Graft W. H., (1998), “Hydraulics of Sediment Transport”. Water Resources Publications, Third Printing, 123–159. [6] Parker G., (1990a), “Surface-based bedload transport relation for gravel Rivers”. Journal of Hydraulic Research, 28, 417–436. [7] Almedeji J. H., Diplas P., (2003), “Bedload transport in gravel bed streams with unimodal sediment”. Journal of Hydraulic Engineering, 129, 896–904. [8] Bravo –Espinosa M., Osterkamp W. R., Lopes V.L., (2003), “Bedload transport in alluvial channels”. Journal of Hydraulic Engineering, 129, 783–795. [9] Wong, M., Parker, G., (2006). “Re-analysis and correction of bed load relation of Meyer-Peter and Muller using their own database”, Journal of Hydraulic Engineering, 132, 1159–1168. [10] Recking, A. (2013). “Simple Method for Calculating Reach-Averaged Bed-Load Transport.” Journal of Hydraulic Engineering, 139(1), 70–75. [11] Hinton, D., Hotchkiss, R., and Ames, D.P. (2016), "Comprehensive and Quality-Controlled Bedload Transport Database", Journal of Hydraulic Engineering, 143(2).
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