Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and                    Applicatio...
Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and                    Applicatio...
Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and                    Applicatio...
Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and                    Applicatio...
Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and                    Applicatio...
Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and                    Applicatio...
Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and                    Applicatio...
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  1. 1. Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.528-534 Effect Of Off-Take Angles On Spatial Distribution Of Silt Materials At Concave Channel Bifurcation OBASI1, N.L., OLOKE2, D.A. AND AGUNWAMBA3, J.C. 1. PhD MNSE, Department of Civil Engineering, Enugu State University of Science and Technology, Nigeria. 2. PhD CENG MICE MNSE, Built Environment, School of Technology, University of Wolverhampton, WV1 1LY, UK 3. PHD MNSE, Department of Civil Engineering, University of Nigeria, Nsukka, Nigeria.AbstractA meandering physical channel was constructed M(S3) Measured off-take channeland used to investigate the effect of off-take angles sediment concentrationon suspended sediment distribution at concave P(S3) Predicted off-take channelchannel bifurcation. Four different off-take angles sediment concentrationof 300, 450, 600 and 900 with varied main channel R Correlation Coefficientflow rates Q16, Q17 , Q18, and Q19 were used for thestudy. Predicting statistical equations dependent Introductionon the off-take angles and main channel A bifurcation occurs when a river or streamdischarges for the evaluation of the tributary splits into two branches and naturally, it occurs whenchannel sediment intake were developed. Results a middle bar forms in a channel or a distributaryof the studies showed that even with constant carries flow from the main river.main channel discharge, the tributary channel In the case of a meandering river/stream, thesediment intake increased significantly with outer curve alignment is known as the concave parthigher off-take angles. It was observed that the of the channel. When an intake is sited on this part ofpredicting equation under estimated the tributary the curve as is the case of the Obinna river intakechannel sediment yield for off-take angles between works supplying water to Adani rice farm at Nsukka30o – 70o and for those between 70o - 90o the in Enugu State, Nigeria, it is said to have a concavesediment values were over estimated for all the channel bifurcation. According to Abdel (1949), themain channel flow rates considered. The angle that the off-take channel makes with the outerpredicting tributary sediment values equaled the part of the main channel is called the off-take angle,experimental values at the off-take angles of 50o – or angle of Twist/Diversion. Some of the factors that70o but varied differently for each of the main may influence suspended and bed load sedimentchannel flow rates. It could be seen from the distribution includes main channel discharge,various off-take angles considered that the geometry and streamlining of bifurcation anddivergence in results obtained from the conditions of the approaching channel.experimental works and predicting equation is in The study of flow diversion andthe range of 2.9% - 17.8% for minimum main development of equations that model the physicalchannel flow rate and 12% - 36% for maximum movement of suspended sediment throughmain channel flow rate suggesting that the bifurcations and confluences in open channels arepredicting equation could be useful in the still in progress. It is the desire of most hydraulicevaluation of sediment yield at concave channel engineers to minimize the amount of sediment beingbifurcation. transported by the rivers/streams into the branching canal. The sediment delivery if not controlled mayKeywords: concave section, off-take angles, lead to some attendant problems such as frequentchannel bifurcation, flow rates and suspended breakdown of the installations downstream likesediment. pumps and turbines, reduction in flow capacity and vegetation growth due to sedimentation, erosion ofNOTATIONS channel walls due to the transport of rough materials,Q16, Q17 , Q18, Q19 Main channel discharges; dredging of accumulated sediment is quite expensiveQ3 Off-take discharge and may cause interruption in water supply (Neary etq1, q3 Main and Off-take channel specific al, 1993). According to Shen and Julien, (1993);discharges Krishnappan, (1990); and Ziegler and Nisbet, (1994)0, 1, 2, 3 Regression constants; the understanding of sediment transport in rivers and Off-take angle streams is extensive. However, the pattern ofS1 Measured main channel sediment movement of fine grained particles through multi-concentration channel systems is still very unclear. Pickup and 528 | P a g e
  2. 2. Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.528-534Higgins, (1979) investigated sediment transport in can operate properly (Chanson, 1999).The physicalbraided river by treated the system as a multi-channel model used for the experimental work wasnetwork, though their work was limited to bed-load constructed using metal sheets on scale ratios of 1:50transport. Fassnacht (1997) has examined the for horizontal and 1:15 for the vertical with asuspended sediment transport through multi-channel distortion of 3.30 and covering about 200m of thesystems using mass balance theory at bifurcations river channel. Three structural metal sheets having aand confluences. In spite of the challenges imposed width of 30cm each were welded together to form theby the undefined nature of sediment transport pattern base and walls of the main channel which representsat channel bifurcations, water diverted for domestic fixed banks and bed of a natural river/stream. Thepurposes is expected to be sediment free while water main rectangular channel was 850cm long withfor power generation has definite limits on sediment straight and meandering features. Similarly, the off-content. According to Mosonyi (1965), high head take channels having width of 10cm and length ofplants with over 100m should not contain sediments 90cm each were welded together to form the base andlarger than 0.01mm while for medium head plants the walls of the branch channels. Four numbersediment size should be smaller than 0.5mm to avoid rectangular branch channels were designed andsevere and rapid erosion of the turbines. Habermaas constructed such that the fitting ends would have one(1935) conducted series of model experiments on of the required off-take angles (30o, 45o, 60o and 90o)sediment distribution at river bifurcations in various after welding them to the main channel. Thechannel curvatures, though he arbitrary sited the off upstream and downstream sections of the maintake channels without considering the influence of channel were covered with square metal sheets ofthe off take angles and variation in main channel 30cm by 30cm by welding to maintain the water leveldischarge. Vries (1992) stated that the sediment required while the experiment was in progress. Thedistribution ratio into branches could be determined downstream section was provided with a spillway toby local three-dimensional flow pattern. Wang et al. drain excess water from the main channel. At the(1993) emphasized that the determination of the invert level of -15cm, a rectangular opening wassediment distribution ratio (S1/S2) is a difficult task created on the main channel at the concave side ofwhich resulted in several nodal point relations as the model and branching channels were introduced tosolution. form the bifurcation. The meandering section of the Similarly Tarekul Islam et al (1997), Dekker model has an outer and inner radius of 135cm andand Van Voorthuizen (1994), Roosjen and 105cm respectively indicating a mild bend that wouldZwauenberg (1995) and Hannan (1995) have studied not require future river training works. The detailedthe morphology of a symmetrical river bifurcation plan views of the model and its cross section arewith the help of physical models which concentrated shown in Figure 1.on the distribution of sediment over the downstreambranches with nose angle as the major variable. 2m 2mThe determination of the optimum off-take angle tolimit the rate of siltation of the secondary canals 1m 1mwould obviously reduce the frequency of dredging Overhead Overheadand ultimately minimize the total cost associated with Tank A Tank B V Vthe operation and maintenance of installationsdownstream. As engineers become involved in managingrivers for new environmental purposes, reliable Fig. 1: Plan views of main channel, off-take channelprediction tools and models should be available to and cross- section.examine the performance of various design options. Consultants and Hydraulic engineers particularly Experimental Procedurethose responsible for the planning of water projects The experimental work was carried out atmay be expected to consider the optimum off-take the hydraulic laboratory of the Civil Engineeringangle for the concave channel bifurcation as one of Department, University of Nigeria, Nsukka in Enuguthe important factors to be considered in the State of Nigeria. The experiment set up was subalignment of the off-take channels. divided into three major components namely the water supply unit, the sediment supply unit and theMaterials and Method regulatory/measuring unit. The circulation of waterExperimental Setup within the model was a closed system with a When a hydraulic problem is beyond an sediment trap provided at downstream section whereanalytical solution, physical and numerical models water flows through a filter medium as it outfalls intocould be used to address such problems which may the sump.include sediment transport problems (Chanson, The measurement of the sediment distribution1999). Physical models are commonly used to patterns at concave channel bifurcation wasoptimize structural designs or ensure that a structure conducted by varying the off-take angles and the 529 | P a g e
  3. 3. Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.528-534main channel flow rates consecutively. Four flow of water and was stirred properly before beingrates with corresponding flow depths of 16cm, 17cm, introduced at the beginning of the main channel. This18cm and 19cm were established and represented by was done after one of the desired main channel flowQ16, Q17, Q18, and Q19 respectively. The flow depths rates has been established by allowing the water levelcorresponding to each of the flow rates were to rise to the specified reference point. In each case,established and marked on the walls of the main the main channel flow rate and the sedimentchannel as bench marks to ascertain each of the concentration were kept constant while the off-takerequired flow rates. The water in the sump was angles were varied. At a given time interval, samplespumped to the elevated tanks that supplied water to were collected with plastic containers at differentthe channel at controlled rates in line with the locations including the upstream of the bifurcation,established bench marks while the weir and spillway bifurcation point, off-take channel and downstreamprovided at the downstream section maintained the of the bifurcation for each of the off-take angles (30o,required water level in the main channel. 45o, 60o and 90o) considered. About 50mls each of these samples were measured out in beakers for every Some light weight materials that could be experiment performed. The beakers were weighedused for the study of suspended sediment transport in while empty and thereafter weighed with the samplesrivers and streams such as polystyrene coal, bake lite, before oven dried at a temperature of 103oC – 105oCwood sawdust, polystyrol, Plexiglas, PVC, for twenty four hours. The samples were alsodiatomaleous earth, natural sand, rice husk and silt reweighed after oven dried to determine the totalhave been recommended (Matondo and Skolersik, solids which were analyzed in accordance with the1985; Obasi, 1988). The sediment material used in standard methods for examination of Water andthis study was silt from clay material with a size Waste Water (Apha et al., 1992) and the resultsrange of 0.053 – 0.064mm diameter and fall velocity obtained were recorded as presented in Table 1.of 0.0037m/s. About 500 grams of silt materials wereweighed out and added into a small bath with a litreTable 1: Measured and predicted sediment distribution ratios at concave channel bifurcation Θ Q16 Q17 Q18 Q19 M M(S3) P(S3) M M(S3) P(S3) M M(S3) P(S3) M M(S3) P(S3) q1/q3 S1/S3 S1/S3 q1/q3 S1/S3 S1/S3 q1/q3 S1/S3 S1/S3 q1/q3 S1/S3 S1/S3 300 1.79 2.95 3.03 1.15 1.78 2.92 0.76 1.40 2.3 0.56 1.21 1.89 450 1.49 2.66 2.48 0.86 1.50 1.81 0.61 1.20 1.48 0.47 0.95 1.28 600 1.23 1.50 1.38 0.72 1.07 1.26 0.54 0.97 1.07 0.40 0.75 0.9 900 0.84 1.20 0.99 0.60 0.91 0.81 0.41 0.79 0.66 0.32 0.65 0.57Formulation of Empirical sediment yield However, introducing the log and semi log toEquations. linearize equation 2 would yield equations 3 – 5, thus:Tarekul Islam et al (1997) in their investigative Log S1/S3 =a1 a2 (q1/q3)a3studies established an empirical expression for ………………….……………………………..……3sediment distribution at channel bifurcation, thus: k S1/S2 = M (q1/q2) ……………………………………………… …………….….. 1 S1/S3 = Log [a1 a2 (q1/q3)a3In the present study, the authors have proposed some ]………………….………………………………..4equations relating the off-take sediment concentrationwith the bifurcation angles and specific discharge Log (S1/S3) = Log [a1 a2ratios in the form thus: a3 (q1/q3) ]………………….…………………………5 S1/S3 =a1 a2 (q1/q3)a3 Where 1, 2, and 3 are constants.………………….…………………………….2 530 | P a g e
  4. 4. Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.528-534Table 2: Empirical equations for sediment distribution at concave channel bifurcation Coefficients Regression Standard S/No Proposed Model Equations Coeff. ( R ). Error 1 2 3 -0.005573 0.180104  1 θ  2 (q1/q3)  3 0.258811 1.0 Log (S1/S3) = 0.98884 0.03974 -0.8199521 (S1/S3 ) = Log (  1 θ  2 (q1/q3)  3 ) 4.736665 2.0 0.95680 0.23792 2.125059 (S1/S3) =  1 θ  2 (q1/q3)  3 -0.819952 1.581895 3.0 0.99434 0.02834 0.573933Results and Discussion The data obtained from the experimental equation yielded the second highest correlationwork carried out were used for the multiple coefficient value of 0.98884 with standard error valueregression analysis to ascertain the nature and degree of 0.03974. Equally, equation (7) with log on theof relationship existing between the selected right hand side of the equation had the least value ofparameters and the sediment distribution ratios in correlation coefficient of 0.95680 with a standardeach of the proposed empirical equations. The error value of 0.23792.regression model constants 1, 2, and 3 weredetermined through simulation process by using the Fig. 2a depicts the effect of discharge on theSPSS + PC statistical package and the results sediment distribution ratios as obtained from theobtained from each of the proposed equations are experimental works conducted. It could be seen frompresented in Table 2. The values of these constants Fig. 2a that the slopes of the plots of the sedimentare interpreted and substituted as shown in equations ratios against the off-take angles decrease with6 – 8. increase in main channel discharge. This implies that an increase in the main channel discharge will Log (S1/S3) = (0.1801(q1/q3)0.259)/(0.0056) substantially increase the off-take discharge and……………….……………..… 6 consequently increases the off-take sediment concentration. For instance, the off-take angle of 60o S1/S3 = Log [(4.74 (q1/q3)2.13)/(0.82)] with main channel flow rates of Q16, Q17, Q18 and Q19………………….… …..…………….. 7 yielded off-take sediment values of 0.67S1, 0.94S1, 1.03S1 and 1.33S1 respectively. These off-take (S1/S3) = [(1.582 (q1/q3)0.574)/(0.82)] sediment concentration values indicate that the………………….…….……… 8 minimum main channel flow rate of Q16 yielded the minimum off-take sediment concentration values Equations 6 – 8 are for the prediction of while Q19 which was the maximum main channelsuspended sediment distribution pattern at concave flow rate yielded the maximum off-take sedimentchannel bifurcation. These equations explicitly concentration values for each of the off-take anglesindicate that the sediment distribution ratios are considered. This agrees with the previous studiesproportional to the specific discharge ratios and (Obasi et al, 2008) which indicated that the increaseinversely proportional to the off-take angles. The in main channel discharge resulted equally in anproposed expressions gave values of correlation increase in the off-take discharge which has probablycoefficients from 0.95680 – 0.99434 with standard influenced the off-take sediment intake due to higherror values from 0.02834 – 0.23792. Equation (8) velocity of flow. In addition, Asselman, (2000) in hiswith log on both sides produced the highest work found that the transportation of substantialcorrelation coefficient value of 0.99434 with a sediment load usually vary as a function of thecorresponding standard error value of 0.02834 while discharge rate.equation (6) with log on the left hand side of the 531 | P a g e
  5. 5. Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.528-534Table 2 shows that virtually all the proposed Similarly, the results of the values obtained from thepredicting equations produced very high values of predicting equation for various off-take anglescorrelation coefficients in the multiple regression indicate that about 33% of the main channel sedimentanalysis carried out. However equation (8) with the concentration would enter the tributary channel at 30ohighest correlation coefficient gave off-take sediment off-take angle while about 40% would be delivered atvalues that are close to those obtained from the 45o off-take angle. Correspondingly, about 73% ofexperimental work. Fig. 2b shows the effect of the main channel sediment concentration would enterdischarge on the sediment distribution using data the branching channel at 60o off-take angle whileobtained from the evaluation of equation 8 which has about 100% would enter the off-take channel at 90othe same trend as shown in Fig. 2a in the sense that off-take angle. It seems that at higher off-take anglesthe slopes of the plots of the sediment ratios against virtually all the main channel sediment concentrationthe off-take angles were decreasing with increase in will be delivered to the tributary channels. Figs. 4 - 7main channel discharges. Conversely, the generally show that the predicting equation underconsideration of the off-take angle of 60o with main estimated the tributary channel sediment yield forchannel flow rates of Q16, Q17, Q18 and Q19, yielded off-take angles between 30o – 70o while for thoseoff-take sediment concentration values of 0.73S1, between 70o - 90o the sediment values were over0.79S1, 0.94S1 and 1.11S1 respectively. estimated for all the main channel flow rates considered. The predicting tributary sediment values The relationship shown in Figs. 2a and 2b equaled the experimental values at the off-take anglesequally indicate that the sediment delivered to the of 50o – 70o but varied for the various main channeltributary channels increased with increase in off-take flow rates.angles for any of the main channel flow rates The difference in sediment values deliveredconsidered. to the tributary channels using the predicting equation at off-take angles of 30o and 45o is about 17.5% while The sediment distribution pattern depicts those of 45o and 60o is 45%. The tributary channels atthat for any of the main channel flow rates 60o and 90o off-take angles have a difference of aboutconsidered, the tributary channels at 30o off-take 27% of the sediment values received.angle received the minimum sediment concentration Vershney et al. (1988) proposed that for thevalues while those at 90o off-take angle received the control of excessive silt entry into the off takemaximum sediment concentration values. channel, an off take angle of 60o – 80o should be The result of the physical models conducted considered suitable which is in disagreement with theby Bulle (1926), Raid, (1961), Den Dekker and results of the current study. The studies of Bulle etVorthuizen (1994), Fokkink and Wang (1993) and al. (1926) show that more than 90% of transportedIslam (2000) emphasized that sediment distribution is matter enters the diversion canal branching off at agenerally linearly related to the discharge conventional angle of between 30o – 90o from thedistribution. In other words, the higher diverting main water course, but with about half of the originalangle attracts more suspended sediment load and is discharge. According to Bulle (1926) the variation ofproportional to the discharge distribution or the silt quantities with diverted flow showed that asediment distribution is a function of the discharge balance (50-50%) distribution of silt attained only ifdistribution. some 25% of the original discharge is allowed to The result of the experimental studies on enter the canal. If the discharge carried by thesediment distribution at concave channel bifurcation diversion canal exceeds 60%, the entire silt loadfor the main channel flow rate of Q16 indicates that enters the off take canal. He concluded by sayingabout 34% of the main channel sediment that the size of the optimum intake angle increasesconcentration entered the channel bifurcating at 30o as the diversion ratio decreases. Habermassoff-take angle while about 38% of the main channel (1935) recommended in his work that off-takes besediment concentration entered the channel branching located towards the downstream of the concaveat 45o off-take angle. Similarly, the branching section for minimum sediment entering the off-takechannel at 60o off-take angle received about 67% of canal. However, it was observed that he was arbitrarythe main channel sediment concentration while about sitting the off-take locations without considering the83% of the main channel sediment concentration influence of the off-take angles and variation in mainentered the branching channel at 90o off-take angle. channel discharge. This suggests that the off-takeThe difference in sediment values delivered to angles to a large extent influenced the sedimenttributary channels at off-take angles of 30o and 45o is delivery to the tributary channel at concave channelabout 10.5% while those of 45o and 60o is 43%. The bifurcations.tributary channels at 60o and 90o off-take angles have For intakes in bends, the decrease in thea difference of about 19.3% of sediment values strength of secondary currents would lead to thereceived. increase in the sediments delivered Randkivi (1993) or Novak et al (1990). 532 | P a g e
  6. 6. Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.528-534Conclusion Results of both the experimental works andpredicting equation on the off-take sedimentdistribution at the concave channel bifurcation reveal measure sediment values predicted sediment values Off-take sediment values. 1.2that the minimum main channel flow rate of Q16 1yielded the minimum off-take sediment concentration 0.8values while Q19 which was the maximum main 0.6channel flow rate yielded the maximum off-take 0.4sediment concentration values for the off-take angles 0.2 0considered. The sediment distribution pattern equally 0 20 40 60 80 100depicts that for any of the main channel flow rates Off-take Angles.considered, the tributary channels at 30o off-take Fig.4: Plot of sediment values against off-take angles for Q16.angles received the minimum sediment concentrationvalues while those at 90o off-take angles received themaximum sediment concentration values for both theexperimental study and predicting equation. It wasobserved that the predicting equation under estimated measure sediment values predicted sediment values Off-take sediment values.the tributary channel sediment yield for off-take 1.4 1.2angles between 30o – 70o and for those between 70o - 190o the sediment values were over estimated for all 0.8the main channel flow rates considered. The 0.6predicting tributary sediment values equaled the 0.4experimental values at the off-take angles of 50o – 0.270o but varied differently for each of the main 0channel flow rates. It could be seen from the various 0 20 40 60 80 100 Off-take Angles.off-take angles considered that the divergence in Fig.5: Plot of sediment values against off-take angles for Q17.results obtained from the experimental works andpredicting equation is in the range of 2.9% - 17.8%for minimum main channel flow rate and 12% - 36%for maximum main channel flow rate suggesting thatthe predicting equation could be useful in theevaluation of sediment yield at concave channel measure sediment values predicted sediment values Off-take sediment values. 2bifurcation. 1.5 1 0.5 0 0 20 40 60 80 100 Off-take Angles. Fig.6: Plot of sediment values against off-take angles for Q18. measure sediment values predicted sediment values Off-take sediment values. 2 1.5 1 0.5 0 0 20 40 60 80 100 Off-take Angles. Fig.7: Plot of sediment values against off-take angles for Q19. 533 | P a g e
  7. 7. Obasi, N.L., Oloke, D.A., Agunwamba J.C. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.528-534REFERENCES Case Study of Upper Ruvu Intake, proc. of 1. Ackers, P. and White, W.R. (1973), the third Int. Symp. On River and Sediment Transport: New approach and Sedimentation, Jackson Mississippi, analysis, Hydraulic Division, ASCE. Vol. pp1051-1062. 99, No HY11, PP2041-2060. 17. Mehdi, K. M., Mahmood, S. B. and Hossein, 2. Asselman, N. E. M. (2000). Fitting and S. (2010). Sediment Entry Investigation at Interpretation of sediment rating curves, 30 Degree Water Intake installed at a Journ. of Hydro. 234, 228-248. Trepezoidal channel, World Appl. Sci. 3. Barkdoll, B. D. (1999). Sediment Control at Journ. 11 (1): 82-88 lateral Diversions: Limits and Enhancements 18. Neary, V. S., Sotiropoulos, F. and Odgaard, to vane use. Journ. Hydr. Engrg, ASCE., A.J. (1999). Three dimensional numerical 125(8): 826-870. model of lateral intake inflows, Journ. Hydr. 4. Breusers, H.N.C. (1984). Sediment Engrg. ASCE, 125 (2) 126-140. Transport Lecture Notes, Int. Course Hydr. 19. Obasi, N. L. (1988). The study of sediment Engrg., Delft. problems at Upper Ruvu river intake 5. Bulle, H. (1926). Investigations on the structure, MSc.Thesis, Civil Engrg. Dept. trapping of bed load in branching rivers, University of Dar es Salaam, Tanzania. VDI-verlag, Forchungsarbiet auf dem 20. Raudkivi, A. J. (1993). Sedimentation, Gebiets des Ingeneurswesens, Berlin, Heft Exclusion and Removal of sediment from 280. diverted water, IAHR, Hydraulic structures. 6. Chow, V.T. (1985). Open Channel 21. Shafai, B. M. and Nazari, S. (1999). The Hydraulics. Mc Graw-Hill, New York pp Impression of the diversion angle of intake 512-516. on the entering sediments to the lateral 7. Dekker, P.D., and van Voorthuizen, intakes at a vertical bond of river. Journ. Of J.M.(1994) “Research on the Morphological Agric., Chamran University 22(1). Behavior of Bifurcations in Rivers”, Delft 22. Shen, H. W. and Julien, P. Y. (1993). University of Technology, The Netherlands. Erosion and sediment transport. In 8. Fassnacht, S. R. (2000). Flow modeling to Handbook of Hydrology, (ed. D.R. estimate suspended sediment travel times for Maidment), Mc. Graw-Hill. two Canadian Deltas, Hydro. and Earth Syst. 23. Vries, M. de, (1992). “River Engineering Sci., 4(3), 425-438. Lecture notes, Int. Course Hydr. Engrg, 9. Fassnacht, S. R. (1997). A Multi-channel Delft, The Netherlands. suspended sediment transport model for 24. Vries, M.de. (1985). Engineering Mackenzie Delta, NWT Journ. of Hydro. Potamology Lecture Notes, Int. Course 10. Hannan, A.,(1995). “A Laboratory study of Hydr. Engrg., IHE, Delft, The Netherlands. sediment Distribution at channel 25. Vries, M. de, (1986). Scale models in Bifurcation,” M.Sc. Engineering Thesis, Hydraulic Engineering, Lecture notes; Int. Department of Water Resources Course Hydr. Engrg, IHE, Delft, The Engineering, BUET, Dhaka, Bangladesh. Netherlands. 11. Islam, G.M.T., Kabir, M.R., and Nishat, A. 26. Yang, F., Chen, H. and Guo, J. (2009). (1997). “Influence of nose angle on Study on diversion angle effect of lateral sediment distribution at channel bifurcation, intake flow. 33rd IAHR Congress, 3rd International conference on river flood Vancouver, Canada, pp4509-4516. hydraulics, 27. Ziegler, C. K. and Nisbet, B. (1994) Fine 12. Stellenbosch, South Africa, 247-254. grained sediment transport in Pawtnxer 13. Kazins, C. (1973). Water Intake problems in river, Rhode Island, Journ. Hydra. Engrg, Torrents, IAHR, Int. Symp. On river 120, 561-576. mechanics, Bangkok. 14. Krishnappan, B. G. (1991). Modeling cohesive sediment Transport, River Research branch, National water research institute, environment, Canada, Burlington, Ontario, 18pp. 15. Mosonyi, E.I. (1965), Water Power Development, vol.1, Low-head power plants, Akademiai Kiado, Hungarian Academy of Sciences, Budapest. 16. Matondo, J.I., and Skolersik, Z. (1986). “Sediment problems at intake structures. 534 | P a g e

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