Esmaili, Kazem

Mansouri, Ramin

Ziaei, Ali N.

English

Hydraulic Engineering Repository

Conference Paper, Published VersionMansouri, Ramin; Ziaei, Ali N.; Esmaili, KazemStudy of Hydraulic Properties and Design Criteria for aRiver Subsurface Intake without Cut OffVerfügbar unter/Available at: https://hdl.handle.net/20.500.11970/104409Vorgeschlagene Zitierweise/Suggested citation:Mansouri, Ramin; Ziaei, Ali N.; Esmaili, Kazem (2013): Study of Hydraulic Properties andDesign Criteria for a River Subsurface Intake without Cut Off. In: Bung, Daniel B.; Pagliara,Stefano (Hg.): IWLHS 2013 - International Workshop on Hydraulic Design of Low-HeadStructures. Karlsruhe: Bundesanstalt für Wasserbau. S. 199-206.Standardnutzungsbedingungen/Terms of Use:Die Dokumente in HENRY stehen unter der Creative Commons Lizenz CC BY 4.0, sofern keine abweichendenNutzungsbedingungen getroffen wurden. Damit ist sowohl die kommerzielle Nutzung als auch das Teilen, dieWeiterbearbeitung und Speicherung erlaubt. Das Verwenden und das Bearbeiten stehen unter der Bedingung derNamensnennung. Im Einzelfall kann eine restriktivere Lizenz gelten; dann gelten abweichend von den obigenNutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte.Documents in HENRY are made available under the Creative Commons License CC BY 4.0, if no other license isapplicable. Under CC BY 4.0 commercial use and sharing, remixing, transforming, and building upon the materialof the work is permitted. In some cases a different, more restrictive license may apply; if applicable the terms ofthe restrictive license will be binding.1 INTRODUCTION Rivers are considered as one of the providers of water and energy for the nature and the human. The provision of water has been the most important economical role of the rivers and the suitable design of a river intake is one of the oldest issues in hydraulic engineering. However, due to complexity of river flows, designing an intake in a natural river has remained as an important topic in the river engineering. The water diversion method depends on flow conditions, topology and morphology of river and economical considerations. The multitude of types of intake from rivers can be divided into lateral intakes, frontal intakes and bottom intakes (Raudkivi, 1993). In bottom intakes that are used mostly in mountainous rivers; the flow is diverted through a conduit installed underneath the river bed. Some parts or all of the length and width of the conduit in river bed are made as openings and water is unloaded into the conduit through these openings. Garot (1939) conducted experiments on the bottom intake with longitudinal bars as the horizontal grid. Other researches such as De Marchi (1947), Bouvard (1953), Kuntzmann and Bouvard (1954), Noseda (1956 a, b), Mostkow (1957), Brunella (2003), Righetti and Lanzoni (2008) and Maghrebi and Razaz (2009) have investigate different aspects of the bottom intakes with the reticular bottom. Problems such as clogging, corrosion, freezing, storage and discharge of sediment to the system limit the applicability of this type of intake (Castillo and Lima, 2010). These disadvantages caused the replacing the meshed conduit with a porous media to be advised. Naqhavi et al. (2010) studied the properties of bottom intake with the porous material experimentally. The efficiency of the porous bottom intake is also reduced via the sedimentation and reduction of the media transmissivity (Koorosh Vahid et al., 2010). Furthermore, the subsurface flow that is crucial in seasonal rivers of the arid and semiarid regions cannot be extracted using this intake. To diminish these problems a method (based on infiltration gallery idea) for diversion of surface and subsurface flow in the seasonal rivers has been implemented. In this type of intake a subsurface drainage system is buried in very porous media in the river bed. Although the subsurface drainage is an elder idea the hydraulic properties of this type of intake has been rarely investigated.  In this study, the effective parameters on subsurface intake efficiency are experimentally investigated. Moreover, based on the hydraulic parameters and dimensionless groups obtained by dimensional analysis, Study of Hydraulic Properties and Design Criteria for a River Subsurface Intake without Cut Off  R. Mansouri1, A. N. Ziaei2, K. Esmaili3,1 MSc. Student, Water Eng. Dep., Ferdowsi University of Mashhad, Iran, 2, 3 Assist. Prof., Water Eng. Dep., Ferdowsi University of Mashhad, Iran ABSTRACT: In this study a subsurface intake introduced. This intake acts as a river drainage network. In this study an experimental model of the subsurface intake was constructed and the effective parameters such as upstream discharge, installation depth, and drains interval were evaluated. The results showed that the water diversion mostly influenced by the upstream flow rate. Small drain interval caused the discharge of each drain to be reduced. It was also revealed that the total drained discharge in the very transmitting media was mostly controlled with the number of drain and drain interval did have a marginal effect. Finally the regression equations were established to estimate the discharge of each drain based on dimensional analysis, which facilitate the design of this structure. Keywords: subsurface intake, porous media, drainage system, design criteria IWLHS, 20-22/02/2013, Aachen - Bung & Pagliara (eds) - © 2013 Bundesanstalt für Wasserbau ISBN 978-3-939230-04-51993 RESULTS AND DISCUSSION 3.1 The effect of drain distance and upstream discharge As the first step, the diverted water from the drainage system was measured under different upstream discharges and drain intervals. It was observed that the drains flow rate changed along the model. The water head measured with the piezometers also varied along the model even where the uniform surface water depth existed. The flow rate from the central drains (drain No. 7 and No. 8 for two installation depth D= 30, and D= 50 cm, respectively) was evaluated in different upstream discharges and drain intervals that are depicted in Fig. 4. It is observed that increasing the drain intervals caused the drain flow rate to be increased. The greater drain interval in a constant model length led to the smaller number of drains and consequently the increased upstream discharge which introduced the greater flow rate. Note that the flow pattern was identical for the different upstream discharge and the significant difference between 60 cm and 150 cm drain interval was not observed in the all upstream discharges. The direct effect of upstream discharge on the drains discharge can be obviously observed in this figure.    Figure 3. The central drain discharge in different drain intervals and upstream discharge The discharge relation for the central drain (indicated in Fig.2) (Fig. 4) obeyed from a logarithmic function and the flow rate reached a constant value depending on the media hydraulic conductivity and the drain conductance capacity. The great difference between 10 cm interval and other intervals can be related the side effect of the radial flow of the very close drains.   Figure 4. The central drain discharge – flow rate relation for the central drain in different drain intervals for D=50 cm 3.2 The effect of distance from the upstream The flow rate of each drain along the model in different upstream discharge and installation depth was presented in Fig. 5. The drain flow rate always reduced with different slope in length of model.  010203040506070800 40 80 120 160q (ml/s) w(cm) Q= 1.6 L/s, D=30 cmQ= 1.6 L/s, D=50 cmQ= 1.2 L/s, D=30 cmQ= 1.2 L/s, D=50 cmQ= 0.8 L/s, D=30 cmQ= 0.8 L/s, D=50 cmQ= 0.4 L/s, D=30 cmQ= 0.4 L/s, D=50 cmR² = 0,9103 R² = 0,9941 010203040506070800 0,5 1 1,5 2q (ml/s) Q (L/s) w=10 cmw=30 cmw=40 cmw=50 cmw=150 cm202Figure 5. The drain discharge changes along the model in different flow rate and installation depth (w=10cm) The variation of the drain flow rate in different intervals for Q=1.2 L/s and D= 30 was shown in Fig. 6. As the interval increased the q variation along the model has decreased. It means that the flow rate of each drain was less influenced by the neighbor drains when the intervals were increased. Furthermore, there is a decreased parabolic trend of drainages discharge along the porous media length.  Figure 6. The drain discharge variations along the model length for Q= 1.2 L/s and D= 30 cm in different drain intervals 3.3 The relationships between effective parameters Based on dimension analysis and Buckingham theory two effective dimensionless variables were selected and related to each other as follows: 𝑞𝑘3𝜌𝐷𝑄𝜇𝑔𝑥 = ∅�𝑥𝐿�   (4) In this equation a dimensionless parameter involving the drain discharge, the hydraulic conductivity and upstream discharge is related to distance ratio. To obtain ∅ function in Eq. 4, a curve was fitted to the dimensionless variables (Fig. 7) based on least square analysis.  01020304050607080901000 40 80 120 160q (ml/s) x (cm) Q=1.6 L/s, D=30 cmQ=1.6 L/s, D=50 cmQ=1.2 L/s, D=30 cmQ=1.2 L/s, D=50 cmQ=0.8 L/s, D=30 cmQ=0.8 L/s, D=50 cmQ=0.4 L/s, D=30 cmQ=0.4 L/s, D=50 cm01020304050607080901000 40 80 120 160q (ml/s) x (cm) w=10 cmw=20 cmw=30 cmw=40 cmw=50 cmw=60 cm203Figure 7. The variations of dimensionless drain discharge in different distance ratio The 70 percent of the experimental data were randomly selected for curve fitting and the last 30 % adopted for evaluation of the obtained equations. The statistical measures of the fitted model were tabulated in Table 1. Figure 8 shows the curves fitted to the experimental data in different upstream discharge. Table 1. Model Obtained from the fitted over 70% of the Experimental data Model Q Std. Error Residual Sum Residual Avg. RSS R2 Ra2 Variable Value Y=a+b/x+c/x2 1.6 L/s 2.39×10-7 -9.37×10-21 -1.91×10-22 2.62×10-12 0.982 0.981 a -2.61×10-7b 4.15×10-7 c 2.42×10-9 1.2 L/s 4.77×10-7 -3.59×10-19 -7.19×10-21 1.07×10-11 0.948 0.946 a -4.15×10-7b 6.24×10-7 c -6.21×10-90.8 L/s 5.50×10-7 0 0 1.30×10-11 0.962 0.960 a -6.90×10-7b 8.73×10-7 c 4.26×10-10 0.4 L/s 9.61×10-7 -1.36×10-20 -2.82×10-22 4.16×10-11 0.960 0.958 a -1.88×10-6b 1.71×10-6 c -1.12×10-8Figure 8. The curve fitted to 70% of the observed value in different upstream discharges To evaluate the goodness of the fitted curve, the equation was used to estimate the drain discharge of the 30% of the experimental data (Fig. 9). It was revealed that the maximum discrepancy was less than 37%. This error was for the minimum upstream discharge (Q=0.4 L/s). 0.000E+00200E-08400E-08600E-08800E-081.000E-081.200E-080 0,2 0,4 0,6 0,8 1qk3 ρD/Qµgx x/L Q=1.6 L/sQ=1.2 L/sQ=0.8 L/sQ=0.4 L/s204Finally, the achieved model can be expressed as Eq. 5. The equation constants (a, b and c) are shown in Table 1 for the different water heads. 3 2(qk ) ( ) ( ) ( )D Q gx a b x L c x Lρ µ = + +  (5) The estimated discharges using Eq. 5 have been compared with the 30% of the observed value and good agreement was observed (Table 2). Table 2. Statistical measure for the comparison of the estimated drain discharges with 30% of the observed values Upstream Discharge (Q) d (Wilmot,1981) RMSE MAE elative  Error an Relative Error 1.6 L/s 0.849 0.0136 0.0011 18.94% 27.85% 1.2 L/s 0.865 0.0127 0.0017 29.35% 0.8 L/s 0.922 0.0123 0.0021 20.88% 0.4 L/s 0.916 0.0148 0.0032 42.23% Figure 9. Comparison of the estimated drain discharges with the 30% of observed values 4 CONCLUSION In this study a rather new method for surface and subsurface water diversion in the seasonal rivers of the arid and semi-arid regions was introduced. In this type of intake a subsurface drainage system is installed in a very porous media buried on the river bed. The effective parameters on water diversion efficiency of this type of intake were experimentally evaluated. It was shown that the water diversion mostly influenced by the upstream flow rate. The water head also varied along the porous media even when a constant upstream discharge existed. The very small drain interval caused the discharge of each drain to be reduced. It was also revealed that the total drained discharge in the very transmitting media was mostly controlled with the number of drain and drain interval did have a marginal effect. The regression equations were present to relate the effective parameters of the water diversion. This equation can be utilized to design the subsurface intake with a porous media. NOTATION ρ fluid density g gravity acceleration Sb bed slope φ roughness geometry function τ  total fluid stress z vertical coordinate µ  water viscosity q a drain flow rate Q upstream discharge n media porosity d50 the median diameter of the fill material k hydraulic conductivity  R² = 0,6848 00,020,040,060,080,10 0,05 0,1q (Observation) q (Prediction) 205L length of porous media  w lateral distance between drains  D installation depth  x distance from the media upstream dp drain diameter  S0 the river bed slope Sl drain lateral slope Ad perforated drain opening area  nf envelop resistance factor form installation form parameter  REFERENCES Bouvard, M. (1953). “Discharge passing through a bottom grid.” Houille Blanche. Vol.3, pp. 290–291.  Bouvard, M. (1992). “Mobile Barrages and Intakes on Sediment Transporting Rivers.” IAHR monograph series, Rotterdam, Balkema.  Brunella, S., Hager, W. H., and Minor, H. E. (2003). “Hydraulics of bottom rack intake” Journal of Hydraulic Engineering. 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Vol.4, pp.570–580.  Noseda, G. (1955). “Operation and design of bottom intake racks” Proc, VI General Meeting IAHR. Vol.3, No.17, pp.1-11. Ramamurthy, A.S., Qu, J., and Vo, D. (2007). “Simulation of flow past an open- channel floor slot” Journal of Hydraulic Engineering. Vol.133, No.1, pp.106-110. Righetti, M., lanzoni, S. (2008). “Experimental study of the flow field over bottom intake racks” Journal of Hydraulic Engineering. Vol.134, pp.1-15. Subramanya, K. and Shukla, S.K. (1988). “Discharge diversion characteristics of trench weirs” Inst. Engineering. Vol.69, No.11, pp.163–168. Willmott, C. J. (1981). “On the validation of models”. Phys. Geog., Vol.2, pp.184-194. 206

Study of Hydraulic Properties and Design Criteria for a River Subsurface Intake without Cut Off

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Study of Hydraulic Properties and Design Criteria for a River Subsurface Intake without Cut Off

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