Experimental Investigation on the Deviated Sediment and Flow to Sediment Bypass Tunnels (SBTs) Using Submerged Plates

Document Type: Research Paper

Authors

Civil Engineering, Shahrood University of Technology, Shahrood, Iran.

Abstract

Sediment Bypass Tunnels (SBTs) are deviant channels that convey the current containing sediments from the upstream of the reservoir to the downstream of the dam. In this research, by applying submerged plates on the entrance of a 90-degree diversion channel for sediment transport, the effect of hydraulic parameters of flow and changes in the angle of plates on sediment transport and deviated flow are studied and compared with the state without using submerged plates. The experiments were conducted on a 10-meter-long Laboratory Flume, with a main channel of 60 cm width and a secondary channel of 30 cm width and a height of 75 cm. In this regard, the variables of Froude number and flow depth in three angles of 30, 45 and 60 degrees were considered. The results of this study highlight that an increase in Froude number on average would result in reduction of 22.2% of the channel deviated flow and reduction of 53.3% of the deviated sediment to the secondary channel. The 60-degree angle of the plates is effective in decreasing the deviated flow while the 30-degree angle is responsible for the increased deviated sediments. With a decrease in Froude number and depth along with submerged plates with a 30 degree angle, the optimum condition in conveying sediments is achieved where the maximum amount of sediments are conveyed in the minimum flow rate. Based on prediction results, the best equation to calculate the deviated sedimentation flow using the Genetic Algorithm (GA) is suggested.

Keywords


  1. Emamgholizadeh, S., Fathi Moghadam, M. (2014). Pressure Flushing of Cohesive Sediment in Dam Reservoir. Journal of Hydrology, ASCE, 2014.19:674-681.
  2. Morris GL, Fan J. 1998. Reservoir sedimentation handbook: design and management of dams, reservoirs, and watersheds for sustainable use. McGraw Hill: New York (NY).
  3. Torabi,H. Emamgholizadeh, S., Fathi, M. ,2014. Experimental study of the velocity of density currents in convergent and divergent channels. International Journal of Sediment Research, Elsevier, 29 (4) 518–523
  4. Emamgholizadeh, S., Bateni, S.M. Nielson, J.R. 2018. Evaluation of different strategies for the management of reservoir sedimentation in semi-arid regions: a case study (Dez Reservoir). Journal of Lake and Reservoir Management. 35. https://doi.org/10.1080/10402381.2018.14.
  5. White R, (2001). Evacuation of sediments from reservoirs. Thomas Telford.
  6. Vischer D, (1997). Bypass tunnels to prevent reservoir sedimentation. In Proc. 19th ICOLD Congress, Florence, Italy, 1997.
  7. Boes RM, Auel C, Hagmann M, Albayrak I, (2014). Sediment bypass tunnels to mitigate reservoir sedimentation and restore sediment continuity. Reservoir sedimentation, 221-228.
  8. Cajot S, Schleiss A, Sumi T, Kantoush S, (2012). Reservoir sediment management using replenishment: a numerical study of Nunome Dam. In Proceedings (on CD) of the International Symposium on Dams for a changing world-80th Annual Meeting and 24th Congress of CIGB-ICOLD (No. EPFL-CONF-178312, pp. 2-131).
  9. Emamgholizadeh S, Samadi H, (2008). Desalting of deposited sediment at the upstream of the Dez reservoir in Iran. Journal of Applied Sciences in Environmental Sanitation, 3(1), 25-35.
  10. Auel, C. & Boes, R. (2011) Sediment bypass tunnel design – review and outlook Dams and reservoirs under changing challeges. Taylor & Farncis Group, London
  11. Barkdoll B D, (1977). Sediment control at lateral diversion, Ph.D. dissertation, Civil and Environmental Engineering, University of Iowa
  12. Barkdoll BD, R Ettema, AJ Odgaard, (1999). Sediment control at lateral diversion: limits and enhancements to vane use. Journal of Hydraulic Engineering ASCE, 125(8): 862-870.
  13. Izadpanah Z, Salehi Neishabouri A, (2003). Investigation of sediment transport in lateral intakes. Journal of Agriculture, 26:15-24.
  14. Pirestani M. (2004). Investigation on flow pattern and scouring at intakes incurved channels. Ph.D. Thesis on irrigation engineering, Islamic Azad University, Science and Research center, Tehran Branch. p17.
  15. Abbasi, A. (2003). Experimental investigation on sediment control at lateral intakes in straight channels. Ph.D. Thesis on civil engineering, Tarbiat Modares University.
  16. Behbahani H, Shafaei Bajestan M, (2004). Investigation on hydraulic conditions at intakes with diversion angles 90° and 75° by using a physical model. Master thesis, water structures engineering, Shahid Chamran University.
  17. Karami Moghadam M, Shafai Bajestan M, Sedghi H, (2010). Sediment entry investigation at the 30- degree water intake installed at a trapezoidal channel, World Applied Sciences Journal 11 (1):82-88
  18. Salemnia A, Shafaei-Bajestan M, (2011). Investigation on the effect of submerged vanes on the amount of sediment entrance of trapezoidal channel into the lateral intake by changing the discharge diversion ratio. Proceeding of the 10th Iranian Hydraulic Conference. The University of Guilan. Rasht. Iran. (in Farsi)
  19. Jafari-Mianaei S, Ayyoubzadeh SA, (2014). Experimental investigation of the effect of inclined main channel wall on the amount of delivered sediment into the lateral intake with/without submerged vanes. Iranian J. Irrig. Drain. 4(7): 521-534.
  20. Hashid M, Hussain A, Ahmad Z, (2015). Discharge characteristics of lateral circular intakes in open channel flow. Flow Measurement and Instrumentation, 46: 87-92