Home / Regular Issue / JST Vol. 30 (3) Jul. 2022 / JST-3290-2021


Experimental Investigations on Scour Volume Upstream of a Slit Weir

Naeem Zaer Nkad, Thamer Ahmad Mohammad and Haider Mohammed Hammoodi

Pertanika Journal of Science & Technology, Volume 30, Issue 3, July 2022

DOI: https://doi.org/10.47836/pjst.30.3.09

Keywords: Nonuniform sediment, scour volume, slit weir, uniform flow

Published on: 25 May 2022

The frequent removal of sediment accumulation from reservoirs by dredging requires interruption of power generation. Alternatively, this can be avoided by using a slit weir. In the present study, the impact of sediment nonuniformity, slit weir dimensions, weir slit position, and discharge on the effectiveness of sediment removal was experimentally investigated using a flume with a length of 12m, a width of 0.30m, and a depth of 0.30m. In the flume, a slit weir was tightly fixed at the end of a 2m working section filled with nonuniform sediments up to 110mm. Results showed that using coarser sediment (d50 = 0.70mm) reduces the scour volume by 22-folds compared to finer sediment (d50=0.30mm). This study tested five different slit weir dimensions using two weir slit positions (slit positioned in the center and slit positioned on the side). The maximum scour volume was recorded when the crest level, z of the slit weir, was 0 cm from the mobile bed. The study concluded that a 3-fold increase in discharge corresponds to a 10-fold increase in scour volume regardless of bed material nonuniformity. The existing model for estimating scour volume for uniform sediments was validated using the data of this study, and it was observed that the model predicts the scour volume in nonuniform sediments with sufficient accuracy. Thus, the model can determine the scour volume, and maximum scour depth occurring upstream of a slit weir near a hydropower intake in reservoirs.

  • Abdollahpour, M., Ali, H. D., David, F., & Carlo, G. (2017). Experimental study on erosion and sedimentation patterns downstream of a W-weir in a sinusoidal mild bend. Water, 9(638), Article 638. https://doi.org/10.3390/w9090638

  • Azamathulla, H. M., Deo, M. C., & Deolalikar, P. B. (2008). Alternative neural networks to estimate the scour below spillways. Advances in Engineering Software, 39(8), 689-698. https://doi.org/10.1016/j.advengsoft.2007.07.004

  • Boroujeni, H. S. (2012). Hydropower - Practice and application. InTech Rijeka Publisher.

  • Guan, D., Liu, J., Chiew, Y. M., & Zhou, Y. (2019). Scour evolution downstream of Submerged weirs in clear water scour conditions. Water, 11(1746), Article 1746. https://doi.org/10.3390/w11091746

  • Kamarudin, A. M. K., Wahab, N. A., Mamat, A. F., Juahir, H., Toriman, M. E., Wan, N. F. N., Ata, F. M., Ghazali, A., Anuar, A., & Saad, M. H. M. (2018). Evaluation of annual sediment load production in Kenyir Lake Reservoir, Malaysia. International Journal of Engineering and Technology, 7(3), 55-60.

  • Khalili, M., & Honar, T. (2017). Discharge coefficient of semi-circular labyrinth side weir in subcritical flow. Water, 43(3), 433-441. https://doi.org/10.4314/wsa.v43i3.08

  • Lauchlan, C. (2004). Experimental investigation of bed-load and suspended-load transport over weirs. Journal of Hydraulic Research, 42(5), 551-558. https://doi.org/10.1080/00221686.2004.9641224

  • Melville, W. B., & Coleman, S. (2000). Bridge scour. Water Resources Publication.

  • Muller, S., Guiraud, P., & Line, A. (2011). Particle bed deformation in front of a weir induced by subcritical laminar flow. Journal of Hydraulic Research, 4 (2), 194-204. https://doi.org/10.1080/00221686.2011.552460

  • Noseda, M., Ivan, S., Michael, P., & Anton, J. S. (2019). Upstream erosion and sediment passage at piano key weirs. Journal of Hydraulic Engineering, 145(8), 1-9. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001616

  • Okumura, H., & Sumi, T. (2012, June 5). Reservoir sedimentation management in hydropower plant regarding flood risk and loss of power generation. In Proceedings of International Symposium on Dams for Changing World (pp. 1-6). Kyoto, Japan.

  • Ota, K., Sato, T., Arai, R., & Nakagawa, H. (2017a). Local scour upstream of a slit weir: Ordinary differential equation-based model under steady and unsteady flow conditions. Journal of Hydraulic Engineering, 143(1), Article 04016073. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001215

  • Ota, K., Sato, T., Nakagawa, H., & Kawaike, K. (2017b). Three-dimensional simulation of local scour around a weir-type structure: Hybrid Euler LaGrange model for bed-material load. Journal of Hydraulic Engineering, 143(4), 1-15. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001263

  • Ota, K., & Sato, T. (2015). Experimental and numerical study of the local scour caused by sediment releasing through a dam gate. Journal of Japan Society of Civil Engineers, 3(1), 184-190. https://doi.org/10.2208/journalofjsce.3.1_184

  • Ota, K., Sato, T., Arai, R., & Nakagawa, H. (2016). 3D numerical model of sediment transport considering transition from bed-load motion to suspension-application to a scour upstream of a cross-river structure. Journal of Japan Society of Civil Engineers, 4(1), 173-180. https://doi.org/10.2208/journalofjsce.4.1_173

  • Powell, D. N., & Khan, A. A. (2012). Scour upstream of a circular orifice under constant head. Journal of Hydraulic Research, 50(1), 28-34. https://doi.org/10.1080/00221686.2011.637821

  • Rajkumar, V. R., Wang, C., Shih, H., & Hong, J. (2016). Prediction of contraction scour using ANN and GA. Flow Measurement and Instrumentation, 50, 26-34. https://doi.org/10.1016/j.flowmeasinst.2016.06.006

  • Reisenbüchler, M., Bui, M. D., Skublics, D., & Rutschmann P. (2020). Sediment management at run-of-river reservoirs using numerical modelling. Water, 12(1), Article 249. https://doi.org/10.3390/w12010249

  • Sayed, B., Vosoughifar, H., Truce, B., & Jeng, D. S. (2019). Estimation of clear-water local scour at pile groups using genetic expression programming and multivariate adaptive regression splines. Journal of Waterway Port Coastal and Ocean Engineering, 145(1), 1-11. https://doi.org/10.1061/(ASCE)WW.1943-5460.0000488

  • Subramanya, K. (2015). Flow in open channels. McGraw Hill.

  • Wang, L., Melville, B. W., Whittaker, C. N., & Guan, D. (2018). Scour estimation downstream of submerged weirs. Journal of Hydraulic Engineering, 144(3), 1-9. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001431

  • Wang, S., Wei, K., Shen, Z., & Xiang, Q. (2019). Experimental investigation of local scour protection for cylindrical bridge piers using anti-scour collars. Water, 11(7), Article 1515. https://doi.org/10.3390/w11071515

  • Zhang, Z., Bing, S., Yakun, G., & Daoyi, C. (2016). Improving the prediction of scour around submarine pipelines. Proceedings of the Institution of Civil Engineers-Maritime Engineering, 169(4), 163-173. https://doi.org/10.1680/jmaen.2015.22

ISSN 0128-7702

e-ISSN 2231-8534

Article ID


Download Full Article PDF

Share this article

Recent Articles