Pressure Flushing of Cohesive Sediment in Large Dam Reservoirs
Publication: Journal of Hydrologic Engineering
Volume 19, Issue 4
Abstract
Pressure flushing of deposited sediments behind large dam walls causes development of a funnel-shaped crater due to the induced vortex and considerable shear flow around the outlets. Laboratory experiments were conducted to investigate interaction of flow and sediment parameters on the development and final size of the scour cone. The volume of the flushed sediment increases with increase of discharge, and decreases with increase of sediment bulk density and the water level above the sediment. While the water depth over the sediments is the most significant parameter in the collapse of sediments above the intake and the initial development of the cone, sensitivity analysis indicated bulk density of cohesive sediment to be the most effective parameter to determine the final size of the scour cone. Using experimental results, two equations were developed to estimate scour cone volume and length with readily defined and measurable parameters of flow and sediment. The field measurements confirm the capability of the equations for large-scale application and flushing practice.
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Acknowledgments
The authors would like to acknowledge the journal editors and the five anonymous reviewers for their insightful comments and suggestions on this paper. The acknowledgement is also extended to the Shahid Chamran University of Ahwaz, Shahrood University of Technology, and the Centre of Excellence on Operation Management of Irrigation and Drainage Networks for financial support and facilitation of the experiments.
References
Amos, C. L., et al. (2004). “The stability of tidal flats in Venice Lagoon: The results of in-situ measurements using two benthic, annular flumes.” J. Mar. Syst., 51(1–4), 211–241.
ASTM International. (2010). “Standard Test Methods for Specific Gravity of Soil Solids by Water Pycnometer.” ASTMD854, West Conshohocken, PA.
Avnimelech, Y., Ritvo, G., Meijer, L. E., and Kochba, M. (2001). “Water content, organic carbon and dry bulk density in flooded sediments.” Aquacult. Eng., 25(1), 25–33.
Bale, A. J., Stephens, J. A., and Harris, C. B. (2007). “Critical erosion profiles in macro-tidal estuary sediments: Implications for the stability of intertidal mud and the slope of mud banks.” Cont. Shelf Res., 27(18), 2303–2312.
Bale, A. J., Widdows, J., Harris, C. B., and Stephens, J. A. (2006). “Measurements of the critical erosion threshold of surface sediments along the Tamar Estuary using a miniannular flume.” Cont. Shelf Res., 26(10), 1206–1216.
Coastal Engineering Manual. (2002). “Erosion, transport and deposition of cohesive sediments.” Chapter III-5, U.S. Army Corps of Engineers, Washington, DC.
Fang, D., and Cao, S. (1996). “An experimental study on scour funnel in front of a sediment flushing outlet of a reservoir.” Proc., 6th Federal Interagency Sedimentation Conf., Las Vegas, NV, I-78–I-84.
Fathi-Moghadam, M., Arman, A., Emamgholizadeh, S., and Alikhani, A. (2011). “Settling properties of cohesive sediments in lakes and reservoirs.” J. Waterway Port Coastal Ocean Eng., 204–209.
Garg, V., and Jothiprakash, V. (2010). “Modeling the time variation of reservoir trap efficiency.” J. Hydrol. Eng., 1001–1015.
Grabowski, R. C., Droppo, R. I., and Wharton, G. (2011). “Erodibility of cohesive sediment: The importance of sediment properties.” Earth Sci. Rev., 105(3–4), 101–120.
Hwang, K. N., and Mehta, A. J. (1989). “Fine sediment erodibility in Lake Okeechobee,” Rep. UFLICOEL-891019, Coastal and Oceanographic Engineering Dept., Univ. of Florida, Gainesville, FL.
Jepsen, R., Roberts, J., and Lick, W. (1997). “Effects of bulk density on sediment erosion rates.” Water Air Soil Pollut., 99(1–4), 21–31.
Jothiprakash, V., and Garg, V. (2009). “Reservoir sedimentation estimation using artificial neural network.” J. Hydrol. Eng., 1035–1040.
Julien, P. Y. (1996). “Transforms for runoff and sediment transport.” J. Hydrol. Eng., 114–122.
Lai, J. S., and Shen, H. W. (1996). “Flushing sediment through reservoirs.” J. Hydraul. Res., 34(2), 237–255.
Lee, H.-Y., Lin, Y.-T., and Chiu, Y.-J. (2006). “Quantitative estimation of reservoir sedimentation from three typhoon events.” J. Hydrol. Eng., 362–370.
Lick, W., and McNeil, J. (2001). “Effects of sediment bulk properties on erosion rates.” Sci. Total Environ., 266(1–3), 41–48.
Liu, J., Liu, B., and Ashida, K., (2002). “Reservoir sedimentation management in Asia.” 5th Int. Conf. on Hydro-science and Engineering, Warsaw Univ. of Technology, Poland.
Millar, R. G., and Quick, M. C. (1998). “Stable width and depth of gravel bed rivers with cohesive banks.” J. Hydraul. Eng., 1005–1013.
Mizumura, K. (2012). “Prediction of sediment concentration in rivers by recursive least-squares and linear minimum variance estimators.” J. Hydrol. Eng., 851–857.
Morris, G. L., and Fan, J. (1997). Reservoir sedimentation handbook, McGraw-Hill, New York.
Pejrup, M., and Mikkelsen, O. A. (2010). “Factors controlling the field settling velocity of cohesive sediment in estuaries.” Estuarine Coastal Shelf Sci., 87(2), 177–185.
Qian, N. (1982). “Reservoir sedimentation and slope stability; technical and environmental effects.” 14th Int. Congress on Large Dams, Transactions, Vol. III, Rio de Janeiro, Brazil, 639–690.
Raudkivi, A. J. (1998). Loose boundary hydraulic, Balkema, Rotterdam, Netherlands, 271–311.
Reddy, Y. R., and Pickford, J. A. (1972). “Vortices at intakes in conventional sump.” Int. Water Power Dam Constr., 24(3), 108–109.
Roberts, J., Jepsen, R., Gotthard, D., and Lick, W. (1998). “Effects of particle size and bulk density on erosion of quartz particles.” J. Hydraul. Eng., 1261–1267.
Samadi Boroujeni, H., Fathi-Moghadam, M., and Shafaei-Bejestan, M. (2009). “Investigation on bulk density of deposited sediments in Dez Reservoir.” Trends Appl. Sci. Res., 4(3), 148–157.
Senthil Kumar, A. R., Ojha, C. S. P., Kumar Goyal, M., Singh, R. D., and Swamee, P. K. (2012). “Modelling of suspended sediment concentration at Kasol in India using ANN, fuzzy logic and decision tree algorithms.” J. Hydraul. Eng., 394–404.
Shen, H. W. (1999). “Flushing sediment through reservoirs.” J. Hydraul. Res., 37(6), 743–757.
Ulke, A., Tayfur, G., and Ozkul, S. (2009). “Predicting suspended sediment loads and missing data for Gediz River, Turkey.” J. Hydrol. Eng., 954–965.
U.S. Dept. of the Interior, Bureau of Reclamation. (2001). Water measurement manual, 3rd Ed., 〈http://www.usbr.gov/pmts/hydraulics_lab/pubs/wmm/index.htm〉.
White, W. R. (2001). Evacuation of sediment from reservoirs, Thomas Telford, London.
Winterwerp, J. C., Cornelisse, J. M., and Kuijper, C. (1990). “Parameters to characterize natural muds.” Int. Workshop on Cohesive Sediments, Royal Belgian Institute of Natural Sciences, Brussels, 103–105.
Winterwerp, J. C., and van Kesteren, W. G. M. (2004). Introduction to the physics of cohesive sediment in the marine environment, 1st Ed., Elsevier, Amsterdam, Netherlands, 576.
Wu, B., Wang, G., and Xia, J. (2007). “Case study: Delayed sedimentation response to inflow and operations at Sanmenxia Dam.” J. Hydraul. Eng., 483–494.
Yang, M., and Wang, G. (1996). “Formulas for incipient motion of mud with various densities.” Int. J. Sediment Res., 11(1), 34–42.
Zreik, D. A., Krishnappan, B. J., Germaine, J. T., Madsen, O. S., and Ladd, C. C. (1998). “Erosional and mechanical strengths of deposited cohesive sediments.” J. Hydraul. Eng., 1076–1085.
Information & Authors
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Published In
Journal of Hydrologic Engineering
Volume 19 • Issue 4 • April 2014
Pages: 674 - 681
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Mar 21, 2012
Accepted: Jun 1, 2013
Published online: Mar 14, 2014
Published in print: Apr 1, 2014
Discussion open until: Aug 14, 2014
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