Abstract
To alleviate problems caused by reservoir sedimentation, the hydrosuction removal of sediment deposits is an attractive option. In this technique, pumping or siphoning is used to draw water and sediment into the inlet of a pipe and convey the slurry to settling ponds. A key performance target is then to maximize the delivered sediment concentration. For fine sediment (silt and clay), deposit behavior largely depends on its degree of consolidation. To investigate how this parameter affects hydrosuction performance, a series of laboratory experiments were conducted using a small-scale suction pipe equipped with an online densimeter to measure the time evolution of the outflow sediment concentration. To help interpret the resulting signals, the evolving shape of the deposit surface near the pipe inlet was recorded. Measurements were then compared with predictions from inviscid selective withdrawal theory. Depending on the duration of self-weight consolidation prior to hydrosuction, a transition was observed between two highly contrasted sediment responses. Up to a degree of consolidation of approximately 90%, loose deposits respond much like a dense inviscid layer. Beyond this degree, consolidated deposits resist withdrawal, causing rapid freshwater breakthrough and an abrupt drop in hydrosuction performance.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The present research was motivated by an applied study conducted with Sinotech Engineering Consultants for the Water Resources Agency, Taiwan, with additional support provided by the Taiwan Ministry of Science and Technology. At Sinotech, Wen-Shiang Chung, Kuo-Cheng Hsieh, Chun-Yao Hou, and Allen Lin provided useful feedback. At National Taiwan University, we gratefully acknowledge the contributions of Che-Bo Chang, Yu-Chou Chiang, Louis Ge, Jeff Keck, Fu-Liang Lian, Wei-Jay Ni, Hsin-Yi Yeh, and Ting-Sia Ye to the experimental work.
References
Agisoft Photoscan is version 1.1 [Computer software]. Agisoft LLC, St. Petersburg, Russia.
Craya, A. (1949). “Recherches théoriques sur 1’écoulement de couches superposées de fluides de densités différentes.” La Houille Blanche, 4(1), 44–55 (in French).
Fan, J. (2008). “Stratified flow through outlets.” J. Hydro-Environ. Res., 2(1), 3–18.
Fan, J., and Morris, G. (1992). “Reservoir sedimentation. II: Reservoir desiltation and long-term storage capacity.” J. Hydraul. Eng., 370–384.
Gaudin, C., Bienen, B., and Cassidy, M. J. (2011). “Investigation of the potential of bottom water jetting to ease spudcan extraction in soft clay.” Géotechnique, 61(12), 1043–1054.
Hotchkiss, R. H., and Huang, X. (1995). “Hydrosuction sediment-removal systems (HSRS): Principles and field test.” J. Hydraul. Eng., 479–489.
Ides, S., and Plancke, Y. (2014). “Mud research to optimize the dredging strategy in the Deurganckdok in the port of Antwerp.” 33rd PIANC World Congress—Navigating the New Millenium, PIANC, San Francisco, 15.
Ivey, G. N., and Blake, S. (1985). “Axisymmetric withdrawal and inflow in a density-stratified container.” J. Fluid Mech., 161(1), 115–137.
Jenzer Althaus, J. M. I., De Cesare, G., and Schleiss, A. J. (2014). “Sediment evacuation from reservoirs through intakes by jet-induced flow.” J. Hydraul. Eng., 04014078.
Machin, J. B., and Allan, P. A. (2011). State-of-the-art jet trenching analysis in stiff clays, D. White, CRC Press, 871–876.
Miedema, S. A. (1999). “Considerations on limits of dredging processes.” 19th Annual Meeting and Technical Conf. of the Western Dredging Association, WEDA, Louisville, KY, 21.
Perng, A. T. H., and Capart, H. (2008). “Underwater sand bed erosion and internal jump formation by travelling plane jets.” J. Fluid Mech., 595, 1–43.
Rehbinder, G. (1994). “Sediment removal with a siphon at critical flux.” J. Hydraul. Res., 32(6), 845–860.
Schleiss, A., De Cesare, G., and Jenzer Althaus, J. M. I. (2010). “Reservoir sedimentation threatens the sustainable use of hydropower.” Wasser Energie Luft-Eau Énergie Air, 102(1), 31–40.
Sinotech Engineering Consultants. (2013). “Sediment releasing planning in Tseng-Wen reservoir desilting alternatives research.” Water Resources Planning Institute, Taipei, Taiwan, 450.
Spigel, R. H., and Farrant, B. (1984). “Selective withdrawal through a point sink and pycnocline formation in a linearly stratified flow.” J. Hydraul. Res., 22(1), 35–51.
Ullah, S. M., Mazurek, K. A., Rajaratnam, N., and Reitsma, S. (2005). “Siphon removal of cohesionless materials.” J. Waterw. Port Coastal Ocean Eng., 115–122.
Van den Berg, J. H., Van Gelder, A., and Mastbergen, D. R. (2002). “The importance of breaching as a mechanism of subaqueous slope failure in fine sand.” Sedimentology, 49(1), 81–95.
Winterwerp, J. C., van Kesteren, W. G. M., van Prooijen, B., and Jacobs, W. (2012). “A conceptual framework for shear flow-induced erosion of soft cohesive sediment beds.” J. Geophys. Res., 117(C10), C10020.
Wood, I. R. (2001). “Extensions to the theory of selective withdrawal.” J. Fluid. Mech., 448, 315–333.
WRA (Water Resources Agency). (2012). “Tsengwen Reservoir sedimentation measurements.” Southern Region Water Resources Office, Ministry of Economic Affairs, Tainan, Taiwan, 110.
Yu, W. S., Hsu, S. M., and Fan, K. L. (2004). “Experiments on selective withdrawal of a codirectional two-layer flow through a line sink.” J. Hydraul. Eng., 1156–1166.
Zreik, D. A., Krishnappan, B. G., 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
Information
Published In
Journal of Hydraulic Engineering
Volume 142 • Issue 10 • October 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Mar 1, 2015
Accepted: Jan 5, 2016
Published online: May 30, 2016
Published in print: Oct 1, 2016
Discussion open until: Oct 30, 2016
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.