Taiwan’s rugged, mountainous terrain, a result of active tectonics, and its monsoonal climate create conditions that produce the greatest sediment yield compared to all land surfaces on Earth. It is estimated that, on average, Taiwanese rivers discharge ~ 150 million tons of sediment annually into Taiwan Strait. The rivers discharge most of the sediment during the relatively short time periods of torrential rains often associated with typhoons, and thus the waters have a high mud fraction (fine-grained sediment, mainly composed of clay). The voluminous amount of sediment that rapidly accumulates near river mouths is dispersed effectively. On a longer time scale, there is persistent northward sediment transport. In this study, we examine the Jhoushuei River system, which has the largest average annual sediment load in Taiwan. The first survey was conducted in 2008, 40 hours after peak fluvial discharge caused by Typhoon Kalmaegi. We measured sediment discharge in the lower reach of the river channel and surveyed suspended sediment distribution in the coastal zone near the river mouth. During Kalmaegi’s landfall on Taiwan, suspended-sediment concentration in the Jhoushuei River reached as high as 120 g L–1 and the estimated total sediment discharge was about 30 million tons. Since then, we have conducted surveys on four more occasions in the coastal zone near the river mouth, where we measured suspended-sediment concentrations and currents, and sampled surface sediments over several tidal cycles. The initial results shed light on the mechanism of efficient sediment dispersal during massive sediment-discharge events. Fine-grained sediments originally deposited near the river mouth following typhoon floods, generally in summer and fall, are dispersed during winter. The transport mechanism responsible for the sediment removal warrants further investigation.

Chien, H., W.-S. Chiang, S.-J. Kao, J.T. Liu, K.-K. Liu, and P.L.-F. Liu. 2011. Sediment dynamics observed in the Jhoushuei River and adjacent coastal zone in Taiwan Strait. Oceanography 24(4):122–131, https://doi.org/10.5670/oceanog.2011.100.

Dadson, S., N. Hovius, S. Pegg, W.B. Dade, M.J. Horng, and H. Chen. 2005. Hyperpycnal river flows from an active mountain belt. Journal of Geophysical Research 110, F04016, https://doi.org/10.1029/2004JF000244.

Draut, A.E., G.C. Kineke, D.W. Velasco, M.A. Allison, and R.J. Prime. 2005. Influence of the Atchafalaya River on recent evolution of the chenier-plain inner continental shelf, northern Gulf of Mexico. Continental Shelf Research 25:91–112, https://doi.org/10.1016/j.csr.2004.09.002. 

Geyer, W.R., P.S. Hill, and G.C. Kineke. 2004. The transport, transformation, and dispersal of sediment by buoyant coastal flows. Continental Shelf Research 24(7–8):927–949. https://doi.org/10.1016/j.csr.2004.02.006. 

Hovius, N., C.P. Stark, H.T. Chu, and J.C. Lin. 2000. Supply and removal of sediment in a landslide-dominated mountain belt: Central Range, Taiwan. Journal of Geology 108:73–89, https://doi.org/10.1086/314387.

Hu, C.-K., C.-T. Chiu, S.-H. Chen, J.-Y. Kuo, S. Jan, and Y.-H. Tseng. 2010. Numerical simulation of barotropic tides around Taiwan. Terrestrial, Atmospheric and Oceanic Sciences 21:71–84, https://doi.org/10.3319/TAO.2009.05.25.02(IWNOP).

Huh, C.A., W. Chen, F.-H. Hsu, C.-C. Su, J.-K. Chiu, S. Lin, C.-S. Liu, and B.-J. Huang. 2011. Modern (< 100 years) sedimentation in the Taiwan Strait: Rates and source-to-sink pathways elucidated from radionuclides and particle size distribution. Continental Shelf Research 31:47–63, https://doi.org/10.1016/j.csr.2010.11.002.

Kao, S.J., S. Jan, S.C. Hsu, T.Y. Lee, and M. Dai. 2008. Sediment budget in the Taiwan Strait with high fluvial sediment inputs from mountainous rivers: New observations and synthesis. Terrestrial, Atmospheric and Oceanic Sciences 19:525–546, https://doi.org/10.3319/TAO.2008.19.5.525(Oc).

Kao, S.J., T.Y. Lee, and J.D. Milliman. 2005. Calculating highly fluctuated suspended sediment fluxes from mountainous rivers in Taiwan. Terrestrial, Atmospheric and Oceanic Sciences 16(3):653–675. Available online at: http://tao.cgu.org.tw/index.php?id=700 (accessed November 1, 2011).

Kao, S.J., and J.D. Milliman. 2008. Water and sediment discharges from small mountainous rivers, Taiwan: The roles of lithology, episodic events, and human activities. Journal of Geology 116:431–448, https://doi.org/10.1086/590921.

Lin, C.W., C.L. Shieh, B.D. Yuan, Y.C. Shieh, S.H. Liu, and S.Y. Lee. 2004. Impact of the Chi-Chi earthquake on the occurrence of landslides and debris flows: Example from the Chenyulan River watershed. Engineering Geology 71:49–61, https://doi.org/10.1016/S0013-7952(03)00125-X.

Liu, J.T., H.-L. Lin, and J.-J. Hung. 2006. A submarine canyon conduit under typhoon conditions off southern Taiwan. Deep Sea Research Part I 53:223–240, https://doi.org/10.1016/j.dsr.2005.09.012.

Milliman, J.D., and S.J. Kao. 2005. Hyperpycnal discharge of fluvial sediment to the ocean: Impact of Super-Typhoon Herb (1996) on Taiwanese Rivers. Journal of Geology 113:503–506, https://doi.org/10.1086/431906.

Milliman J.D., S.W. Lin, S.J. Kao, J.P. Liu, C.S. Liu, J.K. Chiu, and Y.C. Lin. 2007. Short-term changes in seafloor character due to flood-derived hyperpycnal discharge: Typhoon Mindulle, Taiwan, July 2004. Geology 35(9):779–782, https://doi.org/10.1130/G23760A.1.

Milliman, J.D., and J.P.M. Syvitski. 1992. Geomorphic/tectonic control of sediment discharge to the ocean: The importance of small mountain rivers. Journal of Geology 100:525–544, https://doi.org/10.1086/629606.

Nittrouer, C.A., and J.H. Kravitz. 1996. STRATAFORM: A Program to study the creation and interpretation of sedimentary strata on continental margins. Oceanography 9(3):146–152. Available online at: http://tos.org/oceanography/issues/issue_archive/issue_pdfs/9_3/9.3_nittrouer_kravitz.pdf (accessed November 1, 2011).

Nittrouer, C.A., D.J. DeMaster, A.G. Figueiredo, and J.M. Rine. 1991. AmasSeds: An interdisciplinary investigation of a complex coastal environment. Oceanography 4(1):37. Available online at: http://tos.org/oceanography/issues/issue_archive/issue_pdfs/4_1/4.1_nittrouer_et_al.pdf (accessed November 1, 2011).

Sherwood C.R., J.W. Book, S. Carniel, L. Cavaleri, J. Chiggiato, H. Das, J.D. Doyle, C.K. Harris, A.W. Niedoroda, H. Perkins, and others. 2004. Sediment dynamics in the Adriatic Sea investigated with coupled models. Oceanography 17(4):58–69. Available online at: http://tos.org/oceanography/issues/issue_archive/issue_pdfs/17_4/17.4_sherwood_et_al.pdf (accessed November 1, 2011).

Walsh J.P., and C.A. Nittrouer. 2009. Understanding fine-grained river-sediment dispersal on continental margins. Marine Geology 263(1–4):34–45, https://doi.org/doi:10.1016/j.margeo.2009.03.016.

Wright, L.D., and C.A. Nittrouer. 1995. Dispersal of river sediments in coastal seas: Six contrasting cases. Estuaries 18:494–508, https://doi.org/10.2307/1352367.

Wu, C.-C., and Y.-H. Kuo. 1999. Typhoons affecting Taiwan: Current understanding and future challenges. Bulletin of American Meteorological Society 80:67–80, https://doi.org/10.1175/1520-0477(1999)080<0067:TATCUA>2.0.CO;2.

Yu, S.B., L.C. Kuo, Y.J. Hsu, H.H. Su, C.C. Liu, C.S. Hou, J.F. Lee, T.C. Lai, C.C. Liu, C.L. Liu, and others. 2001. Preseismic and coseismic displacements associated with the 1999 Chi-Chi, Taiwan, earthquake. Bulletin of the Seismological Society of America 91:995–1,012, https://doi.org/10.1785/0120000722.

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.