Quantity, distribution, and impacts of coastal driftwood triggered by a typhoon

Published Date
Marine Pollution Bulletin
July 2011, Vol.62(7):1446–1454, doi:10.1016/j.marpolbul.2011.04.021

Author 

• Dong-Jiing Doong ^a,,
• Hui-Chieh Chuang ^a,
• Chjeng-Lun Shieh ^b,
• Jian-Hwa Hu ^a,1,

• aDepartment of Marine Environmental Informatics, National Taiwan Ocean University, Keelung, Taiwan
• bDepartment of Hydraulic and Ocean Engineering, National Cheng Kung University, Tainan, Taiwan

Available online 26 May 2011. 

Abstract

Typhoon Morakot pounded Taiwan in 2009 with record-breaking rainfall, washing an unprecedented amount of driftwood into the sea that was partially deposited at the coastal areas. According to the satellite imagery analysis, more than three million trees fell and were washed away to occupy 83.2% of the Taiwanese coastline, including 52 fishing harbors. The amount cleaned-up was only 1/7 of the total coastal driftwood. It was found that the amount of coastal driftwood is not only related to the amount of precipitation but is also related to the distance from the location of the landslide to the river mouth and to the landslide area. The amount of accumulated coastal driftwood demonstrated log-profile declines with increasing distance to the river mouth. Nearshore current and wave motion are the critical factors for driftwood deposition. Much of the driftwood washed into the sea harmed the tourism and fishing industries, endangered navigation and oceanic activities, and impacted the marine environment and ecosystem.

Highlights

► More than three million trees fell and washed into the sea during a typhoon. 83.2% of Taiwanese coastline and 52 harbors were influenced by coastal driftwood. ► The accumulated coastal driftwood demonstrated log-profile declines with increasing distance to the river mouth. ► Quantity of coastal driftwood is related to the distance of the landslide location to river mouth as well as the landslide area, not the rainfall. ► Nearshore current is a critical factor for the deposition of coastal driftwood, not the ocean current.

Keywords

Driftwood

Floating marine debris (FMD)

Typhoon disaster

Coastal hazard

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  Corresponding author. Address: Department of Marine Environmental Informatics, National Taiwan Ocean University, 2, Beining Rd., Keelung 20224, Taiwan. Tel.: +886 2 24622192x6318, fax: +886 2 24621047.

Copyright © 2011 Elsevier Ltd. All rights reserved.

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