Energy pollution: the relative influence of wind-wave and vessel-wake energy in Tallinn Bay, the Baltic Sea

The role of frequent vessel wakes on the wave energy budget of 5cmi-sheltered beaches has been re-evaluated for the almost tideless Tallinn Bay, the Baltic Sea. High-resolution water surface time series containing signals of >650 ship wakes collected over 30 days at a depth of ~2.7 m shows that (i) the daily maximum heights of vessel wakes have increased considerably since the beginning of the decade while (ii) the leading wave periods (W-13 s) and integral properties of vessel wakes such as the total wave energy and its flux have remained largely unchanged. The typical daily largest ship waves (1.2-1.4 m) are equivalent to the annual highest 0.8-1.8% of wind waves and the highest ship waves (l.7 m) to the highest 0.25% of wind waves. Unlike the Baltic Proper, the overall wind wave intensity has varied insignificantly over the last three decades in Tallinn Bay where vessel wakes contribute about 10% in terms of wave energy and 25% in terms of energy flux. Substantial seasonal variation of wave intensity with markedly low wind waves in the biologically most active season suggests that vessel wakes may play a decisive role during some seasons even in areas with overall high wind wave activity.

[1]  Stan Stumbo,et al.  The Prediction, Measurement, and Analysis of Wake Wash from Marine Vessels , 1999 .

[2]  Henrik Kofoed-Hansen,et al.  Wakes from Large High-Speed Ferries in Confined Coastal Waters: Management Approaches with Examples from New Zealand and Denmark , 2001 .

[3]  M. Donelan,et al.  Dynamics and Modelling of Ocean Waves , 1994 .

[4]  Ira Didenkulova,et al.  Far-field vessel wakes in Tallinn Bay , 2008 .

[5]  N. Macdonald,et al.  Sediment Transport in Response to Wave Groups Generated by High-Speed Vessels , 2007 .

[6]  T. Soomere,et al.  Trends and extremes of wave fields in the north-eastern part of the Baltic Proper , 2006 .

[7]  Kevin Parnell,et al.  Shoreline effects of vessel wakes, Marlborough Sounds, New Zealand , 2007 .

[8]  Ira Didenkulova,et al.  Implications of fast-ferry wakes for semi-sheltered beaches: a case study at Aegna Island, Baltic Sea , 2009 .

[9]  David H. Schoellhamer,et al.  Anthropogenic Sediment Resuspension Mechanisms in a Shallow Microtidal Estuary , 1996 .

[10]  Lars Bergdahl,et al.  Guidelines for Managing Wake Wash from High-speed Vessels , 2003 .

[11]  T. Soomere.  Wind wave statistics in Tallinn Bay , 2005 .

[12]  Tarmo Soomere,et al.  Nonlinear Components of Ship Wake Waves , 2007 .

[13]  T. Soomere,et al.  Estimates of wave climate in the northern Baltic Proper derived from visual wave observations at Vilsandi , 2007, Estonian Journal of Engineering.

[14]  T. Soomere,et al.  Shoaling and runup of long waves induced by high-speed ferries in Tallinn Bay , 2009 .

[15]  S. Talke,et al.  The Influence of Oceanic Swell on Flows Over an Estuarine Intertidal Mudflat in San Francisco Bay , 2003 .

[16]  Dmitry Kurennoy,et al.  Variability in the properties of wakes generated by high-speed ferries , 2009 .

[17]  Tarmo Soomere,et al.  Fast Ferry Traffic as a Qualitatively New Forcing Factor of Environmental Processes in Non-Tidal Sea Areas: A Case Study in Tallinn Bay, Baltic Sea , 2005 .