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A Decision Support Tool for Assessing the Impact of Boat Wake Waves on Inland Waterways

Abstract and Figures

The generation, propagation, attenuation and forces related to boat generated wake waves are currently being investigated due to increasing concerns regarding their impact on coastal and inland waterways. To ensure that these concerns are objectively addressed, a Decision Support Tool (DST) to assist in waterway management has been developed. The DST is based on standardised field measurements of boat wake waves, which have been specifically developed for this field of study, local wind wave energy calculations, and an assessment of the waterway's erosion potential. Importantly, the tool incorporates both individual and cumulative wave energy calculations and a field methodology for assessing the erosion potential of a selected site. An interactive spreadsheet has been developed to assist in applying the DST at selected sites. Field testing of the DST has assisted in refining and validating the assessment methods. The DST can be easily adapted to assess the impact of boat wake waves in a variety of waterways and can be expanded to include additional vessels. While there is currently a large demand for this type of decision support tool in coastal and inland waterways, no alternative comprehensive method currently exist.
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A Decision Support Tool for Assessing the Impact of
Boat Wake Waves on Inland Waterways
William C. Glamore
Senior Research Engineer, Water Research Laboratory, School of Civil and
Environmental Engineering, University of New South Wales, Australia
The generation, propagation, attenuation and forces related to boat generated wake
waves are currently being investigated due to increasing concerns regarding their impact
on coastal and inland waterways. To ensure that these concerns are objectively
addressed, a Decision Support Tool (DST) to assist in waterway management has been
developed. The DST is based on standardised field measurements of boat wake waves,
which have been specifically developed for this field of study, local wind wave energy
calculations, and an assessment of the waterway’s erosion potential. Importantly, the
tool incorporates both individual and cumulative wave energy calculations and a field
methodology for assessing the erosion potential of a selected site. An interactive
spreadsheet has been developed to assist in applying the DST at selected sites. Field
testing of the DST has assisted in refining and validating the assessment methods. The
DST can be easily adapted to assess the impact of boat wake waves in a variety of
waterways and can be expanded to include additional vessels. While there is currently a
large demand for this type of decision support tool in coastal and inland waterways, no
alternative comprehensive method currently exist.
Over recent years community concern regarding the perceived impact of boat generated
waves (or wake waves) on coastal and inland waterways has increased. At the same
time, the popularity of recreational boating and watersports, such as wakeboarding, has
grown dramatically. Determining whether boat wake waves are responsible for river
bank damage has been difficult to assess due to the wide range of influencing factors
and a paucity of data. In the absence of a comprehensive assessment methodology,
common management strategies have been to enforce speed limits, restrict recreational
or commercial boats movements, or limit wave heights generated in the waterway. In
many situations, however, these solutions are neither effective nor based on adequate
science, and a more comprehensive strategy, supported by field investigations, is
Attempts to create waterway management strategies to manage boat wakes have been
problematic due to (1) the lack of standardised wave measurement criteria, (2) the
different wave and shoreline monitoring techniques, (3) the diverse forms of boat wakes
generated and (4) the wide range of shoreline types encountered. As such, the majority
of boat wake investigations to date have focused on specific types of vessels, such as
passenger ferries, located in high risk areas. These studies are typically undertaken in
Decision Support Tool for Inland Waterways 2
reaction to a specific problem at a specific location and lack a standardised approach.
This piecemeal approach results in a range of methodologies, monitoring techniques
and management strategies being developed throughout the world, of which few are
Due to the gaps in current knowledge and the complexities inherent in assessing
shoreline dynamics it is easy to understand the difficulty in establishing a standardised
boating management criterion. Indeed, AMC (2003) suggests that due to the relatively
new science of monitoring boat wake propagation, combined with the multitude of
erosion parameters, a comprehensive boat wake management strategy is likely to be
decades away. Nonetheless, several attempts have been made to manage boat wakes at
individual sites and, as detailed in Table 1, these methodologies vary widely in scope
and focus. Importantly, the previously proposed wave management criteria do not take
into account the natural background wave energy, nor the condition of the bank.
Table 1 Previous Wake Wave Management Criteria
Wave Management Criteria Source
Maximum Wave
Height (Hmax)
28 cm from peak to trough measured 300 m from
sailing line in deep water.
Stumbo et al. (1999).
Maximum Wave
Height (Hmax)
< 20 cm no action on bank stabilisation required.
20-30 cm requires monitoring.
30-40 cm requires bank engineering assessment and
Patterson Britton and
Partners (2001).
Maximum Wave
Height (Hmax)
Based on wave height criteria:
Where Hh is Hmax and Th is mean wave period.
(Equates to 0.75m for 2.0 second wave period.)
Parnell and Kofoed-Hansen
Wave Energy < 2450 joules/m (150 lb/ft) in the highest significant
wave of the wave train as measured 300m from
sailing line in deep water.
Stumbo et al. (1999).
Wave Energy, Wave
Period and Speed
Energy: 1962Hm
2 <60 joules/m or <180 joules/m;
Period: Comparison of boat length and energy in the
from of 3.04L
Speed: Blanket Speed Limit of 5-6 knots
Australian Maritime
College (2003)
To improve waterway management, this paper presents a comprehensive Decision
Support Tool (DST) designed to assess the impact of boat wake waves along a stretch of
inland waterway. The DST is based on standardised field assessment methods,
comprehensive site assessment techniques and has been field validated. The DST
discussed within this paper varies from previous methods as it attempts to include all of
the major components associated with rapidly assessing a selected reach of a waterway
within a single methodology. The primary aim of the DST is to quantitatively
Decision Support Tool for Inland Waterways 3
determine the impact of a boat wake wave on a shoreline, and based on the
susceptibility of a shoreline to erode, determine whether vessels should be restricted,
managed or allowed. In brief, the DST compares the natural background wind-wave
energy with the vessel generated wave energy, the operating frequency of the boats and
the erosion potential of the bank. A short description of each step involved in applying
the DST is provided below.
The first step of the DST is to determine the natural wind wave energy at the site using
standard methods. The energy of the passing boat wave train is then determined based
on previous field measurements. The third step involves assessing the potential for the
bank to erode based on a series of weighted factors that incorporate physical and
ecological features of the bank. Once these initial steps have been undertaken, the wake
wave energy is compared to the average recurrence interval of the wind wave energy.
This comparison is undertaken for both the maximum generated wake wave and the
total wave energy generated from a typical day involving multiple boat passes. The
comparison of these wake wave energies with the average recurrence interval of the
wind wave energy provides an indication of the likely impact of the boat waves on the
shoreline. These results are then compared with a ‘bank erosion rating’ to determine the
most appropriate boating management strategy for the site.
An interactive spreadsheet has been developed to assist in applying the tool at
individual sites. A methodology for selecting sites is also provided and, based on the
management outcomes, the timeframes between reassessment of a site is prescribed.
Important issues such as wave attenuation, operating versus maximum wave conditions
and wave duration time limits have all been included within the methodology.
To test the applicability of the method, desktop and field assessments of a range of sites
has been completed. Based on this development process, the DST is currently being
adopted by the New South Wales’ Maritime Authority for application on multiple sites.
This paper is divided into 8 sections with each section detailing an individual
component of the DST. Following this brief overview, Section 3 discusses the
standards developed in measuring wake waves and the specific field tests undertaken for
the study. This section also details how this information was subsequently employed
within the DST and interactive spreadsheet. Section 4 details the wind wave component
of the DST and Section 5 outlines how the shoreline erosion potential is calculated.
Based on this information, Section 6 details how the DST determines the appropriate
management outcome for each waterway. Finally, Section 7 presents the tools
Decision Support Tool for Inland Waterways 4
developed to easily apply the DST at various sites and discusses experiences gained
from recent field applications.
This section details the boat wake wave data obtained and subsequently employed
within the DST. Particular emphasis is placed on the development of standardised
methods developed to undertake the field measurements with the intention that further
measurements undertaken by others can be incorporated within the DST. Other factors
including wave attenuation, the frequency of boat movements and the individual wave
energy versus the entire wave train energy are discussed.
As a boat travels through the water, it generates a series of waves. The height and
period of these waves vary depending on boat speed and type. Once fully formed, the
group of waves are termed a ‘wave train’. In deep water the height of the waves within
the wave train will attenuate with distance, though the period will remain relatively
unchanged. The key descriptors of these waves are schematically displayed in Figure 1.
The energy within a boat wake wave may cause damage to a shoreline by initiating
sediment transport. Damage may be caused by the effect of a single wave or the
cumulative effect of several wave trains from many boats. Often the general public are
concerned with waves of observably large amplitudes, however damage caused by a
wave is a function of both the wave height and wave period. The preferred criteria for
analysing the relative effects of waves is, therefore, wave energy; a function of both
wave height and wave period (Equation 1). Within the DST, wave energy calculations
have been used to calculate both the maximum wave generated by a single boat pass,
and the cumulative energy of multiple waves over a specific time period.
222 THg
E= (1)
Where, ρ is the water density, g is the gravitational constant, and π is a constant = 3.14.
The total energy of the wave train is equal to the sum of the energy of each individual
Decision Support Tool for Inland Waterways 5
2.1 Standard Methods:
Boat Wave Data
In deep water (depth
/wavelength > 0.5), boat wakes
from different boats should be
comparable across different
sites. To date, a range of
measurement techniques have
been employed to obtain boat
wake data. While laboratory
tests are commonly undertaken,
the most scientifically sound
means is via full-scale tests
with a series of well spaced
capacitance probes. Three
wave staffs (or more) should be
located away from the
generated wave at: (i) the cusp
locus point (approx 2 boat
lengths); (ii) within 5 boat
lengths from the sailing line and if feasible, (iii) at a sufficient distance to measure 75%
attenuation of wave height (or approximately 10 boat lengths).
The selected field site should have water deep enough to limit shallow water wave
effects, have limited currents so that the probes remain vertical and unobstructed, and be
sufficiently wide to reduce the restricted channel effect. The field tests should not be
undertaken during windy conditions as wind waves may increase background noise and
turbidity levels. Boats should be tested at a range of speeds including Sub-critical (Fd <
1), Critical (Fd = 1) and Super-critical (Fd > 1) Froude modes as well as trim and
ballasting configurations. Boat speed should be calculated using appropriate methods
considering the ambient currents. A calibrated radar gun is recommended to measure
both the vessel speed and the distances between each wave staff. Particular attention
should be given to wave reflection and a site should be chosen that absorbs the wave
energy effectively. If wave reflection is apparent, especially from transverse waves
generated at critical speeds, sufficient time should be taken between vessel tests to allow
for the wave energy to dissipate. A typical field deployment schematic is given in
Figure 2.
Figure 1. Schematic of Boat Wake Waves
Decision Support Tool for Inland Waterways 6
As part of this study, full scale field testing of several wakeboarding and waterski
vessels was undertaken to determine the characteristic waves generated by different
boats. The entire testing results are outlined in Glamore and Hudson (2005) and are
based on the methodologies detailed above. During the tests 6 wakeboarding vessels
and 5 waterski vessels were tested under 8 speed and towing conditions. Test runs
included various ballasting configurations, with and without skiers, various speed
levels, and turning/starting runs. Each test was repeated 6 times and wave heights were
measured using purpose built submersible wave capacitance probes at 4 distances from
the sailing line in a location without currents, fluctuations in water depth or significant
background noise. Vessel speed and distances were calculated using a calibrated radar
Figure 2. Schematic of Wake Wave Field Testing Protocols
Based on the field results, the differences between wakeboarding vessels and waterski
vessels are most pronounced at their operating conditions (i.e. the speed for towing
skiers; 30 knots for waterski boats and 19 knots for wakeboarding boats). The
maximum waves produced through the vessel testing were measured 22 m from the
sailing line and are detailed in Table 2.
Decision Support Tool for Inland Waterways 7
Table 2 Wave of Operating Conditions
Boat Velocity
(knots) Velocity
(m/s) Hmax (m) Tpeak
(s) Boat Length
Lw (m) FL Energy Hmax
Waterski 30 15.42 0.12 1.50 6.1 2.0 62
Wakeboard 19 9.76 0.25 1.57 6.1 1.3 293
The maximum waves recorded during field tests at all speeds are given in Table 3.
Table 3 Maximum Wave as predicted by the length based Froude Number (FL)
Boat Velocity
(knots) Velocity
(m/s) Hmax (m) Tpeak
(s) Boat Length
Lw (m) FL Energy Hmax
Waterski 8 4.11 0.35 1.73 6.1 0.5 701
Wakeboard 8 4.11 0.33 1.86 6.1 0.5 700
Based on the wave energy calculations, it is clear that the maximum wave energy is not
produced when the boats are at operating conditions, but rather at the slower velocities
of 8 knots; the velocity at which the maximum wave is produced, as predicted by the
length-based Froude number.
2.2 Wave Train Energy
Using the field experiment data, the energy of the entire wave train (not just the
individual wave) was calculated for each boat pass. A good correlation (r2 = 0.88) has
been found between the total energy of the wave train and the energy of the maximum
wave (Figure 3), as calculated by Equation 2. A power relationship was fitted to the
data (r2 = 0.87) and can be used to estimate the total energy of the wave train where the
characteristics of the maximum wave are known:
ETot = 10.8EHmax0.82 (2)
Figure 3. Relationship of Energy of Maximum Wave Versus Energy of Entire Wave Train
y = 10.796x
= 0.8687
0 200 400 600 800 1000 1200 1400
Total Wave Train Energy
Energy of Hmax
Decision Support Tool for Inland Waterways 8
2.3 Wave Attenuation
A wave train generated by a boat initially appears as an accumulation of super-imposed
waves. As the waves travel away from the sailing line, the wave train develops until all
of the waves can be individually characterised by wave height and wave period, at
which point the wave train may be considered fully developed. This occurs within 2-5
boat lengths from the sailing line. After the wave train becomes fully developed, the
wave period remains constant while the wave height decreases in proportion to distance
from the sailing line.
While it is important to calculate the maximum energy that may be inflicted on a
shoreline by boat waves, attenuation of wake waves prior to impacting the shoreline
should also be calculated to determine if boats may be managed within the available
channel width or if width limitations should apply. If attenuation reduces the wave
energy sufficiently to make boating more acceptable in a waterway, the distance away
from the shore that the boats must travel should be specified in a boating management
Attenuation of divergent waves may be calculated using the formula:
H = wave height (m)
= variable dependent on the vessel type and velocity
y = lateral distance from the sailing line (m)
Manipulation of Equation 3 results in Equation 3a.
Hy (3a)
Hy = wave height y metres from the sailing line(m)
H0 = wave height when generated (m)
Maximum wave heights have been measured at a distance 22 m from the sailing line.
According to Equation 3a, the wave height at 22 m from the sailing line is 36% of the
original wave height. Therefore, to calculate Hy at any distance from the sailing line, H0
must first be back-calculated from the known wave height 22 m from the sailing line
and multiplied by y-1/3. If the wave train is not fully developed (i.e. is still within 22 m
Decision Support Tool for Inland Waterways 9
of the sailing line), it is considered more appropriate to use the maximum wave statistics
rather than attenuated values.
Attenuated wave heights should be calculated at a distance equal to half of the channel
width. This represents the maximum attenuation possible at a site.
2.4 Frequency of Boat Movements
Erosion may be caused by the impact of a single wave or by the cumulative energy of
many waves over a period of time. Consequently, a method of comparing the
cumulative energy of many boat passes with the cumulative energy of wind waves over
the same period must be defined. For every boat passing, the energy of the entire wave
train will impact the shoreline. The cumulative effect of boats passing is, therefore, the
product of the number of boats passing and the energy of the total wave train. Since it is
assumed that most of the boat usage will occur over the daylight hours (8 - 12 hours),
this period is used to compare cumulative energies.
If boats are already in use at a site, available data on boat use frequency on the peak day
of the week should be used. If no data is available, a boat management survey should
be conducted to determine the number of boat passes in a day. Surveys should be
conducted on the same day of 5 consecutive weeks. The day should be chosen
according to the heaviest use, but then averaged over the total number of weeks of
surveys. This should prevent both damping of the frequency by averaging with very
low use days such as weekdays, and exaggeration of likely boat use by surveying on
highly trafficked public holidays.
If boats are not already in use at a site, projections should be made as to the likely
number of boat passes on the peak day of the week. Alternatively, if boats are not
already onsite, then this variable could be altered within the DST to determine the
allowable number of boats on a particular stretch of a river.
2.5 Boat Wake Wave Data: Application within the DST
The vessel related data presented above is employed within the boat wake wave
components (Stage 1) of the DST. During the development of the DST, the maximum
wave was extracted from boat wake wave field data and the associated energy
calculated. Then the energy of the maximum wave was interpolated to the energy of the
entire wave train. The energy of the entire wave train can then be multiplied by the
number of boat passes over a specific time period to give the cumulative boat wake
Decision Support Tool for Inland Waterways 10
wave energy over a specific duration (8 - 12 hours). Within the interactive spreadsheet,
users are given the option to select from a range of vessels and also to select whether the
vessel of concern is to be tested at its operational speed or its maximum wave producing
speed. Users also input the number of boats over the specified time period and the
width of the river (for wave attenuation calculations). All calculations are then
undertaken automatically, without the user having to have a high level understanding of
the background data.
The natural wind-wave environment along a stretch of a river is one of the shaping
factors of the waterway. Wind waves are generated by wind blowing across a fetch.
The size of the waves may be limited by either the duration of the wind blowing or the
length of the fetch. It is assumed that, in the absence of large floods, a waterway
subjected to a certain wind-wave climate will establish equilibrium with that
environment over time. For this reason, the natural wind wave climate should be
assessed for each site and then compared with the energy of boat wake waves. Where
the energy of the boat wake waves is of similar magnitude to the energy of the natural
wind wave environment, it is unlikely that the boat wake waves will cause significant
damage. If, however, boat wake wave energy greatly exceeds the wind wave energy of
the site, erosion is anticipated. This section describes the method used to calculate wind
wave energy at a site.
It is important to note that the factors that determine whether a wave will erode a river
bank are complex and not fully understood. The erosion potential depends on many
factors including, but not limited to, both the maximum wave energy of a single wave
and the long-term impact of several waves over a period of time. For this reason, the
wind wave energy of a location is characterised in two ways. First, the maximum fetch-
limited wave energy is determined based on different wind speeds. Second, the
cumulative wind wave energy for an extended duration is calculated to determine
cumulative energy effects. Eight to twelve hours has been selected as an appropriate
duration for calculating cumulative energy as it approximates the daylight hours during
which boats are likely to be travelling.
In order of preference, the following types of wind data would be used to predict wind
waves at a site in Australia:
Site wind data (specifically collected for the study)
Local airport data
Decision Support Tool for Inland Waterways 11
Regional wind data based on 3 second design wind gust data outlined in
Australian Standards AS1170.2:2002
Ideally, wind data would be specific to the location of interest, thereby capturing local
wind effects. In most cases, wind data of this nature will not be available in sufficiently
long record sets to analyse for annual recurrence intervals. If local wind data is
available, a wind rose should be made from the data to show percent occurrences of
different wind speed intervals for the site.
Wind data is readily available at most locations in Australia in the form of wind roses at
local airports. Data is presented as percent occurrence for different wind speed intervals
and is typically divided into 16 wind directions. It is expected that this will be the
primary source of wind data used for wave hindcasting. This data is typically in the
form of 10 minute duration winds at z = 10 m height. Care should be taken in defining
the wind speed intervals for presenting the data to ensure that low frequency high speed
data is not neglected in the analysis. For example, the final bin may simply be >35
km/hour, however without including more detail regarding this data, a very conservative
picture of the wind wave climate may be drawn.
If there is no local wind data available, regional 3 second gust design wind data for
Australia can be found in AS1170.2:2002. This can be converted to a site wind speed
for the 8 cardinal wind directions at the reference height of 10 m using the following
Vsit,β = VRMd(Mz,catMsMt) (4)
Where, VR = regional 3 s gust wind speed (m/s) for annual exceedance probability of
1/R; Md = wind directional multipliers for the 8 cardinal directions; Mz,cat =
terrain/height multiplier; Ms = shielding multiplier, Mt = topographic multiplier.
Wind wave generation in deep water is governed by the wind speed, wind fetch and
wind duration. If the development of the wave is hindered by the length of the fetch, the
wind waves are termed fetch-limited, whereas if development is hindered by the
duration of the wind, the waves are duration-limited. The Coastal Engineering Manual
(2003) outlines relevant methods for predicting wind waves for a selected site and
relevant equations are utilized within the DST and detailed below.
Decision Support Tool for Inland Waterways 12
The following steps are used to calculate the maximum fetch-limited wind waves at a
site. These values are used to compare the single maximum energy wind waves at a site
with the maximum boat wake waves.
1. Determine the fetch length in 16 compass directions to the point of interest (i.e.
the distance over water for which the waves can develop). This will most likely
be completed using aerial photographs or topographic maps. Where available,
GIS applications can be used for these calculations.
2. Using the fetch length for each direction and the matrix of wind speeds for the
location, calculate the time (tx,u) in seconds for the waves to become fetch
limited using Equation 5. The wind speed used is the upper limit of each
,23.77 gu
tux = (5)
Where, X = fetch length (m); u = wind velocity (m/s); g = acceleration due to gravity
(9.81 m/s2).
3. If the time, tx,u, is less than the wind duration, the wave is duration limited. For
comparison, the waves can be converted to fetch limited waves by increasing the
wind duration to the time for the waves to become fetch limited tx,u. To calculate
the wind speed at varying durations, the wind speed is first converted to a one
hour wind speed u3600 before being converted to the wind speed ui for the
appropriate duration using the following equations:
If 1<ti<3600,
If ti>3600,
+= i
Wave growth with fetch can then be calculated using the following equations:
0, 1013.4
Decision Support Tool for Inland Waterways 13
Where, Hm,0 = energy-based significant wave height; Tp = wave period (s); u* = friction
velocity = (u2CD)1/2 ; and CD = drag coefficient = 0.001(1.1 + 0.035u).
Based on the percentage of time the wind has been blowing in a certain direction at a
certain speed, these calculations generate a matrix of wind waves that occur for a
percentage of time.
While the above steps (Equation 5-9) detail how to determine the height and period of a
wind wave at a specific site, they do not include a duration or time period over which
this event will occur. The steps used to calculate the cumulative waves generated at a
site over a period of time (12 hours) are the same as above with the following minor
Equations 6 & 7 are used to convert the 10 minute wind speeds to 8 - 12 hour
duration wind speeds.
Wave growth with fetch is calculated according to Equations 8 & 9 using the
duration adjusted wind speeds.
The number of waves calculated over 8 - 12 hours is calculated by dividing the
duration by the wave period.
The output of these calculations is a matrix of wind waves that occur for a percentage of
time based on the percentage of time the wind has been blowing in a certain direction at
a certain speed. For each wind speed, the energy associated with the wave generated is
calculated. Wind wave energy generated over 8-12 hours duration is simply the product
of the energy of a single wave and the number of waves generated over the duration.
The Average Recurrence Interval (ARI) provides the likelihood of a wave occurring
within the selected time period. In this methodology, the ARI represents the probability
of a wave occurring at a site based on the available wind data. Calculating the wind
wave ARI’s for both individual waves and waves over a period of time is important for
comparing these waves against boat generated waves.
Using the record length of the wind data, the ARI of the wind wave energies can then be
approximated using the following steps:
1. Sort the wind wave energies from least to greatest, where the greatest is rank 1.
2. Calculate the cumulative percent occurrence for each of the records.
Decision Support Tool for Inland Waterways 14
3. Convert the cumulative percent occurrence to an approximate ARI by dividing
the cumulative percent occurrence rank 1 record by the cumulative percent
occurrence for each record (i) and then multiplying it by the record length (n).
These steps are completed for the energy of the single short-duration maximum fetch-
limited waves and the cumulative energy of the 8 - 12 hour duration wind waves,
thereby generating two sets of ARI’s, which can be compared to the wake wave data.
Once the boat wake waves and the wind waves likely to be encountered onsite have
been calculated, the bank erosion potential should be assessed. The bank erosion
potential is calculated using a number of key criteria that are then summarized to form a
erosion potential rating for the site. Sites with highly negative erosion potentials have a
low resistance to erosion, whereas sites with strongly positive erosion potentials are
well protected from bank erosion.
To determine which variables should be included within the methodology, a detailed
literature review was completed. From the literature, key factors in the stability of river
banks include river type, vegetation coverage and extent, erosion descriptors, adjacent
land use and channel features. A full list of the categories, indicators and weightings
used within the DST is provided in Table 4. A detailed description of the 22 indicators,
including several that were chosen specifically for this study, and why they were
selected for the DST is available in Glamore and Badenhop (2006).
For each of the 22 indicators a number of options are provided to assist in determining a
score for that indicator. In general, indicators that reflect positively on the erosion
resistance score positively, whereas indicators that detract from the erosion resistance
score negatively. For instance, when determining the indicator ‘wave zone cover’ a
user must select between <10% cover, 10 – 30% cover, 30 – 60% cover or >60% cover.
Each of these options has a score associated with it ranging from -1 for <10% cover, to
+2 for >60% cover. Based on the importance of each indicator, a weighting factor is
then applied (i.e. Extreme, High, Moderate or Low importance, with corresponding
weightings of 4, 3, 2 and 1) so that the final score for the indicator is the score
multiplied by the weighting. The erosion potential indicator for the entire site is the
sum of all 22 weighted scores.
Decision Support Tool for Inland Waterways 15
Table 4 Erosion Potential Indicators Used in DST
Category Indicator Weighting Indicator Options
Valley Setting High Confined, Partially Confined,
Laterally Unconfined, Completely
Armoured, Partially Armoured
River Type
Stage variability Moderate Tidal, Natural, Regulated
Longitudinal continuity of bank
vegetation over stretch
High <10%, 10-30%, 30-60%, >60%
Verge cover
(10 m from top of bank)
<10%, 10-30%, 30-60%, >60%
Upper Bank Cover High <10%, 10-30%, 30-60%, >60%
Wave Zone Cover High <10%, 10-30%, 30-60%, >60%
Native canopy species
regeneration (< 1 m tall)
Low None, Scattered, Abundant
Native understorey regeneration Low None, Scattered, Abundant
Dominant Wave Zone Cover High Bare (vertical slope), Bare (1:3
slope), Bare (<1:7 slope), Rocks,
Tree Roots, Mangroves, Grasses,
Bank Slope* High Near-Vertical, 1:3, 1:5, 1:7
Bank Height Moderate <1 m, 1-3 m, >3 m
Channel width High <36 m, 36 -120 m, >120 m
Bank Sediment Type Moderate Bedrock/Boulders/Armour,
Cohesive, Non-Cohesive, Complex
Lateral Stability Moderate High, Moderate, Low (based on
evidence of channel migration)
Sinuosity Moderate
<1:3, >1:3
Erosion above the wave zone Moderate Absent, <10%, 10-30%, >30%
Slumping Moderate
Absent, <10%, 10-30%, >30%
Undercutting in the wave zone Extreme Absent, <10%, 10-30%, >30%
Desnagging Low
None, Conducted in Last Year
Excavation High
Present, Absent
Extraction Low
None, Water, Sediment
Land use
Stock access Extreme Present, Absent
*Note that the bank slope indicator is dependent on the sediment type.
The final erosion potential rating determines the site’s Erosion Potential Category, as
summarised in Table 5. The highest possible score for a Confined valley setting (as
selected in the Valley Setting Indicator) is 67 points, whilst the lowest possible score in
a Confined setting is -24. The highest possible score for a Laterally Unconfined valley
setting is 58 points, while the worst is –90.
The area to be assessed will be predetermined by the overall extent of the waterway
feasible for recreational boating. As shown in Figure 4, this length is then divided into
500 m stretches on each side of the river, of which 30% are randomly selected. Each
stretch is then divided into three sections and a 10 m wide transect at the midpoint of
each section assessed. The erosion potential of the three transects should be averaged
Decision Support Tool for Inland Waterways 16
for each stretch. Along the entire testing area, the lowest scoring stretch (i.e. that with
the lowest final rating) is taken as the final score. Onsite assessments should be made at
low tide and not during floods, as it is important that the banks can actually be observed
during the assessment process.
Table 5 Final Erosion Potential Categories
Indicator Rating Score* Erosion Category
40 Highly Resistant
20 to 40 Moderately Resistant
20 to 0 Mildly Resistant
0 to -25 Moderately Erosive
-25 to -97 Highly Erosive
*Note that the Indicator Rating Score is the summation of all 22 weighted scores for each transect.
Figure 4. Schematic of Field Assessment Selection Process
Decision Support Tool for Inland Waterways 17
The above sections have outlined relevant methods for determining the boat wake wave
energy, for calculating wind wave energy, developing Average Recurrence Intervals
(ARI), and for assessing the onsite erosion potential. Once this information has been
gathered then the data is fed into a series of matrices that determine the management
The first matrix (Table 6) compares the ARI of the wind wave energy against the boat
wave energy for both a single maximum boat wave train and an extended duration
period (8 - 12 hour). The aim of this assessment is to determine the equivalent ARI of
the boat wake wave energy (i.e. to establish if the boats wake wave energy is the
equivalent of a 2-year wind wave event or a 20-year wind wave event). For instance, if
the single maximum boat wave energy is equivalent to a 3-year ARI maximum wind
wave AND the longer duration boat wave energy is comparable to the energy of a 3-
year ARI wind wave, then the site would fall within a Category C rating.
Table 6 Comparison of ARI for Wind and Boat Waves
Equivalent ARI of boat wake wave energy over an extended period
(typically 8 - 12 hours)
ARI for
boat wake
wave energy <1 1-2 2-5 5-10 10-20 >20
<1 A A B C C C
1-2 A B B C C D
2-5 A B C C D D
5-10 B B C C D D
10-20 B C C D D E
>20 B C C D E E
Based on the outcome from Table 6, which compares the boat wave data against the
wind wave data, an assessment is then made against the calculated site Erosion Potential
(Table 7). As shown in Table 7, a site with a ‘C’ ARI Rating (as determined from Table
6) can either gain one of three management outcomes (Permit, Monitor, Assess) based
on the erosion potential calculated for the site. The final management outcome is then
applied to this entire stretch of the river.
Decision Support Tool for Inland Waterways 18
Table 7 Final Management Outcome
Erosion Potential
Rating Highly
Resistant Moderately
Resistant Mildly
Resistant Moderately
Erosive Highly
Depending on the management outcome determined above, a varying reassessment
period would apply. A site with a ‘Monitor’ management outcome should be assessed
every 2 years, whereas the ‘Permit’ option allows reassessment every 5 years. If
warranted, the DST could also be used to assess the impact of wave attenuation and, in
certain scenarios, may result in an alternative management outcome.
For ease of use and understanding, the equations and methods presented above have
been incorporated within a user-friendly interactive spreadsheet. The interface is
divided into five main categories: Introduction, Boat Wake Waves, Wind Waves,
Shoreline Erosion Potential and Management Outcome. The spreadsheet is coded to
only allow the user access to the key areas for data input, yet can be easily adapted to
include additional components. A depiction of each primary assessment stage within
the DST spreadsheet is provided in Figure 5.
In addition, a DST User’s Manual has been developed to assist in using the interactive
spreadsheet and to provide additional resources (i.e. field sheets, onsite checklists,
representative photos with marked guidelines, etc) for the field assessment. A
theoretical manual has also been developed (Glamore and Badenhop, 2007) to present
the science behind the selected methodologies and to discuss the rationale for the
erosion potential indicators.
Decision Support Tool for Inland Waterways 19
Figure 5. Images of the Assessment Stages Within the DST Spreadsheet
A Decision Support Tool has been developed to determine if vessels should be
permitted on a waterway based on whether the boat wake waves are likely to cause
erosion at a selected site. The tool is structured around three major components: (i)
determining the wave energy (from both a single wave train and multiple wave trains
over a period of time) for selected boats based previously measured field data, (ii)
calculating the average recurrence interval for wind waves (for both maximum and
Decision Support Tool for Inland Waterways 20
cumulative energy) at the selected site, and (iii) assessing a series of shoreline stretches
of the waterway to determine the erosion potential. A decision matrix is then used to
compare the energy from the boat wake waves relative to the local wind wave energy.
The outcome from this matrix is then used against a matrix of erosion potential
indicators for the site and a final management outcome is determined. Field protocols,
resources (User and Theory Manuals, Onsite field spreadsheets and checklists, etc) and
an interactive spreadsheet have been developed to assist in the decision making process.
The author wishes to thank the NSW Maritime Authority for their financial and
technical support.
AS 1170.2:2002 (2002) Structural Design Actions. Part 2: Wind Actions Standards
Australian Maritime College (2003) Vessel Wash Impacts on Bank Erosion, Noosa
River and Brisbane River. Technical Report # 01/G/18 for Moreton Bay Waterways
and Catchment Partnership.
Glamore, W. C. and R. Hudson (2005) Field Investigation and Comparative Analysis
of Boat Wash Waves WRL Technical Report 2005/10
Glamore, W. C., Hudson, R. and R. J. Cox (2005) Measurement and Analysis of Boat
Wake Waves: Management Implications. Proceeding of the 17th Australasian Coastal
and Ocean Engineering Conference and the 10th Australasian Port and Harbour
Conference, Adelaide, Australia September 21-24 2005, Eds. (Townsend, M. and D.
Walker). ISBN 0-646-45130-30.
MacFarlane, G. & Cox, G. (2003) "Vessel Wash Impacts on Boat Erosion" AMCSearch
Report No. 01/G/18.
Parnell K., (2001) Wakes from Large High-Speed Ferries in Confined Coastal Waters:
Management Approaches with Examples from New Zealand and Denmark, Coastal
Management, 29:217-237, 2001
Patterson Britton & Partners (2001) Parramatta River Long-term Shoreline Monitoring
Study: Final Report. Prepared in association with the Water Research Laboratory for the
NSW Waterways Authority, June 2001.
Stumbo S, Fox, K., Dvorak F., & Elliot L (1999) The prediction, measurement and
analysis of wake wash from marine vessels. MARINE TECHNOLOGY AND SNAME
NEWS. 36 (4): 248-260.
US Army Corp of Engineers (2003) Coastal Engineering Manual. EM 1110-2-1100
(Part II) (Change 1) US Army Corp of Engineers.
... Historically, these tools mainly consist of sitespecific or case-specific ship wake criteria for maximum allowable waves (De Roo and Troch, 2015;Macfarlane and Cox, 2004;Osborne et al., 2009;Parnell and Kofoed-Hansen, 2001;Stumbo et al., 1999). However, these criteria need to be developed specifically for each case and are not necessarily transferable to other fairways (Glamore, 2008). More generic approaches include screening tools to predict the ship wave height and the associated erosion. ...
... More generic approaches include screening tools to predict the ship wave height and the associated erosion. Existing screening tools in the literature for supporting management decisions are typically developed for channels and rivers (Fonseca and Malhotra, 2012;Glamore, 2008;Hartman and Styles, 2020). ...
... In the decision support tool by Glamore (2008), the boat wakes are not predicted but based on standardized field measurements. The boat wakes are categorized based on the annual re-occurrence interval for hindcasted WGW. ...
Full-text available
The negative impact of maritime traffic in terms of shore erosion in sheltered coastal fairways can be mitigated by sustainable fairway management. Mitigation measures include regulating the ship traffic in terms of speed, routes, or size of ships, but can also involve erosion protection along a fairway. For effective shoreline management of a fairway, it is essential to predict ship waves, to identify sites with potential erosion problems, and to investigate the effectiveness of different measures before implementing them. Several attempts have been made to develop site-specific criteria for managing ship waves. However, few available generic models consider primary waves generated by large ships in confined fairways. Therefore, a tool for supporting decisions in fairway management was developed. The decision support tool is based on simplified formulas for ship- and wind-wave prediction, combined in a framework that enables automatic, rapid assessments on large spatial and temporal scales. Moreover, the tool requires only readily available input data, such as data on AIS, bathymetry, shoreline geometry, wind, fairway centreline, and grain size. The output from the model includes ship and wind wave heights and potential erosion sites. The decision support tool was applied to the Furusund Fairway, Sweden, by simulating one year of ship traffic to validate its capability of identifying potential erosion sites. The simulation demonstrated that the tool was capable of identifying known erosion sites in the fairway. Additionally, scenarios with different speed regulation strategies for the Furusund Fairway were investigated using the decision support tool. Overall, it is concluded that the developed tool enables rapid assessment of ship waves, wind waves, and potential erosion over large areas in fairways.
... Boat wake energy is event-dependent and influenced by vessel length, water depth, and boat speed (Sorensen, 1973;Glamore, 2008). While each boat passage generates a complex series of waves with unique characteristics, wake wave height can be reasonably predicted by vessel speed (Sorenson, 1973;Zabawa and Ostrom, 1980;Fonseca and Malhotra, 2012). ...
... Adding to the complexity, the relative amount of wave energy attributable to boats versus wind may vary temporally because the intensity of boating activity may vary throughout the year (Zabawa and Ostrom, 1980;Maynord et al., 2008). The frequency of vessel passage influences the overall amount of boat wake energy impacting a given shoreline, with highly traveled waterways more likely to experience boat wake-induced shoreline erosion than those that are less frequently traveled (Zabawa and Ostrom, 1980;Glamore, 2008). ...
... Prior to development of a truly quantitative understanding of boat wake-induced erosion at a systems-level, interim protective measures can be applied on the basis of documented effects of boat wakes in the literature. Wave height-or wave energy-based criteria have been used to establish wake management strategies (Stumbo et al., 1999;Glamore, 2008). Wave decay studies indicate that, in general, even small (< 9 m) power boats traveling within 150 m of the shore are capable of generating wave heights that can cause erosion of vegetated marsh shorelines (Zabawa and Ostrum, 1980;Coops et al., 1996;Coops et al. 1996Coops et al. , 1996Schafer et al., 2003;Roland and Douglas, 2005). ...
Full-text available
Coastal economies are often supported by activities that rely on commercial or recreational vessels to move people or goods, such as shipping, transportation, cruising, and fishing. Unintentionally, frequent or intense vessel traffic can contribute to erosion of coastlines; this can be particularly evident in sheltered systems where shoreline erosion should be minimal in the absence of boat waves. We reviewed the state of the science of known effects of boat waves on shoreline stability, examined data on erosion, turbidity, and shoreline armoring patterns for evidence of a response to boat waves in Chesapeake Bay, and reviewed existing management and policy actions in Chesapeake Bay and nearby states to make recommendations for actions to minimize boat wake impacts. In the literature, as well as in our analyses, boat wake energy may be linked to elevated turbidity and shoreline erosion, particularly in narrow waterways. In Chesapeake Bay, three lines of evidence suggest boat waves are contributing to shoreline erosion and poor water clarity in some Bay creeks and tributaries: 1) nearshore turbidity was elevated in many waterways during periods of expected high boating activity, 2) armoring was placed along about a quarter of the low energy shorelines of three examined tidal creeks that are exposed to relatively high boating pressure, and 3) 15% of the shorelines we examined throughout the Bay (9000 km) are low energy shorelines that are experiencing high erosion (≥0.3 m/yr) that cannot be attributed to wind wave energy. Still, there remain significant data gaps that preclude the determination of the overall contribution of boat waves to shoreline erosion throughout the Bay, notably, shoreline erosion data in low energy waterways, recreational boating traffic patterns, and nearshore bathymetry. Interim protective measures can be (and have been) applied in high risk waterways, such as small, low energy waterways that have high recreational boating activity, to help reduce shoreline erosion. Policy options used in Bay states and elsewhere include setbacks from the shore, wake restrictions, and speed restrictions; other more restrictive policies may include prohibition on boats of a certain size or limiting the number of passages. Finally, a systems-approach to boat wake impact management using uniform boat wake policies is likely to be the most effective for consistent shoreline protection.
... The level of importance of vessel-generated waves for the shoreline dynamics widely varies from being a significant control [19,23,26] to no impact [27]. Ship wake energy depends on the vessel length, water depth, vessel speed, and channel shape [28,29], and could result in shoreline erosion [18,19] and sediment resuspension and transport that temporarily change the water turbidity. According to [30], even small recreational vessels within 10 m of the shoreline could produce wakes that could result in shoreline erosion. ...
... Marsh edge erosion and, thus, marsh deterioration could be a long-term consequence of large ship wakes generated in these deep channels. It is known that the amount of ship wake energy is not only a function of the size and speed of vessels, but also the frequency of vessels [30,29]. ...
Full-text available
Aerial photographs and field studies have revealed a rapid deterioration of salt marshes in Jamaica Bay, New York. Past studies have linked marsh deterioration to sediment supply, water quality, storms, and sea level rise. Yet ship wakes and their potential impacts on marsh edge erosion are not understood. Here, we study ship wake transformation in Jamaica Bay and their potential impacts on salt marsh erosion. We apply short-time, Fourier transform (spectrogram) on existing water level measurements collected during 2015 and 2016. Our analysis reveals the existence of typical wake components. Among the observed wake components is a long wave component which propagates over shallow areas where short wind waves do not reach. We further implement a phase-resolving wave model to study wake transformation in the vicinity of salt marsh islands Little Egg and Big Egg and the consequent morphological changes. The selected marshes are located near a deep shipping channel and a ferry station, making them exposed to wakes of vessels with different size and sailing speed. A series of numerical experiments show that ship wakes can result in erosion spots near the border of deep shipping channels and their banks, i.e., edges of mudflats and marsh substrates. We show that the cumulative erosion increases rapidly with the number of vessels that pass through the study area. For instance, the magnitude of final bed erosion after the passage of 10 vessels is two to three times larger than that after the passage of five vessels.
... For example, as a result of the research project at Ghent University the magnitude and nature of these interactions (Lataire et al., 2012;2011) were measured with the use of a Very Large Crude Carrier (VLCC) and a smaller tanker ship model in a towing tank. Lightering is a quasi-stationary process because of the low relative speed difference, which according to Lataire et al. (2012;2009) cannot be modelled in the same way as the process of overtaking. For this reason, modification of the mathematical model of the process for replenishment operations was performed. ...
... Therefore, measurements were carried out in the configuration shown in Figure 11(b), corresponding to the actual situation shown in Figure 12 at a distance of 30 m, where wake wave height is about 0·06 m and can be treated as negligible. Wake wave height was computed according to Equation (7) (Glamore, 2009). The Ship To Be Lightered during the test experiments was fully loaded and the Service Ship was in ballast condition. ...
Knowledge of forces and yaw moments which exist between a pair of vessels moving parallel to each other is crucial to the design of their automatic motion control system. Studies involving measurements of forces and moments occurring between a pair of ships were undertaken. The research was carried out on the basis of two real floating training ship models made at 1:24 scale in real conditions on the Silm Lake in Ilawa Kamionka. As a result, suction forces and yaw moments occurring between the pair of vessels calculated according to semi-empirical formula were verified. It was found that the process of overtaking and parallel motion (which is a quasi-stationary motion) could not be modelled in the same way. Nevertheless, the results confirmed the presence of forces and moments with values similar to those in the catch-up and parallel motion phases during the ships’ overtaking manoeuvre. Thanks to this confirmation, it was possible to use the results of the analytical calculation for the catch-up phase during design of the ships' parallel motion automatic control system.
... Introduction The impact of ship generated wake on aquatic ecosystems [17], coastal environments [20] [9][7] [26] and as a source of environmental pollution [5] [6] have been well documented. Studies that focus on the contribution of ship wake to environmental pollution and environmental damage investigate the impacts of vessel traffic on local shoreline erosion [7] [21]. ...
Conference Paper
Full-text available
The characteristics of ship wake have been well defined through studies into the contribution of ship wake to environmental pollution and environmental damage. Specific focus has been on the impacts of vessel traffic on local shoreline erosion. The value of ship wake information is not confined to the impacts on environmental pollution and damage and may potentially be utilised for other purposes such as: maritime safety; vessel monitoring; and turbidity monitoring. The identification of ship wake within water surface and velocity measurements has helped improve understanding of the characteristics of ship wake particularly within low energy environments. As international shipping movements generally occur within the more exposed open ocean shipping channels and lanes there is a need to quantify ship wake in high energy environments, this has had less attention. This paper assesses the suitability of using current methods of ship wake extraction from high frequency wave buoy data collected near high traffic shipping channels in Queensland. The long-term wave record is used to quantify the similarities and differences between ship wake and the background wave climate.
... Waves, wave-and/or wind-induced currents, and tidal currents can alter backbarrier morphology from reworking sediments (Nordstrom and Jackson, 1992), with rapid changes induced by storms (Nordstrom and Roman, 1996). Human-induced erosion can also result from boat wake waves (Glamore, 2008), particularly where commercial and recreational boat traffic is frequent and speed limits are not reduced (Bauer et al., 2002) (Castillo et al., 2000). The shoreline erosion of a backbarrier due to sea level rise and storms threaten to cause permanent erosion if the rate of supply of sediments from rivers, over-wash, and inlet processes cannot keep up with the rate of erosion (Timmons et al., 2010). ...
Open coast beach-dune environments are vulnerable to erosion, due to storms, lack of sediment, or coastal squeeze; however, they serve important societal and ecological functions. Backbarrier shorelines are also susceptible to erosion, often due to tidal currents or boat wakes. Beach erosion is often mitigated using offshore, upland, or channel sediment resources for restoration projects. However, dune restorations generally use upland mine sediments and backbarrier restorations typically use sediments dredged from channels. Offshore resources are not often considered for dune or backbarrier shoreline restoration. However, because the geotechnical properties suitable for dunes and backbarriers differ from beach quality sediment, offshore sediments may provide an alternative source for restoration of lower-energy environments without adversely impacting the available volume of sediment needed for beach nourishment. This study presents an approach to evaluate sediment borrow area for suitability in non-traditional coastal restoration projects (i.e., dune and backbarrier shorelines). Kriging interpolation provided a better estimation of volume than using a linear average method based on comparison with simulated models of known volumes and should be used when a limited number of cores are available. The volume of sediment suitable for dune or backbarrier placement based on a case study in Palm Beach County, FL was much lower than the volume of beach compatible sands, suggesting that other regions require exploration for potential use in low-energy environments.
... Previous models and tools to estimate potential erosion in waterways are rational yet empirical in nature (Glamore, 2008;Spruyt et al., 2012). The model presented here addresses this challenge with a process-based approach, requiring measured wave heights and soil characteristics. ...
Full-text available
Vessel‐induced waves affect the morphology and ecology of banks and shorelines around the world. In rivers used as waterways, ship passages contribute to the erosion of unprotected banks, but their short‐ and long‐term impacts remain unclear. This work investigates the effects of navigation on bank erosion along a reach of the regulated Meuse River with recently renaturalized banks. We apply UAV‐SfM photogrammetry, RTK‐GPS, acoustic Doppler velocimetry, aerial and terrestrial photography, soil tests, and multibeam echosounding to analyze the progression of bank retreat after riprap removal. After having analyzed the effects of ship‐generated waves and currents, floods, and vegetation dynamics, a process‐based model is proposed to estimate the long‐term bank retreat. The results show that a terrace evolves in length and depth across the bank according to local lithology, which we clustered in three types. Floods contribute to upper‐bank erosion‐inducing mass failures, while near‐bank flow appears increasingly ineffective to remove the failed material due to terrace elongation. Vegetation growth at the upper‐bank toe reduces bank failure and delays erosion, but its permanence is limited by terrace stability and efficiency to dissipate waves. The results also indicate that long‐term bank retreat is controlled by deep primary waves acting like bores over the terrace. Understanding the underlying drivers of bank evolution can support process‐based management to optimize the benefits of structural and functional diversity in navigable rivers.
... Strong interference between the transverse waves generated by the vessel can occur at critical speed (Molland et al., 2008). Sufficient time is required for the wave energy to dissipate at critical speed if the strong wave interference effect persists (Glamore, 2005). ...
Resistance analysis is an important analytical method used to evaluate the hydrodynamic performance of High Speed Craft (HSC). Analysis of multihull resistance in shallow water is essential to the performance evaluation of any type of HSC. Ships operating in shallow water experience increases in resistance because of changes in pressure distribution and wave pattern. In this paper, the shallow water performance of an HSC design concept, the semi-Small Waterplane Area Twin Hull (semi-SWATH) hull form, is studied. The hulls are installed with fin stabilizers to reduce dynamic motion effects, and the resistance components of the hull, hull trim condition, and maximum wave amplitude around the hull are determined via calm water resistance tests in shallow water. These criteria are important in analyzing semi-SWATH resistance in shallow water and its relation to flow around hull. The fore fin angle is fixed to zero degrees, while the aft fin angle is varied to 0º, 5º, 10º, and 15º. For each configuration, investigations are conducted with depth Froude numbers (FrH) ranging from 0.65 to 1.2, and the resistance tests are performed in shallow water at the towing tank of UTM. Analysis results indicate that the resistance, wave pattern, and trim of the semi-SWATH hull form are affected by the fin angle. The resistance is amplified whereas the trim and sinkage are reduced as the fin angle increases. Increases in fin angle contribute to seakeeping and stability but affect the hull resistance of HSCs.
Houser C, Smith A, Lilly J. 2021. Relative importance of recreational boat wakes on an inland lake. Lake Reserv Manage. XX:XX–XX. Wakes generated by recreational boats have the potential to erode the shoreline, damage infrastructure, or disrupt aquatic ecosystems. Therefore, boat wakes are an increasingly important focus of coastal management, particularly along vulnerable shorelines. This short communication quantifies the relative importance of recreational boat wake energy along the shoreline of an inland cottage lake in Northern Ontario, Canada. Measurements of recreational boat wakes at the end of one of the longest fetches for locally generated wind waves on the lake account for >61% of total wave energy. Based on this result, recreational wake energy likely is the primary source of wave activity along sections of the lake adjacent to the primary sailing lines but not aligned to the primary directions of wind wave energy. Recreational boat wakes may be a significant source of wave energy on other inland lakes.
In the marine environment, wake wash from passing vessels can be detrimental to shoreline environment, damage shoreline property and disturb or damage other marine operations. Slowdowns to prevent such impact can hamper or curtail high-speed vessel operations that depend on speed for successful service. To prevent this failure, low-wash vessel designs are needed and success must be assured before significant dollar investments are made. This paper describes: establishment of `no harm' wash criteria, prediction of wash using computational fluid dynamics for various speeds of high-speed aluminum catamarans, techniques of measurement and analysis of the wash from actual vessels, and agreement between wash predictions and wash measurements. This paper documents a successful program which Washington State Ferries used to procure new, high-speed environmentally friendly passenger ferries for operation on Puget Sound.
Large high-speed craft carrying passengers and vehicles produce wake waves that are different from both conventional vessels and smaller fast vessels. Wakes from these high-speed craft can cause environmental problems (such as beach change, ecological disturbance, and damage to structures and archaeological sites) and safety problems (for navigation and for users of the beach and nearshore) in confined waters. As a consequence of the higher speed, the vessel wakes also have a longer period than wakes caused by conventional ships and may lead to substantial wave action in shallow water environments. In both New Zealand and Denmark, issues relating to high-speed craft wakes were not addressed until after the vessels had begun operation, and complex coastal management issues with possibly broader application have had to be addressed. Emerging management strategies have involved regulation using speed and wave height criteria.
Field Investigation and Comparative Analysis of Boat Wash Waves WRL Technical Report Measurement and Analysis of Boat Wake Waves: Management Implications
  • W C Glamore
  • R Hudson
  • W C Glamore
  • R Hudson
  • R J Cox
Glamore, W. C. and R. Hudson (2005) Field Investigation and Comparative Analysis of Boat Wash Waves WRL Technical Report 2005/10 Glamore, W. C., Hudson, R. and R. J. Cox (2005) Measurement and Analysis of Boat Wake Waves: Management Implications. Proceeding of the 17th Australasian Coastal and Ocean Engineering Conference and the 10th Australasian Port and Harbour Conference, Adelaide, Australia September 21-24 2005, Eds. (Townsend, M. and D. Walker). ISBN 0-646-45130-30
Vessel Wash Impacts on Boat Erosion
  • G Macfarlane
  • G Cox
MacFarlane, G. & Cox, G. (2003) "Vessel Wash Impacts on Boat Erosion" AMCSearch Report No. 01/G/18.
Measurement and Analysis of Boat Wake Waves: Management Implications. Proceeding of the 17 th Australasian Coastal and Ocean Engineering Conference and the 10 th Australasian Port and Harbour Conference
  • W C Glamore
  • R Hudson
  • R J Cox
Glamore, W. C., Hudson, R. and R. J. Cox (2005) Measurement and Analysis of Boat Wake Waves: Management Implications. Proceeding of the 17 th Australasian Coastal and Ocean Engineering Conference and the 10 th Australasian Port and Harbour Conference, Adelaide, Australia September 21-24 2005, Eds. (Townsend, M. and D. Walker). ISBN 0-646-45130-30.
Field Investigation and Comparative Analysis of Boat Wash Waves WRL Technical Report
  • W C Glamore
  • R Hudson
Glamore, W. C. and R. Hudson (2005) Field Investigation and Comparative Analysis of Boat Wash Waves WRL Technical Report 2005/10
Measurement and Analysis of Boat Wake Waves: Management Implications
  • W C Glamore
  • R Hudson
  • R J Cox
  • M Townsend
  • D Walker
Glamore, W. C., Hudson, R. and R. J. Cox (2005) Measurement and Analysis of Boat Wake Waves: Management Implications. Proceeding of the 17 th Australasian Coastal and Ocean Engineering Conference and the 10 th Australasian Port and Harbour Conference, Adelaide, Australia September 21-24 2005, Eds. (Townsend, M. and D. Walker). ISBN 0-646-45130-30.