Self-reported water and drowning risk exposure at surf beaches

180 AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH 2009 vol. 33 no. 2© 2009 The Authors. Journal Compilation © 2009 Public Health Association of Australia

Self-reported water and drowning

risk exposure at surf beaches

Damian Morgan, Joan Ozanne-Smith and Tom TriggsAccident Research Centre, Monash University, Victoria

Private pool fencing is an effective

drowning countermeasure addressing

an identified risk factor (unsupervised

private pool access by young children).1,2

Additional evidence-based drowning

countermeasures, suitable for other locations

including surf beaches, require accurate

quantification of the drowning risk posed

by candidate factors. Establishing a factor’s

drowning risk contribution relies in turn on

risk exposure measures derived from accurate

denominator data.3 However, location specific

information for water exposure and behaviour

patterns is seldom available.4

In Australia, surf beach bathing accounted

for 8.8% of national drowning deaths from

1992 to 1997.5 Environmental hazards

associated with surf beach drowning are

breaker height and type, variations in water

depth and currents.6 The potential drowning

risk from these hazards is influenced by

natural processes and features including tide,

wind (strength and direction), rocks, reefs and

surface formations. Yet the operation of these

and other candidate drowning risk factors is

unclear because bather risk exposure patterns

have not been established.

Australian surf beach drowning deaths

of recreational bathers (N=129) over four

years (2001-2005) were more frequent

during summer, afternoons and on heavily

patronised beaches (published and

unpublished findings).7 Males comprised

85% of drownings. Most decedents (74%)

were swimming or wading with the remainder

using equipment to surf (16%) or snorkel/

dive (11%). Seaward moving rip currents

were implicated in 22% of cases. The two

most frequently drowned residential groups

Abstract

Objective: To document patterns of water

exposure at surf beaches by gender

and identify factors that predict bather

confidence to return to shore if caught in a

rip current.

Method: Recreational surf beach bathers

(N=406) provided self-completed data

on water exposure patterns, surf activity

behaviours and potential drowning risk and

protective factors.

Results: Relative to females, males visited

surf beaches more frequently, expected to

spend longer in the water and in deeper

water, and more often bathed after using

alcohol (p<0.05). Confidence to return

to shore if caught in a rip current was

predicted by confidence to identify a rip

current, self-rated swimming ability, gender,

times visited any beach, and age in a

standard linear regression model (adjusted

R2=0.68).

Conclusion: The study supports

explanations that high male drowning rates

result from more frequent exposure to

water than females at high situational risk

levels.

Implications: Controlled studies are

required to determine the role in drowning

of overconfidence, swimming ability,

surf experience, floatation devices and

response to sea conditions.

Key words: bathing beaches, drowning,

environmental exposure, self report.

Aust N Z J Public Health. 2009; 33:180-8

doi: 10.1111/j.1753-6405.2009.00367.x

Received: March 2008 Revision requested: July 2008 Accepted: November 2008Correspondence to: Damian Morgan, School of Business and Economics, Monash University Gippsland Campus, Northways Road, Churchill, Victoria, 3842. Fax: (03) 9902 6610; e-mail: [email protected]

were those who lived within 10 km of the

coast or international tourists.

Mindful of the high ratio of male drownings,

Morgan et al. found no statistically significant

gender differences among drowning cases on

likely surf drowning risk factors including

age, onset of a medical condition, presence

of drugs or alcohol, swimming alone and

rips.7 While the small number of females

drowned (n=18) limited the study’s statistical

power, crude water exposure offered a

logical explanation for apparent male over-

representation in surf beach drowning. The

divergent drowning risk profile of males and

females may also be influenced by person

factors (e.g. overconfidence in swimming

ability) or bathing in high risk surf locations

(e.g. deep water, high energy wave zones or

unsupervised locations). To summarise, surf

beach drowning risk is hypothesised to be a

function of exposure to water by frequency

and duration plus person and location risk

factors.

Assessing the risk contributions,

interactions and causation of these variables

for drowning requires controlled analytic

studies. An alternative more accessible

approach is to use statistical control of

self-reported data to assess co-occurring

factors based on a theory of causation.8

Ideally, samples should be collected in situ

to enhance ecological validity and measure

effects from environmental variables.

ObjectivesStudy objectives were to: 1) Measure

by self-report water exposure patterns

(frequency, duration and situation risk

Risk and prevention Article

2009 vol. 33 no. 2 AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH 181© 2009 The Authors. Journal Compilation © 2009 Public Health Association of Australia

level) and exposure to candidate drowning risk factors among

recreational bathers (by gender) at surf beaches; 2) Determine

whether identified gender differences were consistent for surf

activities (wave swimming and surfing) presenting uniform levels

of situational crude drowning risk; 3) Investigate the contribution

of situation and person variables to bather confidence to return to

shore if caught in a rip current.

MethodSampling frame

This study was part of a wider investigation of surf beach use

and drowning risk. The sampling frame comprised 20 consecutive

wave dominated beaches identified by Short,9 situated along the

south-east Australian coastline, approximately 110 km by road from

central Melbourne (2006 population, 3.7 million).10 The access, size,

environmental features, facilities, services and amenities varied

among the beaches. For example, three beaches have regular summer

lifesaving patrols, a National Park entrance charge, toilets/change

rooms, dedicated car parks and kiosk. Other beaches have no built

facilities or services, with access only by 300 m long walking tracks.

Beach length ranged from 50 to 4,000 m.

InstrumentA self-report survey instrument was piloted in two stages

for content validity and respondent comprehension. Questions

reported in this study elicited data in five categories. Scales and

nominal categories were determined in consideration of variable

characteristics, ease of response, required data and analyses.

Demographics/ personal characteristicsRespondents provided residence information (town/suburb,

postcode, country), gender, age, country of birth, language spoken

at home, main ancestry/ethnicity, occupational grouping and

highest education qualification. Categories replicated Australian

census data to assess generalisability of the sample (95%

confidence intervals) to the Victorian state population.11

Surf beach visitation patterns and water exposureBeach exposure was measured by number of visits to any

surf beach and this surf beach (collected in situ) in the previous

12 months. For the present visit, respondents provided expected

length of stay, anticipated total time in water and accompanying

persons.

Surf activitySurf activity questions were: proportion of time in water too

deep to touch bottom; preference for proximity to others in the

water; and chief water activity (standing/wading; swimming in

waves; surfing with equipment).

Swimming ability and rip current identificationBeyond standing depth at surf beaches, swimming movement

is required to maintain adequate buoyancy for breathing and

propulsion to return to shore.12,13 No validated self-report measure

of recreational swimming ability exists. In this study, respondents

rated their unaided swimming and floating ability in a flat water

pool. Confidence relating to the surf conditions at the time of

response was measured for: identifying the location of a rip

current; returning unaided to shore if caught in a rip current and

meeting or exceeding rated pool swimming ability at the outer

surf break zone. To specify confidence, respondents placed an

‘x’ on a line anchored by 0% − not at all confident and 100% −

totally confident.

Risk and protective factors or behavioursRecalling the previous most recent water entry at a surf beach

within two hours of drinking alcohol, respondents stated the

number of standard drinks consumed. The frequency of surf beach

water entries in the past year following alcohol consumption was

also obtained.

Gulliver and Begg suggest that knowledge of CPR and lifesaver

training is indicative of an overall safe attitude towards the water.14

Extending this assumption, holding a first aid qualification, being

rescued from the surf and participation in formal swimming lessons

may also promote safety consciousness among surf beach users.

Protective behaviours were measured as: first aid qualification and

knowledge of cardiopulmonary resuscitation. Respondents also

indicated whether they had been rescued from the water at a surf

beach. For formal swimming lessons, respondents provided age

begun, length of participation and award received.

Study population and sampling procedureThe study population was surf beach users participating in

recreational water activities over a 49 day high-use period from

December 2003 to February 2004. From pilot observational

surveys conducted in summer 2001/2002, the study population

was estimated at approximately 100,000 persons, on average,

bathing twice per beach visit. Based on this, a sample size of 384

was required to gain 95% confidence of survey score being within

5% of the true population score.15 As pilot sampling indicated up

to a 10% discard rate for missing data, the target sample size was

set at 440 respondents.

Data was collected over 16 sampling days by trained research

assistants with extensive surf beach experience. Environmental

conditions, presumed to influence water entry or location of

water activities, were recorded onsite including wind meter

measurement of the strongest gusts and maximum wave breaker

height. Recorded maximum daily temperature for the general

location was sourced from the Bureau of Meteorology.16

Up to 50 respondents were sought each survey day. Based on

previously observed beach user patterns and study aims, purposive

sampling approximated a representative sample of the study

population with increased precision. Procedures were: 50:50

random sampling of beaches on weekdays/weekend days; and

50:50 random sampling for patrolled/non-patrolled beaches.

Risk and prevention Self-reported drowning risk at surf beaches


On collection days, every third person found along an imaginary

transect line in the sand parallel to the water’s edge was selected.

Research participation was sought from persons 18 years and over

engaging in recreational water activities. Over the sixteen days,

455 persons were asked to participate, with 48 refusals (10.5%).

Reasons for non-participation, gender and estimated age were

noted. Respondents self-completed the survey instrument which

was then sealed for later retrieval. The total dataset for analysis

was N=406, comprising 196 males and 210 females, with one

incomplete survey discarded.

Data analysisData were analysed using the Statistical Package for Social

Science.17 All variables were grouped by gender. Case counts

and percentage are reported for categorical and ordinal measured

variables (medians reported for ordinal data). Means with standard

deviations are reported for interval data. Distance travelled to

the beach from residence was estimated from nearest associated

postcode boundary.18 Demographic results were compared to 2001

Victorian census data by manual calculation.11

Ordinal scale items were grouped for the question who came

with you to the beach today (alone versus not alone). Ordinal

scale codings were reversed for: time in water too deep to touch

bottom and water entries in last 12 months associated with alcohol

in previous two hours. Respondent confidence reported on the 71

mm line was measured in millimetres.

The Kolmogorov-Smirnov test identif ied non-normal

distributions within gender groups on all interval measures

(p<0.05). Hence, gender differences for all continuous variables

were assessed by Mann-Whitney (U) test with estimate of effect

size r calculated manually (r= -0.1 small, -0.3 medium, -0.5

large).19 Pearson chi-square determined associations between

gender and categorical variables. Association size was estimated

by Cramer’s v with interpretation from Rea and Parker (v<0.1

negligible, 0.2 weak, 0.4 moderate, 0.6 relatively strong).20 Tests

were two-tailed with alpha level of 0.05.

Comparable analyses of gender differences for study variables

in two surf activity groupings (wave swimmers and surfers) were

conducted to confirm results for the entire sample. This procedure

relied on the assumption that respondents within each activity

sub-group were exposed to homogeneous levels of situational

drowning risk; test results are reported where gender differences

were found.

The final analyses applied standard multiple linear regression

to investigate the unique contributed variance of selected person

and situation variables to the criterion variable (CV), confidence

to return to shore if caught in a rip current. Selected variables

were hypothesised to co-occur with the CV (this acting as a proxy

measure for confidence in ability to avoid surf beach drowning);

these were confidence to identify a rip current (drowning hazard

awareness factor), swimming ability (drowning protective

factor), times visit any beach (proxy for beach experience, this

being a drowning protective factor), and wave breaker height

(environmental risk factor). Potential confounding variables age,

gender and chief-in-water (surf beach) activity were included in

the model for statistical control.

ResultsTable 1 lists environmental conditions over the 16 sampling

days. No gender differences were found for day type, wind strength

on the day, wave breaker height and maximum daily temperature.

A higher proportion of males were sampled at a patrolled beach,

although this association proved weak.

Table 2 lists demographic and personal characteristics. The

majority of males (94.8%) and females (93.2%) lived in Victoria.

Similar gender patterns were found for age, country of birth,

language spoken at home, main ancestry/ethnicity and highest

educational qualif ication. Genders differed on occupation

categories. Also, males more frequently resided within 30 km

of the study beaches compared to females. The median resident

distance from the beach was 30-90 km for both genders.

Table 1: Beach location, day type, and environmental conditions by gender.

Males Females Case count % Case count % Test statistic

At patrolled beach

Yes 110 56.1 90 42.9 χ2(1, N = 406) = 7.14,a v = 0.13

No 86 43.9 120 57.1

Day type

Weekday 74 37.8 91 43.3 χ2(1, N = 406) = 1.3, v = 0.06

Weekend day 122 62.2 119 56.7

Wind strength on day (km/h)

Light 134b 68.4 145b 69.0 U = 20440, r = -0.01

Moderate 62 31.6 65 31.0

Mean SD Mean SD

Wave breaker height

Metres 1.3 0.5 1.4 0.5 U = 19990.5, r = -0.03

Maximum daily temperature Degrees Celsius 30.1 6.8 30.2 6.1 U = 19294, r = -0.05

Note: (a) significant at p<0.01. (b) Median of distribution on ordinal scale.

Morgan, Ozanne-Smith and Triggs Article



Compared to Victorian census figures, this water-exposed surf

beach population was more likely to be born in Australia, speak

English at home, have UK ancestry, hold a tertiary qualification

and be a professional or manager (results available on request).

The higher frequency of males in the trades/labour category was

consistent with state occupation proportions.

On average, males visited surf beaches more often than females

but the effect was marginally above small (Table 3). Although no

gender differences were found between expected length of beach

stay, males anticipated spending more time in the water (medium

effect). The majority of both genders visited the beach with others,

although a higher proportion of males visited the beach alone (weak

association). Surf activity behaviours differed between genders

(Table 4). Males reported on average spending a larger proportion of

time in deep water, with medium effect and were less inclined to be

close by others (moderate association). Males were more likely than

females to surf with equipment and less likely to stand or wade.

Table 5 lists results for swimming ability and confidence

measures associated with surf activity. Males on average rated

their pool swimming ability higher than females (close to medium

effect) and were more confident of meeting their rated swimming

ability for the surf conditions on the day. The pattern of higher

male confidence was repeated for identification of rip currents and

returning to shore unaided if caught in a rip current with medium

and large effect, respectively.

Table 6 shows factors and behaviours assumed related to risk

and protection. Genders were of similar proportions for holding

a first aid qualification, CPR ability, being rescued from the surf

and swimming lesson participation (including age lessons begun

and duration). Gender differences for alcohol behaviours were

significant with small effect size. Males were more likely to have

consumed alcohol two hours prior to bathing at a surf beach. This

pattern was confirmed within the previous 12 months. However,

for respondents indicating previous alcohol use within two hours of

bathing, no gender differences were found on the quantity of alcohol

consumed the last time this had occurred or the frequency of water

entries associated with alcohol use in the previous 12 months.

Wave swimmer and surfer groupsStatistical differences between male and female wave swimmers

(chief-in-water activity, Table 4) confirmed overall sample gender

differences for: male wave swimmers over-represented at patrolled

beaches (χ2(1, N = 168) = 5.65, p=0.02; v=0.18); variations in

occupational group proportions (χ2(3, N = 165) = 21.33, p<0.01;

v=0.36); consumption of alcohol two hours before a previous

swim at a surf beach (U = 2802.0, p<0.01; r=-0.20); and alcohol

Table 2: Demographics and personal characteristics by gender.

Males Females Mean SD Mean SD Test statistic

Age 32.5 11.4 32.8 10.5 U = 19797, r = -0.03

Case count % Case count %

County of birth

Australia 168 86.2 169 81.3 χ2(1, N = 403) = 1.77, v = 0.18

Other 27 13.8 39 18.8

Language spoken at home

English 191 97.4 200 96.2 χ2(1, N = 404) = 0.54, v = 0.04

Other 5 2.6 8 3.8

Main ancestry/ ethnicity

United Kingdom 93 49.2 113 55.7 χ2(3, N = 392) = 3.83, v = 0.01

Italian or Greek 20 10.6 27 13.3

Australian 22 11.6 20 9.9

Other 54 28.6 43 21.2

Occupation grouping

Trades/ labour 52 27.2 3 1.4 χ2(3, N = 400) = 65.53,b v = 0.41

Clerical/ administration 12 6.3 31 14.8

Professional/ manager 95 49.7 106 50.7

Other 32 16.8 69 33.0

Highest educational qualification

No qualification 8 4.1 3 1.4 U = 18841.5, r = -0.07

School Certificate 16 8.2 17 8.1

High School certificate 32 16.5 45 21.4

Trade/ TAFE 49c 25.3 27 12.9

Tertiary 89 45.9 118c 56.2

Residence postcode boundary distance from beach

Within 30 km 27 14.1 13 6.3 U = 17982,a r = -0.12

30 km to 90 km 147c 77.0 171c 82.2

Over 90 km 7 3.7 10 4.8

Interstate resident 8 4.2 10 4.8 International resident 2 1.0 4 1.9

Note: (a) significant at p<0.05. (b) significant at p<0.01. (c) Median of distribution on ordinal scale.


use before surf beach swimming within the previous 12 months

(U = 2543.0, p<0.01; r=-0.29). Male wave swimmers also had

higher confidence to return to shore if caught in a rip current

(U = 2371.0, p<0.01; r=-0.28).

Gender differences identified in the overall sample were

not found in the wave swimmer group for residential distance

from the beach, going to the beach alone (this chi-square result

should be interpreted with caution as the minimum expected cell

Table 3: Surf beach visitation patterns and water exposure by gender.


Times visit any beach in the last 12 months 1 5 2.6 13 6.2 U = 17438.5,a r = -0.13 2-5 43 22.1 56 26.8 6-9 33 16.9 34 16.3 10-13 11 5.6 26b 12.4 Over 13 103b 52.8 80 38.3

Times visit this beach in the last 12 months 1 64 32.8 82 39.4 U = 17135.5,a r = -0.14 2-5 53b 27.2 75b 36.1 6-9 26 13.3 19 9.1 10-13 5 2.6 9 4.3 Over 13 47 24.1 23 11.1

Accompanying persons

Alone 18 9.2 2 1.0 χ2(3, N = 406) = 14.67,a v = 0.19

Not alone 178 90.8 208 99.0

Expected stay at beach ≤ ½ hour 0 0.0 1 0.5 U = 20107, r = -0.03 >½-≤ 1 hour 9 4.7 8 3.8 >1-≤ 2 hours 53 27.5 54 25.8 >2-≤ 3 hours 74b 38.3 86b 41.1 >3-≤ 5 hours 42 21.8 52 24.9 >5-≤ 7 hours 13 6.7 8 3.8 >7 hours 2 1.0 0 0.0

Expected time in water

>½ hour 48 24.6 105b 52.0 U = 12284,a r = -0.34

>½-≤ 1 hour 53b 27.2 57 28.2

>1-≤ 2 hours 57 29.2 33 16.3

>2-≤ 3 hours 30 15.4 5 2.5

>3-≤ 5 hours 3 1.5 2 1.0

>5-≤ 7 hours 3 1.5 0 0.0 >7 hours 1 0.5 0 0.0


Table 4: Surf activity behaviours by gender.


Time in water too deep to touch bottom Never in this deep 6 3.1 46 22.1 U = 10076,a r = -0.45 Just about none of the time 21 10.7 56 26.9 Some of the time 79b 40.3 76b 36.5 Most of the time 40 20.4 26 12.5 All the time 50 25.5 4 1.9 Preference for proximity to others in water Alone and far away 7 3.6 4 1.9 χ2(3, N = 404) = 88.61,a v = 0.47 Alone and in sight 26 13.3 15 7.2 Close by others 121b 62.1 169b 80.9 no preference responses excluded No preference 41 21.0 21 10.0 U = 12836.5,a r = -0.16Chief in-water activity Stand/ wade 29 14.8 111 54.1 χ2(2, N = 401) = 93.69,a v = 0.48 Swim in waves 88 44.9 80 39.0 Surf with equipment 79 40.3 14 6.8

Note: (a) significant at p<0.01. (b) a Median of distribution on ordinal scale.




count was 3.3), time in water, time in water too deep to touch the

bottom, preference for being alone in water, swimming ability

in a flat water pool, confidence in meeting or exceeding rated

swimming ability in today’s surf conditions and confidence in

identifying rip currents. Compared to male wave swimmers,

female wave swimmers indicated more frequent visits to any beach

(U = 2825.0, p=0.04; r=-0.16) and to this beach (U = 2796.0,

p=0.02; r=-0.18), reversing the gender difference for the overall

Table 5: Swimming ability and confidence measures by gender.


Unaided swimming ability in flat water pool

Cannot float or swim 1 0.5 0 0.0 U = 15317.5,a r = -0.23

Float 1 min and swim a little distance 4 2.1 17 8.1

Float and gently swim for 15 minutes 33 16.9 62 29.5

Float and gently swim for 60 minutes 78a 40.0 82a 39.0

Float and constantly swim for more than one hour 79 40.5 49 23.3

Mean SD Mean SD

Confidence in meeting or exceeding rated flat water swimming

ability at outer surf zone (scale 0-71 mm) 46.7 20.1 30.9 20.0 U = 11745,a r = -0.37

Confidence in identifying rip current

(scale 0-71 mm) 43.4 23.1 23.0 20.3 U = 10607.5,a r = -0.42

Confidence of returning to shore unaided if caught in rip (scale 0-71 mm) 48.6 20.2 25.5 19.7 U = 8443.5,a r = -0.51


Table 6: Risk and protective factors or behaviours by gender.


Previous surf bathing episode with alcohol consumption in prior two hours

Never consumed 111b 56.9 158b 76.3 U = 15881,a r = -0.22

1 standard drink 25 12.8 19 9.2

2 standard drinks 22 11.3 18 8.7 for alcohol use only

3 standard drinks 15 7.7 5 2.4 U = 1673, r = -0.16

4 standard drinks 10 5.1 3 1.4

5 standard drinks 10 5.1 3 1.4

5 + standard drinks 2 1.0 1 0.5

Water entries in past 12 months associated with alcohol in previous two hours

Nil 123b 62.8 171b 81.8 U = 16517,a r = -0.22

Less than half 60 30.6 33 15.8

Half 5 2.6 2 1.0 for alcohol use only

More than half 3 1.5 0 0.0 U = 1326.5, r = -0.06

Every time 5 2.6 3 1.4

Current first aid qualification

Yes 66 33.8 66 31.6 χ2(1, N = 404) = 0.24, v = 0.02

No 129 66.2 143 68.4

Know how to do CPR

Yes 138 70.4 129 61.7 χ2(1, N = 405) = 3.40, v = 0.09

No 58 29.6 80 38.3

Been rescued from surf

Yes 12 6.2 11 5.2 χ2(1, N = 404) = 0.17, v = 0.02

No 182 93.8 199 94.8

Participated in formal swimming lessons

Yes 156 79.6 171 81.4 χ2(1, N = 406) = 0.22, v = 0.02

No 40 20.4 39 18.6

Mean SD Mean SD

Age began (years) 7.0 5.2 6.6 6.0 U = 11053.5, r = -0.10 Length of lessons (years) 5.7 3.6 6.5 3.9 U = 7423.5, r = -0.11

Notes: (a) significant at p<0.01. (b) Median of distribution on ordinal scale


sample. Non-significant gender differences in the overall sample

were confirmed for the wave swimmer group for remaining study

variables except that females took swimming lessons for more

years than males (U = 1214.5, p=0.03; r=-0.21). On average,

female wave swimmers began swimming lessons at an earlier age

than males but this finding was just above the significant level

(U = 1722.0, p=0.05; r=-0.17).

Statistical power was limited for gender differences for surfers

by the small number of females sampled in this activity (n=14).

Otherwise, surfers showed similar gender differences to the overall

sample. These were: variations in occupational group proportions

(χ2(5, N = 93) = 13.50, p<0.02; v=0.38); more males resided closer

to the surveyed beach (U = 372.5, p=0.04; r=-0.22); male surfers

visited any beach more frequently (U = 312.5, p<0.01; r=-0.34)

and this beach more frequently (U = 231.0, p<0.01; r=-0.37);

males spent a longer time in water (U = 273.5, p=0.01; r=-0.29);

in deeper water (U = 89.5, p<0.01; r=-0.55) and they self-rated a

higher pool swimming ability (U = 344.0, p<0.01; r=-0.25). Male

surfers also had greater confidence for meeting pool swimming

ability in surf conditions (U = 179.5, p<0.01; r=-0.42), confidence

in rip current identification (U = 105.5, p<0.01; r=-0.50) and

confidence in returning to shore unaided if caught in a rip current

(U = 150.5, p<0.01; r=-0.45).

In contrast to signif icant gender differences found in

the overall sample, no significant gender differences were

found for the surfer group for being at a patrolled beach,

travelling to the beach alone, preference for being alone in the

water, alcohol consumption two hours before a previous surf

beach swim and frequency of consumption before bathing

within the previous 12 months. Although no significant gender

differences were found for the overall sample, compared to

female surfers, male surfers were more likely to be surveyed

on week days (χ2(1, N = 93) = 5.72, p=0.02; v=0.24). Gender

similarities on remaining study variables were replicated for the

surfer subgroup.

Modelling bather confidenceStandard multiple regression met required assumptions specified

by Field19 (including inspection for outliers, influential cases,

multicollinearity and normality, homoscedasity, or linearity

of residuals) without transformations or case deletions. Table

7 reports the derived model of eight selected independent

variables (IVs) significantly predicting the criterion variable (CV)

confidence to return to shore if caught in a rip current; adjusted

R2 = 0.68; F8,386

= 104.0, p<0.01 (Table 7). All IVs, except wave

breaker height and surf activity, were significant predictors of the

CV at p<0.05.

DiscussionStudy participants approximated a representative sample

of summer surf bathers at 20 consecutive beaches located in

Victoria, Australia. Further study is required to determine whether

demographic differences between the sample and the Victorian

census apply to other surf beach populations or result from factors

unique to the study frame population (e.g. beach accessibility).

Given the former, this finding reveals that drowning rates among

demographic sub groupings (e.g. ethnicity or educational level)

will have increased accuracy where risk exposure measures are

limited to beach patrons.

The study findings revealed males were over-represented

at patrolled surf beaches, more likely to be in a trade/labour

occupation grouping and on average resided closer to the beach.

No gender differences were found on beach conditions experienced

or other measured demographic or person variables (Tables 1 and

2). However, the study identified clear differences in exposure

patterns between genders. Males visited surf beaches more often,

were more frequently alone and on average expected to spend

longer in the water. Males also reported longer exposure to deeper

water and being more likely to be far from others in the water.

Overall, males self-rated superior pool swimming competence

compared to females. Both males and females are known to hold

Table 7: Standard multiple regression of selected person and situation variables on confidence to return to shore if caught in a rip current.a

B SE B β t Partial correlation

Constant 8.48 5.67

Confidence to identify a rip current 0.43 0.04 0.45*** 11.53 0.51

Swimming abilityb 7.29 0.85 0.28*** 8.54 0.40

Times visit any beach 1.55 0.54 0.09** 2.87 0.15

Wave breaker height 0.29 1.35 0.01 0.22 0.11

Gender -9.18 1.55 -0.20*** -5.92 -0.29

Age -0.16 0.06 -0.08* -2.59 -0.13

Activity

Surfersc − − − − −

Waders -4.32 2.23 -0.09 -1.93 -0.10 Swimmers -1.05 1.89 -0.02 -0.56 -0.03Note:R2 = 0.68 (enter method). * Significant at p<0.05; ** Significant at p<0.01; *** Significant at p<0.001.(a) Criterion variable confidence to return to shore if caught in a rip current.(b) Unaided swimming ability in flat water pool.(c) Reference group.



accurate perceptions of their fitness when measured on skill

performance in recreational activities such as running and gym

work.21 However, drivers are known to overestimate their skill

level and more generally, unrecognised skill incompetence leads

to inflated self-assessments.22,23 Clearly, the perceptual measure of

recreational swimming competence used here requires validation.

Even if males have superior actual swimming competence, this

skill may increase drowning risk exposure by providing confidence

to negotiate deeper water or more challenging conditions.13 Males

were found to be more confident than females on their ability

to identify rip currents, meet stated swimming ability in the

prevailing surf conditions and return to shore if caught in a rip

current. These self-reported gender differences may result from

male overconfidence leading to an underestimation of drowning

risk.24 The role of confidence in surf beach exposure requires

further study.

While males may be overconfident of their ability to avoid

drowning, this study found no difference between genders for

factors assumed to indicate a safety attitude. In contrast, 37.2%

of males had consumed alcohol in a two-hour period before surf

beach swimming in the last 12 months compared to 18.2% of

females. This difference is important as alcohol is considered a risk

factor for drowning due to physiological effects and impairment

of judgement.25 More than 1 in 10 males reported bathing with

sufficient alcohol consumption (over three standards drinks in

two hours) to exceed Victoria’s legal driving limit (blood alcohol

concentration 0.05g/100 mL).

Wave swimmers and surfersMore females (54.1% compared to male 14.8%) engaged in

standing and wading activities. Intuitively, the drowning risk

posed by shallow water activities is relatively low, suggesting

males have larger proportional exposure to high level situational

drowning risk. Yet male (n=88) and female (n=80) wave swimmers

were randomly sampled in close to equal proportions. Drowning

statistics indicate that among wave swimmers, males drown

at a considerably higher rate than females.7 Hence, assuming

the sample gender proportions represent the wave swimmer

population, factors other than crude exposure may influence the

differences in gender drowning rates of this group.

Compared to females, male wave swimmers visited the beach

less frequently, more often consumed alcohol before swimming

and held higher confidence to return to shore if caught in a rip

current. A speculative explanation for the higher male drowning

rate in this activity is that female wave swimmers have greater

surf experience providing better calibration of their skill level in

the prevailing conditions. This explanation requires further study

of perceptions and surf experience to determine its validity.

Surfers comprise approximately one-eighth of recreational surf

beach drownings.7 In this study, the surfing group (79 males and

14 females) demonstrated similar gender differences to the overall

sample, suggesting comparative gender drowning rates for surfers

result principally from differences in crude exposure. Further study

is required to determine whether the use of floatation devices or

more extensive surf experience offer surfers drowning protection

in comparison to other bathers.

Factors associated with bather confidence to return to shore

Factors that predict the CV confidence to return to shore if

caught in a rip current were modelled to assess unique variance

contributions. Presumably, increasing wave breaker height would

reduce bather confidence. But theorising from the model results,

confidence to identify a rip current, perceived swimming ability

and beach experience mediate any reduction in confidence to return

to shore caused by increased wave breaker size.

At increasing wave heights, rip currents become faster and

run farther from shore, while increasing wave energy can cause

bathers to loose balance, be held underwater, or be dumped onto

sand.9 In this study, wave breaker height varied from 0.5 to 2.0

metres. Given that Short9 reports about a 40-fold increase in

wave energy over this range, increasing wave height should be

expected to affect bather confidence more than was found. The

association of surf drowning with rip currents may therefore result

from overconfidence in swimming ability and/or limited surf

experience in testing wave conditions. Further study is required

to test this hypothesis, perhaps using rescued persons as proxies

for surf drowning.

Study limitationsThe study results may be biased by 48 refusals to participate.

Most common reasons for refusal were watching children and

keen to enter the water. This group comprised 23 males and

25 females, with an estimated average age 40.1 and 38.2 years

respectively. As refusals were older on average relative to the

sample, interactions between age and gender may not have been

captured fully in the results. Another potential bias relates to over

sampling.26 Given that persons visiting a beach more often had a

greater chance of being sampled, their exposure patterns may be

over-represented and so distort the results. Any introduced bias

requires assessment by comparison to observational data of water

users or representative community samples that replicate exposure

measures used in this study.

The generalisability of the sample to other surf beach populations

was limited by the number of beaches in the sampling frame (20);

this being just 3.4% of Victoria’s 588 identified wave dominated

beaches.9 Data collection was limited to summer months and may

not be representative for other seasons. The implications of the

results should also be considered in light of the small sample size

for some sub-groupings (e.g. female surfers), potential interaction

between study variables not controlled for in the data analysis (e.g.

wind strength and wave size), questionable accuracy of recall on

some variables (e.g. childhood swimming lessons) and sampling

procedure surveying only those bathers sitting on the beach close

by the water.

Risk and prevention Self-reported water drowning at surf beaches


ImplicationsStrategies to reduce surf beach drowning in Australia include

the provision of supervised swimming locations, surf education,

targeted safety campaigns and swimming training. While these

strategies are suitable for both male and female surf beach users,

the study findings suggest specific measures targeting males

should highlight the presumed increased drowning risk resulting

from overconfidence in surf ability, swimming alone and the use

of alcohol around water. General measures should instil in beach

users recognition that drowning risk increases with wave height,

regardless of a bather’s perceived ability. Further controlled studies

on the role of these factors in surf beach drowning are required

to assess the actual risk posed and to identify susceptible beach

users.

AcknowledgmentsEthical approval granted by Monash University Standing

Committee on Ethics in Research Involving Humans, project

no. 2001/431. National park access provided by the Department

of Sustainability and Environment Research Permit 10002639.

Funded by the first author’s PhD candidature with the Monash

University Accident Research Centre. The authors acknowledge

with thanks Jude Charlton for helpful advice and the journal

reviewers for suggestions used to improve the manuscript.

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Self-reported water and drowning risk exposure at surf beaches