ORI GIN AL PA PER

Behavior of crossing flood on foot, associated risk factorsand estimating a predictive model

Hamidreza Shabanikiya • Hesam Seyedin • Hamid Haghani •

Abbasali Ebrahimian

Received: 14 August 2013 / Accepted: 1 March 2014� Springer Science+Business Media Dordrecht 2014

Abstract Crossing the flood on foot is one of the two major causes of flood-related death.

This study was aimed to determine risk factors associated with risky behavior of crossing

the flood on foot and modeling behavior of people when exposed to the flood. Data were

gathered by a questionnaire in Quchan, a city of Iran. People with the age of 18–35 years

old, those who do not take flood warnings seriously, individuals who do not have expe-

rience of exposure to flood and those who believe they have moderate to advanced level of

swimming skills were identified as high risk groups. Appropriate group training programs

can be set for them to reduce risky behavior of crossing the flood on foot.

Keywords Crossing on foot � Risk behavior � Flood � Iran

1 Introduction

Flood is the most common type of natural hazards and causes many disaster-related

casualties (Ciottone et al. 2006; Clements 2009). Iran is located in flood-prone areas, and in

recent decades, it has brought over four million homeless, eight thousand casualties and

many injured (EM-DAT). Moreover, frequency of flood occurrence is increasing, both in

the world and in Iran (Ardalan et al. 2009). The primary cause of flood-related morbidity

H. Shabanikiya � A. EbrahimianHealth in Emergencies and Disasters, School of Health Management and Information Sciences,Iran University of Medical Sciences, Tehran, Iran

H. Seyedin (&)Health Management and Economics Research Center, School of Health Management and InformationSciences, Iran University of Medical Sciences, Tehran, Irane-mail: h.seyedin@iums.ac.ir

H. HaghaniStatistics Department, School of Health Management and Information Sciences, Iran Universityof Medical Sciences, Tehran, Iran

123

Nat HazardsDOI 10.1007/s11069-014-1124-5

and mortality is drowning (Ciottone et al. 2006). Result of a study indicates that 93 %

flood-related death is due to drowning, of this percentage, 43 % is related to those who are

drowned in vehicles and 43 % are swept into the water while trying to cross the water on

foot (Coates 1999). Jonkman and Kelman (2005) reported that 70 % of flood deaths are

due to drowning, 33 % due to drowning in vehicles and 25 % due to drowning as a

pedestrian, This means that the main causes deaths are preventable two high risky

behaviors (driving into flood and crossing the flood water on foot). By examining and

analysis of these behaviors among populations located in the flood-prone areas, reaction of

people during flooding can be predicted. As a result, high risk groups can be identified and

proper educational material can be provided for the identified high risk groups in order to

reduce the incidence of these behaviors. The majority of studies that are conducted on

flood, as natural disaster, are about the rate and cause of mortalities due to flood (Fitz-

Gerald et al. 2010; Fillmore et al. 2011; Kellar and Schmidlin 2012) and diseases and

morbidities related to flood (Janerich et al. 1981; Tapsell and Tunstall 2008). Also, there

are some researches in the field of evaluation of preparedness for natural disasters, such as

earthquake and flood and assessment of behaviors and reactions of individuals against a

variety of these natural disasters (Tapsell et al. 2002; Kreibich et al. 2005; Coulston and

Deeny 2010; Molinari and Handmer 2011; Seyedin et al. 2011; Schad et al. 2012). Fur-

thermore, some studies have been carried out on flood risk assessment, the perceived risk

of flooding and the role of communication in this regard. In a study conducted by Sorensen

(Sorensen 2000), social factors were considered as potential risk factors influence the

behavior of people in disasters.

Few studies have been conducted on one of the two dangerous behaviors during a flood

i.e., driving into flood. Drobot et al. (2007) examined the association of some risk factors

and dangerous behavior of driving in flood. However, the researchers did not find any study

on dangerous behavior of crossing the flood on foot. This study is aimed to determine risk

factors associated with dangerous behavior of crossing the flood on foot and use of these

risk factors for modeling to predict the behavior of people when exposed to the flood.

2 Method

This study was performed in Quchan, which is located in northeastern of Iran, as one of the

areas prone to flooding (2012). A researcher-made questionnaire was used to collect the

data. The validity of the questionnaire was tested by experts in an expert panel.

A pilot study was performed to test the reliability of the questionnaire. The reliability of

questionnaire was proved by test–retest.

The questionnaire was arranged in two parts. The first part of the questionnaire was

devoted to assessing the dependent variable of study, i.e., risky behavior of crossing the

flood on foot. In this section, we want to determine whether the respondents say at the flood

situation will pass it on foot or not, they were given the following scenario:

Imagine you’re going to pass a constant flow of water, such as rivers or temporary

streams such as streams of water flowing in the streets, roads, valleys, and plains

after a heavy rainfall. What do you do in this situation?

Then they were asked to respond to six multiple-choice questions with a Likert scale

from ‘‘strongly agree’’ to ‘‘strongly disagree.’’ Internal reliability of these six questions was

measured by Cronbach’s alpha test, and with regard to alpha value obtained that was

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greater than 7, internal validity of this part of questionnaire was proved. The first and last

questions of this section are listed below:

Question 1: I will cross the stream if its height is 25 cm (Approximately four fingers

above the ankle of an adult person with average height)

Question 2: Regardless of the height of the water, if others begin to cross the stream,

I will pass it, too.

Four central questions in this section were also quite similar to the first one, except that

the level of hypothetical stream water in each question was more than the previous one.

Given that the flow of water to a height of approximately 25 cm can cause a person to fall

down and sweep (Clements 2009), respondents who didn’t answer ‘‘agree’’ or ‘‘strongly

agree’’ to any of questions, considered as code 0 and others as code 1. Logistic regression

was used for statistical analysis in this study, and therefore, variables were coded in such

way (nominal dichotomous).

The second part of the questionnaire consisted of 10 questions to assess 10 independent

variables of study, i.e., the potential risk factors could be associated with risky behavior of

crossing the flood on foot. The independent variables included: age, gender, marital status,

level of education, attitude toward flood warning, experience expose to flood, experience

loss due to flood, perceived of flood threat, attitude toward level of swimming skills,

knowledge about consequences of flood. Since the optimal state to do logistic regression

can be achieved when the independent variables are nominal dichotomous, like dependent

variable, although different scales such as ordinal, nominal and interval were used to

measure independent variables, but these variables were considered as nominal dichoto-

mous and were coded as 0 and 1, then data entered into logistic regression model and, of

course, after applying Chi-square test.

As there is no specific formula to calculate the sample size for logistic regression

analysis, it is recommended that 15–20 samples per an independent variable should be

considered (Norman and Streiner 2000). According to the nine independent variables, and

with considering 10 % loss of the samples, the sample size was calculated as below:

15 � 10 ¼ 150; 150þ 15 ¼ 165

Target population in this study was residents over 18 years old of Quchan city that was

equivalent to over 18-years-old urban population auspices of the health network of Quchan

district. Noted population was 102,150 (2012).Of these, 165 persons were selected by

multi-stage sampling method. Seven Urban Health Centres (UHC) in Health Network of

Quchan district were considered as seven clusters. Considering the sample size and the

population coverage of each cluster, random sampling based on the last two digits of the

household health record number was performed. The inclusion criterion was the age of at

least 18 years old.

Data collection period was from April 24, 2013, to May 23, 2013. Researcher gathered

data by going directly to the homes of sample group; their addresses were obtained from

their health records of household. Researcher delivered the questionnaires and asked them

to return it, after completing.

As in this study, the dependent variable and the independent variables, both were

nominal dichotomous, at first, 2 9 2 cross tables were used to determine potential risk

factors associated with risky behavior of crossing the flood on foot. Then, significant

correlation between independent variables (potential risk factors) and the dependent var-

iable was examined by Pearson Chi-square test. Significance level of the test was con-

sidered B0.05 (P value B 0.05). Those independent variables that had a significant

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correlation with dependent variable were entered into logistic regression analysis for

estimating predicting model of risky behavior of crossing the flood on foot.

3 Results

Totally, 159 subjects completed the questionnaire (response rate was around 96 %). The

relationships between possible individual risk factors and risky behavior of crossing the

flood on foot are described according to the results of 2 9 2 cross tables and results of

Pearson Chi-square test. Results of Pearson Chi-square test are reported in Table 1.

According to the results of 2 9 2 cross tables, 80 % of the age group 18–35 years were

positive to the question of whether or not they will pass through the flood on foot, while

only 60 % of age group 35? years had a positive response to the same question. As

Table 1 shows, the difference is statistically significant.

The percentage of positive responses to the question of passing through the flood on foot

was equal between men and women, respectively, 25 and 28 %. This minor difference was

not statistically significant (see Table 1).

The percentage of married respondents who say they would cross the flood on foot was

87 % married versus 70 % single, and the difference was almost significant (P = 0.053).

Sixty-seven percent of participants with a college degree say that they would pass

through the flood on foot, while the percentage of people with a lower education level that

stated would pass through the flood was 78. As shown in Table 1, the relationship between

level of education and risky behavior was not significant.

The percentage of people who took flood warning seriously, i.e., the ones state they

would leave immediately by alerts of receiving floods and cross the flood on foot, was 62

vs. to 87 % i.e., those who didn’t take flood warning seriously and say they would cross the

flood on foot. This difference was statistically significant (P = 0.001).

Eighty-one percent of respondents who did not have any experience of exposure to flood

say they would cross the flood on foot, which was higher than 61 % of those who say they

have had experience of exposure to flood and would pass through the flood on foot. This

difference was statistically significant (P = 0.022).

Percentage of respondents who had experience of loss due to flood and say they would

cross the flood on foot was close to percentage those respondents who had not experience

of loss due to flood and say they would cross the flood on foot (respectively, 79 and 72 %).

Certainly, the result of Chi-square test to examine the relationship between experience

losses due to floods and crossing the flood on foot was not significant.

The results showed percent of who had a proper perception of flood threat and say they

would cross the flood on foot was approximately equal to those who didn’t have a proper

perception of flood threat and say they would cross the flood on (75 vs. 72 %).

Seventy-eight percent of people with the right knowledge about immediate health

consequences of floods say they would cross the flood on foot, while the proportion of

people without right knowledge about immediate consequences of flooding on health that

state they would pass through the flood was 70 %. This difference was not statistically

significant.

In this study, 86 % of respondents who said their skill level in swimming were above

average, say they would cross the flood on foot, while only 66 % of those who stated their

swimming skills were in a elementary level or cannot swim, say they would pass through

the flood on foot and this difference was significant (P = 0.006).

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As mentioned in the method, the independent variables that had a significant rela-

tionship with the dependent variable were entered into the logistic regression model as

probable predictors. These were four variables: age, attitude toward flood warning,

experience of exposure to flood and attitude toward level of swimming skills. The esti-

mated coefficients of the variables in the logistic regression model are presented in

Table 2. Hazmer and Lemeshow test indicated the values predicted by the model fitted to

the observed values (P = 0.0079).

According to the estimated odds ratios that are shown in the Table 2, the probability that

a person 18–35 years will cross the flood on foot (respond positively to question of sce-

nario of crossing the flood on foot) is 2.2 times than those over 35 years. The findings of

this table show that people who do not take seriously the warnings of flooding, two times

more likely than others to say they would cross the flood on foot. The odds ratio for the

variable of experience of exposure to flood is 1.948, i.e., the probability that people who

have experience of exposure to flood cross the flood on foot is almost half of those without

experience of exposure to flood. In the case of attitude toward level of swimming skills,

people who think they are in moderate to advanced level of swimming skills 2.3 times are

more likely to cross the flood on foot than those who think they are in a elementary level of

swimming skills or do not know swimming.

4 Discussion and conclusion

As expected, the percentage of the younger age group who say they would pass through the

flood on foot was more than the older age group. More experience and less level of

acceptable risk in elderly than youth could be the reason. Findings of a study conducted by

Ashley and Ashley (2008) were consistent with the findings of this study, as the death toll

from floods in the age group of 10–29 years were higher than in the older age groups.

Although it was expected the percentage of women who say they would cross the flood

on foot to be more than men, however, findings were contrary to expectations, as among

women are slightly higher. The results of a study conducted by Booth and Nolen (2012)

showed gender differences between boys and girls at the level of accepting risk at

uncertainty are not result of inherent differences between the sexes, but it can be a

reflection of social learning.

Table 1 Results of Pearson Chi-square test

Possible risk factor P value Chi square

Age 0.009 6.741

Gender 0.544 0.368

Marital status 0.053 3.743

Level of education 0.123 2.373

Attitude toward flood warning 0.001 10.417

Experience expose to flood 0.022 5.261

Experience loss due to flood 0.325 0.969

Perceived of flood threat 0.734 0.116

Attitude toward level of swimming skills 0.006 7.697

Knowledge about consequences of flood 0.231 1.435

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It was expected married people to have lower level of accepting risk rather than single,

but percentage of married respondents who say they would cross the flood on foot was

larger than that of singles, and the difference was almost significant (P = 0.053). The

relationship between marital status and risky behavior of crossing the flood seemed to be

under the influence of other factors such as age or sex. Study of Molloy et al. (2009)

supports the finding. They indicated that after adjustment for age, sex and socioeconomic

status, the rate of death from cardiovascular disease (in fact, rate of high risk behaviors

leading to death from cardiovascular disease) was higher in single than in married, but

other studies show different results (Johnson et al. 2000; Ikeda et al. 2007). Generally, it

can be claimed that it depends on location and time.

The result of this study about relationship between level of education and risky behavior

is not consistent with the results of Geckova et al. (2002) Their finding shows a strong

correlation between level of education, as one of the three socioeconomic indicators and

some health risk behaviors such as smoking and alcohol consumption. However, the results

of that study indicated those with lower level of education are more likely to have risky

behaviors, which support our results.

As expected, the percentage of people who took flood warning seriously and cross the

flood on foot was lower than that of who didn’t take flood warning seriously and say they

would cross the flood on foot. As mentioned in the results, this difference was statistically

significant (P = 0.001) and was consistent with the findings of a research which investi-

gated the factors affecting driving behavior in floods. There was also a relationship

between flood warning attitude and behavior of driving into the flood (Drobot et al. 2007).

Lack of sufficient awareness and sensitivity toward the flood warning or warning of nat-

ural/manmade disasters can cause ignoring the warnings by some people.

The reason why people without any previous experience to deal with floods pass the

floods can be related to the fact that previous experience in exposure to a specific situation

or phenomenon result in more informed and more accurate decision making as this fact

proved in the study of Grothmann and Reussewing (2006).

In our study, there is no significant relationship between experience losses due to floods

and crossing the flood on foot that is consistent with the results of a research which

conducted by Drobot et al. (2007) they also could not prove any relationship between

experience loss due to flood and behavior of driving into the flood.

As the results showed percent of those who had a correct perception of flood threat and

say they would cross the flood on foot was approximately equal to percent of those who did

not have a correct perception of flood threat and say they would cross the flood (75 vs.

72 %). This was conflicting with our expectations. The relationship between these two

variables could be more depend on the time and place. Results of a study conducted by

Solis et al. (2009) support this reason.

The relationship between knowledge about consequences of flood and decision making

about crossing the flood on foot was not significant. It seems having knowledge about the

Table 2 Results of logistic regression

Variable b SE Wald Sig Odds ratio

Age 0.794 0.407 3.793 0.051 2.211

Attitude toward flood warning 1.008 0.457 4.864 0.027 2.740

Experience expose to flood 0.667 0.392 2.895 0.089 1.948

Attitude toward level of swimming skills 0.835 0.432 3.732 0.053 2.306

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dangers of a particular phenomenon result in correct decisions, but when people want to

decide to do something (in our study, passing the flood or not), at first they analyze the

risks of that action. Slovic (2001) in his study concluded that risk is more than just knowing

the consequences and probability of consequences of an action. Considering such a defi-

nition of risk can help explain our result (in this case).

We use the level of swimming skills to determine whether respondents have ‘‘per-

ception of self-protection’’ or not. ‘‘The perception of self-protection’’ means an individual

believe he/she has the ability to save his/her health in a threatening situation. It is expected

if people face with a threatening situation have related ‘‘the perception of self-protection,’’

are more tend to deal with it than others. As it was expected proportion of respondents who

had ‘‘perception of self-protection’’ in floods (those who stated their skill level in swim-

ming is above average) and say they would cross the flood on foot was significantly more

than those who had not ‘‘perception of self-protection’’ in floods (those who stated their

swimming skills is in elementary level or cannot swim).

According to the results of logistic regression, four variables (age, attitude toward flood

warning, experience of exposure to flood and attitude toward level of swimming skills)

were determined as the four main predictors of risky behavior of crossing the flood on foot.

People with the age 18–35-years-old, those do not take flood warnings seriously, indi-

viduals who do not have experience of exposure to flood and those who believe they have

moderate to advanced level of swimming skills were identified as high risk groups in this

field, Accordingly, appropriate group training programs can be set for them to reduce

dangerous behavior of crossing the flood. Programs can be arranged to increase public

awareness on the importance and seriousness of flood warnings. It is suggested that

researches should be conducted to find solutions for the question of why some people do

not take the flood warnings seriously or to answer the question of why some people

crossing the flood on foot, despite the danger which threatens the people.

In addition, notification messages can be delivered to the public that swimming ability,

at any level, cannot help a person survive when he/she is being caught in the flood.

Based on our knowledge, we did not have any confounder for this research. The only

limitation for this research was that we had difficulty in separating those participants who

experienced the flood with those who did not have any experience.

Acknowledgments This research has been supported by School of Health Management and InformationSciences, Iran University of Medical Sciences.

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