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Flood vulnerability assessment of donstream area in Mono basin in Yoto district, south-eastern Togo


par Abravi Essenam KISSI
University of Lome - Master 2014
  

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2.3.2 Indicators for Measuring Vulnerability

Indicators are widely recognized as useful measurement tools in distinct fields of research (Damm 2010, p 42) but researchers disagree on their definitions. According to Gallopin (1997, p 14) indicator is defined as a sigh that summarizes information relevant to a particular phenomenon. Some authors (Adriaanse, 1995) define indicators in relation to an aggregation process starting with variables or basic data, followed by processed information and indicators, finally ending up with highly aggregated indices. While others view them as a single variable or an output value from a set of data that describes a system or process. According to Birkman ( 2013, p 88), defining indicator in terms of the level of aggregation neglects an essential aspect: goals. For this researcher, every indicator-development process needs to be related to goals, or at least to a vision which serves as a basis for defining the state or characteristic of interest.

The Hyogo Framework for Action (HFA) 2005-2015 stresses the need to develop systems of indicators of disaster risk and vulnerability at national and sub-national levels that will enable decision-makers to assess the impact of disasters (UN/ISDR 2005). An indicator, or set of indicators, can be defined as an inherent characteristic that quantitatively estimates the condition of a system (Balica et al. 2012). «Indicators necessarily limit themselves to the sphere of the measurable» (Moldan and Dahl 2007: 9). A vulnerability indicator can be defined as a variable which is an operational representation of a characteristic or quality of an object or subject able to provide information regarding the susceptibility, coping and adaptive capacity and resilience of a system (Birkman, 2013, p 87).

Vulnerability indicators are widely used in vulnerability assessment. The first step in an indicator-based vulnerability assessment is the selection of the study area; second, one has to select indicators based on criteria, such as the availability of data, personal judgement or previous research. The procedures for indicator selection follow two general approaches. These are deductive and inductive approaches (Adger et al.,2004). In deductive approach, indicators are selected based on relationships established from theories and conceptual frameworks, whilst inductive approach involves statistical procedures to relate a large number of variables to vulnerability in order to identify the factors that are statistically significant. While a range of widely-accepted relevant characteristics and indicators is being presented in literature, (Adriaanse, 1995; World Bank, 2005.), the actual conditions that determine flood vulnerability are, to a certain degree, very site-specific, location, and hazard-dependent (Muller et al, 2011, p 2113). It can be expressed in terms of functional relationships between expected damages regarding all systems and exposure, susceptibility and resilience characteristics of the affected system, referring to all the different types of possible flood hazards (Balica, 2007).

A total of 30 indicators have been identified under the three factors of vulnerability through various literature. Exposure and susceptibility both have a positive influence on vulnerability, and resilience has a negative influence on vulnerability "Table 1"

Table 1: Flood indicators information

 

No

Defined indicator

Factors

Unit

Functional relationship with vulnerability (+ or -)

References

1

Flood frequency

Exposure

year

Higher is the number of flood events, higher is the vulnerability (+)

Balica (2007)

2

Flood duration

Exposure

days

The higher the flood duration, the higher the vulnerability (+)

Balica (2007)

4

Flood water depth

Exposure

m

The higher the flood water level, the higher the vulnerability (+)

Balica (2007)

5

Proximity of the village to the water body

Exposure

m

The Closer is the place to the river, the higher is the vulnerability (+)

Balica (2007)

7

population in the flood area

Exposure

#

The higher the number of population, the higher the vulnerability (+)

Balica (2012); Fekete (2009);

8

Heavy rainfall

Exposure

mm

The higher the value of the variance, the higher the vulnerability (+)

Balica (2012)

9

Maximum discharge in the past ten years

Exposure

m3/s

The higher the discharge, the higher the vulnerability (+)

Balica (2012);

10

Land use: Farmland

Exposure

%

The higher the %, the higher the vulnerability (+)

Balica (2012); Fekete (2010); Bowen and Riley (2003)

11

Gender

Susceptibility

%

The higher the % of women, the higher the vulnerability (+)

Wisner et al. (2004); Haki et al. (2004); Cutter et al. (2003); Muller et al. (2011)

12

Elderly

Susceptibility

%

The higher the % of elderly, the higher the vulnerability (+)

Clark et al. (1998); Muller et al (2011); Steinführer and Kuhlicke (2007); Thieken et al. (2007); Birkmann et al. (2008)

13

Children under 15

Susceptibility

%

The higher the % of children, the higher the vulnerability (+)

Schneiderbauer (2007); Cutter et al. (2003); Muller et al. (2011); Birkmann et al. (2008)

14

Agriculture workers

Susceptibility

%

The higher the % of household having agriculture activity the higher the vulnerability (+)

Fekete (2010)

15

Female headed household

Susceptibility

%

The higher the %, the higher the vulnerability (+)

McLanahan (1983); Snyder et al. (2006);

16

Literacy Level

Susceptibility

%

The higher the %, the higher the vulnerability (+)

Fekete (2010); Schneiderbauer (2007); Haki et al. (2004); Steinführer and Kuhlicke 2007

17

Household size

Susceptibility

%

The higher the %, the higher the vulnerability (+)

Haki et al. (2004); Cutter et al. (2003); Muller et al. (2011); Martens and Ramm (2007)

18

Number of houses with poor material (wall, roof, floor)

Susceptibility

#

The higher the number of houses with poor material, the higher is the vulnerability (+)

Schneiderbauer (2007); Clark et al. (1998);

Cutter et al. (2003); Muller et al (2011)

19

Past experience

Susceptibility

%

The lower the %, the higher the vulnerability (+)

Balica (2007); Birkmann (2005a); Velasquez and Tanhueco (2005); Wisner et al (2004); Muller (2011)

20

Preparedness

Susceptibility

%

The lower the % of people with flood experience, the higher the vulnerability (+)

Balica (2012); Birkmann (2005a); Velasquez and Tanhueco (2005); Wisner et al. (2004); Cardona (2003); Muller (2011)

21

Awareness

Susceptibility

%

The lower the % of people, the higher the vulnerability (+)

Balica (2007)

22

Emergency services

Resilience

%

The higher the % of people reported to get help from government or institution during and after flood, the lower the vulnerability (-)

Balica (2007)

23

Ability to evacuate

Resilience

%

The higher the %, the lower the vulnerability (-)

Cardona (2003); Muller (2011); Balica (2012); Birkman et al (2013)

24

Knowledge about private protection measures

Resilience

%

The higher the %, the lower the vulnerability (-)

Muller et al (2011)

25

Knowledge about flood hazard

Resilience

%

The higher the percentage, the lower the vulnerability (-)

Cardona (2003); Muller (2011)

26

Warning system

Resilience

%

The existence of warning system lowers the vulnerability (-)

Balica (2007); Balica(2012); Veenstra (2013)

27

Recovery Time to flood

Resilience

%

The faster the recovery time, the lower the vulnerability (-)

Balica (2012)

28

Emergency service

Resilience

%

The higher the %, the Lower the vulnerability (-)

Balica (2012); Aall and Norland (2005); Veenstra (2013)

29

Long term residents

Resilience

%

The higher the %, the lower the vulnerability (-)

Fekete (2010)

30

Environmental recovery

Resilience

%

The higher the %, the lower the vulnerability (-)

Balica (2007)

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