11
Tecnología y Ciencias del Agua
, vol. VIII, núm. 2, marzo-abril de 2017, pp. 5-18
Lee
et al
.,
Relationships between floods and social fragmentation: A case study of Chiayi, Taiwan
ISSN 2007-2422
•
are transformed from long-term statistics to a
stationary description of local characteristic.
Thus, this study will not attempt to analyze
the longitudinal statistical data year by year.
Restated, the longitudinal statistical data are
used for realizing the types of social fragmenta-
tion of social system, and the flood map data
are used for mapping the spatial distribution
of the natural hazards. By so doing, this study
can examine different disaster exposure risks,
trends in responsive capacities, and differences
among townships.
Analysis Method
The analytical procedure comprises two steps.
The first step is to analyze social fragmentation
during 1983-2011. Meanwhile, the second step is
to overlay the flood map on top of that of social
fragmentation trends in Chiayi County by GIS.
To obtain meaningful comparisons among
the three variables and integrate them into a
social fragmentation index, this study subjects
the variable to a standardization procedure
whereby social fragmentation increases with
decreasing social increase and marriage rate,
and decreases with decreasing divorce rate.
Therefore, before summing the standardized
scores, this study reverses the direction of the
standardized scores of divorce rate. Next, this
study sums the standardized scores of variables
and calculates the annual averages for each
variable as an annual social fragmentation
index. The longitudinal data is from 1983-2011.
To clearly interpret the characteristics of social
fragmentation, this study divides the 18-year
period into six sub-periods, namely 1983-1985,
1986-1990, 19991-1995, 1996-2000, 2001-2005
and 2006-2011. This study sums the standard-
ized scores and then averages them for each
time period. Thus, due to the standardization
procedure, the different longitudinal data could
be utilized to explain the trend of social frag-
mentation in different periods. Furthermore,
this study overlays the spatial distribution of
flood maps and the six time period map of social
fragmentation.
Results
According to the range of standardized sco-
res of the rate of social increase from 1983 to
2011, Fanlu is the township with the highest
in-migration, while Dongshi and Xikou are the
townships with the highest out-migration. The
townships that changed from out-migration to
in-migration are Dalin, Lucao, Xinkang, Yizhu
and Liujiao. Moreover, Zhuqi, Taibao and
Minxiong show decreased in-migration. Finally,
Puzi, Meishan, Zhongpu and Shuishang chan-
ged from in-migration to out-migration (tables
2 and 3).
Tables 4 and 5 list the standardized scores
of crude divorce rate, which are original and
not subject to reverse adjustment. The differ-
ent range of standardized scores of divorce
rate from 2000 to 2011 shows that townships
with increased divorce rates are, ranked from
low to high, Xikou, Dongshi, Yizhu, Xinkang,
Zhongpu, Zhuqi and Alishan. Specifically, Xink-
ang, Zhongpu, Zhuqi and Alishan transformed
from negative to positive values. Meanwhile,
the townships with decreased divorce rates
are Taibao, Dalin, Budai, Shuishang, Puzi, Liu-
jiao and Meishan. Lucao, Minxiong and Fanlu
changed from positive to negative values.
Based on the distribution of the range of
standardized scores of marriage rate from 2000
to 2011, table 6 shows that the townships with
increased marriage rate were Fanlu, Meishan,
Minxiong, Taibao, Shuishang, Budai, Zhuqi,
Zhongpu, Puzi and Alishan. Meanwhile,
the townships with decreased marriage rate
were Lucao, Dalin, Xinkang, Dongshi, Xikou,
Liujiao and Yizhu. Townships where marriage
rate changed from decreasing to increasing are
Minxiong, Taibao, Zhuqi, Puzi and Alishan.
Finally, marriage rate changed from increasing
to decreasing in Minxiong, Taibao, Zhuqi, Puzi
and Alishan (tables 6 and 7).
Tables 8 and 9 point out that townships with
increased standardized social fragmentation
scores include Alishan, Meishan, Zhuqi, Zhong-
pu, Shuishang and Minxiong. Meanwhile,
townships with decreased standardized social
