Use of GIS to Estimate Socioeconomic Losses Caused by Urban Floods: A Tool …
651
• Maximum flood height—6.63 m;
• Minimum height of flooding—0.00012 m.
It should also be noted that the resulting higher heights are found within the
drainage channel, in the region of the flatter relief of the hydrographic basin. In
addition to the relief, it is also observed that the flood spot has greater coverage in
the western region of the water body in question.
From the flood spot, overlapping urban plots made available by IPPUC (2019)
was made. However, since the format of the flood spot data is of the matrix type, it
was necessary to reclassify this data to whole numbers and transform it to the vector
format. And so, create the overlap of these data, resulting in the height of flood water
for each urban structure affected.
Due to the referred conversion, the flood spot has its precision reduced, where
it was necessary to establish six classes of water height, which were conveniently
adopted according to the proposal prepared by the European Union. Table 1 shows
the classification of the flood spot according to the height and the average damage
factor to the structures.
With the combination of the flood spot and urban structures, it was possible to
identify 5,591 structures affected with the proposed class limitation, of the most
diversified uses and territorial occupation. It is noteworthy that a considerable part of
the lots does not have identification of use and occupation, which limits and partially
compromises the analysis because it does not consider the economic dimension of
the structures. Of the named lots, there were 489 areas of flooded lots registered as
residential, which were chosen to apply the economic loss methodology (Huizinga
et al. 2017).
The European Union methodology also provides an estimate of economic losses
per square meter according to the average damage, making it possible to estimate it
according to the areas obtained.
Finally, by establishing the ratio of the flooded area (m
2 ) by type of class in
relation to the Average damage factor, economic losses can be estimated according
to the referred methodology (Table 2).
It should be noted that the lack of identification of the lots, made it impossible
to make a more accurate estimate, using only the damage separately per lot. It is
also noteworthy that in the analysis of the data, it was observed that the largest flood
structure in the same class was 7,039.69 m
2 classified as class 1, and the smallest
structure with 0.000123 m
2 classified as class 4.
5 Conclusion
The present study demonstrated the possibility of carrying out the mapping of flood
areas according to the intense rains. However, it is a mathematical model that lacks
input data, which requires monitoring, which is not always accessible or existing,
but which determines the accuracy of the result.
651
• Maximum flood height—6.63 m;
• Minimum height of flooding—0.00012 m.
It should also be noted that the resulting higher heights are found within the
drainage channel, in the region of the flatter relief of the hydrographic basin. In
addition to the relief, it is also observed that the flood spot has greater coverage in
the western region of the water body in question.
From the flood spot, overlapping urban plots made available by IPPUC (2019)
was made. However, since the format of the flood spot data is of the matrix type, it
was necessary to reclassify this data to whole numbers and transform it to the vector
format. And so, create the overlap of these data, resulting in the height of flood water
for each urban structure affected.
Due to the referred conversion, the flood spot has its precision reduced, where
it was necessary to establish six classes of water height, which were conveniently
adopted according to the proposal prepared by the European Union. Table 1 shows
the classification of the flood spot according to the height and the average damage
factor to the structures.
With the combination of the flood spot and urban structures, it was possible to
identify 5,591 structures affected with the proposed class limitation, of the most
diversified uses and territorial occupation. It is noteworthy that a considerable part of
the lots does not have identification of use and occupation, which limits and partially
compromises the analysis because it does not consider the economic dimension of
the structures. Of the named lots, there were 489 areas of flooded lots registered as
residential, which were chosen to apply the economic loss methodology (Huizinga
et al. 2017).
The European Union methodology also provides an estimate of economic losses
per square meter according to the average damage, making it possible to estimate it
according to the areas obtained.
Finally, by establishing the ratio of the flooded area (m
2 ) by type of class in
relation to the Average damage factor, economic losses can be estimated according
to the referred methodology (Table 2).
It should be noted that the lack of identification of the lots, made it impossible
to make a more accurate estimate, using only the damage separately per lot. It is
also noteworthy that in the analysis of the data, it was observed that the largest flood
structure in the same class was 7,039.69 m
2 classified as class 1, and the smallest
structure with 0.000123 m
2 classified as class 4.
5 Conclusion
The present study demonstrated the possibility of carrying out the mapping of flood
areas according to the intense rains. However, it is a mathematical model that lacks
input data, which requires monitoring, which is not always accessible or existing,
but which determines the accuracy of the result.