Open - IHDP - United Nations University

Indentifying the Poor in Cities
There is an uncontrolled influx of people from rural
regions to the megacity of Dhaka (BEguM 1999), yet this in-
flux or city in-migration, is not accompanied by growth of
urban infrastructure and supply. Thus, many migrants move
into marginal areas already in critical situations, and result
in the persistent and increasing resource pressure in these
settlements. Insufficient water supply, waste disposal and
waste water treatment as well as traumatic hygienic conditions
and lack of access to basic services mark the living conditions
in these slums. Slum dwellers, on average, have poorer
health and are more vulnerable to disasters such as floods
(uN MILLENNIuM ProjECt 2005). At present, about one third
of Dhaka’s population lives in marginal settlements or slums
(BurkArt Et AL. 2008).
A further problem is that of environmental pollution
as a result of poorly developed infrastructure. Soil, air and
water pollution occurs through the burning of wastes such
as plastics and through a lack of sanitation. A rudimentary
suburban traffic system does not offer
alternatives and people thus use small motorcycles
and cars for mobility. The constantly growing
traffic that results with its associated emissions
adds to the contamination of urban air.
The three large rivers systems, the Gangha,
Brahmaputra and Meghna, flood each year, since
the artificially installed drainage systems cannot
handle the water masses sufficiently. The result
is an amplified surface discharge during the
monsoon season in particular, which lasts from
March until October. The slums, with all their
shanties, are thus seasonally threatened by such
floods, exacerbating the already precarious situation
faced by the inhabitants (CALdwELL 2004;
khAN 2007).
In the current investigation on the structure
of slum settlements in Dhaka, Bangladesh,
the goal is to prepare a vegetation-index (NDVI)
based analysis exploiting Quickbird VHR satellite
data in an object oriented classification scheme
and further GIS analysis to investigate the living
conditions and health endangerment for the inhabitants
in the slums of Karail and Badda. The
informal settlement of Karail has been choosen
due to its prominent status as largest marginal
quarter in Dhaka. (sEE FIg. 1). The vast majority
of Karail was mapped as slum area, and on closer
inspection of the original Quickbird data, an extremely
high building density was uncovered. The
land-use/land-cover classification and the NDVI
mapping shown in Figure 2 highlight the tremendous differences
in land-use patterns which can be found in Dhaka on
a very large scale, showing an extreme lack of vegetation in
poor areas and dispersed green spaces for middle and upper
class areas. The slum area of Karail is located in the west of
the map shown and identified as the one with the smallest
NDVI-values. On the island in between the water bodies,
there are upper middle to upper class residential neighbourhoods,
including some residents with diplomatic status.
These neighbourhoods show dispersed, multi-storey apartment
buildings and a high proportion of green and open
spaces. Again, this area contrasts with the urban area in the
east of this study, where one can find a land-use mosaic of
different building densities with a mix of rapidly changing
apartment blocks and shanties.
Figure 3: Santiago de Chile, District Lo Barnechea: Social housing building complex. Courtesy of
Juliane Welz, Risk Habitat Megacity, Field of Application “Socio-spatial Differentiation”
Figure 4: Santiago de Chile, District Lo Barnechea: Marginal area at river. Courtesy of Juliane Welz,
Risk Habitat Megacity, Field of Application “Socio-spatial Differentiation”
26 IHDP Update 1.2009