Abstract
Karachi, a metropolitan city, is facing rapid
population growth causing environmental, social and economic
stresses and challenges. Beside planned development, unplanned
urbanization, urban slums, illegal and informal settlements, and
encroachments on natural drains have radically changed landuse
and drainage pattern of Karachi. One of the biggest challenges
that Karachi is facing now-a-days is localized floods after heavy
rain episodes due to increased surface overflow rates coupled
with the blockages of natural drains. In Karachi there are two
main rivers, Lyari and Malir, which play a major role in
draining storm water of the city. At present, these rivers are
severely affected by urbanization and bad management that
caused blockages at many locations. This paper investigates the
changes in landuse and their impacts on natural drainage pattern
of Malir River basin over the past 16 years (2000-2015).
Geospatial techniques are used to analyze landuse and landcover
changes of upper Malir River basin. Satellite derived Digital
Elevation Model (DEM) and topographic sheets (1950s) are used
to delineate natural drainage pattern of Malir district.
Landuse/landcover and river drainage maps are overlaid to
identify critical areas where natural river bed has been
encroached. Most part of the Malir River basin has been
occupied by agricultural fields and urban settlements which
caused narrowing of the river and complete blockage at some
locations. The blockages shown on the output maps can be
utilized for the revival of natural drainage network of Malir
River basin. The beneficiaries of this study may include, but not
limited to, the urban planners, Sindh development authorities
and flood mitigation and management agencies.
Sumaira Zafar, Arjumand Zaidi. (2015) Landuse Changes and their Impacts on Natural Drainage System of Malir River Basin, Journal of Space Technology , Volume 5, Issue 1.
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