Quantifying Rapid Urbanization and its impact on Urban Green Spaces:
Directional and Zonal Analysis integrated with Landscape Expansion Index
Abstract
Addis Ababa, the capital of Ethiopia, is urbanizing rapidly in recent
years mainly through the destruction of environmental resources. This
study aimed at the dynamics of urban green spaces (UGS). Remote Sensing
and Geographical Information System (GIS) was used to extract land use
and land cover data. The Landscape Expansion Index (LEI) was employed to
measure urban growth patterns. The result showed that a more noticeable
growth was observed in the peri-urban zone (40.1km2 to 176.1km2),
followed by the inner urban zone (from 67.1km2 to 105km2). The expansion
in the urban core zone was marginal and followed a non-unidirectional
trend i.e. increased in the first period (1989-1999) and second period
(1999-2009) by (0.11% and 4.2%), while decreased in the third period
(2009-2019) by 3.6%. The result for LEI dynamics showed that the city
experienced a pronounced outlying growth (98%) pattern, while edge
expansion and infilling growth were insignificant. Conversely, the UGS
declined in the inner urban zone by (18.03%), (28.61%) and (18.97%)
in the first, second, and third periods. Similarly, in the peri-urban
zone, the UGS persistently declined by (11.5%), (17.1%) and,
(28.03%). The directional analysis showed that urban areas
significantly expanded in SEE, SSE, SSW, and NEE with a net increase of
5.35, 4.4 km, 2.83, and 2.3 km2/year, respectively. Conventional
large-scale /citywide/ dynamics investigations are not robust enough to
represent the actual magnitude and directions of change, while the zonal
and directional study is more effective in characterizing the
Spatio-temporal dynamics for better urban planning towards.