Gis and Remote Sensing Based Solid Waste Landfill Site Selection: A Case of Addis Ababa City, Ethiopia
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Date
2011-01
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Addis Ababa Universty
Abstract
Solid waste management system is the most difficult task that many countries, both developing
and developed, are facing. Landfill method is one of the easy and cheap management systems
which are always needed for sustainable management of solid waste. However, if not sited and
managed properly, it will result in environmental pollution and public health problems. The open
dumping system that the city of Addis Ababa has been using is not environmentally sound and
socially acceptable as its location is in inappropriate site. Therefore, it is necessary to select new
landfill site for the city that is environmentally sound, socially acceptable and economically
feasible. The present study was conducted by integrating Geographic Information System and
remote sensing for selecting suitable landfill sites. Factors such as geology, slope, depth to
ground water table, permeability, land use/ land cover, proximity from roads, faults, airport,
groundwater well and streams/rivers were used for selecting suitable landfill within the study
area. GIS-based Multi-Criteria Evaluation methodology was followed to have advantages of both
GIS and Multi-Criteria Evaluation method and solve spatial decision making problems. All the
factor maps were reclassified and standardized in GIS environment followed by preparation of
their suitability map. Analytical Hierarchy Processes pair-wise comparison module was used to
derive internal and external weights for all factor parameters and factors respectively. More
weight was given to groundwater related criteria so as to protect groundwater pollution from
landfill negative effects. Weighted Linear Combination was also used to integrate the factor maps
and produce overall landfill suitability map. Accordingly, 40.5km2(7.7%), 68.7km2(13%),
0.7km2(0.01%) and 417.8km2(79.3%) of the total study area is highly, moderately, marginally
and unsuitable for landfill respectively. Among the highly suitable landfill sites, those with area
greater than 0.5km2 were also evaluated against other criteria like area, distance from the center
of the city and distance from nearby settlements so as to choose the most suitable landfill sites.
Analytical Hierarchy Processes was applied again to compare and derive weight for the 12
candidate sites in relation to those evaluating criteria. Landfill site 2 which is located in the
north eastern part of the city in Yeka sub-city, north of road to Dessie is chosen as the most
suitable site, because of the larger area and optimum distance from the nearby settlements and
from the center besides their fulfillments of the environmental and socioeconomic factors set
before. Landfill site 11 (located in the south eastern part in Bole sub-city) and landfill site
1(found in the northern part of the city in Yeka sub-city) is the second and third most suitable
sites respectively due to their larger area and/or distance from nearby settlements and center
than the rest of the sites. Landfill 11 is more suitable than landfill 1 due to its safe location from
nearby settlements. Therefore, landfill sites 2, 11 and 1 are ranked from 1 to 3 based on their
area and distance from the center and nearby settlements compared to the other sites hence their
negative effects on the environment and public heath will be minimum.
Key Words: Landfill, Multi-Criteria Evaluation, Addis Ababa Solid Waste Management, GIS,
Remote Sensing.
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Keywords
Landfill, Multi-Criteria Evaluation, Addis Ababa Solid Waste Management, GIS, Remote Sensing