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THE APPLICATION OF GEOGRAPHIC INFORMATION SYSTEMS IN ENVIRONMENTAL 
IMPACT ASSESSMENT IN AFRICA: CHALLENGES AND OPPORTUNITIES 
MLENGE FANUEL MGENDI* 
University College of Lands and Architectural Studies UCLAS; P.o. Box 35176, Dares Salaam, Tanzania. 
Email: mlenge@usa.net 
KEYWORDS: Environmental Impact Assessment (EIA), Geographic Information Systems (GIS), Environment, Environmental 
Information Systems (EIS), Africa, Tanzania. 
SUMMARY 
Environmental Impact Assessment (EIA) involves collection of data used to predict the potential impacts of proposed 
activities. The environmental problems vary both in space and in time, hence cannot be tackled without consideration of the 
spatial and temporal contexts. The capacity to map, monitor and model the spatial component of the environmental problems 
offered by the Geographic information Systems (GIS) can successfully be used in conducting the EIA. This paper discusses 
the challenges and opportunities of the use of GIS in EIA in Africa, zooming in on Tanzania. 
INTRODUCTION 
Environmental Impact Assessment (EIA) can generally be 
defined as a formal study process used to determine the 
environmental consequences of a proposed development 
project. (6) . The Geographic Information System Systems 
(GIS) offer a special environment to deal with the spatial 
properties of a project. (8) GIS can be applied in all EIA 
stages: from the generation, storage and display of the 
thematic information relative to the vulnerability of the 
affected resources, to impact prediction and quantification, 
evaluation and finally, presentation. (5) 
There have been initiatives of linking GIS to Regional ElAs 
in different locations such as industrial ElAs in India, 
Transportation ElAs in Malaysia and Water Resources and 
Thermal Power ElAs in Thailand. Several applications of 
GIS integration to EIA are also reported in the UK. (7) . GIS is 
found to be a very effective tool for conducting EIA studies 
and it can be used for various environmental applications. (2) 
The adoption, adaptation and applications of GIS together 
with Remote Sensing (RS) and Geographic Positioning 
Systems (GPS) in other continents have not only shown that 
they provide better and timely resource and environmental 
information, their combined analytical and integrative power 
has also been found to provide the greatest opportunity to 
stimulate and understand the spatial and temporal dynamics 
of the real world in a comprehensive manner. (10) 
APPLICATION OF GIS IN EIA 
GIS have emerged as very powerful technologies because 
they allow integration of data and methods in ways that 
support traditional forms of geographical analysis, such as 
map overlay analysis as well as new types of analysis and 
modelling that are beyond the capability of manual methods 
A study on the role of GIS in improving environmental 
assessment effectiveness revealed that GIS was used for a 
wider range of EIA applications as anticipated by the 
researchers (Joao & Fonseca (1997), in Looijen (1997)). 
In order to determine how EIA practitioners use GIS, a 
questionnaire was sent to 98 environmental consultants in 
the United Kingdom and Portugal. In the questionnaire each 
practitioner was asked to fill what type of GIS operation was 
used for which particular EIA stage. The EIA stages 
included: screening and scoping, description of the project, 
description of baselin'e conditions, impact identification, 
prediction of impact magnitude, assessment of impact 
magnitude, impact mitigation and control, public consultation 
and participation, and monitoring and auditing. 
Preliminary results of that study - based on 36 recipients - 
showed the use GIS in different EIA stages: 
• Screening and scoping: data gathering, spatial 
modelling, impact assessment and calculation of impact 
magnitude. 
• Project description: geographical context of the project. 
• Baseline conditions description: documentation of 
environmental aspects and attributes, including 
biophysical inventories. 
• Impact Identification: overlay analysis, e.g. the 
distribution of pollutants with resource maps or the 
integration of air quality modelling and habitat suitability 
analysis. 
• Impact magnitude prediction: quantitative assessment 
of the percentage of a resource (conservation area) 
affected by a pollution or the creation of impact 
magnitude maps derived form the integration of the 
result of risk and air quality modelling with other data 
layers, e.g. soil susceptibility to acidification. 
• Impact significance: spatial distribution of the impact 
and the variation between the different project 
alternatives, including the zero alternative. 
• Mitigation & control: model and map distribution of 
pollutants. The result can be used to concentrate 
Currently on study leave at International Institute for Aerospace Survey and Earth Sciences (ITC). 
Box ¡77, Post bus 6, ~500AA Enschede. The Netherlands Email: mgendi@ilc.nl