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LAND DEGRADATION ASSESSMENT IN THE AFRAM 
PLAINS OF GHANA - A CASE STUDY 
Charles K.O. Asare 
Programme Officer, Environmental Protection 
Council, P. O. Box M.326, Accra, Ghana. 
ISPRS Commission Number: 60. 
ABSTRACT 
Many areas under development in Ghana are susceptible to soil erosion and therefore require extensive 
management in order to preserve soil resources. Conventional field techniques for identifying and 
monitoring potential problem areas are slow and inadequate and need to be supplemented. 
A potential problem area in Eastern Ghana which is subject to erosion as a result of its shallow, sandy 
soils was assessed for its susceptibility to land degradation through soil erosion. 
Nine (9) landcover classes were established using ERDAS (EARTH RESOURCE DATA ANALYSIS) and ELAS (EARTH 
LABORATORY ANALYSIS SOFTWARE) to classify the Landsat-4MSS generated on 24th January, 1987. 
Principal Component Analysis (PCA) and Tassled Cap Transformation were performed on the raw satellite data 
to increase the accuracy of the classification. This was assessed to test the level of accuracy achieved. 
Matrix analysis revealed that 0.377 of the project area is susceptible to severe soil erosion hazard. 
This research, undertaken during a training course by the author at EPFL/GRID (Geneva) in 1989, was 
designed to provide a technique for predicting which areas are most likely to be degraded in the future 
and demonstrated the advantages of GIS and Remote Sensing in resource management. 
KEY WORDS: GIS, Remote Sensing, Land degradation, Assessment. 
INTRODUCTION 
system, present conventional techniques are however 
inadequate, slow and costly. To redress these 
deficiencies, they could be supplemented by Geogra- 
phical Information System (GIS) and Remote Sensing 
to ensure a more satisfactory spatial data acquisi- 
tion and management. 
A sound environmental management of a country's 
natural resources is crucial to its sustainable 
development. In most developing countries, how- 
ever, gross negligence and poor management of the 
natural environment, coupled with the failure to 
recognise and act on their close inter-relation- 
ship leads to the alarming depletion of their 
resource base thus compromising the survival of 
the present and future generations. 
The present report is therefore designed to demons- 
trate the operational use of GIS and Remote Sensing 
for environmental assessment studies in Ghana. 
It is to reverse this serious trend of environ- 
mental degradation by forging a new perception of Ghanaian soils are susceptible to all forms of 
environmental issues as a key strategy of the erosion. It has been observed that most of the 
country's developmental efforts, that the Govern- soil nutrients are found within the top-soil up to 
ment of Ghana through the Environmental Protection 15-20cm and that the organic matter and plant 
Council, key ministries as well as relevant nutrients content decrease sharply below the top- 
research and academic institutions, formulated an soil. These top-soils are lighter in texture, weak 
Environmental Action Plan (EAP) to harness all fine to medium crumbs and of fragile consistency. 
available data, establish new environmental data These are properties that make them erode very 
in new problem areas as well as systematically fast. 
co-ordinate efforts between various implementing 
agencies. The successful implementation of this 
plan, based upon a concerted effort to create in 
the people a sense of responsibility regarding 
the safe and healthy maintenance of the ecosystem, 
is expected to add a new dimension to the nation's 
development efforts. 
The Ghana Soil Research Institute (SRI) has report- 
ed alarming figures on erosion of affected areas. 
In the interior savannah zone which comprises of 
the study area, a land area of 35,172sq.km. is 
affected by slight-to-moderate sheet erosion, 
27,306sq.km. by moderate-to-very severe sheet and 
gully erosion and 33,494sq.km. by moderate-to-very 
Presently, there are a number of reports dealing severe and gully erosion. 
with various enviornmental issues in the country. 
What the EAP seeks to do primarily, is to ensure 
that all planning decisions are based upon impact 
predictions at the project planning stage. Thus 
information on the enviornment will henceforth be 
gathered, screened, compiled and analysed at the 
very beginning of the project planning stage, and 
integrated within the overall planning system so 
as to ensure a new integrated developmental 
approach that respects the inter-relationship 
between people and their environment. 
Available literature indicates that the removal of 
protective vegetation cover for woodfuel utiliza- 
tion and farming, has contributed much to the high 
incidence of erosion in the area. It has been 
estimated that women spend 1 hour per working day 
to gather firewood from fields. 
The need to combine diverse information to consider 
a broad range of alternatives and supplement rather 
tedious and cumbersome manual techniques in addres- 
sing environmental problems which are dynamic in 
For the purpose of such an integrated planning time and space, has been well documented. An 
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