Nyarko, Benjamin Kofi
According to Stig (1996), three main approaches to risk usage can be identified in the following
areas in geography, namely;
e Medical geography (corresponding to epidemiology)
e Applied geography and planning (bearing connections to probabilistic risk analysis)
e The hazard-tradition (with connection to physical geography as well as social theory and
cultural theories)
In this study risk is used to imply the probability of human life and properties within the study
area to be affected by high rainfall that generates into flood.
Flooding refers the inundation of an area by unexpected rise of water by either dam failure or
extreme rainfall duration and intensity in which life and properties in the affected area are under
risk. Accra, the capital of Ghana, accommodates major institutions, industries and government
Ministries in the country, it also attracts migrants from various parts of the country and the entire
world. In recent times, Accra has seen continually erection of concrete structures by private
estate developers in areas that experience periodic floods. Between 1955 and 1997, about c300
billion worth of properties has been destroyed, 100 lives have been lost either during the flood
period or after the floods and 10,000 people have been displaced from their homes (Gyau-Boaky,
1997; Adinku, 1994). This has prompted the government to setup statutory supervisory agencies
such as Ministry of Works and Housing, City Engineers of Accra Metropolitan Assembly and
Lands Department and also commissioned consultants (NEDECO, 1962,1967; WATERTECH,
1991) to see to the reduction of the effects of flooding on life and properties.
Consequently it is expected that these government statutory supervisory bodies will help prevent
the erection of such structures at areas that continuously experience floods. To identify potential
flood risk areas these agencies use methods such as identifying watermarks on structures, media
reports and aerial photographic interpretation as in Kuma (1996). These methods used by the
agencies are woefully inadequate, because there are always new areas that periodically
experience floods. Therefore, there is a need to explore new approaches at identifying and
mapping flood risk zones that will help in planning and managing the problem. This paper
presents the procedure through which the flood risk zone map of Accra was generated.
1.2 Study area
The proposed study area is within the Greater Accra and covers approximately about 786.59km?
(Figure 1.1). It stretches from Botianor to Sakumo, and James Town to Oyarifa. Tema bounds it
on the East, on the South by the sea, West by the Weija dam, and North by the Akwapim hills.
Using the geographical co-ordinates it lies within Longitude 0°.03 and 0°.25 West and Latitude
5°30 and 5°.53 North.
Figure 1.1 Study Area
Map Of Ghana
Map of Study Area in Accra N
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1040 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.
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