Accra has been experiencing periodic flooding that affects properties and lives. For
instance on 41h and Sib June 1994, 8 persons lost their lives and 80 million cedis worth of
properties belonging to Paloma Company were destroyed due the floods that occurred at
that time. The government seeing the dangers involved. commissioned institutions such
as ~linistIy of Works and Housing, Tovm and Country Planning and City Engineers to
identify such areas and adopt measures that will help reduce the effect ofthis unexpected
extreme event The measures used by these institutions in order to identify and prevent
the occurrence of such extreme event have been woefully inadequate and inefficient
Hence this thesis examines new methods of identification of potential flood risk zones
stressing the possible combination of hydrological models with remote sensing and
geographic infonnation system models.
The main objective ofthe study is to determine flood risk zones in Accra and its environs
using a hydrological model and a geographical information system model. Specifically,
the study aims at assessing how the urban watershed has been modified in-terms of
drainage networking, soil texture. runoff and their influences on flooding. A flood risk
zones map and the paleogeomorphology ofthe study area were also constructed.
Data for the study were from secondary and primary sources. The secondary sources
included rai.nfut~ discharge, and topography data, which were collected through literature
search from institutions such as Hydro Division of Ministry of Works and Housing,
Survey Department, Meteorological Service and \Vater Research Institute. The primary
data collected included drainage cros~ sectional measurement and soil characteristics.
These data were collected using field measurements. field observations. satellite image
interpretation and laboratory analyses.
The anaI~es ofthe data were based on the integration ofthe hydrological model into the
-Geographic Infonnation System model using an overlay operation.
The result ofthe research showed that potential areas likely to experience periodic floods
with a given input of rainfall (140.2 mmlhour) are mostly below the 350-meter contour
and about 45 percent ofthe study areas fall \vithin flood risk zone. It was also noted that
the flood experienced by an area is mostly dependant on rainfall intensity no matter the
catchment area. However other factors such as, landuse, storage and runoff coefficient
were identified as contributory mctors to flooding in the study area..
In search for a method to detennine flood risk zones, the use of a hydrological model
within a geographic infonnation system model is very effective if only the appropriate
decision rule is defined. The studies will enable the supervisory agencies such as Ministry
of Works and Housing, Town and Country Planning and City Engineers enforce landuse
policies to prevent people from developing areas prone to floods.
SSA, R (2021). DETERMINAnON OF FLOOD RISK ZONES IN ACCRA AND TEMA METROPOLIS. Afribary.com: Retrieved April 23, 2021, from https://afribary.com/works/determinanon-of-flood-risk-zones-in-accra-and-tema-metropolis
Research, SSA. "DETERMINAnON OF FLOOD RISK ZONES IN ACCRA AND TEMA METROPOLIS" Afribary.com. Afribary.com, 02 Apr. 2021, https://afribary.com/works/determinanon-of-flood-risk-zones-in-accra-and-tema-metropolis . Accessed 23 Apr. 2021.
Research, SSA. "DETERMINAnON OF FLOOD RISK ZONES IN ACCRA AND TEMA METROPOLIS". Afribary.com, Afribary.com, 02 Apr. 2021. Web. 23 Apr. 2021. < https://afribary.com/works/determinanon-of-flood-risk-zones-in-accra-and-tema-metropolis >.
Research, SSA. "DETERMINAnON OF FLOOD RISK ZONES IN ACCRA AND TEMA METROPOLIS" Afribary.com (2021). Accessed April 23, 2021. https://afribary.com/works/determinanon-of-flood-risk-zones-in-accra-and-tema-metropolis