New Water Policy and Practice Volume 1, Number 2 - Spring 2015 | Page 37

New Water Policy and Practice

economic developments. Given the fact that rice is Liberia’s stable food, majority of
Liberians are engaged in subsistence farming. Therefore, upland farming is a major
occupation for most residents in Nimba County. The practices of upland farming as
carried out in Nimba, often ensured that some plots of timber are cleared annually and
burned for the cultivation of rice and other vegetables. Geographically, Nimba County
is situated in the Northeastern part of Liberia and borders Countries such as Guinea
and Ivory Coast. It borders Guinea to the north and Ivory Coast to the east. On the
other hand, Nimba internally borders Counties such as Grand Gedeh, Grand Bassa and
Bong. Although emphasis of this paper is on the northern part of Liberia, but portion
of this river lies in Guinea. This river was selected because no previous study had been
carried out to assess its exposure to pollutants. Kpaytuo, being an area that forms a
connecting network of rivers, has a water system that is badly degraded by the types of
land uses described above.

2 - Material and Methods
2.1. Data Sources

T

able 1 provides the various datasets which were used for the deriving of the
estimated environmental pollution potential for the Burl River Basin.
The Burl River basin boundary was derived from the SRTM 90m DEM using
the hydro-processing plug-in in ILWIS Open. The procedure involves the use of D-8
algorithm in the determination of flow direction. The D-8 algorithm used by ILWIS
Open has been found to be sufficient for the delineation of catchments in the West
Africa zone (Anornu, Kabo-bah, & Kortatsi, 2012). Based on the delineated boundary of
the Burl River, the maps (land use, slope, population and soil) were masked to represent
the study area. The key assumption in this study was that a combination of the land use
activity, slope, soil and population growth can provide relevant information for deriving
the potential environmental pollution. The environmental pollution potential (EPP) is
explained as the degree to which the river resources get polluted and contaminated,
as a result of basin’s natural tendency, and human activities. In that case, the EPP map
indicates the areas within the basin that has the potential to contribute to pollution or
contamination of the river resources. Since non-point river pollution is a contribution
of different sources and activities within a particular basin, land use map, slope and soil
were considered as the most critical and important indicators for contribution to nonpoint pollution. The land use provided the existing purpose of the land and, based on
the existing use of the land; it is possible to estimate the potential pollutant transport
to the river. The slope is the catalyst for promoting the flow and hence was included as
one of the core indicators. The soil media, an indicator of the geological formation, was
included as a medium for transport and, therefore, depending on the characteristics
of this medium, pollutant travel to the river could be faster or slower. The population
growth was considered as the changing indicator that affects land use activity. As the
population grows, issues such as urbanization and household and industrial waste also
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