| dc.description.abstract | The ever increasing global population and associated socio-economic development
activities have increased the need for abstraction of fresh water and consequently
release of wastes to the aquatic environment. Due to lack of controlling mechanisms
and treatment facilities, wastes from industries, domestic sewage and agricultural
practices find their way into water sources and result in large scale deterioration of
the water quality. As a result, it has been recognized that water pollution constitutes
a much broader threat than expected and continues to pose serious health risks to
the public as well as aquatic life. These anthropogenic impacts make the definition of
water quality to more complex, which requires simultaneous consideration of multiple
aspects. For possible identification and mitigation of point and non-point contaminant
sources that results from these anthropogenic impacts, geographically referencing
water quality data and relating these data to other information, such as demography
and land use, information is highly important.
Water quality assessment with aid of Geographical Information System (GIS) and
ultimately its application in the monitoring and analyzing processes is a recent
technology driven development. It is a powerful mechanism for establishing
relationships between impacts due to natural as well as human activities and its
effect on water quality. This thesis has explored a water quality assessment with the
aid of Geographical Information System (GIS) and its applications for subsequent
manipulations and analyses based on a case study of water supply for the City of
Nairobi. The study has focused on exploratory analyses of existing water quality data
of Nairobi City Water and Sewerage Company (NCWSC) and relevant field
information with application of GIS software.
For exploratory analyses of existing water quality data, a GIS software package, the
statistical function "Analyzing Patterns and Mapping Clusters" was applied for data
manipulations and analyses. The analyses were made based on selected indicator
parameters of existing water quality data.
The analyses result showed that some of indicator parameters of the water sources
and distribution are spatially or regionally variable while others are randomly
distributed. Parameters' values were also evaluated in relation to established water
quality standards. Based on parameters variability and assessments, it was possible
to get information with respect to water quality conditions and status of sources and
distributions. The information is useful for implementing control measures and
improvements to the water supply system. Furthermore, the study result has
revealed some constraints and allowed development of recommendations on the
current water quality management system for the City of Nairobi Water Supply. Thus,
this case study has proved the validity and applicability of GIS for water quality | en |
