Abstract:
The use of Geographical Information Systems (GIS) has permeated almost every field in the
engineering, natural and social sciences, offering accurate, efficient, reproducible methods for
collecting, viewing and analysing spatial data. GIS do not inherently have all the hydrological
simulation capabilities that complex hydrological models do, but are used to determine many
of the catchment parameters that hydrological models or design flood estimation methods
require. The purpose of this study was to perform catchment parameter analysis using GIS
applications available in the ArcGISTM environment. The paper will focus on the deployment of
special GIS spatial modelling tools versus conventional manual methods used in conjunction
with standard GIS tools to estimate typical catchment parameters, e.g. area, average catchment
and watercourse slopes, main watercourse lengths and the catchment centroid. The manual
catchment parameter estimation methods with GIS-based input parameters demonstrated an
acceptable degree of association with the special GIS spatial modelling tools, but proved to
be sensitive to biased user-input at different scale resolutions. GIS applications in an ArcGISTM
environment for the purpose of catchment parameter analyses are recommended to be used as
the standard procedure in any proposed hydrological assessment.
