Spatial decision support system for hydrogeological studies in Table Mountain Group Aquifers, Western Cape Province, South Africa
Date
2007-12
Authors
Mlisa, Andiswa
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
The Western Cape province of South Africa is a water scarce area with a Mediterranean
climate. The majority of rainfall occurs in the cold winter months and the area experiences hot
and dry summers. Studies done to investigate various water supply and water demand
management options for the City of Cape Town, concluded that the Table Mountain Group
(TMG) aquifer has the potential of yielding high volumes (estimated at 70Mm3/a) of good
quality water, but that further research about this source as a potential augmentation supply to
the City of Cape Town was necessary before extraction could commence.
The aim of the study is to develop a spatial decision support system (SDSS) to be used by a
hydrogeology project team, which includes hydrogeologists, environmentalists, ecologists,
engineers and other stakeholders. The Table Mountain Group Aquifer (TMGA) SDSS is
meant to be a decision support tool, but should also raise awareness about the use of spatial
data and information and its capabilities for earth science and other multidisciplinary
applications.
By means of team discussions and interviews data, spatial analysis and data manipulation
requirements were determined. Based on these requirements, four spatial analysis tools were
developed. The spatial tool named “Borehole Analysis” analyses stratigraphic information
obtained from existing boreholes and hydrogeological point data. The tool determines what
groundwater use and monitoring has been undertaken in the area of interest. The
“Topographic Analysis” tool identifies any topographical (e.g. rivers) and cadastral (e.g. farm
boundaries) data within a certain distance from a possible borehole site. The “Sensitive Area
Analysis” tool addresses queries with respect to sensitive areas, such as wetlands, statutory
protected areas and private nature reserves. The “Image Classification” tool gives the team
members an opportunity to use band ratios during image interpretation.
The TMGA SDSS was developed using TNTmips v70, Extensible Markup Language (XML)
and Spatial Manipulation Language (SML) and can be run on TNTAtlas v70, which is a free
software.
The TMGA SDSS enables the team members to have equal and ready access to data acquired
by other members. This was found to support intra- and interdisciplinary conversation and
facilitate understanding of how the data is being (or could be) used. It also contributes to levels of confidence in decision-making and supports a holistic approach to project design and
implementation.
Keywords: decision-making, geographic information system (GIS), spatial decision support
systems (SDSS), spatial manipulation language (SML)
Description
Thesis (MA (Geography and Environmental Studies))--University of Stellenbosch, 2007.
Keywords
Dissertations -- Geography and environmental studies, Theses -- Geography and environmental studies, Aquifers -- South Africa -- Western Cape, Hydrogeology -- South Africa --Western Cape, Decision support systems, Water-supply -- South Africa -- Western Cape, Geographic information systems