Spatial decision support system for hydrogeological studies in Table Mountain Group Aquifers, Western Cape Province, South Africa

[摘要] The Western Cape province of South Africa is a water scarce area with a Mediterraneanclimate. The majority of rainfall occurs in the cold winter months and the area experiences hotand dry summers. Studies done to investigate various water supply and water demandmanagement 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 goodquality water, but that further research about this source as a potential augmentation supply tothe 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 ahydrogeology project team, which includes hydrogeologists, environmentalists, ecologists,engineers and other stakeholders. The Table Mountain Group Aquifer (TMGA) SDSS ismeant to be a decision support tool, but should also raise awareness about the use of spatialdata and information and its capabilities for earth science and other multidisciplinaryapplications.By means of team discussions and interviews data, spatial analysis and data manipulationrequirements were determined. Based on these requirements, four spatial analysis tools weredeveloped. The spatial tool named 'Borehole Analysis analyses stratigraphic informationobtained from existing boreholes and hydrogeological point data. The tool determines whatgroundwater 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. farmboundaries) data within a certain distance from a possible borehole site. The 'Sensitive AreaAnalysis tool addresses queries with respect to sensitive areas, such as wetlands, statutoryprotected areas and private nature reserves. The 'Image Classification tool gives the teammembers 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 freesoftware.The TMGA SDSS enables the team members to have equal and ready access to data acquiredby other members. This was found to support intra- and interdisciplinary conversation andfacilitate 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 andimplementation.Keywords: decision-making, geographic information system (GIS), spatial decision supportsystems (SDSS), spatial manipulation language (SML)

[发布机构] Stellenbosch University