Development of a decision tool for groundwater management

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Date
2007-05
Authors
Dennis, Stefanus Rainier
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University of the Free State
Abstract
English: Water in South Africa is becoming a scarce and important resource and therefore has to be managed and protected in order to ensure sustainability, equity and efficiency. The SAGDT is designed to provide methods and tools to assist groundwater professionals and regulators in making informed decisions concerning groundwater use, management and protection, while taking into account that groundwater forms part of an integrated water resource. The SAGDT is spatially-based software, which includes: • A GIS interface to allow a user to import shape files, various CAD formats and georeferenced images. The GIS interface also provides for spatial queries to assist in the decision-making process. The GIS interface contains default data sets in the form of shape files and grid files depicting various hydrogeological parameters across South Africa. • A risk assessment interface introduces fuzzy logic based risk assessments to assist in decision making by systematically considering all possibilities. Included risk assessments relate to the sustainability of a groundwater resource, vulnerability of an aquifer, pollution of a groundwater resource (including seawater intrusion), human health risks associated with a polluted groundwater resource, impacts of changes in groundwater on aquatic ecosystems and waste site impact on an area. • Third-party software such as a shape file editor, an interpolator, a georeference tool, a unit converter and a groundwater dictionary. • A report generator, which automatically generates documentation concerning the results of the risk assessment performed and the input values for the risk assessment. • A scenario wizard for the novice to obtain step by step instructions in setting up a scenario. All case studies presented in this thesis is available in the scenario wizard. • The SAGDT allows problem solving at a regional scale or a local scale, depending on the problem at hand. This thesis discusses the origin, research, development and implementation of the SAGDT. Case studies are included to demonstrate the working of the SAGDT. They include: • Vunerability (Fish River Lighthouse) • Waste Site (Bloemfontein Suidstort) • Sustainability (De Hoop) • Mine (Van Tonder Opencast) The SAGDT relies heavily on the expertise of hydrogeologists, assumptions and approximations of real world conditions. Together with the heterogeneities present in groundwater systems it is impossible to guarantee the accuracy of the methodologies and this must be taken into consideration.
Afrikaans: Water word ‘n skaars en belangrike bron in Suid Afrika en moet om die rede goed bestuur en bewaar word om volhoubaarheid, gelykheid en effektiwiteit te verseker. Die SAGDT is ontwerp en ontwikkel om metodes te bied om kundiges en kontroleurs van grondwater te ondersteun om ingeligte besluite met betrekking tot grondwater gebruik, bestuur en bewaring te neem, met die feit in gedagte dat grondwater ‘n integrale deel van die land se waterbronne is. Die SAGDT is ruimtelik gebasseerde sagteware wat insluit: • ‘n GIS-koppeling om die gebruiker in staat te stel om ‘n geografiese vektorlêer, verskeie CAD formate en geo-verwysingsbeelde in te voer. Die GIS-koppeling maak ook voorsiening vir ruimtelike navrae ter ondersteuning van die besluitnemingsproses. Die GIS-koppeling bevat vektor- en roosterlêers met verskeie hidrogeologiese veranderlikes van oral in Suid Afrika. • ‘n Risiko-assesseringskoppeling wat “fuzzy logic” risiko-assesserings invoer om behulpsaam te wees met besluitneming deur sistematiese beskouing van alle moontlikhede. Die ingeslote risiko-assesserings het betrekking op die volhoubaarheid van ‘n grondwaterbron, die kwesbaarheid van ‘n grondwaterdraer, besoedeling van ‘n grondwaterbron (insluitend die indringing van seewater), menslike gesondheidsrisiko geassosieer met besoedelde grondwaterbronne, impak van veranderinge in grondwater op die akwatiese ekosisteme en die impak van afval stortingsterreine op ‘n omgewing. • Derde party sagteware soos ‘n vektorlêerverwerker, ‘n interpolator, ’n geoverwysingsverwerker, ‘n eenheidsomskakelingsverwerker en ‘n grondwater biblioteek. • ‘n Verslag generator wat outomaties dokumentasie mbt die resultate van risikoassessering verskaf en die invoer van risiko-assesseringswaardes. • ‘n Senario skepper wat vir die nuweling operateur stap vir stap instuksies verskaf vir die opstel van ‘n senario. Al die gevalle studies in die proefskrif is beskikbaar in die senario skepper. • Die SAGDT kan probleemoplossing op ‘n streeks- en ook op ‘n plaaslike vlak hanteer, afhangend van die tersaaklike probleem. Hierdie tesis bespreek die oorsprong, navorsing, ontwikkeling en implementering van die SAGDT. Gevallestudies om die die werking van die SAGDT te illustreer is ingesluit nl: • Kwesbaarheid (Visrivier Ligtoring) • Afvalstortingsterrein (Bloemfontein-Suidstort) • Volhoubaarheid (De Hoop) • Myn (Van Tonder Oopgroefmyn) Die SAGDT leun swaar op die kundigheid van geohidroloë asook aannames en benaderings van egte wêreld toestande. Tesame met heterogene teenwoordigheid in grondwatersisteme is dit onmoontlik om akkuraatheid van metodologie te waarborg.
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Thesis (Ph.D. (Institute for Groundwater Studies))--University of the Free State, 2007, Groundwater -- South Africa -- Data processing, Groundwater -- Management, Water supply -- Management, Environmental protection
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