Thesis (MSc)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: Water resources in South Africa are limited and groundwater plays an important role in supporting basic human needs, sustaining ecosystems and enabling industrial and agricultural development. Sound management practices are necessary to ensure sustainable development of water resources. All groundwater usage must be licensed in compliance with the National Water Act of 1998. A Spatial Decision Support System (SDSS) can be used to assist in the groundwater usage licensing process of the Department of Water Affairs and Forestry (DWAF). The main aim of this study was to develop a SDSS, named Groundwater Abstraction & Licence Evaluation Tool (GALET), that could assist in the process of allocating water use licences and determining the local impact of abstraction, based on existing theory and data. The development was done within ArcView 3.2 using the scripting language Avenue. The Sandveld, an arid stretch of land along the west coast of South Africa that is heavily impacted by groundwater abstraction, was the chosen study area. The data collected for this study included existing borehole, recharge, rainfall and geological information. GALET proved to be capable of calculating essential information needed to evaluate groundwater abstraction, which included drawdown in the water table, zone of influence and the possible effects on features such as rivers and wetlands. Targeted potential users regarded GALET as a useful tool in the process of licensing and groundwater abstraction impact assessment and plans are under way to implement GALET or a derivative thereof at the DWAF regional offices. / AFRIKAANSE OPSOMMING: Waterhulpbronne in Suid-Afrika is beperk en grondwater speel 'n belangrike rol in die ondersteuning van basiese menslike behoeftes, volhouding van ekosisteme asook industriële en landbou-ontwikkeling. Betroubare bestuurspraktyke is noodsaaklik om die volhoubare ontwikkeling van waterhulpbronne te verseker. Alle grondwatergebruik moet volgens die Nasionale Waterwet van 1998 gelisensieer word. 'n Ruimtelike Besluitnemings Ondersteuning Stelsel (RBOS) kan as 'n hulpmiddel gebruik word in die lisensiëringsproses van die Departement van Waterwese en Bosbou. Die hoofdoel van hierdie studie was om 'n RBOS, genoem Groundwater Abstraction & Licence Evaluation Tool (GALET), te ontwikkel wat as hulpmiddel gebruik kan word in die allokeringsproses van watergebruiklisensies en die bepaling van die impak van grondwateronttrekking op die omgewing, gebaseer op bestaande teorie en data. Die ontwikkeling is in ArcView 3.2 met die programmeringstaal Avenue gedoen. Die Sandveld, 'n ariede streek aan die weskus van Suid-Afrika wat onderhewig is aan grootskaalse grondwateronttrekking, is gekies as die studie area. Die data wat vir hierdie studie ingesamel is sluit bestaande boorgat, grondwateraanvulling, reënval en geologiese inligting in. GALET was in staat om belangrike inligting aangaande die evaluering van grondwateronttrekking te bereken, o.a. die daling van die grondwatervlak, die impaksone en die moontlike effekte op landvorms soos riviere en vleilande. Die teikengroep potensiële gebruikers het GALET as 'n nuttige hulpmiddel in die proses van lisensiëring en grondwateronttrekking impakbepaling beskou en planne is onderweg om dit of 'n aangepaste program by die streekskantore van die Departement van Waterwese en Bosbou te implementeer.