Characterisation of some fractured-rock aquifers in Limpopo province, South Africa : review and case study

dc.contributor.advisorWitthuser, K.T.en
dc.contributor.advisorVan Rooy, J.L. (Jan Louis)en
dc.contributor.emailmatthys.dippenaar@up.ac.zaen
dc.contributor.postgraduateDippenaar, Matthys Alois
dc.date.accessioned2013-09-07T14:05:29Z
dc.date.available2009-11-02en
dc.date.available2013-09-07T14:05:29Z
dc.date.created2009-04-17en
dc.date.issued2008en
dc.date.submitted2009-10-13en
dc.descriptionDissertation (MSc)--University of Pretoria, 2008.en
dc.description.abstractThis dissertation collates all available data from the Department of Water Affairs and Forestry’s (DWAF’s) National Groundwater Database (NGDB), DWAF’s Groundwater Resource Information Project (GRIP) and tests conducted during the progress of this project in order to evaluate Basement aquifers. The project was commenced at the request of the Water Research Commission (WRC), situated in Pretoria, South Africa. The study area (Limpopo and Luvuvhu-Letaba Water Management Areas, WMA1 and WMA2 respectively) is underlain by fractured, crystalline Basement terrain. The influences of structures (i.e. joints, faults and shear zones) and the neotectonic stress conditions were also studied to address the influence on groundwater flow and occurrence. The aim of the project was to address the determination of the aquifer parameters (essentially transmissivity and sustainable yield) in Basement terrane. Pumping test data was used and analysed via the Flow Characteristic Programme (Institute for Groundwater Studies, University of Free State). The methods of Logan (1964), Theis (1935), Cooper-Jacob (1946) and Birsoy-Summers (1980) were applied for comparative purposes. Statistically, all four methods supplied results within the same order of magnitude, with Theis and Cooper-Jacob correlating extremely well. Results from the Logan and Birsoy-Summers methods correlated very well too, but the T-values calculated via Logan’s method were almost double those obtained from the step-drawdown data analysed via the Birsoy-Summers method. The combined results adhered to a developed model-setting-scenario approach where each borehole can be evaluated based on three parameters. Firstly, the model refers to the potential water-bearing and/or water-barring features. In the study area, it was found that water predominates in the Hout River Shear Zone, and that the neotectonic stress fields have little influence on determining the orientation of favourable water-bearing structures. Geological contacts often resulted in higher yielding boreholes than geological structures. Secondly, the setting refers to the climatic and tectonic setting of the site. This determines the recharge and the orientation of structures. Based on this, supposedly closed structures (due to prevailing neotectonic stress fields) often supplied higher yielding boreholes than the supposedly open structures. Rainfall and climate however had little influence on the results. Finally, the scenario ranks a borehole in terms of high, intermediate or low transmissivity and subsequently potential yield. High T-values typically exceeded 100 m2/d whereas low T-values were generally below 5 m2/d. Significantly low yielding boreholes therefore formed part of the Low T Scenario, and high yielding boreholes of the High T Scenario. Copyrighten
dc.description.availabilityunrestricteden
dc.description.departmentGeologyen
dc.identifier.citationDippenaar, MA 2008, Characterisation of some fractured-rock aquifers in Limpopo province, South Africa : review and case study, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/28689 >en
dc.identifier.otherE1391/gmen
dc.identifier.upetdurlhttp://upetd.up.ac.za/thesis/available/etd-10132009-203134/en
dc.identifier.urihttp://hdl.handle.net/2263/28689
dc.language.isoen
dc.publisherUniversity of Pretoriaen_ZA
dc.rights© 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.en
dc.subjectDepartment of water affairs and forestryen
dc.subjectBasement aquifersen
dc.subjectPumping testen
dc.subjectGroundwateren
dc.subjectFractured aquiferen
dc.subjectNeotectonicen
dc.subjectGroundwater flowen
dc.subjectDwafen
dc.subjectNgdben
dc.subjectNational groundwater databaseen
dc.subjectUCTDen_US
dc.titleCharacterisation of some fractured-rock aquifers in Limpopo province, South Africa : review and case studyen
dc.typeDissertationen

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