Groundwater Resource Assessment for Town Water Supply in Steynsrus in the Free State Province of South Africa
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GROUNDWATER RESOURCE ASSESSMENT FOR TOWN WATER SUPPLY IN STEYNSRUS IN THE FREE STATE PROVINCE OF SOUTH AFRICA Lebogang Malefane Submitted in fulfilment of the requirements in respect of the Master’s Degree qualification Magister Scientiae in Geohydrology at the Institute for Groundwater Studies Faculty of Natural and Agricultural Sciences at the University of the Free State Supervisor: Dr Gomo M January 2016 DECLARATION (i) “I, Lebogang Malefane, declare that the Master’s Degree research dissertation that I herewith submit for the Master’s Degree qualification MSc (Geohydrology) at the University of the Free State is my independent work, and that I have not previously submitted it for a qualification at another institution of higher education.” (ii) “I, Lebogang Malefane, hereby declare that I am aware that the copyright is vested in the University of the Free State.” (iii) “I, Lebogang Malefane, hereby declare that all royalties as regards intellectual property that was developed during the course of and/or in connection with the study at the University of the Free State, will accrue to the University.” (iv) “I, Lebogang Malefane, hereby declare that I am aware that the research may only be published with the dean’s approval.” Lebogang Malefane 29 January 2016 ACKNOWLEDGEMENTS I would hereby like to express my sincere gratitude to all who have motivated and helped me in the completion of this dissertation: The study leader, Dr Modreck Gomo, for his continuous assistance, guidance and academic support. Will forever be grateful for the insight and encouragement even when the chips were down; Mr Mfundi Biyela for his interest, insight and time; Personnel at IGS: Dr François Fourie, Ms Amy Allwright, Mr Eelco Lukas and Prof Danie Vermeulen for insight and advice; Mr Ray van Rensburg of Geotron Systems for his insight and advice; Mr Jaco Hough of Geo-Hydro Technologies for permission to use their data for presentation of this document; The Department of Water and Sanitation for funding the study; Ms Keamogetswe Bokala, Ms Tshimologo Leeuw, Ms Keitumetse Nkoana, Mr Lukholo Macala, Mr Lehlohonolo Nkate, Mr Phemelo Diseko, Mr Mogapi Malebo and Ms Thato Kgari for their encouragement and belief. And finally, thanks to my family and friends for their prayers and support through the good and the bad times. A special thanks to my mother who has been an inspiration. Groundwater resource assessment for town water supply in Steynsrus in the Free State Province of South Africa iii TABLE OF CONTENTS CHAPTER 1 INTRODUCTION ..................................................................................................................... 1 1.1 RESEARCH FRAMEWORK ......................................................................................................................... 1 1.2 WATER SUPPLY BACKGROUND ................................................................................................................ 2 1.3 PROBLEM STATEMENT ............................................................................................................................ 3 1.4 METHODOLOGY ...................................................................................................................................... 4 1.5 AIMS AND OBJECTIVES ............................................................................................................................ 4 1.6 STRUCTURE OF DISSERTATION ................................................................................................................ 5 CHAPTER 2 LITERATURE REVIEW ........................................................................................................... 7 2.1 INTRODUCTION........................................................................................................................................ 7 2.2 OVERVIEW OF GROUNDWATER RESOURCE ASSESSMENT.......................................................................... 7 2.3 GROUNDWATER RESOURCE ASSESSMENT CONCEPTS .............................................................................. 8 2.3.1 Groundwater Occurrence ............................................................................................................. 8 2.3.2 Groundwater Flow and Storage ................................................................................................. 11 2.3.2.1 Borehole sustainability and aquifer parameters ................................................................ 12 2.3.3 Groundwater Recharge .............................................................................................................. 13 2.3.3.1 The Chloride Mass Balance Method (CMB) ...................................................................... 15 2.3.3.2 Qualified guesses .............................................................................................................. 16 2.3.4 Borehole Sustainable Yields ...................................................................................................... 16 2.3.5 Groundwater Quality .................................................................................................................. 18 2.3.5.1 Interpretation of chemical data .......................................................................................... 19 2.3.5.1.1 Piper and Durov diagrams ............................................................................................ 19 2.3.5.1.2 Schoeller diagram ......................................................................................................... 21 2.3.5.1.3 Groundwater salinity ..................................................................................................... 21 2.3.5.2 Statistical analysis ............................................................................................................. 21 2.4 SUSTAINABLE DEVELOPMENT ................................................................................................................ 22 2.5 GROUNDWATER ASSESSMENT CASE STUDIES ......................................................................................... 23 2.6 SUMMARY ............................................................................................................................................. 25 CHAPTER 3 SITE DESCRIPTION .............................................................................................................. 26 3.1 OVERVIEW AND ECONOMIC DEVELOPMENT ............................................................................................ 26 3.2 PHYSIOGRAPHY AND DRAINAGE ............................................................................................................. 27 3.3 RAINFALL AND CLIMATE ......................................................................................................................... 28 3.4 VEGETATION AND LAND USE .................................................................................................................. 29 3.5 WATER RESOURCES ............................................................................................................................. 31 3.5.1 Surface Water ............................................................................................................................ 31 3.5.2 Local Groundwater ..................................................................................................................... 32 3.5.3 Groundwater Potential ............................................................................................................... 33 3.5.4 Water Use in the Moqhaka Local Municipality ........................................................................... 33 Groundwater resource assessment for town water supply in Steynsrus in the Free State Province of South Africa i 3.6 GEOLOGY AND GEOHYDROLOGY ............................................................................................................ 34 3.6.1 General Geology ........................................................................................................................ 34 3.6.2 Geohydrology ............................................................................................................................. 36 3.7 SUMMARY ............................................................................................................................................. 37 CHAPTER 4 DESKTOP STUDY ................................................................................................................ 38 4.1 INTRODUCTION...................................................................................................................................... 38 4.2 REMOTE SENSING AND MAP ANALYSIS .................................................................................................... 38 4.2.1 Borehole Siting ........................................................................................................................... 43 4.3 BOREHOLE INFORMATION ..................................................................................................................... 44 4.4 SUMMARY ............................................................................................................................................. 45 CHAPTER 5 GEOPHYSICAL INVESTIGATIONS ....................................................................................... 46 5.1 INTRODUCTION.....................................................................................................................................