JAPAN INTERNATIONAL COOPERATION AGENCY DEPARTMENT OF WATAR AFFAIRS MINISTRY OF AGRICULTURE, WATER AND RURAL DEVELOPMENT THE REPUBLIC OF NAMIBIA THE STUDY ON THE GROUNDWATER POTENTIAL EVALUATION AND MANAGEMENT PLAN IN THE SOUTHEAST KALAHARI (STAMPRIET) ARTESIAN BASIN IN THE REPUBLIC OF NAMIBIA DRAFRT FINAL REPORT SUPPORTING REPORT JANUARY 2002 PACIFIC CONSULTANTS INTERNATIONAL, TOKYO IN ASSOCIATION WITH SANYU CONSULTANTS INC., TOKYO TABLE OF CONTENTS SUPPORTING REPORT SUMMARY STUDY AREA TABLE OF CONTENTS List of Tables List of Figures Abbreviations CHAPTER 1 INTRODUCTION..................................................................................... 1 – 1 1.1 Background of the Study......................................................................................... 1 - 1 1.2 Objectives of the Study ........................................................................................... 1 - 1 1.3 Study Area............................................................................................................... 1 - 2 1.4 Implementation of Study......................................................................................... 1 - 2 CHAPTER 2 METEOROLOGY AND HYDROLOGY ................................................. 2 - 1 2.1 Meteorology ............................................................................................................ 2 - 1 2.1.1 Meteorological Network........................................................................ 2 - 1 2.1.2 General Climate..................................................................................... 2 - 1 2.2 Hydrology................................................................................................................ 2 - 9 2.2.1 General .................................................................................................. 2 - 9 2.2.2 Drainage Systems .................................................................................. 2 - 9 2.2.3 Study Area Related Rivers .................................................................... 2 - 10 2.2.4 Water Balance ....................................................................................... 2 - 19 2.2.5 Issues ..................................................................................................... 2 - 19 CHAPTER 3 GEOMORPHOLOGY............................................................................... 3 - 1 3.1 General Geomorphology ......................................................................................... 3 - 1 3.2 Methodology of Geomorphologic Analysis ............................................................ 3 - 1 3.3 Geomorphologic Characteristics ............................................................................. 3 - 3 CHAPTER 4 GEOLOGY................................................................................................ 4 - 1 4.1 General Geology...................................................................................................... 4 - 1 - i - 4.2 Geological Description............................................................................................ 4 - 3 4.2.1 Pre-Karoo Basement.............................................................................. 4 - 3 4.2.2 Karoo Sequence..................................................................................... 4 - 3 4.2.3 Kalahari Beds ........................................................................................ 4 - 13 4.3 Geological Structure................................................................................................ 4 - 15 4.3.1 Cross Section......................................................................................... 4 - 15 4.3.2 Lineaments and Faults........................................................................... 4 - 15 CHAPTER 5 GEOPHYSICAL SURVEY....................................................................... 5 - 1 5.1 Purpose of Survey ................................................................................................... 5 - 1 5.2 Time Domain Electro-magnetic Survey (TEM Method) ........................................ 5 - 1 5.2.1 Survey Area........................................................................................... 5 - 1 5.2.2 Survey Method and Interpretation Procedures ...................................... 5 - 1 5.2.3 Survey Results....................................................................................... 5 - 4 5.2.4 Conclusions ........................................................................................... 5 - 12 5.3 Aeromagnetic Survey.............................................................................................. 5 - 12 5.3.1 Survey Area........................................................................................... 5 - 12 5.3.2 Survey Method and Interpretation Procedures ...................................... 5 - 12 5.3.3 Survey Results....................................................................................... 5 - 13 CHAPTER 6 TEST BOREHOLE ................................................................................... 6 - 1 6.1 Drilling Program...................................................................................................... 6 - 1 6.1.1 Outline of the Program.......................................................................... 6 - 1 6.1.2 Structure and Specification ................................................................... 6 - 2 6.1.3 Drilling Procedure ................................................................................. 6 - 5 6.1.4 Materials Used....................................................................................... 6 - 8 6.1.5 Drilling Method..................................................................................... 6 - 11 6.1.6 Sampling, Measurement and Testing .................................................... 6 - 13 6.1.7 Borehole Logging.................................................................................. 6 - 15 6.1.8 Result of Drilling................................................................................... 6 - 18 6.2 Pumping Test........................................................................................................... 6 - 37 6.2.1 Outline of the Test................................................................................. 6 - 37 6.2.2 Measurement ......................................................................................... 6 - 38 6.2.3 Method of Analysis ............................................................................... 6 - 39 6.2.4 Borehole Hydraulics.............................................................................. 6 - 43 6.2.5 Aquifer Constants.................................................................................. 6 - 45 - ii - 6.2.6 Interaction Between the Aquifers.......................................................... 6 - 47 6.2.7 Pumping Test Analysis of Existing Boreholes...................................... 6 - 48 6.3 Installation of Water Level Recorder ...................................................................... 6 - 61 6.3.1 Recorders, Installed ............................................................................... 6 - 61 6.3.2 Specification of Water Level Recorder ................................................. 6 - 61 6.3.3 Technical Transfer on Operation and Maintenance of the Recorder..... 6 - 62 6.3.4 Recommendation on Operation and Maintenance ................................ 6 - 63 CHAPTER 7 WATER QUALITY AND ISOTOPE ANALYSIS .................................... 7 - 1 7.1 Introduction ............................................................................................................. 7 - 1 7.1.1 Background and Need for Study ........................................................... 7 - 1 7.1.2 Terms of Reference ............................................................................... 7 - 2 7.1.3 Parallel IAEA Project Coordination and Linkage to JICA Project ....... 7 - 2 7.2 Hydrochemical Information .................................................................................... 7 - 3 7.2.1 Utilization of Hydrochemical Information............................................ 7 - 3 7.2.2 Sources and Extent of Existing Chemical Data from Earlier Surveys .. 7 - 3 7.2.3 Electronic Capturing of Earlier Data..................................................... 7 - 5 7.2.4 Present JICA Project Surveys................................................................ 7 - 5 7.2.5 Present IAEA Project Surveys............................................................... 7 - 6 7.2.6 Changes of Water Quality with Time.................................................... 7 - 7 7.2.7 Linking of Earlier Data with Present JICA and IAEA Project Information................................................................................ 7 - 7 7.2.8 Hydrochemical Profiles......................................................................... 7 - 9 7.3 Stable and Radioactive Isotope Information ........................................................... 7 - 10 7.3.1 Utilization of Isotope Information in Hydrogeology............................. 7 - 10 7.3.2 Sources and Extent of Existing Isotope Data from Earlier Surveys...... 7 - 14 7.3.3 Present JICA Project Surveys................................................................ 7 - 15 7.3.4 Present IAEA Project Surveys..............................................................