Environmental Considerations Pertaining to the Orange River
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Study Name: Orange River Integrated Water Resources Management Plan Report Title: Environmental Considerations Pertaining to the Orange River Submitted By: WRP Consulting Engineers, Jeffares and Green, Sechaba Consulting, WCE Pty Ltd, Water Surveys Botswana (Pty) Ltd Authors: R Heath, C Brown Date of Issue: August 2007 Distribution: Botswana: DWA: 2 copies (Katai, Setloboko) Lesotho: Commissioner of Water: 2 copies (Ramosoeu, Nthathakane) Namibia: MAWRD: 2 copies (Amakali) South Africa: DWAF: 2 copies (Pyke, van Niekerk) GTZ: 2 copies (Vogel, Mpho) Reports: Review of Existing Infrastructure in the Orange River Catchment Review of Surface Hydrology in the Orange River Catchment Flood Management Evaluation of the Orange River Review of Groundwater Resources in the Orange River Catchment Environmental Considerations Pertaining to the Orange River Summary of Water Requirements from the Orange River Water Quality in the Orange River Demographic and Economic Activity in the four Orange Basin States Current Analytical Methods and Technical Capacity of the four Orange Basin States Institutional Structures in the four Orange Basin States Legislation and Legal Issues Surrounding the Orange River Catchment Summary Report TABLE OF CONTENTS 1 INTRODUCTION ................................................................................................................ 7 1.1 Future demands on the Orange River ..................................................................... 9 2 ENVIRONMENTAL ISSUES IN LESOTHO ..................................................................... 14 2.1 Conservation Areas ............................................................................................... 14 2.2 Cultural and Historical Heritage ............................................................................. 17 2.3 Biodiversity in Lesotho ........................................................................................... 25 2.4 Impacts of Dams on Lesotho ................................................................................. 36 3 ENVIRONMENTAL ISSUES IN SOUTH AFRICA ........................................................... 46 3.1 Introduction ............................................................................................................ 46 3.2 Flow Changes in Orange River ............................................................................. 48 3.3 Water Quality Changes ......................................................................................... 54 3.4 Trajectory of Change in Orange River .................................................................. 57 3.5 Habitat Integrity of Upper Orange River ................................................................ 58 3.6 Ecological Consequences of Flow Changes ......................................................... 60 3.7 Macroinvertebrates in Lower Orange River .......................................................... 63 3.8 Conservation Areas in Orange River .................................................................... 64 3.9 National Heritage Sites .......................................................................................... 68 4 ENVIRONMENTAL ISSUES IN BOTSWANA ................................................................. 69 4.1 Environmental Overview of the Molopo River Basin ............................................. 69 4.2 Environmental Protection and Conservation ......................................................... 87 4.3 Conservation Areas ............................................................................................... 91 4.4 Archeological and Cultural Heritage Resources ................................................... 95 4.5 Ecological Sensitivity ............................................................................................. 97 4.6 Environmental Impacts from Previous Developments in the Molopo River Basin and other Concerns ............................................................................................... 98 5 ENVIRONMENTAL ISSUES IN NAMIBIA ..................................................................... 102 5.1 Background .......................................................................................................... 102 5.2 Conservation Areas ............................................................................................. 106 5.3 Environmental Challenges .................................................................................. 107 5.4 A Focus on the Orange River .............................................................................. 119 5.5 The Ecological Importance and Sensitivity of the Lower Orange River Downstream of 20º Longitude to the Orange-Fish Confluence .......................... 120 5.6 Orange River Mouth Development Plan ............................................................. 121 5.7 Heritage Sensitivity .............................................................................................. 122 5.8 Sendelingsdrif Proposed Irrigation Scheme ........................................................ 122 5.9 Land Capability and Alternative Options ............................................................. 123 5.10 Conclusion ........................................................................................................... 129 6 COMMON ENVIRONMENTAL ISSUES ........................................................................ 130 7 ENVIRONMENTAL FLOWS ........................................................................................... 133 7.1 Background to Environmental Flows ................................................................... 133 7.2 Lesotho and Environmental Flows ...................................................................... 136 7.3 South Africa and Environmental Flows. .............................................................. 138 7.4 Botswana ............................................................................................................. 149 7.5 Namibia ................................................................................................................ 150 7.6 Possible international implications related to environmental flows ..................... 150 8 DATA AVAILABLE AND GAPS ...................................................................................... 152 9 RECOMMENDATIONS AND CONCLUSIONS ............................................................. 156 10 REFERENCES ............................................................................................................... 158 11 APPENDIX A .................................................................................................................. 188 LIST OF FIGURES AND TABLES Figure 1-1: Orange River ............................................................................................................ 7 Figure 1-2: Approximate Water Balance for Natural Runoff in the Orange River Basin (ORASECOM Inception report 2004) ................................................................................. 8 Figure 1-3: Major Water Demands along the Lower Orange River. ........................................ 11 Figure 1-4: Major Water Transfer Schemes from Gariep and Vanderkloof dams. ................. 12 Figure 1-5: Phase 1 of the Lesotho Highlands Water Project. ................................................ 13 Figure 2-1: Locality of Lesotho National Parks, Nature reserves and Transfrontier National park. ................................................................................................................................... 15 Table 2-1: Legal Instruments and Special Events as Driving Forces for environmental change. .............................................................................................................................. 18 Table 2-2: Biological Diversity in Lesotho ................................................................................ 27 Table 2-3: Numbers of known Lesotho Plant taxa ................................................................... 27 Table 2-4: Mammals which are found in Lesotho’s checklist .................................................. 30 Table 2-5: Red Data Book Checklist of bird species occurring in Lesotho ............................ 32 Table 2-6: Checklist of Lesotho’s reptiles ................................................................................ 33 Table 2-7: Checklist of Lesotho amphibians ............................................................................ 34 Table 2-8: Checklist of Lesotho fish. ........................................................................................ 36 Table 3-1: Details of main reservoirs and weirs on the Orange River ..................................... 48 Figure 3-1: Box and whisker plots of the average monthly flows for weir D1H003 for the period 1959 to 1998 .......................................................................................................... 51 Figure 3-2: Box and whisker plots of the average monthly flows for weir D1H003 for the period 1999 to 2003 .......................................................................................................... 52 Figure 3-3: MAR for 10-Year Periods of the Observed Records from D7H008 ...................... 53 Figure 3-4: Seasonal Distribution of Flows (Monthly Averages) for Each 10-Year Period ..... 53 Figure 3-5: Mean monthly flows measured at Boegoeburg Dam before and after upstream dam regulation. .................................................................................................................