REPUBLIC OF ZAMBIA FEDERAL REPUBLIC OF Ministry of Energy and GERMANY Water Development Federal Institute for Geosciences and Natural Resources The Groundwater Resources of Southern Province, Zambia (Phase 1) Volume 1 - Technical Report - Technical Co-operation, Project No. BMZ PN 2003.2024.2 Lusaka 2007 The Groundwater Resources of Southern Province, Zambia (Phase 1) Volume 1 - Technical Report - Authors (in alphabetical order): Dr. Roland Bäumle (BGR) Dr. Christoph Neukum (BGR) Jack Nkhoma (DWA) Oscar Silembo (DWA) Commissioned by: Federal Ministry for Economic Cooperation and Development (BMZ: Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung) Project Numbers: BMZ PN 2003.2024.2 BGR 05-2315-01 Implementing Agencies: Ministry of Energy and Water Development, Department of Water Affairs, Lusaka, Choma Federal Institute for Geosciences and Natural Resources (BGR: Bundesanstalt für Geowissenschafen und Rohstoffe, Hannover) Pages: 132 Place and date of issuance: Lusaka, November 2007 Page - I - T ABLE OF C ONTENTS 1. Introduction........................................................................................... 1 1.1. Project Framework .................................................................................1 1.2. Objectives and Tasks..............................................................................2 1.3. The Significance of Groundwater in the Province......................................4 2. Physiography ......................................................................................... 5 2.1. Topography ...........................................................................................5 2.2. Vegetation .............................................................................................8 2.3. Soils ......................................................................................................9 2.3.1. Soil Units........................................................................................9 2.3.2. Soil Thickness...............................................................................12 3. Climate................................................................................................. 13 3.1. Temperature and other Climatic Parameters ..........................................13 3.2. Rainfall ................................................................................................14 3.2.1. Secular Rainfall and Droughts ........................................................14 3.2.2. Monthly Rainfall ............................................................................18 3.3. Evaporation .........................................................................................19 4. Hydrology............................................................................................. 21 4.1. River Systems and Runoff.....................................................................21 4.1.1. Zambezi River...............................................................................21 4.1.2. Kafue River...................................................................................27 4.2. Dams and Reservoirs............................................................................28 4.3. Catchments .........................................................................................30 4.4. Surface Water Potential ........................................................................35 5. Geology ................................................................................................ 37 5.1. Stratigraphic Succession .......................................................................38 5.2. Lithology .............................................................................................45 5.3. Tectonics.............................................................................................51 5.3.1. Fault Systems ...............................................................................51 5.3.2. Dyke Systems...............................................................................54 6. Water Use, Supply and Sanitation ....................................................... 57 6.1. Water Use and Irrigation ......................................................................57 6.2. Water Supply .......................................................................................59 6.3. Sanitation ............................................................................................62 7. Groundwater Information System....................................................... 65 7.1. Groundwater Database.........................................................................65 7.2. Geographic Information System - GIS....................................................70 8. Groundwater Resources ...................................................................... 72 8.1. Aquifer Classification System.................................................................72 8.1.1. Aquifer Parameters .......................................................................72 8.1.2. Empirical Relationship between Transmissivity and Specific Capacity 74 8.1.3. Aquifer Categories ........................................................................75 8.2. Major Aquifer Systems..........................................................................77 8.2.1. Aquifer Lithology...........................................................................77 8.2.2. Hydraulic Test Statistics ................................................................78 8.2.3. Aquifer Potential ...........................................................................81 Page - II - 8.3. Regional Groundwater Flow ..................................................................89 8.4. Groundwater Recharge and Potential.....................................................92 8.5. Springs................................................................................................93 8.6. Groundwater Level Monitoring ..............................................................96 8.7. Chemical Groundwater Composition and Quality ....................................98 8.7.1. Groundwater Quality Sampling Campaign.......................................98 8.7.2. Overall Groundwater Chemistry ................................................... 101 8.7.3. Groundwater Contamination ........................................................ 104 8.7.4. Regional Distribution Patterns...................................................... 107 8.7.5. Waterborne Diseases .................................................................. 109 8.7.6. Water Quality Discussion ............................................................. 113 8.8. Groundwater Vulnerability................................................................... 113 8.9. Hydrogeological Maps......................................................................... 118 9. Conclusions and Recommendations .................................................. 121 10. References...................................................................................... 125 Page - III - L IST OF F IGURES Figure 1-1 Project Area: The Southern Province ...................................................2 Figure 1-2 Flowchart showing the concept of developing a groundwater information system ...............................................................................3 Figure 2-1 Shaded relief and block diagram generated from the DEM..................6 Figure 2-2 Digital Elevation Model with elevation zones at 200 m- intervals .........7 Figure 2-3 Mopane woodland with patches of miombo woodland near Siavonga during the rainy season ........................................................................8 Figure 2-4 Soils of the SP and adjacent areas in Zambia......................................9 Figure 2-5: Estimation of the soil thickness distribution in the SP ........................12 Figure 3-1 Isohyetal map of annual rainfall..........................................................16 Figure 3-2 Long-term (secular) rainfall (since 1950) at Choma ...........................17 Figure 3-3 Seasonal rainfall (1995 – 2006) at rainfall stations in SP ...................17 Figure 3-4 Approximate position of the ITCZ .......................................................18 Figure 3-5 Frequency of daily rainfall at Choma during the 2005/06 rainy season ............................................................................................................19 Figure 3-6 Seasonal variation of monthly mean temperature, rainfall and evaporation at Choma ........................................................................20 Figure 4-1 Area of Zambezi Catchment from its headwaters to the Luangwa confluence. .........................................................................................23 Figure 4-2 Annual runoff of the Zambezi River between Zambian border in Western Province and Luangwa confluence ......................................24 Figure 4-3 Specific Runoff of the Zambezi between the Zambian border in Western Province and the Luangwa confluence ................................24 Figure 4-4 Average monthly discharge at selected gauging stations in the Kafue and Zambezi catchments ...................................................................25 Figure 4-5 Area of Kafue Catchment along its course .........................................25 Figure 4-6 Annual runoff of the Kafue River ........................................................26