Index aerial photography 20, 78-9 electromagnetic surveys 96-7 Algeria 68 Landsat surveys 90-4 aluminium mobilization 127 vegetation indicators 95--6 Angola 68 Burundi 68 aquifers Bushveld Igneous Complex 45 characteristics 163-4, 248-9 lithology and fractures 166-7 Cameroon 68 rest water 164-6 Cape Supergroup 53 specific capacity 166 Cape Verde 68 water quality 170-1 catena studies weathering 168-70 Chimimbe dambo development 2-3, 25 profile 105-10 exploration techniques 19-22 stratigraphy 116 occurrence 3 texture 110-13 Archaean cratons 33 water movement 117-19 Aswa shear zone 52 water quality 121,125 Linthembwe dambo Bangweulu Block 47 profile 110 Barberton Greenstone Belt 33 stratigraphy 116 bas-fonds see dambos texture 113-16 base flow analysis 16, 70-2 water movement 119 Base Flow Index 70 water quality 121,122, 125 bedrock characteristics 4-6 Central African Republic 68 Beitbridge Group 184, 247 Chad 68 Benin 68 chemistry biotite weathering 7-9 dambo profile 108, 110 Birrimian Group 43, 45 rainfall 12 boreholes runoff water 18 correlation analysis 81-3 seepage zone water 122 design 250-2 spring water 124 yield 252--6 well water 125 correlation with terrain 136-48 Chikore 214 bornhardt 194-5 Chimimbe dambo Botswana 68 electromagnetic survey 213 brittle deformation 91-2 profile 105-10 Bua 19 stratigraphy 116 Buganda Supergroup 37, 43 textures 110-13 Bukoban Group 48 water movement 117-19 Bulawayan Group 78 water quality 18, 121,125 Burkina Faso 87 Chiota 235-40 basement geology 88, 89 chloride balance 17-18 hydrology studies 68 Choma-Kalomo Block 47 comparison of methods 97-9 Chuan shear zone 52 260 INDEX clay mineralogy 111, 114-15 faults, hydrology of 195 collapse zone 6 fracture patterns 93-4, 162-3, 166-7 collector wells 22-3 EM analysis 173-9 Comoros 68 French Reunion 68 conductivity 121,171,172 mapping 211-16 Gabon 68 Congo 68 Gambia 68 Congo Craton 33, 35 gamma signatures 109 conjugate shears 90-4 gauging stations 68-9, 70 Cote d'Ivoire 68 geology crescentic springs 122-4 basement 29-30, 77-8, 156-7 cover 30-3, 158, 160 dambos 13, 15, 65 maps 2, 30, 60, 88, 184, 246, 247 area in Malawi 136 Phanerozoic 52-3 catenary studies post-1050 Ma 51-2 profiles 105-10 post-2500 Ma 43-50 stratigraphy 116 pre-2500 Ma 33-43 textures 110-16 geomorphology origin 103-4, 116-17, 149 Malawian studies 132-4 stream development 136 borehole analyses 134-5, 136-7 water movement 117-20 statistical analysis of factors water quality 120-6 methods 137-48 Darwendele 18 results discussed 148-52 deformation analysis 90--4 terrain classification 135--6 depth/yield studies 11-12 role in hydrology 132 Diamphe 19 geophysical methods Djibouti 68 role in well siting 249-50 Dowa 8, 18, 105 see also electromagnetic surveys also drainage basins 14 resistivity dry season flow 73 Ghana 68 ductile deformation 90 gneiss 79 dykes/dyke swarms 53, 174, 195 Gondoi, Mt 194-5 granite 40, 52, 78, 79 Egypt 68 Great Dyke 41, 45, 77, 78 electrical conductivity 121,171,172, 211-16 greenstone belts 33-9, 77 electromagnetic (EM) surveys 20, 88 groundwater flow advantages 171-2 Malawi 117-19 data quality 188-91 Malawi and Zimbabwe compared 70-2 methods 186-7, 211-17 role in recharge 15-16 fractures 96-7, 173-9 Guinea 68 regolith 172-3 Guinea Bissau 68 Equatorial Guinea 68 Gwana 192-3 erosion surfaces 103, 133 etchplanation 103 Hatcliffe 8 Ethiopia 68 horizontal loop electromagnetic (HLEM) evaporation 63--4 method 96 evaporites 125--6 hydraulic conductivity, orientation analysis evapotranspiration 17 90--4 INDEX 261 hydraulic parameters 5, 8 profile 110 stratigraphy 116 igneous rock history see intrusive rocks also texture 113-16 volcanic events water movement 119 inselbergs 145 water quality 121,122, 125 Intertropical Convergence Zone (ITCZ) 59, lithology 61 effect on aquifer 161-2, 166-7 intrusive rocks 40, 45, 51, 52, 53 effect on borehole yield 149 iron in water 170 effect on remote sensing 100 Irumide Belt 47 Livulezi 8, 10, 11, 18, 19 Luiza Supergroup 43 joints see fractures Lulua Group 48

Kaapvaal Craton 33, 34 Madagascar 68 Kafwe volcanics 48 Magondi Belt 44 Kambui Supergroup 38 Mahusekwa 235-40 Kampine 18 Malawi kaolinite and kaolinization 111, 114-15, 162, current water resources 131-2 184 dambo area 136 Karoo Supergroup 53 dambo catenary studies Kasai Craton 33, 35 groundwater flow 117-19 Katangan Supergroup 51 profiles 105-10 Kenya 68 stratigraphy 116 Kerri Kerri Formation 159 texture 110-16 Khan Pegmatite 51 water movement 117-20 Kibaran Belt 47 water quality 120--6 kopje 194-5 dambo formation 103-4, 116-17 Kwara erosion studies 103 geology 246 geomorphology 132--4 rainfall 244 hydrology 68, 69-70 State Rural Water Supply Project 244-6 dry season flow 73 aquifer character 248-9 groundwater flow 70-2 borehole design 250-2 recharge patterns 74-5 borehole siting 249-50 terrain classification 135-6 borehole yield 252-6 terrain/borehole yield correlations 126-48 well testing 230-5 Landsat 78-9, 88, 89, 95-6 Mali 68 Lesotho 68 manganese in water 170 Liberia 68 Marondera 235-40 Libya 68 Masvingo 8, 10, 78, 81,184, 192-3. 215 Lilongwe 8, 18 Mauritania 68 Limpopo Mobile Belt 41-2, 78 Mauritius 68 lineaments metamorphism 40-1 borehole correlation 81-3 Mhungu Kraal 195 geometrical analysis 90--4 montmorillonite (smectite) 111, 114-15, 184 interpretation 79 Morocco 68 recognition 77 Mozambique 68 Linthembwe dambo 105 Mozambique Orogenic Belt 49-50, 51 262 INDEX

Mponela 8, 230-5 maps 2, 60, 62, 244, 245 Mporokoso Group 43 role in recharge 13, 15 Mubindji event 44 Mukogodo migmatite 51 radon gas survey 22 Mukumba 8 rainfall Multi Spectral Scanner (MSS) imagery 78-9, distribution 63 88 maps 2, 60, 62, 244, 245 Murape 8 role in recharge 13, 15 Muva Supergroup 47 recharge processes 13, 67-9 groundwater flow 15-16 Namaqua Province 46-7 measurement of 16-19, 74-5 Namibia 68 runoff 13-15 Niger 68 recovery tests Nigeria interpretation of results 225-30 aquifer characteristics 248-9 practical applications lithology 166-7 Malawi 230-5. rest water level 164--6 Zimbabwe 235-40 specific capacity 166 theory of method 224-5 water quality 170-1 regolith weathering 168-70 aquifer development borehole studies characteristics 6-9 design 250-2 effect on yield 137-52 siting 249-50 thickness effects 10-12, 40 yield 252--6 development 160-1 fracture analysis 162-3, 173-9 geophysical studies 172-3 geology 156-9, 246 lithology 161-2 hydrology 68 Reguibat Shield 46 rainfall 244 relief 13 regolith studies 172-3 correlation with borehole yield 136-7, development 160-1 139-43 lithology 161-2 analysis of results 148-52 tectonic setting 159-60 methods of classification 135--6 nitrates 170 remote sensing 20, 78-9 Nyanzian volcanics 33 resistivity 20 correlation with weathering 171,172 orogenesis 43, 48, 52-3 correlation with yield 197 data quality 188-91 Pan African Dyke 179 field results 195--6 pediplanation 103 methods of measurement permeability sounding 187-8, 204-10 profile variation 117, 161,185 traversing 210-11 weathering effects 7-9 rest levels 164-6 see also hydraulic conductivity Rhodesian (Zimbabwe) Craton 34, 40 plate tectonic history 52 river flow data 68-9, 70 Pongota S~laergroap 30 Rokel River Group 52 porosity 185 runoff rates 13-15, 64-7 precipitation Rwanda 68 distribution 59--63 INDEX 263

St Liobas 8 Tuareg Shield 46 St Nicholas 8, 235-40 Tunisia 68 Salani Kraal 194 Sao Tome and Principe 68 Uganda 69 saprock 4 saprolite 6, 7, 12 valleys, hydrologic characters of 192-4, 195 satellite imagery 20, 78-9, 88 vegetation, role in groundwater surveys of Sebakwian Group 78 96, 99-100 seepage water 121 Ventersdorp Supergroup 30 Senegal 68 vertical electric sounding (VES) 20, 156, Seychelles 68 171-2, 173, 204-10 Shamvaian Group 38, 78 very low frequency EM (VLF-EM) 96, 216 sheafing studies 90--4 Victoria Province 183 Sierra Leone 68 Drought Relief Project 183, 244-6 smectite (montmorillonite) 111, 114-15, 184 aquifer characteristics 192-5, 248-9 soil profile development 65 borehole design 250-2 Somalia 68 borehole siting 198-200, 249-50 South Africa 68 borehole yield 197-8,252-6 specific capacity 166, 198-9, 254-5 EM survey 186-7 springs 122-4 resistivity sounding 187-8, 195 stratigraphy geological setting 184, 247 groundwater flow 119 rainfall 245 water quality 121,125 vleis see dambos structural geological effects 10 volcanic events 51 Sudan 68 Voltaian Group 52 Swaziland 68 Vumba Greenstone Belt 38, 39

Tanzania 69 water Tanzanian Craton 33, 34 balance analysis 66 Taoudenni Basin 46 consumption and needs 1-2 Tarkwaian Group 45 quality measures 120-6, 165, 170-1 Tati Greenstone Belt 38 weathering tectonic analysis 80-1, 90-4, 159--60 effect on permeability 7-9, 161 tectonothermal events 40-1 effect on specific capacity 168-70 tensile fractures 93-4 profile description 4-7 terrain studies profile variation 185, 221-3 characterization wells methods 13, 135-6 pump testing results 136--7 field applications effect on yield Malawi 230-5 methods 137-48 Zimbabwe 235-40 results 148-52 methods 224-5 Thematic Mapper (TM) system 88, 95-6 results 225-30 Tibesti Belt 51 water quality 124-5 time--domain EM 216-17 West African Cratons 35 Togo 68 West African Shield 88 topography see relief Wilson cycle 52 trace element analysis 108 Witwatersrand Supergroup 30 264 INDEX

XRD/XRF106,107,108,111 borehole design 250-2 borehole siting 249-50 yield studies 11-12, 66, 81-3, 252-6 borehole yield 252-6 geomorphological approach geological setting 77-8, 247 methods 137-48 hydrology 69-70 results discussed 148-52 dry season flow 73 groundwater flow 70-2 Zaire 69 recharge patterns 74-5 Zambesi Belt 47 rainfall 245 Zambia 69 tectonic setting 80-1 Zimbabwe well testing scheme 235-40 aquifer characteristics 248-9 Zimbabwe Craton 34, 40 borehole correlation analysis 81-3