United Republic of Tanzania Water Master Plans for Iringa, Ruvuma and Mbeya Regions
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UNITED REPUBLIC OF TANZANIA DANISH INTERNATIONAL DEVELOPMENT AGENCY • DANIDA 8 2 4 UBRARY TZ.IR 82 INTERNA-IONAL REFERENCE CENTRE FOR CO.VWU. .i!; Y WATER SUPPLY AND SANITATION (IRC) WATER MASTER PLANS FOR IRINGA, RUVUMA AND MBEYA REGIONS HYDROGEOLOGY VOLUME 9 ,••«•••*.«•• CARL BRO - COWICONSULT UNITED REPUBLIC OF TANZANIA DANISH INTERNATIONAL DEVELOPMENT AGENCY • DANIDA WATER MASTER PLANS FOR IRINGA, RUVUMA AND MBEYA REGIONS HYDROGEOLOGY VOLUME 9 ; : P.O. Rox?-3.f..-, ?:'.joAD T!.nij, i! Tel. (070) 8!4i)H ext. 141/142 CARL BRO • COWICONSULT • KAMPSAX - KRLJGER • CCKK 1982 GUIDE TO WATER MASTER PLANS FOR IRINGA,RUVUMA AND MBEYA POPULATION 3/2, W2M, 12/3 DEVELOPMENT LIVESTOCK 3/2, UK/2/3/5, 12/2 FRAMEWORK AGRICULTURE 3/2, AA/3/5, 11/3, 12/2 INDUSTRY 3/2 INVENTORY 5A/1, 12/4 VILLAGES AND DEVELOPMENT 4A/4 EXISTING TRADITIONAL W.S. 4A/6, 12/5 WATER SUPPLY IMPROVED W.S. 4A/6 HUMAN CONSUMPTION 3/5, 5A/4, 12/8 WATER USE AND LIVESTOCK DEMAND 3/5, 5A/4, 12/9 DESIGN CRITERIA TECHNICAL ASPECTS 3/5. 5 A/4 a. OH TECHHOLOGY OPTIONS 5A/5, 12/7 WATER QUALITY 3/5, 4A/6, 4B/7, 5A/3, 12/5/10/11 en WATER SUPPLY SOURCE SELECTION 3/6, 4B/7, 12/5 PLANNING CRITERIA PRIORITY CRITERIA 3/5, 5A/2, 12/12 COST CRITERIA 5A/2/6, 12/12 g REHABILITATION 4B/8 PROPOSED SINGLE VILLAGE SCHEMES 4B/8 SUPPLIES GROUP VILLAGE SCHEMES 4B/8 SCHEME LAY-OUT AND DETAILS 5B, 5C, 5D, 5E IRINGA SCHEME LAY-OUT AND DETAILS 5B, 5C, 5D RUVUMA SCHEME LAY-OUT AMD DETAILS 5B, 5C, 5D MBEYA ECONOMIC COST 3/6, 4B/9/10, 5B, 5C, 5D, 5E IRINGA ECONOMIC COST 3/6, 4B/9/10, 5B, 5C, 5D RUVUMA COST 5D COST ECONOMIC 3/6, 4B/9/10, 5B, 5C, MBEYA FINANCIAL COST 3/6, 4B/9/10 STRATEGIES 3/6, 4B/10 PROGRAMME 3/6. IMPLEMENTATION 4B/10 ORGANISATION 3/6, 4B/11, 12/6 PARTICIPATION 3/6, 4B/10/11, 12/6 RAINFALL 3/3. 7/3 EVAPORATION 3/3, 7/4 HYDROLOGY RUNOFF 3/3, 7/5/6 MODELLING 3/3. 7/7 BALANCES 3/3, 7/7/8 GEOLOGY 3/4 9/5 GROUNDWATER DOMAINS 3/4 9/7 HYDROGEOLOGY GEOPHYSICS 3/4 9/8 CHEMISTRY 3/4 9/9 GROUNDWATER DEVELOPMENT 3/4 9/12 DRILLING 3/4 9/11 WATER RELATED IRRIGATION 11/4, 12/9 PROJECTS HYDROPOWER 11/4 NOTES THE CHAPTERS REFERRED TO ARE THOSE WHERE THE MAIN DESCRIPTIONS APPEAR. THE REFERENCE CODE 5A/6 MEANS, VOLUME 5A, CHAPTER 6. CONTENTS Page 1. INTRODUCTION 1.1 2. APPROACH AND ORGANISATION OF WORK 2.1 2.1 Aproach 2.1 2.2 Organisation of Work 2.1 3. SUMMARY OF BASIS DATA 3.1 3.1 Borehole Data 3.1 3.1.1 Existing Borehole Data 3.1 3.1.2 Borehole Data from Wells Drilled by The Consultants 3.3 3.1.3 Chemical Data 3.U 3.1.1+ Down-the-Hole Logging 3.5 3.2 Geophysical Surveys 3.5 3.2.1 Existing Geophysical Surveys 3.5 3.2.2 Supplementary Geophysical Surveys 3.5 U. PHYSIOGRAPHY U.I k.1 Topography U.1 U.2 Climate U.3 U.3 Surface drainage . U.5 U.U Vegetation and land use U.7 U.5 Soils U.10 5. GEOLOGY 5.1 5.1 Introduction 5.1 5.2 Stratigraphy and Distribution of Rocks 5.1 5.2.1 Pre-Cambrian - Basement Complex 5.1 5.2.2 The Karroo System 5.U 5.2.3 Cretaceous Rocks 5.5 5.2.U Neogene Deposits 5.5 5.3 Structure 5.7 5.3.1 Pre-Cambrian Folds 5.7 5.3.2 Faults 5.9 5.U Rock Weathering and Erosion 5.11 5.U.I Time • 5.12 5.U.2 Climate 5.12 5.U.3 Jointing 5.13 5. U.U Mineral Composition of Parent Rock 5.13 6. GEOMORPHOLOGY 6.1 Introduction 6.1 6.2 The Erosion Cycle Concept . 6.1 6.3 Erosion Cycles in the Regions 6.U 6.3.1 The Gondwane and Post-Gondwana Erosion Cycles 6.5 6.3.2 The African Erosion Cycle 6.7 6.3.3 The Post-African Erosion Cycles 6.8 6.3.U The Coastal/Congo Erosion Cycles 6.9 6.3.5 Scarp Areas 6.9 6.3.6 The Karroo Formation 6.10 6.U Aggradational Land Surfaces 6.11 6.U.I Lake Deposits 6.11 6.U.2 The Rungwe Volcanics 6.11 (cont'd) CONTENTS Page 7. ' HYDROGEOLOGY OF GROUNDWATER DEMAINS 7-1 7.1 Introduction 7.1 7.2 Defining the Aquifers 7-2 7.2.1 The Saprolites of the Basement Complex Pediplains 7-2 - 7.2.2 Scarp Areas 7-3 7.2.3 The Karroo System 7-1+ 7.2.1+ Aggradational Surfaces 7-1+ 7.3 The Gondwana and Post-Gondwana Land Surfaces 7-^ 7.3.1 Physiography 7.*+ 7.3.2 Geology and Structure . 7-5 7.3.3 Infiltration and Drainage 7-5 7.3.1+ Groundwater Level and Movement 7.7 7-3.5 Yield of Wells 7-8 7.3.6 Groundwater Chemistry 7-8 7.1+ The African Land Surface 7-9 7.U.I Physiography 7-9 7.1+.2 Geology and Structure 7-9 7.1+-3 Infiltration and Drainage 7.11 7.U-U Groundwater Level and Movement 7.15 7.1+-5 Yield of Wells 7.18 7.1+.6 Aquifer Hydraulic Parameters 7.20 7.U.7 Groundwater Chemistry 1.2k 7.5 The Post-African Land Surface 7.25 7.5.1 Physiography 7-25 7.5.2 Geology and Structure 7-25 7.5-3 Infiltration and Drainage 7-27 7-5.1+ Groundwater Level and Movement 7.30 7.5.5 Yield of Wells 7-31 7.5.6 Aquifer Hydraulic Parameters 7-33 7.5.7 Groundwater Chemistry 7-36 7.6 The Congo Land Surface 7-37 7.6.1 Physiography 7-37 7.6.2 Geology and Structure . 7.37 7.6.3 Infiltration and Drainage 7-38 7.6.1+ Groundwater Level and Movement 7-39 7.6.5 Yield of Wells 7.^0 7.6.6 Aquifer Hydraulic Properties 7.1+0 7.6.7 Groundwater Chemistry 7-1+0 7.7 Scarp Areas 7.1+0 7.7.1 Physiography 7-^0 7.7.2 Groundwater Occurrence 7-1+1 7-8 The Karroo Sediments 7.1+2 7.8.1 Physiography 7.1+2 7.8.2 Geology 7.1+3 7.8.3 Infiltration and Drainage 7-1+8 7.8.1+ Groundwater Level and Movement 7-52 7-8.5 Yield of Wells and Aquifer Hydraulic Properties 7-53 7-8.6 Groundwater Chemistry 7-55 7.9 The Usangu Flats 7.56 7-9.1 Physiography 7.56 7.9.2 Geomorphology, Geology and Structure 7.59 7-9-3 Hydrogeology 7.62 7-9.1+ yields of Wells 7.67 CONTENTS Page 7.10 The Rukwa Trough 7.68 7.10.1 Physiography 7.68 7.10.2 Geomorphology, Geology and Structure 7-69 7.10.3 Hydrogeology 7-70 7.10.U Yield of Wells 7.72 7.10.5 Groundvater Chemistry 7-73 7.11 The Rungwe Volcanic Province 7-7^ 7.11.1 Physiography 7-7^ 7.11.2 Geology and Structure • 7-7*+ 7.11.3 Infiltration and Drainage 7-75 7.11.U Groundvater Occurrences and Quality 7-78 7.12 Alluvium and Colluvium 7-79 7.12.1 Physiography 7-79 7.12.2 Lithology 7-79 7.12.3 Infiltration and Drainage 7.80 7.12.2 Groundvater Level and Movement 7-80 7.12.5 Yield of Wells 7-82 7.12.6 Aquifer Hydraulic Properties 7-82 7.12.7 Groundvater Chemistry 7-81+ GEOPHYSICAL SURVEY 8.1 8.1 Introduction 8.1 8.2 Geoelectric Soundings 8.1 8.2.1 The Basement Complex 8.2 8.2.2 The Karroo Basins 8.7 8.2.3 Neogene Deposits 8.9 8.2.U Resistivities of Rocks 8.10 8.3 Constant Separation Traverses 8.10 8.U Seismic Profiles 8.12 8.U.I The Basement Complex 8.12 8.U.2 The Karroo Basins 8.lU 8.U.3 Seismic Velocities of Rocks 8.lU 8.5 Down-the-Hole Logging 8.15 8.5.1 Logging in Basement Complex 8.l6 8.5.2 Logging in Karroo Formations 8.l6 GROUNDWATER CHEMISTRY 9.1 9-1 Introduction 9.1 9.2 Transformation of Groundwater Types 9.1 9.2.1 Transformation No. 1 9.3 9.2.2 Transformation No. 2 9.3 9.2.3 Tran s format ion No. 3 9.3 9.2.U Transformation No. h 9.3 9.3 Groundwater Types 9.3 9.3.1 The strong acid alkali type, Type 1 9 .k 9.3.2 Sulphate reduction of strong acids with partial ion exchange, Type 2 9.1+ 9.3.3 Strong acids with non-carbonate hardness Type 3 9.5 9-3.H Strong acids with non-carbonate hardness and normal cation exchange and sulphate reduction, Type U 9-5 9.3.5 The weak acids alkaline earths type, Type 5 9.5 (cont'd) CONTENTS Page 9.3.6 Weak acids with partial ion exchange of alkaline earths with alkali, Type 6 9-6 9.3.7 Carbonate alkali type, Type 7 9.6 9.1+ Relation to Geology and structure 9-6 9.U.I The Basement Complex 9-7 9.1*.