Groundwater Resources for Lusaka and selected Catchment Areas T E C H N I C A L R E P O R T N O . 3 HYDROGEOLOGY OF THE ITAWA SPRING IN NDOLA. BASELINE STUDY ON HYDROGEOLOGY AND HYDROCHEMISTRY by Max Karen, Dr. Tobias El-Fahem and Mumba Kolala Lusaka, December 2015 REPUBLIC OF ZAMBIA Ministry of Energy and Water Development Groundwater Resources for Lusaka and selected Catchment Areas Hydrogeology of the Itawa Spring in Ndola. Baseline Study on Hydrogeology and Hydrochemistry Author: Max Karen (GReSP), Dr. Tobias El-Fahem (BGR), Mumba Kolala (District Water Officer, Department of Water Affairs, Ndola) Commissioned by: Federal Ministry for Economic Cooperation and Development (Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung, BMZ) Project: Groundwater Resources for Lusaka and selected Catchment Areas BMZ-No.: 2011.2010.2 BGR-No.: 05-2361-01 BGR-Archive No.: Date: December 2015 2 of 60 TABLE OF CONTENTS TABLE OF CONTENTS ............................................................................................................................... 3 ANNEX ..................................................................................................................................................... 4 LIST OF FIGURES ...................................................................................................................................... 5 LIST OF TABLES ........................................................................................................................................ 5 Acronyms, abbreviations and units ........................................................................................................ 6 List of reports compiled by the project in Phase III ................................................................................ 7 Summary ................................................................................................................................................. 8 Executive Summary ................................................................................................................................. 9 1. Introduction .................................................................................................................................. 11 2. Project Objective ........................................................................................................................... 12 3. Location of the Itawa Springs ........................................................................................................ 12 4. Background ................................................................................................................................... 13 4.1 General .................................................................................................................................. 13 4.2 Topography and Drainage .................................................................................................... 14 4.3 Climate .................................................................................................................................. 16 4.4 Vegetation ............................................................................................................................. 16 5. Geology ......................................................................................................................................... 18 6. Hydrogeology ................................................................................................................................ 20 6.1 Introduction ........................................................................................................................... 20 6.2 Aquifer Characteristics .......................................................................................................... 21 Aquifer A – Basement Complex ........................................................................................... 21 Aquifer B – Muva Group and Lower Roan Quartzites ........................................................... 23 Aquifer C – Upper Roan Group ............................................................................................ 23 Aquifer D – Kakontwe Limestone ........................................................................................ 23 Aquiclude X - Lower Roan Argillites and Shales .................................................................... 24 Aquiclude Y - Mwashia Formation ....................................................................................... 24 Aquiclude Z - Border Group ................................................................................................. 25 6.3 Groundwater Infiltration ....................................................................................................... 25 6.4 Groundwater Flow Directions ............................................................................................... 26 6.5 Discharge Measurements from Artesian Boreholes and Springs .......................................... 31 7. Hydrochemistry ............................................................................................................................. 32 3 of 60 7.1 Sampling Methodology ......................................................................................................... 33 7.2 Hydrochemical Results .......................................................................................................... 36 8. Environmental Isotopes ................................................................................................................ 37 8.1 Occurrence of Deuterium and Oxygen-18 ............................................................................. 37 8.2 Stable Isotopes in Precipitation and Surface Water .............................................................. 38 8.3 Stable Isotopes in Groundwater ............................................................................................ 40 9. Identification of Threats to Groundwater ..................................................................................... 42 9.1 Local Contamination from Leaking Sewers ........................................................................... 42 9.2 Sanitation .............................................................................................................................. 44 9.3 Effluent Drains ....................................................................................................................... 45 9.4 Heavy Metal and Industrial Contamination .......................................................................... 47 9.5 Reduction of Protective Soil Cover ........................................................................................ 48 9.6 Hydrocarbons ........................................................................................................................ 48 10. Conceptual Hydrogeological Model .............................................................................................. 48 10.1 The Upper Spring Section ...................................................................................................... 49 10.2 The Lower Section ................................................................................................................. 52 10.3 Contamination and Protection .............................................................................................. 52 11. Groundwater Protection Zones .................................................................................................... 52 11.1 Inner Protection Zone - Zone 1 .............................................................................................. 53 11.2 Outer Protection Zone - Zone 2 ............................................................................................. 54 11.3 Total Catchment - Zone 3 ...................................................................................................... 54 12. Groundwater Monitoring .............................................................................................................. 55 13. Slope Stability and Backpressure .................................................................................................. 56 14. Conclusions and Recommendations ............................................................................................. 57 15. Recommendations ........................................................................................................................ 58 References ............................................................................................................................................ 60 ANNEX Annex 1 2015 DGPS Water Level Data Annex 2 2015 DWA Water Level Measurement Annex 3 2015 Inorganic Hydrochemistry Annex 4: 2015 Microbiology Results 4 of 60 LIST OF FIGURES Fig. 1: Location map. ............................................................................................................................. 11 Fig. 2: Location of the Itawa Spring. ...................................................................................................... 13 Fig. 3: Topography and drainage system. ............................................................................................. 14 Fig. 4: Spring eye. .................................................................................................................................. 15 Fig. 5: Itawa spring area. ......................................................................................................................