UNIVERSITY OF ZIMMBABWE FACULTY OF ENGINEERING DEPARTMENT OF CIVIL ENGINEERING An assessment of surface water availability in the Pungwe sub catchment and development of an appropriate water allocation framework By Nyararai Matimba MSc. THESIS IN WREM HARARE, APRIL 2016 UNIVERSITY OF ZIMMBABWE FACULTY OF ENGINEERING DEPARTMENT OF CIVIL ENGINEERING An assessment of surface water availability in the Pungwe sub catchment and development of an appropriate water allocation framework By Nyararai Matimba A thesis submitted in partial fulfilment for the requirements of Masters degree in Water Resources Engineering and Management of the University of Zimbabwe Supervisors Mr A Mhizha Mr E Madamombe An assessment of surface water availability in the Pungwe sub catchment and development of an appropriate water allocation framework DECLARATION I, Matimba Nyararai, declare that this research report is my own work. It is being submitted for the degree of Master of Science in Water Resources Engineering and Management of the University of Zimbabwe. It has not been submitted before for any examination for any degree in any other University. Date Signature Matimba Nyararai MSc WREM Thesis 2016 Page i An assessment of surface water availability in the Pungwe sub catchment and development of an appropriate water allocation framework The findings, interpretations and conclusions expressed in this study neither reflect the views of the University of Zimbabwe, Department of Civil Engineering nor those of the individual members of the MSc Examination committee, nor their respective employees. Matimba Nyararai MSc WREM Thesis 2016 Page ii An assessment of surface water availability in the Pungwe sub catchment and development of an appropriate water allocation framework TABLE OF CONTENTS DECLARATION ........................................................................................................................i TABLE OF CONTENTS......................................................................................................... iii LIST OF FIGURES ............................................................................................................... viii LIST OF TABLES.....................................................................................................................x ABBREVIATIONS ..................................................................................................................xi DEDICATION.........................................................................................................................xii ACKNOWLEDGEMENTS................................................................................................... xiii ABSTRACT............................................................................................................................xiv CHAPTER ONE ........................................................................................................................1 1.0 Introduction......................................................................................................................1 1.1 Background......................................................................................................................1 1.2 Problem statement............................................................................................................2 1.3 Justification for the study.................................................................................................3 1.4 Objectives ........................................................................................................................3 1.4.1 Main objective ..........................................................................................................3 1.4.2 Specific Objectives ...................................................................................................3 1.5 Thesis outline...................................................................................................................4 CHAPTER TWO .......................................................................................................................5 2.0 Literature Review.............................................................................................................5 2.1 Introduction......................................................................................................................5 2.2 International and Regional water management................................................................5 2.3 Water management in Zimbabwe ....................................................................................7 2.4 Challenges for water resource management ....................................................................9 2.5 Models as decision support tools ...................................................................................11 2.5.1 Climate change modelling and future water resources assessment ........................11 2.5.2 Water resources assessment models .......................................................................12 2.6 Pitman Model.................................................................................................................12 2.6.1 Calibration of the Pitman Model.............................................................................14 Matimba Nyararai MSc WREM Thesis 2016 Page iii An assessment of surface water availability in the Pungwe sub catchment and development of an appropriate water allocation framework 2.6.2 Application of the Pitman Model in Water Resources Assessment .......................16 2.7 Catchment water usage ..................................................................................................17 2.7.1 Water use sectors. ...................................................................................................17 2.7.2 Water use estimation...............................................................................................17 2.8 Conflicts in water use and allocation .............................................................................17 2.9 Water allocation practices..............................................................................................18 2.9.1 Priority water allocation practice ............................................................................19 2.9.2 Proportional water allocation system......................................................................19 2.9.3 Market based water allocation practice...................................................................20 2.10 Modelling Water Allocation Practices.........................................................................20 2.10.1 Water Evaluation and Planning (WEAP) Model..................................................21 2.10.2 Water Resources Yield Model (WRYM) .............................................................22 2.10.3 Water Allocation Flow Model in Excel (WAFLEX) Model ................................23 CHAPTER THREE .................................................................................................................24 3.0 Study area.......................................................................................................................24 3.1 Introduction....................................................................................................................24 3.2 Study Area .....................................................................................................................24 3.3 Climate...........................................................................................................................26 3.4 Topography and slopes ..................................................................................................27 3.5 Geology and Hydrogeology...........................................................................................28 3.6 Soils................................................................................................................................29 CHAPTER FOUR....................................................................................................................31 4.0 Materials and Methods...................................................................................................31 4.1 Introduction....................................................................................................................31 4.2 Data collected and data quality control..........................................................................31 4.2.1 Rainfall data............................................................................................................31 4.2.2 Runoff data..............................................................................................................31 4.2.3 Water permits data ..................................................................................................32 4.3 Spatial and temporal surface water availability in the catchment..................................32 Matimba Nyararai MSc WREM Thesis 2016 Page iv An assessment of surface water availability in the Pungwe sub catchment and development of an appropriate water allocation framework 4.4 Estimation of Pitman Model Parameters .......................................................................36 4.4.1 Interception (PI)......................................................................................................36 4.4.2 Maximum moisture storage capacity (ST)..............................................................36