A Case Study of Motoine/Ngong River Sub-Catchment, Nairobi River Basin, Kenya
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UNIVERSITY OF NAIROBI EFFECTS OF LAND USE CHANGE ON STREAM FLOW, CHANNEL EROSION AND RIVER GEOMORPHOLOGY: A CASE STUDY OF MOTOINE/NGONG RIVER SUB-CATCHMENT, NAIROBI RIVER BASIN, KENYA. BY MONENE ALICE KWAMBOKA A Thesis Submitted for the Award of Master of Arts Degree in Geography (Geomorphology) 2014 i DECLARATION I declare that this is my original work and has never been presented for examination in any other university. Signature: _______________________ Date: _________________________ Monene Alice Kwamboka. Reg. No. C50/68816/2011 Student This research Proposal has been submitted for examination with my approval as University Supervisor. Signature: _______________________ Date: _________________________ Prof. George O. Krhoda Supervisor Signature: _______________________ Date: _________________________ Dr. John M. Nyangaga Supervisor ii ACKNOWLEDGEMENT I wish to thank my supervisors, Prof. Krhoda and Dr. Nyangaga. Prof. Krhoda, the Coordinator of Geomorphology in the Department of Geography and Environmental Studies, University of Nairobi, is acknowledged for his guidance, support and advice in this study. Dr. Nyangaga has been instrumental in making this work possible by enabling me understand complex issues and providing reading materials, data and equipment for field work. Dr. Ogembo is also acknowledged for his advice and sharing the knowledge in fluvial Geomorphology that facilitated my decision on the topic for research. I am grateful to Kenneth of the Department of Resource Surveys and Remote Sensing for facilitating the acquisition and analysis of satellite images. To Justus and Dennis, officials from Water Resources Management Authority, I say thank you for providing data and assisting in taking field measurements. Mr. Ayuyo of the University of Nairobi and my daughter Joanne are also acknowledged for editing my work. My family has been very supportive with some of them taking up some of my responsibilities to give me time to accomplish this work. They too are hereby acknowledged. iii LIST OF ABBREVIATIONS DRSRS: Department of Resource Surveys and Remote Sensing FAO: Food and Agriculture Organization. G.O.K: Government of Kenya. HABITAT: United Nations Centre for Human Settlements. ISC: Impermeable Surface Cover. KARI: Kenya Agricultural Research Institute. KSS: Kenya Soil Survey. NRBP: Nairobi River Basin Project. TSS: Total Suspended Solids. UNEP: United Nations Environment Programme. UNICEF: United Nations International Children‘s Emergency Fund UNESCO: United Nations Educational, Scientific & Cultural Organization. WRMA: Water Resources Management Authority. iv TABLE OF CONTENTS Declaration .......................................................................................................................... ii Acknowledgement ............................................................................................................. iii List of Abbreviations ......................................................................................................... iv List of Tables ..................................................................................................................... ix List of Figures ..................................................................................................................... x List of Plates ...................................................................................................................... xi Abstract ............................................................................................................................. xii CHAPTER ONE ............................................................................................................... 1 INTRODUCTION............................................................................................................. 1 1.1 Background of the Study .............................................................................................. 1 1.2 Statement of the Problem .............................................................................................. 2 1.3 Objectives ..................................................................................................................... 4 1.3.1 Broad Objective of the Study ........................................................................................ 4 1.3.2 Specific Objectives ......................................................................................................... 5 1.4 Hypotheses .................................................................................................................... 5 1.5 Justification of the Study .............................................................................................. 5 1.6 Scope and Limitations of the Study .............................................................................. 7 1.7 Definition of Terms....................................................................................................... 7 1.8 The Study Area ........................................................................................................... 10 1.8.1 Position and Size of the Study Area ........................................................................... 10 1.8.2 Climatic Characteristics ............................................................................................... 11 1.8.3 Hydrological Characteristics ....................................................................................... 11 1.8.4 Vegetation Characteristics ........................................................................................... 12 1.8.5 Geology of the Catchment ........................................................................................... 12 1.8.6 Soil Characteristics of the Catchment ........................................................................ 13 1.8.7 Topography and Geomorphology............................................................................... 14 1.8.8 Population ...................................................................................................................... 15 1.8.9 Human Activities and Land Use ................................................................................. 15 v CHAPTER TWO ............................................................................................................ 17 LITERATURE REVIEW .............................................................................................. 17 2.1 Introduction ................................................................................................................. 17 2.2. Theoretical Framework .............................................................................................. 18 2.3 Conceptual Framework ............................................................................................... 19 2.4 Precipitation and Discharge ........................................................................................ 20 2.5 Land Use/Cover and Stream Flow .............................................................................. 21 2.6 Urbanization and River Flow ...................................................................................... 23 2.7 Channel Erosion, Morphology and Sediment Transport ............................................ 24 CHAPTER THREE ........................................................................................................ 30 METHODOLOGY ......................................................................................................... 30 3.1 Introduction ........................................................................................................................... 30 3.2 Land Use Change .................................................................................................................. 30 3.2.1 Data Collection .................................................................................................. 30 3.2.2 Data Analysis ..................................................................................................... 31 3.3 Effects on Stream Flow, Gully and River Bank Erosion ................................................. 32 3.3.1 Data Collection .................................................................................................. 32 3.3.2 Data Analysis ..................................................................................................... 36 3.4 Assessment of Channel Geomorphology .......................................................................... 39 3.4.1 Data Collection .................................................................................................. 39 3.4.2 Data Analysis ..................................................................................................... 39 3.5 Hypothesis Testing ............................................................................................................... 39 CHAPTER FOUR ........................................................................................................... 40 RESULTS AND DISCUSSION ..................................................................................... 41 4.1 Introduction ................................................................................................................. 41 4.2 Land Use Change ........................................................................................................ 41 vi 4.3 Stream flow, Gully and River Bank Erosion .................................................................... 48