Nigeria Erosion and Watershed Management Project (NEWMAP) Draft Report Public Disclosure Authorized Environmental and Social Management Plan (ESMP) for the Amachalla Gully Erosion Site Awka South, Anambra State. Public Disclosure Authorized Public Disclosure Authorized [Document title] [Document subtitle] Abstract [Draw your reader in with an engaging abstract. It is typically a short summary of the document. When you’re ready to add your content, just click here and start typing.] Public Disclosure Authorized Prepared for the State Project Management Unit (SPMU) Anambra State Nigeria Erosion and Watershed Management Project [Email address] Draft Report for the Amachalla gully erosion site Nigeria Erosion and Watershed Management Project (NEWMAP) Draft Report Environmental and Social Management (ESMP) for the Amachalla Gully Erosion Site Awka, Anambra State Prepared for the State Project Management Unit (SPMU) Anambra State Nigeria Erosion and Watershed Management Project ii Draft Report for the Amachalla gully erosion site Table of Contents LIST OF FIGURES ..................................................................................................................................... IV LIST OF PHOTOS ...................................................................................................................................... V LIST OF TABLES ....................................................................................................................................... V EXECUTIVE SUMMARY ............................................................................................................... VII CHAPTER ONE INTRODUCTION ............................................................................................... 1 1.1 OVERVIEW OF THE NIGERIA EROSION AND WATERSHED MANAGEMENT PROJECT (NEWMAP) ................. 1 1.2 PURPOSE OF THE ESMP.................................................................................................................. 3 1.3 OBJECTIVES OF THE ENVIRONMENTAL AND SOCIAL MANAGEMENT PLAN ................................................ 4 1.4 TECHNICAL APPROACH AND METHODOLOGY ...................................................................................... 4 2 CHAPTER TWO DESCRIPTION OF THE STUDY AREA ................................................................. 6 2.1 OVERVIEW OF THE PROJECT STATE ................................................................................................... 6 2.1.1 Physical Environment of Anambra State ........................................................................... 8 2.1.2 Biological Environment of Anambra State ....................................................................... 10 2.2 OVERVIEW OF AWKA .................................................................................................................... 12 2.2.1 Physical Environment ....................................................................................................... 12 2.2.2 Biological Environment of Awka ...................................................................................... 18 2.2.3 Social Environment .......................................................................................................... 19 3 CHAPTER THREE PROJECT DESCRIPTION ................................................................................ 29 3.1 INTRODUCTION ............................................................................................................................ 29 3.2 AMACHALLA GULLY EROSION ......................................................................................................... 29 3.2.1 Land size ........................................................................................................................... 32 3.2.2 Vulnerability ..................................................................................................................... 32 3.2.3 Hydrology ......................................................................................................................... 32 3.2.4 Geology ............................................................................................................................ 32 3.2.5 Physiography and Drainage ............................................................................................. 33 3.3 DESIGN CONCEPTS ....................................................................................................................... 33 3.4 REHABILITATION WORKS/DESIGN SOLUTIONS .................................................................................... 33 3.4.1 Construction of the adjoining roads ................................................................................. 33 3.4.2 Recovering of Land in gully/Filling of gully erosion ......................................................... 34 3.4.3 Construction of Collector drains channels and chute (sloping glacis) .............................. 34 3.4.4 Easing of the sides to stable slopes in sections where space permits .............................. 35 3.4.5 Proper grassing and planting of vegetation to provide cover for the eased out slopes and channels........................................................................................................................................ 35 3.4.6 Control and monitoring of human activity e.g. farming, sand digging, building etc within the recovered areas and eased out side slopes ............................................................................ 35 3.5 DESIGN COMPONENTS .................................................................................................................. 36 3.5.1 Concrete stepped channel ................................................................................................ 36 3.5.2 Chute channel .................................................................................................................. 36 3.5.3 Stilling basing ................................................................................................................... 36 CHAPTER FOUR: SUMMARY OF THE POTENTIAL IMPACTS FOR THE AMACHALLA GULLY EROSION SITE ............................................................................................................................... 38 4.1 INTRODUCTION ............................................................................................................................... 38 4.2 ASSOCIATED AND POTENTIAL ENVIRONMENTAL IMPACTS ....................................................................... 38 4.3 BROAD POTENTIAL BENEFICIAL IMPACTS OF THE REHABILITATION OF THE AMACHALLA GULLY EROSION SITE .. 40 4.3.1 Potential Beneficial Impacts Associated with the Rehabilitation of the Amachalla gully erosion site ................................................................................................................................... 41 4.4 POTENTIAL ADVERSE IMPACTS ASSOCIATED WITH THE REHABILITATION OF THE AMACHALLA GULLY EROSION SITE .......................................................................................................................................................... 42 iii Draft Report for the Amachalla gully erosion site 4.5IDENTIFIED POTENTIAL IMPACTS (BY PROJECT PHASES) ........................................................................... 43 4.6 PROJECT ALTERNATIVES .................................................................................................................... 64 4.6.1 Rock Lined Chute ................................................................................................................. 64 4.6.2 Wood Drop Structure .......................................................................................................... 65 4.6.3 Vegetated Overfall Structure ............................................................................................... 66 4.6.4 Do Nothing Alternative: ....................................................................................................... 66 4.5 THE PREFERRED ALTERNATIVE ........................................................................................................... 66 4 CHAPTER FIVE ENVIRONMENTAL AND SOCIAL MANAGEMENT PLAN .................................... 67 5.1 OVERVIEW .................................................................................................................................. 67 5.2 INSTITUTIONAL ARRANGEMENT FOR ESMP AND MONITORING PLAN ................................................... 67 5.3 ENVIRONMENTAL AND SOCIAL MANAGEMENT PLAN BUDGET ............................................................. 68 5.4 MITIGATION MEASURES FOR AMACHALLA GULLIES ........................................................................... 89 5.4.1 Selection of Mitigation Measures .................................................................................... 89 5.5 ESTIMATION OF CATCHMENT RUNOFF ............................................................................................. 90 5.6 REASONS FOR FAILURE IN GULLY REHABILITATION ............................................................................. 92 5.7 MAINTENANCE AND UTILIZATION OF A REHABILITATED GULLY ............................................................. 92 6 CHAPTER SEVEN STAKEHOLDERS CONSULTATION ................................................................. 94 6.1 INTRODUCTION ...........................................................................................................................