Instituto da Cooperação Portuguesa (Portugal) Ministério da Energia e Águas de Angola SOUTHERN AFRICAN DEVELOPMENT COMMUNITY PLAN FOR THE INTEGRATED UTILIZATION OF THE WATER RESOURCES OF THE HYDROGRAPHIC BASIN OF THE CUNENE RIVER SYNTHESIS LNEC – Laboratório Nacional de Engenharia Civil Page 1/214 LNEC – Proc.605/1/11926 MINISTÉRIO DO EQUIPAMENTO SOCIAL Laboratório Nacional de Engenharia Civil DEPARTMENT OF HYDRAULICS Section for Structural Hydraulics Proc.605/1/11926 PLAN FOR THE INTEGRATED UTILIZATION OF THE WATER RESOURCES OF THE HYDROGRAPHIC BASIN OF THE CUNENE RIVER Report 202/01 – NHE Lisbon, July 2001 A study commissioned by the Portuguese Institute for Cooperation I&D HYDRAULICS Page 2/214 LNEC – Proc.605/1/11926 PLAN FOR THE INTEGRATED UTILIZATION OF THE WATER RESOURCES OF THE HYDROGRAPHIC BASIN OF THE CUNENE RIVER SYNTHESIS Page 3/214 LNEC – Proc.605/1/11926 PLAN FOR THE INTEGRATED UTILIZATION OF THE WATER RESOURCES OF THE HYDROGRAPHIC BASIN OF THE CUNENE RIVER INTRODUCTORY NOTE This report synthesizes a number of documents that have been elaborated for the Portuguese Institute for Cooperation. The main objective of the work was to establish a Plan for the Integrated Utilization of the Water Resources of the Hydrographic Basin of the Cunene River. As the elaboration of this Plan is a multi-disciplinary task, it was deemed preferable to grant independence of reporting on the work of each team that contributed to the final objective. That is why each report consists of a compilation of volumes. REPORT I VOLUME 1 – SYNTHESIS (discarded) VOLUME 2 – PRELIMINARY DESCRIPTION OF THE AVAILABILITY OF SURFACE WATER VOLUME 3 – DESCRIPTION AND PRELIMINARY EVALUATION OF THE AVAILABILITY OF UNDERGROUND WATER VOLUME 4 – INVENTORY OF LAND RESOURCES THAT ARE SUITABLE FOR POTENTIAL IRRIGATION VOLUME 5 – DESCRIPTION OF CURRENT ENVIRONMENTAL INDICATORS VOLUME 6 – THE SOCIAL ECOLOGY OF THE BASIN – PRELIMINARY CHARACTERIZATION VOLUME 7 – OVERALL DESCRIPTION OF THE HYDROLOGIC INFRASTRUCTURES REPORT II VOLUME 1 – SYNTHESIS (discarded) VOLUME 2 – DESCRIPTION OF THE AVAILABILITY OF SURFACE WATER VOLUME 3 – DESCRIPTION AND EVALUATION OF THE AVAILABILITY OF UNDERGROUND WATER VOLUME 4 – EVALUATION OF WATER REQUIREMENTS VOLUME 5 – PROPOSED STRATEGIES FOR THE SUPPLY OF WATER RESSOURCES REPORT III VOLUME 1 – OPTIMALIZATION AND SIMULATION OF THE HYDRO- ELECTRICAL STRUCTURE OF THE UPPER CUNENE VOLUME 2 – SIMULATION OF THE HYDROGRAPHIC BASIN OF THE CUNENE RIVER Page 4/214 LNEC – Proc.605/1/11926 The study was carried out in interaction with Angolan technicians. It is hoped that the elements that were included in these documents may provide pertinent contributions for the implementation of the Master Plan for the Cunene River. July, 2001 The Project Coordinator João Soromenho Rocha Page 5/214 LNEC – Proc.605/1/11926 PLAN FOR THE INTEGRATED UTILIZATION OF THE WATER RESOURCES OF THE HYDROGRAPHIC BASIN OF THE CUNENE RIVER SYNTHESIS Summary A series of studies were carried out by a multi-disciplinary team with the objective to elaborate a Plan for the Integrated Utilization of the Water Resources of the Hydrographic Basin of the Cunene River. Beyond its introduction, the synthesis contains an account of prior studies, a description of existing infrastructures, it refers to international agreements, indicates supporting documentation, summarily describes the hydrographic basin, makes an evaluation of the available water resources, of surface and underground water, assesses water requirements and a provides a description of current environmental indicators. In addition, after proposing strategies for the schemes related to water resources, it presents simulations that were carried out and concludes with the definition of the Plan for the Integrated Utilization of the Water Resources of the Hydrographic Basin of the Cunene River. Page 6/214 LNEC – Proc.605/1/11926 TABLE OF CONTENTS 1. INTRODUCTION ............................................................................................................ 15 2. BACKGROUND ............................................................................................................. 18 2.1 Introduction ............................................................................................................. 18 2.2 Studies by the Mixed Technical Commission (1926) ................................ 18 2.3 Studies by the Southern Angola Mission (1946) ........................................ 19 2.4 Master Plan for a Hydro-electric Scheme for the area upstream from Matala (1962) ..................................................................................................................23 2.5 Water Supply Scheme for the Area Upstream from Calueque (1966) .27 2.6 International Agreements in respect of the allocation / sharing of the use of water resources from the Cunene River (1926, 1964 and 1969) ..... 31 2.7 Studies and Projects carried out after 1969 .................................................35 3. SUPPORTING DOCUMENTS ....................................................................................38 4. DESCRIPTION OF THE HYDROGRAPHIC BASIN .............................................39 4.1 Location ....................................................................................................................39 4.2 Topography .............................................................................................................39 4.3 Hydrographic morphology, relief and structure .........................................42 4.4 Geology.....................................................................................................................50 4.5 Climate ......................................................................................................................56 4.6 Pedology .................................................................................................................. 61 4.7 Vegetation cover ....................................................................................................64 4.8 Demographics and population .........................................................................72 5. EVALUATION OF WATER RESOURCES ..............................................................82 5.1 Surface Water .........................................................................................................82 5.1.1 Hydro-meteorological information, rainfall and river capacities.............82 5.1.2 Compilation and supplementing of missing data ......................................86 5.1.3 Management of artificial drainage systems ...............................................90 5.1.4 Water Resources in the Lower Cunene Area ............................................93 5.2 Underground water ............................................................................................. 106 5.2.1 Description of the hydro-geological systems ........................................... 106 5.2.2 Evaluation of underground water resources ............................................. 111 6. PARTIAL EVALUATION OF WATER REQUIREMENTS ................................. 115 6.1 Introduction ........................................................................................................... 115 6.2 Water supply to rural areas ............................................................................. 116 6.3 Water supply to urban areas ........................................................................... 120 6.4 Water supply for cattle ...................................................................................... 123 6.5 Water supply for irrigation purposes ........................................................... 126 Page 7/214 LNEC – Proc.605/1/11926 6.6 [missing in both index and text] .......................................................................... 133 6.7 Water consumption and water restrictions ................................................ 133 6.8 The flow of water to Namibia ........................................................................... 139 7. SIMULATION OF THE SUPPLY OF WATER RESOURCES........................... 143 7.1 Introduction ........................................................................................................... 143 7.2 The IRAS simulation model ............................................................................. 145 7.2.1 Introduction ...................................................................................................... 145 7.2.2 The simulation process ................................................................................. 147 7.2.3 Structure of the system ................................................................................. 149 7.2.4 Input data for the system .............................................................................. 151 7.2.5 Operating conventions for the system....................................................... 153 7.2.6 The simulation sequence ............................................................................. 155 7.2.7 Simulation procedures, methods and hypotheses ................................. 158 7.3 Results of simulations ....................................................................................... 161 7.3.1 Introduction ...................................................................................................... 161 7.3.2 Perimeters and zones ................................................................................... 162 7.3.3. Diagrams expressed