Nacala Dam Feasibility Study, Environmental and Social Impact Assessment, Design and Supervision

Transcription

1 Nacala Dam Feasibility Study, Environmental and Social Impact Assessment, Design and Supervision PROCUREMENT REF No.: QCBS-MCA-MOZ CONTRACT NO: P015 VOLUME 5 ENVIRONMENTAL IMPACT ASSESSMENT REPORT July 2010 Submitted to: MINISTRY OF PLANNING AND DEVELOPMENT MILLENNIUM CHALLENGE ACCOUNT - MOÇAMBIQUE Submitted by: JEFFARES & GREEN (Pty) Ltd In association with CONSENG And LAMONT

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3 Structure of Reports Volume 1 Volume 6 Main Report Drawings Report No: FS/2010/MR01 Report No: FS/2010/DR05 Volume 2 Volume 3 Volume 4 Hydrological Investigation Report Report No: FS/2010/HI02 Geotechnical Investigation Report Report No: FS/2010/GI03 Preliminary Design Report Report No: FS/2010/PD04 Volume 5A Volume 5B Environmental Scoping Report Report No: FS/2010/ENV05A Environmental Impact Assessment Report Report No: FS/2010/ENV05B

4 EXECUTIVE SUMMARY The Government of the Republic of Mozambique (GOM) has received a grant from the Millennium Challenge Corporation (MCC), an innovative United States established foreign assistance program designed to reduce poverty by promoting sustainable economic growth. The MCC operates on the principle that aid is most effective in countries that promote good governance, economic freedom and investments in people. The GOM, through the Millennium Challenge Account-Mozambique (MCA-Mozambique), a public institution created by the GOM) and its National Directorate of Water (DNA-GOH) organ, intends to use a portion of the proceeds of this grant, to carry out feasibility studies relating to the rehabilitation and augmentation of the Nacala Dam and Reservoir. In June 2009 Jeffares and Green (Pty) Ltd (J&G) was appointed as the lead consultant to undertake the Nacala Dam Feasibility Study, Environmental and Social Impact Assessment, Design and Supervision Project. The aim of this project is to improve the safety associated with the use of the dam, and to increase water storage and supply capacity for the City of Nacala and nearby Nacala Velha. As part of this project, a number of activities are proposed, including the rehabilitation and elevation of the dam wall; an upgrade of the spillway; a road deviation; and the excavation of materials for these activities. Should Nacala Dam not be rehabilitated, the risk of dam failure is a concern both in terms of the structural stability of the dam and community safety. The Nacala Dam is located on the Muecula River approximately 30 kilometres south west of Nacala (refer to locality plan overleaf). The dam is the primary water source for the town of Nacala which is situated approximately 200 kilometres north east of Nampula City. Nacala City is of significant regional importance for potential growth in Mozambique. Several specialist studies were undertaken in support of the project. These included a Terrestrial Ecological study (Appendix C), an Environmental Flow Requirements (EFR) specialist study (Appendix D), a Hydrological specialist study (synopsis included in Appendix E), a Hydrocensus (Appendix F), a Social Impact Assessment (Appendix G) and associated Resettlement Plan Framework (Appendix H), and a Health Impact Assessment (Appendix I). Various other studies, e.g. a geotechnical investigation were undertaken in support of the design of the project and where appropriate, reference has been made to such studies. The raising of the dam wall will result in the inundation of approximately 170ha of land which may have certain ecological impacts. However, the terrestrial ecological study found that additional inundation will not significantly affect the conservation status of eight Red Data Listed plants found in the study area. This is because all of these species are still widespread in Mozambique, and most of these species were originally listed because of the high levels of harvesting they were enduring, not because of small population sizes. i

5 Environmental Impact Assessment: Environmental Impact Report ii

6 During the construction phase, site disturbance will be unavoidable and the risk of increasing the spread of exotic invader weeds is high. Two serious invader plants have already been recorded within the footprint area, namely *Hyptis suaveolens (Horehound Weed) and *Lantana camera (Lantana). The terrestrial ecological survey found that the resident fauna species that are present in the project area are sufficiently resilient to withstand extreme pressures occurring within the study area. The increased inundation zone of Nacala Dam is secondary to the extreme pressure exhibited by the local communities living in the study area. Such human pressures are represented by habitat loss, habitat fragmentation, subsistence hunting, subsistence agriculture, and pollution. The extent of habitat loss in the project area caused by this project will not significantly impact on fauna populations of conservation importance. The rehabilitation and raising of the Dam requires the assessment of the EFR of the Muecula River to determine the optimum flow releases from the dam to maintain a desired ecological state of the river downstream. Due to the Muecula River having insufficient flow for the initial part of the study, an EcoStatus Level III determination was undertaken. The EFR approach aims to give the river a present ecological class based on the site conditions and ecological diversity data obtained during a one-off site visit. The ecological data gathered during the site visit, namely fish, aquatic invertebrate, geomorphological and riparian vegetation, were used to classify the Present Ecological State (PES). The PES outcomes are used to determine a Recommended Ecological Class (REC) for releases from the Nacala Dam. The EFR hydrology was undertaken using the Desktop Support System model (DSS). In this case, the Muecula River had a PES of a Class C, with the final REC also being a Class C. The results of the EFR determination, including the maintenance low flows (base flow) and the maintenance high flows (floods and freshettes) require a release of Mm 3 /ann (= 21.4% MAR). Releases from the dam to support a downstream Class C EFR would cause a decrease in yield for a 2m raised dam from 6.0 million m 3 /a to 4.3 million m 3 /a. The implementation of the EFR has a significant impact on the yield of the system and consideration should be given to postponing its implementation until alternative sources of water are available to augment water supplies. A hydrocensus was undertaken to ascertain the water sources being used by the communities surrounding the dam. The investigation identified the following sources of water: Six boreholes (Afridev hand pumps located close to households). Three stream/ river abstractions (badly discoloured water and no form of protection). A shallow-dug well (badly discoloured water and no form of protection). Stand-pipe with two widgets A wetland abstraction point and the Muecula River Environmental Impact Assessment: Environmental Impact Report iii

7 Some of these sources dry up in the dry season and leave the communities with little to no potable water source in the near vicinity. Water security is non-existent in this area, in spite of the dam being close to it. It is therefore recommended the Nacala Dam Rehabilitation and the Nacala Water Supply Programme considers providing a sustainable and clean source of potable water for the communities surrounding the dam. Presently, the only water that is supplied to the communities from the Nacala Dam is from the dual widget standpipe. Subsistence agriculture in conjunction with an informal economy is the dominant livelihood strategy for local households and communities. Subsistence agriculture is primary aimed at producing basic foods for households with any surplus food being sold at local markets. The greater population around the dam have dry land machambas, which are away from the dam and rely on ground water. Very few households have access to the coveted wet land machambas, which are around the dam and along the small inlets that feed into the dam. There are about 30 dam/river machamba owners affected by the proposed project and this is regarded as economic displacement. Recession agriculture makes use of the falling levels of the dam to open up the dam margins for cultivation. The following key issues and related impacts emerged during the Social Impact Assessment (SIA): Issue 1: Job Creation and Stimulation of Economic growth Impact 1.1: Job opportunities Impact 1.2: Expansion of the local skills base Impact 1.3: Small business opportunities Impact 1.4: Enhanced access to markets for local farmers Impact 1.5: Economic development in the region Impact 1.6: Return of Young People to the Area Impact 1.7: Lack of labour for traditional livelihood strategies Issue 2: Loss of, or Reduced Access to Livelihoods Impact 2.1: Loss of or reduced access to agricultural land Impact 2.2: Loss of and reduced access to natural resources Issue 3: Disruption of Homesteads Impact 3.1: Disruption of Homesteads Issue 4: Reduced Access to Social Infrastructure Impact 4.1: Loss of access routes Issue 5: Social Conflict and Social Problems Impact 5.1: Decreased emotional well being and sense of place Impact 5.2: Occupational adjustment problems Impact 5.3: Changes in the traditional livelihood strategy of households Impact 5.4: Community conflict as a result of differential benefits from the Project Environmental Impact Assessment: Environmental Impact Report iv

8 Impact 5.5: Tensions between outsiders and local communities Impact 5.6: Problems related to influx into the area. Issue 6: Health, Safety and Security Impact 6.1: Increase in communicable diseases Impact 6.2: Traffic safety risks Impact 6.3: Security risks The proposed project will result in the physical displacement of nineteen (19) households that will have to be resettled. These include 17 residential homesteads and a Frelimo Party office affected by the road deviation and the local police station affected by the re-developed spillway. Where displacement cannot be avoided, a comprehensive Resettlement and Compensation programme is to be implemented to ensure the restoration or improvement of the affected individuals livelihoods and standards of living. Specific assistance is to be provided to vulnerable households as part of the resettlement process. Vulnerable households include child-headed households, those headed by people with disabilities or health problems, and the elderly or single-headed households. In line with the MCA s Gender Policy (2006), focus would also be placed on female-headed households. The Health Impact Assessment (Appendix I) found that the project is likely to impart potential future health impacts to the surrounding community for a limited period of time, but their presence also presents an opportunity to improve the existing health status of the community and other communities through direct and indirect benefits. These need to be systematically evaluated so that the proponent, and the broader stakeholders, can develop a community health management plan to avoid, mitigate or enhance any health impacts, opportunities or risks. This needs to be based on priority as well as practicality. Vector-related diseases, e.g. malaria; soil, water and waste-related diseases; sexually transmitted infections including HIV/AIDS; food and nutrition-related issues; and accidents and injuries were all regarded as impacts of potentially high significance. Mitigation measures are provided but these mitigations will require a series of separate management policies, strategies, plans, and programs. To support these programs, adequate training or information, education and communication (IEC) programs will be required, some of which are outlined in the Environmental Management Programme (EMP). This project is of high economic and social importance to Nampula Province and Nacala-a- Velha and it is anticipated that it will achieve important tangible benefits in terms of increased crop production and potable water supply. As Mozambique is prone to floods, there is a serious risk that flooding while the bottom outlets are closed may lead to a total collapse of the dam with serious consequences to human lives and property. Environmental Impact Assessment: Environmental Impact Report v

9 TABLE OF CONTENTS 1. INTRODUCTION PROJECT BACKGROUND AIMS AND OBJECTIVES OF THE EIA DETAILS OF THE APPLICANT DETAILS OF THE EIA TEAM Jeffares & Green CONSENG Environmental Impact Assessment Team POLICY, LEGAL AND ADMINISTRATIVE FRAMEWORK NATIONAL ENVIRONMENTAL LEGISLATION The Constitution of Mozambique The Environment Act Regulations for the Environmental Impact Assessment Process SUPPORTING ENVIRONMENTAL LEGISLATION OTHER LEGISLATION INTERNATIONAL BEST PRACTICE Millennium Challenge Corporation World Bank International Finance Corporation INTERNATIONAL CONVENTIONS AND TREATIES ADMINISTRATIVE FRAMEWORK METHODOLOGY EIA PRE-EVALUATION APPLICATION (SCREENING) ENVIRONMENTAL PRE-FEASIBILITY AND SCOPING STUDY (EPDA) THE PUBLIC PARTICIPATION PROCESS ENVIRONMENTAL IMPACT ASSESSMENT Terrestrial Ecology Assessment Ecological Flow Requirements Hydrology Hydrocensus Social Impact Assessment Resettlement Policy Framework Health Impact Assessment AUTHORITY REVIEW OF THE ENVIRONMENTAL IMPACT REPORT ALTERNATIVE OPTIONS CONSIDERED SPILLWAY UPGRADE OPTIONS ROAD ALIGNMENT EMBANKMENT RAISING OPTIONS THE NO-GO PROJECT OPTION PROJECT DESCRIPTION vi

10 5.1. NACALA DAM KEY COMPONENTS OF NACALA DAM Embankment Reservoir Spillways N12 National Highway RATIONALE FOR THE UPGRADE & REHABILITATION OF NACALA DAM Improving Water Supply Improvement of Dam Safety PROJECT ACTIVITIES Spillway Upgrade Embankment Raising Road Deviation Borrow Pits BASELINE ENVIRONMENT CLIMATE GEOLOGY SOILS TOPOGRAPHY AND LANDFORM VEGETATION General Overview Plant species/communities occurring on site Land-cover TERRESTRIAL FAUNA General overview Mammals Avifauna Herpetofauna AQUATIC FAUNA General Overview Fish Aquatic invertebrates HYDROLOGY Yield Hydrology Environmental Flow Requirements Sediment Yield Analysis Design Flood hydrology GEOHYDROLOGY THE SOCIO-ECONOMIC ENVIRONMENT Magisterial Structure Population Demographics Community and Household Structure Livelihoods and Economy Land-Use Gender Seasonal Calender Environmental Impact Assessment: Environmental Impact Report vii

11 Social Infrastructure Community Perceptions of the Dam Rehabilitation Project RESETTLEMENT POLICY FRAMEWORK Design and Objectives of RPF Magnitude of Displacement Valuation and Compensation Process Compensation and Resettlement Cost Estimate HEALTH IMPACT ASSESSMENT Rapid Health Impact Assessment HIA Methodology Potentially Affected Communities Environmental Health Areas ENVIRONMENTAL IMPACT ASSESSMENT METHODOLOGY IN DETERMINING THE SIGNIFICANCE OF IMPACTS FLORA/VEGETATION TERRESTRIAL FAUNA Mammals Avifauna Herpetofauna Aquatic Fauna ECOSYSTEMS ECOLOGICAL FLOW REQUIREMENTS HYDROLOGY HYDROCENSUS SOCIAL IMPACT ASSESSMENT... ERROR! BOOKMARK NOT DEFINED Issue 1: Job Creation and Stimulation of Economic Growth Issue 2: Loss of or Reduced Access to Livelihood Assets Issue 3: Disruption of Homesteads Issue 4: Reduced Access to Social Infrastructure Issue 5: Social Conflict and Social Problems Issue 6: Health, Safety and Security RESETTLEMENT POLICY FRAMEWORK... ERROR! BOOKMARK NOT DEFINED HEALTH IMPACT ASSESSMENT PUBLIC PARTICIPATION PROCESS NOTIFICATION OF INTERESTED & AFFECTED PARTIES WORKSHOP AND MEETING PUBLIC CONSULTATION REPORT PUBLIC REVIEW OF DOCUMENTATION PUBLIC PARTICIPATION PROCESS UNDERTAKEN TO DATE Awareness Building Issues and Concerns raised SOLUTIONS CONCLUSIONS AND RECOMMENDATIONS REFERENCES Environmental Impact Assessment: Environmental Impact Report viii

12 LIST OF FIGURES Figure 2-1: Nacala Dam Project implementation structure...10 Figure 3-1: The EIA process Figure 4-1: Spillway options considered during preliminary design stage...21 Figure 5-1: Locality plan of Nacala Dam...26 Figure 5-2: Aerial view of Nacala Dam and Surrounds...27 Figure 5-3: Different components associated with Nacala Dam...28 Figure 5-4: Upstream face of Nacala Dam...29 Figure 5-5: Nacala Dam Reservoir...29 Figure 5-6: Downstream Face of Nacala Dam with protective stone grouting...31 Figure 5-7: Dam Crest and N12 Highway...31 Figure 5-8: Layout of preferred Spillway Option Left Hand Side A...35 Figure 5-9: Tailwater Inundation area for LHS Spillway Option A...36 Figure 5-10: Preferred Road Diversion Option Figure 5-11: Locality of identified borrow pits...40 Figure 6-1: Average monthly rainfall in the Nacala Dam Catchment...41 Figure 6-2: Study area for the Nacala Dam Terrestrial Ecological Assessment...44 Figure 6-3: Simulated natural stream flow time-series plotted against the C Class desktop EWR time-series...51 Figure 6-4: Location of Nacala A Velha District...54 Figure 6-5: Typical homestead structures...55 Figure 6-6: Images of machambas located along the dam reservoir margin...57 LIST OF TABLES Table 4-1: Advantages and Disadvantages of various spillway options...18 Table 6-1: Characteristics of rainfall in the Nacala Dam catchment...41 Table 6-2: S-pan evaporation data for the Nacala Dam catchment (1)...42 Table 6-3: Land cover classes in study area...46 Table 6-4: Summary of Yield Analysis Scenarios (Jeffares & Green, 2010)...49 Table 6-5: Summary of Yield Analysis Results (Jeffares & Green, 2010)...49 Table 6-6: Community Water Sources identified during Hydrocensus...52 Table 6-7: Summary of Resettlement Costs...62 Table 7-1: Rating methodology to determine the significance of Impacts...67 Table 7-2: Impact Probability...68 Table 7-3: Overall Environmental Significance Statement...68 Table 7-4: Summary of issues and related impacts identified during SIA...80 Table 7-5: Summary of Environmental Health Areas including Health Determinants and Health Impacts...96 Environmental Impact Assessment: Environmental Impact Report ix

13 APPENDICES Appendix A: Appendix B: Appendix C: Appendix D: Appendix E: Appendix F: Appendix G: Appendix H: Appendix I: Appendix J: Consultancy Certificate MICOA project requirements Terrestrial Ecology Specialist Study Environmental Flow Requirements Specialist Study Synopsis of Hydrological Specialist Study including water quality monitoring programme results Hydrocensus Resource Sheets Social Impact Assessment Resettlement Plan Framework Health Impact Assessment Environmental Management Plan Environmental Impact Assessment: Environmental Impact Report x

14 GLOSSARY AND ABBREVIATIONS DNA-GOH: DNAIA: DPCAA: EFR: EIA: EMP: GOM: HIA: mamsl: MCA-Mozambique: MCC: mcm/a: MICOA: OP 4.12: PPP: RPF: SIA: Direcção Nacional de Águas (National Directorate of Water) - Cabinet of Hydraulic Works Direcção Nacional de Avaliação de Impacto Ambiental (National Environmental Impact Assessment Directorate) Direcção Provincial para a Coordenação da Acção Ambiental (Provincial Directorate for Co-ordination of Environmental Affairs) Environmental Flow Requirements Environmental Impact Assessment Environmental Management Plan Government of Mozambique Health Impact Assessment Metres Above Mean Sea Level Millennium Challenge Account Mozambique Millennium Challenge Corporation million cubic metres per annum Ministério para a Coordenação da Acção Ambiental (Ministry for the Coordination of Environmental Affairs) World Bank s Operational Policy on Involuntary Resettlement Public Participation Process Resettlement Policy Framework Social Impact Assessment Environmental Impact Assessment: Environmental Impact Report xi

15 1. INTRODUCTION 1.1. PROJECT BACKGROUND The Government of the Republic of Mozambique (GOM) has received a grant from the Millennium Challenge Corporation (MCC), an innovative United States established foreign assistance program designed to reduce poverty by promoting sustainable economic growth. The MCC operates on the principle that aid is most effective in countries that promote good governance, economic freedom and investments in people. The GOM, through MCA (Millennium Challenge Account-Mozambique, a public institution created by the GOM) and its National Directorate of Water (DNA-GOH) organ, intends to use a portion of the proceeds of this grant, to carry out feasibility studies relating to the rehabilitation and augmentation of the Nacala Dam and Reservoir. The Nacala Dam is located on the Muecula River approximately 30 kilometres south west of Nacala. The Nacala Reservoir is the primary water source for the City of Nacala, which is situated approximately 200 kilometres north east of Nampula City. The City of Nacala has also received funding for water and sanitation system improvements under a different project that is being developed concurrently with this Nacala Dam Rehabilitation project. Due to a previously identified risk of dam failure, water levels at the dam are reported to be kept low, reducing the water supply for Nacala significantly. In addition, there are significant increases projected for water demands for the city due to population growth and other planned developments. Projected demands for urban growth in the City of Nacala and Nacala Velha greatly exceed the existing water supply capacity of the Nacala Dam Reservoir. The Nacala Dam was designed and constructed from 1968 to In 1982 the dam wall was overtopped for 10 consecutive hours due to the non operation of the spillway gates. This resulted in high seepage through the defective concrete on the right hand side of the spillway which flooded the fill downstream of the core and may have been the trigger for the concentrated erosion of the embankment in this area. In 1983 the wash away area was reinstated and a layer of stone pitching was placed on the downstream face of the wall as a protective measure against the possibility of future overtopping. Further repairs were undertaken in 1995 and 2002 resulting in a pre-feasibility study into the possibility of rehabilitating and raising the dam wall which was undertaken by Michael Baker Jr. Inc. (Baker) in In June 2009, a consortium of firms, with Jeffares and Green (Pty) Ltd (J&G) as the lead consultant, was appointed to undertake the Nacala Dam Feasibility Study, Environmental and Social Impact Assessment, Design and Supervision Project. The Environmental Impact Assessment (EIA), as categorised by the Provincial Directorate for the Co-ordination of Environmental Affairs (15 October 2009), is being undertaken in compliance with the Environmental Law (Law No 20/1997) and the Regulations for the Environmental Impact Assessment Process (Decree No. 45/2004), as amended by Decree 42/2008 and the 1

16 General Directive for Public Participation (Diploma No. 129 and 130/2006). Cognisance has also been taken of the MCC Guidelines (MCC, 2006) for Environmental and Social Assessment AIMS AND OBJECTIVES OF THE EIA The overall aim of the Nacala Dam EIA is to identify and assess potential environmental impacts and risks in balance with potential benefits of the project. Specific objectives of this EIA are to: Identify and assess potential environmental and social impacts, both negative and positive, that are directly associated with the proposed activity. Avoid, minimise, mitigate or compensate for negative impacts while maximising the positive spin-offs of the proposed activity. Ensure open and transparent consultation with Interested and Affected Parties (I&APs) and ensure that their views are incorporated into the assessment of alternatives, impacts and mitigation measures. To promote improved environmental and social performance through better planning and management DETAILS OF THE APPLICANT The applicant is MCA-Mozambique. The details of the applicant are as follows: MCA-Moçambique Contact: Mr. Paulo Fumane (Executive Director) Av. Ahmed Sekou Toré 2539 Tel: Fax: DETAILS OF THE EIA TEAM A joint venture has been established between Jeffares & Green and CONSENG in order to comply with Article 21 (Registration of EIA team) and Article 23 (Responsibility of EIA team) of the Regulations for the Environmental Impact Assessment Process (Decree No 45/2004) and to provide the necessary mix of skills and expertise Jeffares & Green Jeffares & Green (Pty) Ltd is a long-established (since 1922) South African multidisciplinary consultancy company. Jeffares & Green have a full compliment of some 280 professional staff, including expertise in water, sanitation, municipal services, roads, environmental, hydrology, geohydrology and geotechnical engineering. The company, via its in-house environmental division, provides the necessary expertise and skills to undertake an EIA in compliance with local legislation and to International Best Environmental Impact Assessment: Environmental Impact Report 2

17 Practice Standards. Jeffares & Green holds full ISO 9001:2000 Quality Management Certifications. The contact details for Jeffares & Green are: Jeffares & Green Contact: Jan Norris 6 Pin Oak Avenue Hilton, 3245, South Africa Tel: Fax: norrisj@jgi.co.za CONSENG CONSENG (Consultancy Services & Engineering) is a Mozambican Company established in September, 1984, and targets the Mozambican market in the consulting and project management field (See Appendix A for consultancy certificate). The contact details for CONSENG are: CONSENG Contact: Claudio Carvalho Av Kwame Nkrumah No. 460 Polana, Maputo, Mozambique Tel: +285 (82) Fax: +258 (21) carvalho.claudiop@gmail.com Environmental Impact Assessment Team The environmental team consists of the following members: Name Area of Expertise Study/Role Company Marco da Cunha Melissa Moffett Alicia Calane Francisco Mbebe Environmental Impact Assessment Environmental Impact Assessment Environmental Impact Assessment Environmental Impact Assessment Environmental Impact Assessment: Environmental Impact Report 3 Project Management Assistant Project Manager/Reviewer Public Participation Process Manager Public Participation Process Assistant Jeffares & Green Jeffares & Green CONSENG CONSENG Carlos Santana Legal Specialist Environmental Law Review CONSENG Greg Huggins Delmira Mahache Vasco Lino Socio-Economic Specialist Socio-Economic Specialist Economics and Agrarian Policy Social Impact Assessment Resettlement Policy Framework Social Impact Assessment Resettlement Policy Framework Land-Use and Agriculture Independent (J&G) CONSENG CONSENG

18 Name Area of Expertise Study/Role Company Jose Chiocho Agriculture Engineering Land and Asset Valuation CONSENG Mark Divall Martin Taylor Ryan Gray Occupational Medicine and Health Zoology, Conservation Biology Aquatic Ecology & Hydrology Health Impact Assessment Terrestrial Ecology Study Ecological Flow Requirements Study Independent (J&G) Independent (J&G) Jeffares & Green Simon Johnson Hydrologist Hydrology Study Jeffares & Green Jan Norris Geotechnical Specialist Geotechnical Assessment Jeffares & Green Environmental Impact Assessment: Environmental Impact Report 4

19 2. POLICY, LEGAL AND ADMINISTRATIVE FRAMEWORK This chapter provides a summary of the legislative framework and international best practice guidelines and standards that have been adopted for this EIA NATIONAL ENVIRONMENTAL LEGISLATION The EIA process is regulated by a number of laws that include the Constitution of Mozambique as the overarching law in terms of environmental protection. The Environmental Law (Decree No. 20/1997) and the Regulations for the Environmental Impact Assessment Process (Decree No. 45/2004) define the principles and actions needed in the EIA The Constitution of Mozambique The Constitution is the supreme law of the land and any act or conduct inconsistent with it is invalid and will have no force of law. Any development has to ensure that none of its activities will be inconsistent with the constitutional rights of the people of Mozambique. The key provisions relevant to this EIA are: Article 27: The state shall promote efforts to guarantee the ecological balance and the conservation and preservation of the environment for the betterment of the quality of life of its citizens. Article 72: All citizens shall have the right to live in, and the duty to defend, a balanced natural environment The Environment Act The Environmental Law (Decree No. 20/1997 of 1 October) serves as the framework environmental legislation for Mozambique. It provides the overarching principles and foundations for all forms of environmental legislation, policy and practice. Its overall objective is defined as follows: Article 2: The current Act has the objective of defining the legal basis for the utilisation and correct management of the environment and its components, with a view of ensuring a system of sustainable development in this country. Articles 15 to 17 of the Law define, in general terms, that any activities, that by the nature of the location, design or scale may cause significant environmental impacts, will require an environmental license. The basis of obtaining this license is via an EIA Regulations for the Environmental Impact Assessment Process The Regulations for the Environmental Impact Assessment Process Act (Decree No. 45/2004), as amended by Decree No. 42/2008 of November defines the rules and regulations concerning competent authorities, applications for environmental authorisation, and the procedures that must be followed in an EIA. Environmental Impact Assessment: Environmental Impact Report 5

20 These regulations form the central pillar in terms of the procedural requirements for this EIA. This includes undertaking an EIA Pre-assessment Application (Screening), Environmental Pre-Feasibility and Scoping (EPDA) and the Environmental Impact Assessment (EIA), as well as a Public Participation Process. Under Article 6, the proposed project must be assessed against listed activities (Annexures A, B and C) and additional environmental criteria as defined under Article 8. There is no specific reference to dam rehabilitation and upgrading under the listed activities. However the proposed project does trigger the following activities: a) Areas and ecosystems meriting special protection under national or international law such as sources or rivers and other water supplies. b) Populated areas that would require resettlement. e) Areas near water courses or areas used as water sources by the community. 1h) Main roads outside urban area and the construction of new roads. 1o) Dams and walled water storage with a flooded area of more than 5 hectares. No specific reference is made in the regulations with regard to the upgrade and refurbishment of existing infrastructure. The above listed activities have been interpreted as to include the modification, extension or alteration of any existing infrastructure. An application for an Environmental License is to be lodged with the relevant environmental authorities (MICOA Ministério para o Coordenação da Acção Ambiental) as part of the EIA Pre-assessment Application (Screening) phase in compliance with Article 3 of the EIA Regulations. After the Pre-assessment Application, an Environmental Pre-Feasibility and Scoping Study (EPDA) is to be undertaken in compliance with Article 10 of the EIA Regulations. This study identifies potential environmental impacts associated with the project and defines the Terms of Reference of the larger EIA phase. The second and final phase is the EIA, as defined under Article 12 of the EIA regulations. An EIA should, at minimum, include a clear assessment of potential environmental and social impacts. Supporting specialist studies and an Environmental Management Plan (EMP) should be included as annexures to the EIA. Article 14 defines the Public Participation Process (PPP) required as part of a full EIA. This gives rights to potential Interested and Affected Parties (I&APs) to engage in the PPP SUPPORTING ENVIRONMENTAL LEGISLATION A number of Decrees and ministerial Diplomas have been enacted in support of the above acts. The following are considered relevant: Environmental Impact Assessment: Environmental Impact Report 6

21 The General Directive for the Public Participation Process in the Environmental Impact Assessment (Ministerial Diploma No. 129 and 130/2006 of 19 July. Regulations for the Environmental Audit Process (Decree No. 32/2003 of 20 August) Regulations for Environmental Inspections (Decree No. 11/2006 of 15 June) 2.3. OTHER LEGISLATION The following legislation or sectoral legislation may to varying degrees be relevant to the EIA process: The Water Law, Decree 16/1991 of 3 August states that hydraulic works will not be approved without the previous analysis of its effects and impact on the environment, economy and society. The Forestry and Wildlife Law, Decree 10/1999 of 7 July provides lists of economic important timber species and of protected fauna. Projects likely to have an impact on areas where these species predominate even though the area itself is not protected by law, require a more careful evaluation than projects that do not impinge on this kind of resources. The Land Law, Decree 19/1997 of 1 October refers to the extinction of land occupation and usage rights, stating that payment of just compensation will precede any process of expropriation. There is no specific legislation concerning responsibility neither for organizing and implementing compensation and resettlement nor on the procedures to be followed. In the absence of a clearly defined resettlement policy, the GOM has been following the principles set forth in the World Bank s Operational Policy on Involuntary Resettlement (OP 4.12) in order to deal with the issues raised by the need to resettle people. The Emission of Effluents, Decree 18/2004 of June 2 lays out the standards for environmental quality and the emission of effluents. This regulation sets standards for air, water, soil and noise and is of relevance particularly during the construction phase. In general, the emission of effluents should occur in such a manner that there is no change in the quality of the receiving environment which turns the use of its waters for other aims impossible (Article. 16). In Annex IV, the Decree defines the standards for liquid effluents with regard to colour, smell, ph, temperature, Chemical Oxygen Demand, Total Suspended Solids (TDS), Phosphorus and Nitrogen for fresh water bodies. Decree 10/1988 and Decree 27/1994 of 20 July and Regulation for the Protection of Archaeological Heritage protects explicitly any archaeological heritage even if not registered and requires that construction be carried out in such a way that damage to this heritage is avoided. The Regulation determines that the Ministry of Culture (now: the Ministry of Education and Culture) has to be informed about any project involving excavation. If during the execution of the project traces with an archaeological interest are found, the Ministry has to be informed within 24 hours and the works have to be suspended. Environmental Impact Assessment: Environmental Impact Report 7

22 2.4. INTERNATIONAL BEST PRACTICE Millennium Challenge Corporation The Millennium Challenge Corporation (MCC) recognises that all MCC-funded projects are to be environmentally sound, legally compliant and should not result in unacceptable environmental, health, or safety impacts. The MCC have developed three specific guidance documents in this regard the Guidelines for Environmental and Social Assessment (MCC, 2006), Gender Policy (MCC, 2006a) and MCC Guidance on the Implementation of Resettlement Activities (MCC, 2008). These guidelines are briefly described below: Guidelines for Environmental and Social Assessment The purpose of this guideline is to establish the procedures and principles for the review of environmental and social impacts associated with any project funded by the MCC. The ultimate aim is to ensure that the projects undertaken are environmentally sound, and compliant with local regulatory requirements. Under this guideline document, the proposed project is defined as a Category A project as it has the potential to have a significant adverse environmental and social impact. For all Category A projects, the MCC requires an EIA to be undertaken in accordance to MCC guidelines and local regulations. Gender Policy The Gender Policy provides guidance in terms of the responsibilities for the integration of gender into projects funded by the MCC. The ultimate aim of this policy is to address gender inequality as part of its overall mission of promoting economic growth and poverty reduction, and to incorporate gender into the development, design, implementation and monitoring of programs funded by MCC (MCC, 2006) The primary means of integrating gender into the planning process is to ensure full consultation with women. This is being promoted during the EIA as part of the PPP and within the Social Impact Assessment and the Resettlement Policy Framework studies. Throughout the EIA process, cognisance is being taken of the MCC Gender Policy (2006) and MCA Plan for the Integration of Gender Issues (2009). Guidance on the Implementation of Resettlement Activities This guideline defines the principles and actions of how resettlement and compensation of project-affected households and people is to be undertaken in any projects funded by the MCC. This guideline makes specific reference to the World Bank s Operational Policy (OP) 4.12 on Involuntary Resettlement World Bank Although the proposed project is not World Bank funded and therefore not subject to World Bank Standards, the various operational policies and standards are useful in providing guidance in meeting international best practice. Environmental Impact Assessment: Environmental Impact Report 8

23 World Bank Standards have been adopted in support and supplementary to the MCC guidelines. Relevant World Bank Safeguard Policies including the following: Operational Policy 4.01: Environmental Assessments Operational Policy 4.04: Natural Habitats Operational Policy 4.36: Forests Operational Policy 4.11: Physical Cultural Resources Operational Policy 4.12: Involuntary Resettlement Operational Policy 4.10: Indigenous Peoples Operational Policy 4.37: Safety of Dams Of particular importance is Operational Policy 4.12 for Involuntary Resettlement, which forms the key guideline for undertaking and implementing the resettlement process that will be required as part of the project. This guideline defines the procedures and steps required in the development of the Resettlement Policy Framework and the principles under which the resettlement will be undertaken International Finance Corporation The International Finance Corporation (IFC) functions as the private investment arm of the World Bank. As with the World Bank, the IFC Performance Standards have been adopted in support of and supplementary to the MCC guidelines. The Performance Standards for Social and Environmental Sustainability (IFC, 2006) cover eight major themes, namely: Performance Standard 1: Social & Environmental Assessment and Management System Performance Standard 2: Labour and Working Conditions Performance Standard 3: Pollution Prevention and Abatement Performance Standard 4: Community Health, Safety and Security Performance Standard 5: Land Acquisition and Involuntary Resettlement Performance Standard 6: Biodiversity Conservation & Natural Resource Management Performance Standard 7: Indigenous Peoples Performance Standard 8: Cultural Heritage 2.5. INTERNATIONAL CONVENTIONS AND TREATIES Mozambique is a signatory to a number of international conventions and treaties on environmental issues (ACIS, 2007) including: Resolution 18/81, of 30 December, ratifying the African Convention of Nature and Natural Resources Conservation Resolution 17/96, of 24 August, ratifying the UN Convention on Biological Biodiversity Resolution 45/2003, of 05 November, ratifying the Convention on Humid Areas of International Importance which serve as Habitats for Aquatic Birds Environmental Impact Assessment: Environmental Impact Report 9

24 2.6. ADMINISTRATIVE FRAMEWORK MCA-Mozambique was formed to act on behalf of the Government of Mozambique, and is primarily is responsible for the provision of financial resources and coordination of the Nacala Dam project (See Figure 2.1). A critical function of MCA-Mozambique is co-ordination with the Government of Mozambique in terms of providing the required reports, information and resources and ensuring appropriate monitoring and oversight. The National Directorate of Water Cabinet of Hydraulic Works (DNA-GOH) will function as the implementing entity during the feasibility and construction phases of the project. The National Directorate of Water will transfer the operational and post-construction management responsibility to the Regional Water Authority for the North Central Region which has legal standing but is not yet operational. Due to the combined responsibilities, the implementing entity is a co-ordinated effort between the DNA-GOH and the Regional Water Authority for the North Central Region (hereafter termed the Implementation Entity). Figure 2-1: Nacala Dam Project implementation structure DNA-GOH will be responsible for ensuring that all activities of the Project are implemented in a manner consistent with MCC s Environmental Guidelines and applicable Mozambican environmental laws and regulations. DNA-GOH will also have responsibility for overseeing the implementation of Environmental Management Plans (EMPs) for all activities in the Project and verifying that the Works contractors are implementing relevant mitigation measures as defined in and required by the EMPs. All activities should be carried out in close coordination with the MCA Environment and Social Impact Specialist (MCA ESI Specialist). Environmental Impact Assessment: Environmental Impact Report 10

25 3. METHODOLOGY The methods used to undertake this EIA followed the requirements and procedures defined in the Regulations for the Environmental Impact Assessment Process (Decree No 45/2004 of 29 September 2004) and outlined in Figure 3.1. The Regulations are seen as commensurate with international EIA procedures and their requirements are summarised as follows: 3.1. EIA PRE-EVALUATION APPLICATION (SCREENING) All activities were screened against Annexures I, II and III as defined in Article 3 of the Act in order to determine which process is to be undertaken. This included the completion of an Environmental Application Form (Ficha de Informação Ambiental Preliminar), which was submitted to the Provincial Directorate of Environmental Affairs (DPCA-Nampula). Confirmation of the requirement that the project requires a full EIA was obtained from the DPCA-Nampula (per written communication date 15 October 2009, Ref: 469/GD/DPCA/09) (See Appendix B) ENVIRONMENTAL PRE-FEASIBILITY AND SCOPING STUDY (EPDA) An Environmental Pre-feasibility and Scoping Study (Estudo de Pré-Viabilidade Ambiental e Definição de Ambito - EPDA) is obligatory for all Annexure I activities as defined by Article 10 of the EIA regulations. The key objectives of this study are to: Determine any fatal flaws or environmental risks associated with the implementation of the activity. Determine the ambit of the EIA process and develop a Terms of Reference (ToR) for this phase should no fatal flaws be identified. An EPDA report was compiled in both English and Portuguese and it included the following information: Details of the applicant and EIA team. Spatial extent of the proposed activity in terms of both direct and indirect influences. A description of the activity and the different actions to be undertaken, with respect to possible alternatives at the planning, construction, exploration and where relevant, decommissioning stages. Identification of key biophysical and social characteristics of the affected environment. Identification of any potential fatal flaws. Identification of potential environmental issues or impacts. Identification of aspects that need to be addressed in the EIA phase. A ToR for the EIA was included in the EPDA Report. The EPDA report was submitted to the relevant authority for review and has been approved. Environmental Impact Assessment: Environmental Impact Report 11

26 3.3. THE PUBLIC PARTICIPATION PROCESS The Public Participation Process (PPP) undertaken during the EPDA phase involved consultation with the wider public. The process facilitated the dissemination of information and identification of indirectly and directly Interested & Affected Parties (I&APs). Specific objectives of the PPP included providing suitable notification of the proposed project to all identified I&APs; providing I&APs with an opportunity to obtain information on the proposed project; providing I&APs with an opportunity to comment and raise concerns about the proposed project and to suggest possible solutions. This has ensured that I&AP views were incorporated into the assessment of alternatives, potential impacts as well as mitigation measures. The outcomes of the EPDA Phase PPP were described in the EPDA report and appended as a Public Consultation Report. Similarly, the PPP undertaken during this EIA Phase will be described in the final EIA and a Public Consultation Report summarising the PPP and its outcomes will be appended to the final EIA report ENVIRONMENTAL IMPACT ASSESSMENT The Environmental Impact Assessment (EIA), the focus of this report, contains the following information: Executive Summary, a non-technical summary with main conclusions and recommendations. Introduction including project background and motivation for project (Chapter 1). The legal and planning framework for the proposed development and EIA process (Chapter 2). EIA methodology (Chapter 3). A description and comparative assessment of alternatives (Chapter 4). A description of the proposed activity (Chapter 5). The definition of the geographic extent of the project with focus on the biophysical and socio-economic attributes that may be influenced by the project (Chapter 6). Identification and assessment of potential environmental impacts and mitigation measures (Chapter 7). Description of proposed PPP for the EIA Phase of the project (Chapter 8). Conclusions and Recommendations (Chapter 9). An EMP for the project that includes aspects such as a monitoring plan, an environmental education programme and emergency plans, amongst others (Appendix J). In order to address the issues raised during the EPDA, specialist studies have been undertaken to provide a detailed and thorough examination of key environmental impacts. These studies are included as Appendices to this EIA Report. Environmental Impact Assessment: Environmental Impact Report 12

27 Terrestrial Ecology Assessment A Terrestrial Ecology Assessment (Appendix C) was undertaken to determine potential impacts on terrestrial flora and fauna, and to determine changes in local ecosystem function. Tasks to be undertaken as part of this study include determining a regional and local baseline description of the possible vegetation types and faunal habitats, including possible IUCN Red Data listed species; a site visit including data collection; spatially defining ecologically sensitive zones; identification and assessment of potential ecological impacts; and providing recommendations and mitigation measures to reduce negative ecological impacts Ecological Flow Requirements An Ecological Flow Requirements study (Appendix D) was undertaken to determine the volumes of water that must be discharged from Nacala Dam to support the local riverine ecology. This study adopted an EcoStatus Rapid Level III process that determined the study area and identified sample sites on the Muecula River; undertook field surveys for each sample site and determined site characteristics; determined the ecological status of the Muecula River employing relevant EcoStatus modelling; determined habitat integrity for stream and riparian components using the Index of Habitat Integrity Model; determined ecological importance and sensitivity of the Muecula River using the EIS Model; determined and recommended ecological flow volumes using the Hughes DSS Model, assessed the impacts of ecological flow volumes on the riverine and riparian ecology; and assisted in the development of management protocols and procedures to ensure appropriate Ecological Flow Requirement for the operation of the Nacala Dam Hydrology A Hydrological Study (Appendix E) was undertaken that included undertaking a review of existing hydrological studies and information; a gap analysis; review the most appropriate hydrological model to be adopted in this study; establish a detailed water budget; determine domestic water use demand in consultation with the Nacala Water Supply System project; plot storage versus yield for each of the different reservoir storage amount to determine the optimum yield for the dam; provide preliminary operating rules; undertake a Flood Peak Analysis for the catchment of the Muecula River; and provide recommendations for emergency spillway design and for dam operation. Appendix E contains a synopsis of the hydrological study as this study is deemed to be part of the design process rather than a study in support of the EIA. Hydrological information where relevant to the EIA, has been incorporated in this EIA report Hydrocensus A Hydrocensus (Appendix F) to determine the existing status and potential changes to local groundwater/ hydrogeological regime was undertaken that included both a desktop study and fieldwork. Tasks undertaken as part of the hydrocensus included a review all previous studies and designs carried out at the Nacala Dam; an investigation of geological and ground water conditions and propose methods of treatment; undertake ambient hydrogeological Environmental Impact Assessment: Environmental Impact Report 13

28 assessments; evaluate the groundwater/surface water interactions and recharge and any potential environmental impact on these from the raised dam; evaluate the surface water environment downstream ending at the village directly downstream of the dam; identify a ground and surface water monitoring network; conduct a hydrocensus and evaluate the possible impacts that the proposed facilities and operations will have on the geology, surface water, wetlands, and groundwater environments Social Impact Assessment A Social Impact Assessment (SIA) (Appendix G) was undertaken in conjunction with the Resettlement Policy Framework (RPF) (Appendix H). The Terms of Reference for this study included: 1. Determining an appropriate study area that covers all directly affected households and communities including those downstream of the dam. 2. Collecting relevant social data, information and reports and providing a baseline analysis at a national, provincial, regional and local social level including, as a minimum, the following: Population demographics Local community structure including leadership structure. Households structure Livelihood strategies Primary social services in the study area Cultural, historical and archaeological sites Land types and land uses 3. Disaggregation of the above tasks to provide a gender-based analysis. 4. Spatially defining the households and machambas that will form part of the RPF. 5. Spatially defining dominant land-use types within the study area. 6. Providing a detailed analysis of the local socio-economic environment with particular focus on households/communities that will be directly affected by the project. 7. Providing recommendations and mitigation measures that will reduce the negative social impacts and maximise the social benefits of the project, and will be included in the Environmental Management Plan Resettlement Policy Framework A Resettlement Policy Framework (RPF) (Appendix H) was developed as a practical action plan for any form of physical or economic resettlement. The RPF will: 1. In consultation with the project team, define the potential inundation area and any additional activities that will result in resettlement. 2. Provide early recommendations to avoid or minimise resettlement. 3. Identify and establish communication with relevant government and community authorities that are important in the effective development of the RPF. 4. Undertake a detailed household census and asset inventory in affected households that will cover, at minimum, the following: Environmental Impact Assessment: Environmental Impact Report 14

29 Household family structure Type and size of primary and secondary dwelling All physical assets Livelihood strategies Natural resource use Number, size and location of Machambas Crops and trees 5. Establish a Resettlement and Compensation Entitlement Matrix and undertake a consultation process that includes all affected households, local communities and government authorities. 6. Provide a compensation and resettlement plan for each affected household, with a detailed cost schedule. 7. Special attention shall be given to resettlement impacts on women, children and any other vulnerable groups. 8. Provide a broad action plan for the implementation, monitoring and auditing of the resettlement and compensation process. The RPF was undertaken so as to comply with the World Bank Operational Policy on Involuntary Resettlement (OP4.12) Health Impact Assessment A Health Impact Assessment (HIA) (Appendix I) was undertaken in conjunction with the SIA. The aim of this study was to undertake a review of local health regulations; in consultation with the SIA, develop a profile of households/communities that may be affected by the project; identify environmental health areas that include health determinants and health outcomes, as per the accepted HIA methodology under the IFC community health guidelines and HIA toolkit; incorporate data collection efforts in social impact assessments through household questionnaires and focus group discussions; review of relevant health infrastructure and health facility data; meet with relevant stakeholders and conduct key informant interviews; evaluate the existing baseline health data for the potentially affected communities in the project area, including the relevant data gaps that may exist; provide advice as how to address these data gaps so that a clear baseline is established for the next phase; identify and assess potential health risks to all employees on the project; identify and assess direct, indirect and cumulative impacts, either positive or negative, that may arise from the project; and provide recommendations and mitigation measures to avoid or mitigate negative impacts and enhance anticipated benefits. The last task is to develop a Community and Occupational Health Action Plan that can be integrated into the EMP AUTHORITY REVIEW OF THE ENVIRONMENTAL IMPACT REPORT The final EIA report and all associated Appendices as defined in Article 12 of the EIA regulations will be presented to the relevant authority (MICOA) for review. Upon completion of the review, MICOA will provide a final Record of Decision. Based on Article 19 of the EIA regulations this may be one of the following: Environmental Impact Assessment: Environmental Impact Report 15

30 Positive record of decision Total rejection of the activity based on the outcomes of the reports and the final environmental impact statement Partial rejection of the activity based on the outcomes of the reports and the final environmental impact statement In providing an environmental licence, the relevant authority may seek to place conditions of approval that are legally binding on the proponent. Furthermore the authority may request changes to the project scope or additional EIA studies. Environmental Impact Assessment: Environmental Impact Report 16

31 Figure 3-1: The EIA process. Environmental Impact Assessment: Environmental Impact Report 17

32 4. ALTERNATIVE OPTIONS CONSIDERED The various options regarding the spillway upgrade, road alignment and associated bridge options and raising of the embankment that were considered in the preliminary design phase are outlined in this section SPILLWAY UPGRADE OPTIONS As part of the preliminary design, five different spillway types and positions were investigated taking into account factors influencing the positioning such as: Construction sequencing Road alignment including bridge crossings and diversion road Position of existing infrastructure like the Intake Tower, Water Treatment Works (WTW) and the pipeline linking the tower to the WTW Founding conditions (geotechnical considerations) Influence on surrounding community (social considerations) Area available for construction of the required spillway length Options were investigated on both the left (LHS) and right (RHS) flanks of the embankment and have been labelled as follows (): Left Hand Side Option A (LHS A) with a semi-circular overspill crest. Left Hand Side Option B (LHS B) with a side channel. Right Hand Side Option A (RHS A) with a side channel. Right Hand Side Option B (RHS B) with a side channel. Right Hand Side Option C (RHS C) as an open channel by-wash. Table 4-1 lists the spillway options that were identified during the preliminary design stage and summarises the advantages and disadvantages associated with each option. Table 4-1: Advantages and Disadvantages of various spillway options Spillway Option Advantages Disadvantages LHS Option A Relatively good founding conditions with the presence of slightly weathered hard rock at a level of approximately 72mamsl at a point directly beneath the road. No interference with any houses. Environmental Impact Assessment: Environmental Impact Report 18 Interference with the existing bridge providing access to the intake tower as well as the pipeline linking the tower to the WTW. A temporary abstraction works will have to be established to prevent a break in supply of water to Nacala. Requirement for blasting of rock. LHS Option B Good founding conditions with Interference with the existing

33 Spillway Option Advantages Disadvantages the presence of slightly weathered hard rock at a level of approximately 72 mamsl at a point directly beneath the road. No interference with any houses. Shorter bridge crossing than LHS A. LHS Option C Good founding conditions with the presence of slightly weathered hard rock at a level of approximately 72 mamsl at a point directly beneath the road. No interference with any houses. No interference with the existing bridge providing access to the intake tower or the pipeline linking the tower to the WTW. Construction in both wet and dry season. RHS Option C Very little concrete lining required throughout the structure due to the flow being subcritical. It is favourable from a cost perspective. RHS Option B Narrower channel and smaller cut than RHS C. Environmental Impact Assessment: Environmental Impact Report 19 bridge providing access to the intake tower, as well as the pipeline linking the tower to the WTW. A temporary abstraction works will have to be established to prevent a break in supply of water to Nacala. Requirement for blasting of rock. Long bridge crossing that will increase costs. Requirement for blasting of rock. A large 110m wide and 14m deep cut is required at the point where the road crosses the spillway channel. This will effectively cut the existing community in half and is likely to interfere with an existing mosque and a shop. Pedestrian bridges will also have to be considered to allow the people to move between the different areas of the community. The channel will also prevent members of the community obtaining access to certain crops currently planted on the banks of the impoundment. High likelihood of erosion and scour in the area between the discharge channel and the Muecula River. Founding conditions on moderately weathered gneiss rock. Interference with several houses.

34 After analysing the various spillway alignments it was proposed that LHS A (semi-circular overspill crest) and RHS B (side channel spillway) be the preferred options. This provided a preferred option on either side of the embankment. These two options were then compared from a cost perspective and LHS A was significantly less expensive ($2.5 million) due to the smaller amount of concrete required in the structure. To optimise the allowance for the surcharge and the spillway length two freeboard scenarios were investigated, as required in the SANCOLD guidelines: Increased FSL + height of flow over new spillway under SEF flood flow conditions + no freeboard. This equals 3.4m. Increased FSL + height of flow over spillway under RDF conditions + freeboard for wave run up and setup. This equals 1.15m + 2.1m = 3.25m. After reviewing these scenarios it was decided that a spillway of crest level 78.5mamsl, a length of 120m and a spillway discharge coefficient of 2.1 would enable a total Non-Overspill Crest (NOC) raising of 4m, i.e. from 78mamsl to 82mamsl. This provides a total freeboard allowance of 3.5m, which is deemed to be acceptable by the engineers. Environmental Impact Assessment: Environmental Impact Report 20

35 Figure 4-1: Spillway options considered during preliminary design stage 21

36

37 4.2. ROAD ALIGNMENT The raising of the dam embankment required the abandoning of the existing road works and the design of a new road alignment. The road alignment options were considered in conjunction with aspects such as spillway position; bridge positions and span lengths; embankment raising method; construction sequencing; and impacts on the environment and the local community. Three alternative road alignment options were investigated, i.e.: 1. Maintain the same horizontal alignment and construct a new pavement on top of the newly repaired and raised dam, 2. Offset the alignment slightly and combine the construction of the new road with the necessary widening of the existing embankment. 3. Select a new alignment, downstream of the dam. All of these options require a temporary detour, downstream of the dam, and crossing the existing river, in order to accommodate public traffic. Option 1 was discarded based on the cost of building a temporary and permanent road and rehabilitation of a temporary access road; the difficulty of sequencing construction; the cost of a long road bridge across the dam spillway crest; the problem of overpassing the proposed outlet works near the existing radial gates; the long-term risk posed by everincreasing traffic loading on the dam crest, and the pollution risk of the Nacala Water supply source in the event of an accident involving toxic substances. Option 2 having the road alignment at the base of the new dam embankment was identified as the most preferable option. Construction of this option has advantages over Option 1 in that the construction activities can be kept further away from the main embankment works, which will reduce traffic management and construction conflicts between dam and road works. This will greatly reduce construction sequencing problems. The bridging of the channel below the existing spillway channel could in this option be constructed using embankment and culverts rather than a more expensive bridge structure. The bridge structure required over the left flank spillway discharge channel would be shorter and less expensive than for Option A. Option 3 with the road passing downstream of the dam was ruled out due to the long distance required and hence the high cost that would be incurred in constructing this option EMBANKMENT RAISING OPTIONS Three embankment raising options were investigated for the raising of the dam to achieve an increase in full supply level in the reservoir of 2m: 1. Raising with the road along the downstream face of the embankment. 23

38 2. Raising with the road separate from and at the toe of the embankment and placement of additional material on the downstream slope. 3. Raising by steepening the upstream and downstream faces at higher levels of embankment. Option 1 was deemed to be more difficult than the others due to the technicalities involved with having to ensure the correct drainage systems are in place for both the road and the dam embankment. The construction sequencing would also be more difficult because the existing road would need to be kept open to traffic until the new road was complete. This would have to involve a lot of construction work happening very close to the existing road which is often used by large trucks. This was deemed to be a disadvantage of this raising option. The preferred option is to move the existing National Road N12 off the embankment crest and to move it onto a new embankment downstream of the dam wall (Option 2). By removing the national road from the dam crest the crest width can then be reduced from 11m to 6m. The dam embankment can then be raised by 4m, by increasing the side slopes on both the up and downstream face to a 1: 2 slope. The core will also be raised to within 1m of the crest level. The downstream face will be widened by the addition of a gravel aggregate layer, and by the inclusion of a mid slope berm. Internal sand filters will be installed adjacent to the raised core on the downstream face, which will connect into a gravel drain that will link into a surface drain running along the berm. A new rock toe will be incorporated into the downstream face, which will connect into seepage detection weirs at specified intervals THE NO-GO PROJECT OPTION Should Nacala Dam not be rehabilitated, the risk posed by the dam is a concern both in terms of the structural stability of the dam and community safety. Nacala City and Nacala Velha would continue to experience potable water shortages and this would become more problematic with time. Environmental Impact Assessment: Environmental Impact Report 24

39 5. PROJECT DESCRIPTION The key components of Nacala Dam are outlined followed by a description of the proposed rehabilitation and raising of Nacala Dam NACALA DAM The Nacala Dam is located on the Muecula River approximately 30 kilometres south west of Nacala City and approximately 20km north east of Monapo in northern Mozambique (Figure 5-1). It is the primary water source for the city of Nacala, which is situated approximately 200km north east of Nampula City. This underlies the importance of the dam for the future development of Nacala Town and its port. The coordinates for the Dam are 14º South and 40º East (. The Nacala Dam was designed and constructed from 1968 to The dam was overtopped for 10 consecutive hours during the 1982 floods, due to the malfunctioning of the spillway gates. This resulted in the severe erosion of the roadway and downstream face, in particular an area adjacent to and extending some 100m from the spillways towards the right flank. Repairs were undertaken 1983 and involved the reinstatement of the eroded embankment with soil, stone pitching and cement mortar. Further repairs were undertaken in 1995 and subsequently in Technical Reviews undertaken by the MCA-Mozambique (Baker, 2006) concluded that the Nacala Dam is not safe at present and needs to be rehabilitated KEY COMPONENTS OF NACALA DAM An earth-embankment dam is made up of a number of key components that are shown in Figure 5.3 and are briefly described in this section Embankment The main embankment dam is a conventional earthfill dam of low to moderate height (17.4m). It is considered a medium category dam that is approximately 300m in length. Earthfill dams are made of compacted earth with distinct zones of differing materials/soils. In the case of Nacala Dam, this includes zones of clayey-sands and sand-clay mixtures that were most likely sourced locally. The crest is approximately 11m wide with an upstream side slope of 1:2.4 and a downstream side slope of 1:2.7. The upstream face is protected by a layer of hand placed riprap of large rocks (Figure 5-4). Apart from minor irregularities and some weed growth it appeared to be in good condition. The downstream slope is covered by grouted stone pitching that was placed as protection following the overtopping by flood water in 1983 (Figure 5-4). It should be removed when a new substantial spillway is constructed. Overall, this section of the dam appears to be in a reasonable and safe condition. Environmental Impact Assessment: Environmental Impact Report 25

40 Figure 5-1: Locality plan of Nacala Dam Environmental Impact Assessment: Environmental Impact Report 26

41 Figure 5-2: Aerial view of Nacala Dam and Surrounds 27

42 Figure 5-3: Different components associated with Nacala Dam 28

43 Figure 5-4: Upstream face of Nacala Dam Figure 5-5: Nacala Dam Reservoir 29

44 The section of the embankment on the left hand side of the Dam wall, adjacent to the spillway, is of more concern. This is the area that was overtopped and eroded during the flood of 1982, and subsequently the upper portion was reconstructed. Seepage is prevalent here, particularly adjacent to the concrete sidewall of the spillway. During the geotechnical investigation, the stone pitching was removed from the leak area and this revealed a large void centred on two pipes traversing through the embankment. Remodelling of this part of the embankment will be necessary, whether or not the dam is raised Reservoir The Reservoir is the main body of water and extends for approximately 3km from the dam wall (Figure 5-2 and Figure 5-5). It is approximately 400m at its widest point. The volume of water stored in the reservoir varies based on management practices and rainfall. The maximum or gross storage capacity is estimated at 4.4 million m 3 (mcm) Spillways Currently Nacala Dam does not have outlets for the release of water downstream, and water overflows (flooding) are managed by spillways located on the eastern (left) flank of the embankment. Spillways provide for the controlled release of water during flood periods thus preventing water from overtopping and damaging the dam. It functions as a critical mechanism in terms of flood control. During the preliminary feasibility study, the spillway gates were in the closed position, but a large flow of water (± 200l/sec) was escaping through the sill seal and corroded parts of the gate leaf of the right hand side gate. The raising mechanism could not be operated by the electric motors, and the Consultant was informed that it takes two men an hour to raise each gate manually. There were replacement stop logs lying alongside the spillway structure, but the lifting gantry was not in working order. The spillway is understood to be inadequate for the passing of large floods. The lack of maintenance and problems with the existing gates suggests that an ungated spillway would be a preferred solution. 30

45 Figure 5-6: Downstream Face of Nacala Dam with protective stone grouting N12 National Highway The Nampula to Nacala Road (N12) is km in length and links Nampula, the capital city of Nampula Province with the deep-sea port of Nacala. The N12 National Highway runs along the embankment for 304m with a 9m wide bitumen surfaced road, and a 1m wide by 0.3m thick concrete walkway on each side. The road provides for two way traffic along the embankment (Figure 5-7). Figure 5-7: Dam Crest and N12 Highway 31

46 5.3. RATIONALE FOR THE UPGRADE & REHABILITATION OF NACALA DAM The GOM, via the National Directorate of Water and MCA-Mozambique, propose to rehabilitate and raise Nacala Dam. The aim is to increase the water supply capacity of Nacala Dam in order to meet increasing demand of Nacala City and to supply Nacala Velha with water, while ensuring that the dam is structurally safe Improving Water Supply The Nacala Dam is the principal water source for Nacala City, and is thus of strategic importance. During dry years, it falls empty and fails to secure supply. Nacala Dam was almost empty for three years and only filled again after the rains in January Vegetation growth occurred within the basin and most of the vegetation rotted impacting on the water quality within Nacala Dam. Consumers complained about turbidity and smell (Michael Baker Jr., 2006). A baseline analysis was undertaken in 2006 to determine the water supply capacity of Nacala Dam and its ability to meet the current and future water demand of Nacala City. The City of Nacala had a total estimated population of 282,498 in 2005, which is estimated to grow at 3.3% per annum. Estimates (Michael Baker Jr., 2006) based on input from the local water service providers indicated that only 15.7% of the total population receive water from formal water sources. In the upgrade of Nacala Dam, the GOM has not only sought to increase water supply capacity but to increase the coverage of households that will receive water and this will include households in Nacala Velha. The overall program goal is to increase water supply to 50% of the population of Nacala City by 2015 and by 75% in Water demand projections (Michael Baker Jr., 2006) indicate a water demand of 5,490m 3 /day for 2005 increasing to 23,092m 3 /day in 2015 to meet the programme goal of providing water to 50% of Nacala City. At present Nacala Dam is kept at 4m below its full supply level (74.5masl), however at full supply level it provides a total yield of 3.2mcm/a (Michael Baker Jr., 2006). Estimates indicate that based on population growth the supply capacity of the dam would be reached in The raising of Nacala Dam by 2m will increase the supply capacity to 4.99mcm/a (Michael Baker Jr., 2006), thus providing additional water supply capacity to Thereafter new sources of water will need to be explored Improvement of Dam Safety Prefeasibility reports (Baker, 2006) indicate that the dam is operated sub-optimally and concluded that Nacala Dam is a safety risk due the following: The embankment was repaired after being overtopped with permeable gravel zones increasing the risks of piping failure. 32

47 Seepage through the embankment occurs when the water level rises to within 4m of the dam crest. No internal drainage system has been provided which is of concern as the soils were found to be potentially dispersive. The existing spillways are in a state of disrepair and capacity is inadequate. The radial gates are in a state of disrepair. The primary aim of the rehabilitation of Nacala Dam is to ensure the long term stability and safety of the dam PROJECT ACTIVITIES Spillway Upgrade The existing spillway comprises two radial gates, each 6.0m wide x 5.5m high, having a total combined discharge capacity when fully open of approximately 300m³/s. This is insufficient to deal with the routed Recommended Design Flood (RDF) figure of 744m³/s and the Safety Evaluation Flood (SEF) of 1 530m³/s. The existing spillway is in a poor state of disrepair and has resulted in overtopping in the past and is considered a safety risk. The options considered and the analyses that were undertaken as part of the design report tied together road, bridge crossing and water levels under different conditions to optimise spillway position and size. Due to topographical constraints the embankment can only be raised to a maximum non-overspill crest height of 82mamsl. To achieve the required 2m increase in Full Supply Level (FSL) a maximum freeboard allowance of 3.5m is available. Using this maximum freeboard allowance, a 120m long spillway is required to safely discharge the SEF without overtopping the crest of the dam, which supersedes the RDF as being the controlling factor in spillway sizing. The proposed spillway upgrade would involve the increase in capacity from 300m 3 /sec to 734m 3 /sec. The upgraded spillways would have a free overflow crest that does not need to be operated by staff. Spilling will occur automatically when the water level exceeds the spillway crest. The existing malfunctioning spillways will be discontinued and replaced with a concrete bulkhead. Outlet pipes and valves will be introduced to be able to release the required ecological flow requirements. The preferred spillway option, LHS A is a bath tub type spillway positioned approximately 20m from the existing spillway channel with the centre of the bath tub positioned on the northern edge of the N12 (Figure 5-8). The diameter of the semi-circular overspill crest is 76m providing the required 120m overspill length. A spillway chute narrowing from the 76m diameter down to 30m at the outlet will discharge the water into an existing drainage line approximately 50m from the Muecula River. 33

48 Construction of a coffer dam will be required upstream of the proposed position of this spillway. It is possible for the concrete floor/base of the bath tub structure to be founded on solid rock which will prevent it from lifting as a result of water pressure underneath the structure. Advantages of this option are as follows: Relatively good founding conditions with the presence of slightly weathered hard rock at a level of approximately 72mamsl at a point directly beneath the road. No interference with any houses. Disadvantages of this option are as follows: Interference with the existing bridge providing access to the intake tower as well as the pipeline linking the tower to the WTW. A temporary abstraction works will have to be established to prevent a break in supply of water to Nacala. Requirement for blasting of rock. As part of the preliminary design, a tailwater analysis was undertaken using the HEC-RAS hydraulic model. The routed RDF figure of 734m 3 /s was modelled to determine what affect the flood waters would have on the downstream topography once it had left the spillway. Peak flows were hydraulically simulated on the downstream topographical contours provided by the LIDAR Survey. This determined the maximum water levels of the discharging flood around the toe of the dam embankment. This analysis included taking into account the effects of the proposed new road embankment below the toe of the raised dam embankment. In addition the analysis provided an indication of what houses, if any, needed to be relocated. Figure 5-5 shows the results of the tailwater analysis for Spillway LHS A. This figure also shows the footprint of the raised dam embankment and the proposed road embankment. 34

49 Figure 5-8: Layout of preferred Spillway Option Left Hand Side A 35

50 Figure 5-9: Tailwater Inundation area for LHS Spillway Option A 36

51 Embankment Raising Various options of raising the existing embankment were analysed in conjunction with different road alignments and spillway positions (Section 4.1.1). The TOR for the project stipulated that a 2m raising of the FSL was required in order to increase the level of supply to Nacala Town. This resulted in a new FSL of 78.5mamsl. The new freeboard required for the new embankment was 3.5m. The nett result was that the embankment needed to raised by 4m, resulting in a new NOC of 82mamsl (Section 4.1.1). The survey information obtained indicated that the topography was suitable for a raising to this level. The new embankment would need to extended on the left flank up to the WTW position. The preferred option identified was to raise the embankment by steepening the embankment slopes in the upper parts to a slope of 1:2. This would reduce the materials required for construction and provide a simpler and cheaper solution Road Deviation As the Nacala Dam rehabilitation project involves the raising of the dam embankment, it will be necessary to abandon the existing road works. All the alternative road options (Section 4.1.2) including the preferred option require a temporary detour, downstream of the dam, and crossing the existing river, in order to accommodate public traffic. The preferred road alignment option that is recommended for detailed design is Option 2 with the road just downstream of the toe of the raised embankment (Figure 5-10). The overall length of this new section would be approximately 1 288m and it is currently proposed to have a pavement thickness of 350mm, i.e. 2 x 175mm layers of granular base, with a running surface the same as the existing road. It is proposed that the road, bridge and culverts will be constructed during the dry season at the beginning of the contract. The route to be followed is immediately downstream of the existing dam wall and the vertical alignment will be optimised so as to reduce the amount of fill required and thus keep the construction period as short as possible. It is envisaged that the road deviation and associated drainage works will be completed within the first six months of the contract, thus allowing traffic to be diverted off of the existing dam wall to facilitate construction work on the dam wall. 37

52 Figure 5-10: Preferred Road Diversion Option 2 38

53 Borrow Pits A borrow pit survey undertaken for the Nacala Dam project included investigating locations within the immediate vicinity of the Nacala Dam embankment and at a number of potential borrow locations further away from the present dam site location (Figure 5-11). These sites are between approximately 3km to approximately 19km away from the site along the present N12 route and along a prominent granite gneiss ridge which is situated to the north and north east of the Nacala Dam and the N12 route. The borrow materials survey indicates that a plentiful supply of consistently good quality naturally occurring clays (for the dam embankment clay core construction), sands and gravels occur in relatively close vicinity to the site. These sands are suitable for use as lower selected subgrade and subgrade fill layerworks for the proposed road construction and for the proposed dam embankment shoulder material construction. This material was investigated at four locally occurring locations namely to the west, in the immediate western vicinity of the dam embankment and to the east of Nacala Dam along the N12 route. The distance to the west was approximately 3km (N12 Ch 155.6km) and the distance to the east was approximately 9km (N12 Ch 169.1km) east of the site along the N12 route. The closest commercial quarry to the Nacala Dam project site has been identified as the Condor Lda commercial rock quarry. The Condor Quarry is located to the north of the national Route N12 at chainage km 89.1, which is on the eastern side of the town of Namialo and approximately 60km from the site. The quarry s geographical co-ordinates are S, E. The quarry which is a s yenite rock quarry can, at the time of reporting, supply G2 and G1 crushed stone base course material and the full range of concrete stone aggregate and concrete sand materials. The management at the quarry would not allow bulk sampling of the materials at the time of the visit to the quarry site. Two other existing, but inoperative, rock quarries were identified closer to the Nacala Dam project site. 39

54 Figure 5-11: Locality of identified borrow pits 40

55 6. BASELINE ENVIRONMENT This chapter describes the current environmental situation in the proposed location including biophysical, economic and social information CLIMATE Rainfall data for the catchment were calculated using the combined characteristics of the three patched rainfall data sets of the gauges Itoculo (MCA), Lumbo and Sanhute Rio and covers a 50-year period from 1956 to 2005 (hydrological years) and are summarised in Table 6-1. These data were used to determine rainfall-runoff and yield modelling processes. Table 6-1: Characteristics of rainfall in the Nacala Dam catchment Period of record (hydrological years) Length of record Annual statistic Start End (years) MAP (mm) SD (mm) CV % The mean annual precipitation (MAP) for the catchment is estimated to be 913.9mm (Table 6-1). The average monthly distribution of rainfall in the Nacala Dam catchment (Figure 6-1) indicates that the rainy season starts in December and ends in April Monthly average rainfall (mm) Month No. (starting in October) Figure 6-1: Average monthly rainfall in the Nacala Dam Catchment Evaporation data for the Nacala Dam Catchment are summarised in Table 6-2 and represent a mean annual evaporation (MAE) of 1 497mm, based on the Symon s pan (S-pan) standard. Evaporation data were used for the estimation of catchment evapo-transpiration as 41

56 part of the rainfall-runoff modelling process, as well as for the modelling of evaporation losses from the surface area of Nacala Dam in the yield analysis. Table 6-2: S-pan evaporation data for the Nacala Dam catchment (1) Average S-pan evaporation for indicated month (mm) Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Total (MAE) Note: (1) From Baker (2006) GEOLOGY Nacala Dam is underlain by geology of the Nampula Group of the Nampula Supergroup. The Nampula Group comprises mostly of granulitic and migmatitic gneisses, migmatites and their weathered derivatives (Baker, 2006). Gneiss is a common type of metamorphic rock formed from the local Nampula Supergroup. Structurally, the local Gneiss is a slightly weathered, coarse grained, hard rock with tight medium and widely spaced joints. The foundations of the dam overlie residual gneiss overlying Rapala Gneiss bedrock of the Nampula Metamorphic Complex. The bedrock was described as being competent on the right flank of the original river channel and fractured on the left flank SOILS Three soil profiles were undertaken in selected areas of the catchment (Jeffares & Green, 2010). SP 1 Northern Area of Catchment SP 2 Central Area of Catchment Soil Profile 3 South Western Area of Catchment 42

57 The following is a brief summary of the findings of the soil profiling: SP1 Namib 1100 Nortier This soil consists of a very shallow Orthic A-horizon overlying a deep Regic Sand B- Horizon (> 500 mm). The Regic Sand Horizon appears to be of Aeolian origins. It is pale yellowish brown with quartz common throughout the horizon. It had no structure and exhibited no cross-bedding. SP2 Clovelly 1100 Twyfelaar This soil consists of a shallow Orthic A-horizon overlying a deep Yellow-Brown Apedal B-Horizon. The B-Horizon was light brown in colour. The Yellow-Brown Apedal B-Horizon was found to be dystrophic and non-luvic. The soil appeared to have no structure, and was friable and apedal in nature. SP3 Hutton 1100 Lillieburn This soil consists of a shallow Orthic A-horizon overlying a deep Red Apedal B- Horizon. The B-Horizon did not exhibit deep red colouration, but had sufficient chroma to categorise it as red Apedal subsoil. The Red Apedal B-Horizon was found to be dystrophic and non-luvic. The soil appeared to have some structure, but when studied more closely was found to be friable and apedal in nature TOPOGRAPHY AND LANDFORM The local topography may be characterised as Coastal Lowland, i.e., a landscape that is very flat with gentle undulating hills providing some change in local topography. The dam itself is sited at between 60 and 90mamsl VEGETATION General Overview An ecological study that includes a vegetation specialist study is included as Appendix C. The vegetation that will be inundated by the raising of the wall of the Nacala Dam was assessed by desktop analysis of the area s current global and regional characterisation. This was followed up with an extensive site visit during which field sampling methods were undertaken to measure the plant community assemblages, identify plant species and communities and land-cover. The sampling methods used, included: A search and survey of various habitat types looking for plants of conservation importance. Using sample plots to record species composition (10mx10m plots). Using sample plots to verify remote sensing segmentation signatures to train classification algorithms. According to the World Wildlife Fund s Conservation Science Program (Olsen et al. 2001) the Nacala Dam study area occurs within the larger Southern Zanzibar-Inhambane coastal forest mosaic Terrestrial Ecoregion. This Ecoregion is very large and extends from southern Tanzania to Inhambane in Mozambique. The Ecoregion is characterised by a high density of 43

58 endemic species in the northern portion (southern Tanzania) followed by an almost complete lack of data in the central portion (northern and central Mozambique). A relatively dated classification of the study area according to work published by Wild and Fernandes (1968) for the Flora Zambesiaca, the Nacala Dam area falls within Unit 33: Deciduous Woodland and Thicket Dry Deciduous Miombo Savanna Woodland vegetation type. The presence of this vegetation type, and finer-scale communities, was explored during the site visit undertaken in November The study area is illustrated in Figure 6-2. Figure 6-2: Study area for the Nacala Dam Terrestrial Ecological Assessment Plant species/communities occurring on site A total of 194 plant species were recorded for the study area during the site visit. This included 25 plant species that are either exotic or cultivated, and 9 plants that are of conservation importance. A list of the 194 plant species and their status is appended to the Terrestrial Ecological Specialist Study (Appendix C). The natural vegetation around the Nacala Dam can be described as a degraded form of dry deciduous woodland and thicket mosaic. Logging and other disturbances mainly associated with agriculture practices has obscured the natural vegetation boundaries which created difficulties in the identification of definite communities within this Dry Deciduous Woodland and Thicket Mosaic. No pristine areas (areas that show no signs of logging) were observed. Five vegetation communities were identified, i.e.: 44

59 Millettia Dry Thicket/Forest This community is characterised by Millettia stuhlmannii, Millettia bussei, Hugonia busseana, polysphaeria lanceolata, Adansonia digitata, Combertum andradae, Micklethowaitia carvalhoi, Ochna atropurpurea, Strychnos potatorum and Hymenocardia ulmoides. The height of the community is about 8-12m tall, but judging from the occasional emergents still standing, it was once much taller. Saplings of the popular timber tree Milicia excelsa were found in this community. Diplorhynchus Savanna / Woodland This community was characterised by Diplorhynchus condylocarpon, Holarrhena pubescens, Strychnos gerrardii, Diospyros loureiriana, Dalbergia melanoxylon, Ormocarpum kirkii, Bauhinia petersiana, Synaptolepis oliverana, Boscia angustifolia and Combretum adenogonium. This is a more open community with limited timber trees such as Dalbergia melanoxylon. Albizia Savanna / Woodland This community is characterised by Albizia brevifolia, Senna sanguinea, Dichrostachys cinerea subsp. forbesii, Lantana camara*, Barleria kirkii, Senna petersiana, Hyptis suaveolens*, Salacia elegans, Hyperthelia dissoluta and Ehretia amoena. This community is very degraded and is located closest to the residential areas. The invasive Lantana camara* and very invasive Hyptis suaveolens* occur in this community. Cultivated Crop Fields This community is characterised by cultivated crops such as Zea mays* (Maize), Musa acuminate* (Banana), Saccharum* sp. (Sugar Cane), Solanum lycopersicum* (Tomato), Hibiscus sabdariffa* and Vigna unguiculata* (Cowpea). Other weedy species characteristic of this community are Grangea maderaspatana, Sorghum bicolour subsp. arundinaceum, Nidorella auriculata, Persicaria senegalensis, Ricinus communis*, Ziziphus mauritiana, Heliotropium ovalifolium and Coldenia procumbens. The occasional and persisting Flagellaria guineensis was found in this community, highlighting the fact that parts of this community may once have been forest. This community was found all along the dam s edge and in drainage lines. Dry Cashew / Cassava Lands This community was generally made up of Cashew lands found away from the water s edge. This community was characterised by the crops such as Anacardium occidentale (Cashew), Manihot esculenta (Cassava), Mangifera indica (Mango) and Cajanus cajan (Pigeon Pea). Other characteristic weedy and indigenous species include Trichodesma zeylanica, Vernonia poskeana, Hyparrhenia rufa, Abutilon sp., Xylotheca tettensis, Ritchiea pygmaea and Pennisetum polystachion. 45

60 Land-cover The following land-cover classes were recognised in field and used to classify and determine the percentage cover of the study area (Table 6-3): Water; Transformed roads, buildings, bare soil; Degraded, grassland or once woodland; Shrubland, clear-felled woodland; and Woodland. The percentage land-cover is expressed as a portion of a proposed 80m footprint area of the inundated area (approximately 170ha) as well as a portion of the broader Nacala Dam study area (approximately 531ha). The image of the land-cover is included in the Terrestrial Ecological Specialist Study (Appendix C). Table 6-3: Land cover classes in study area Broader Nacala dam study area (approximately 531ha) Nacala Dam 80m footprint (approximately 170ha) LAND- PERCENTAGE PERCENTAGE SIZE (ha) SIZE (ha) COVER (%) (%) Water Transformed Degraded Shrubland Woodland TOTAL TERRESTRIAL FAUNA General overview The faunal species occurring on or within the area to be inundated by the raising of the Nacala Dam wall was assessed, firstly by gathering desktop information with regards to any possible species that might occur and secondly by assessing the species present on the site during a site visit. The site visit investigation made use of field observations (scats, tracks, tree scrapings and breeding / shelter sights), trapping of rodents, interviewing the local residents (through an interpreter) and the analysis of scats of predator species (owl, jackal, domestic dog) for animal remains used in species identification. The specialist terrestrial ecological study that includes faunal aspects is included as Appendix C Mammals The rodent diversity recorded on the study area was low. In total, five species were recorded, namely Tatera leugogaster, Mastomys coucha, Mastomys natalensis, Otomys 46

61 angoniensis and Lemniscomys rosalia. However, the density was overwhelmingly in favour of the primary species, Tetra leucogaster (as estimated by observation, jaw-bones and relative trapping success). The dominance of a single species is indicative of a highly disturbed area in its primary phase of succession. Elephant shrews were seen on site and were subsequently captured and identified as the Four-toed Sengi Shrew (Petradromus tetradactylus). This shrew is locally threatened in some areas of its distribution as a result of subsistence hunting and habitat loss. The species however, has a global status of Least Concern according to the IUCN Red-Data List. Vervet Monkeys are a common species throughout southern Africa and were sighted on a number of occasions during the survey period. In addition, local information gathered from members of the surrounding communities states that the Syke s or Samango Monkey (Cercopithecus albogularis) is often seen in the area but seldom proceeds past the dam wall. Both species are highly mobile and arboreal and will not be affected by the proposed increase in the inundation zone of the dam. Recorded carnivorous species centred on circumstantial evidence from the local communities rather than direct observations is possibly present on in the study area. In this regard a single Slender Mongoose was sighted and a dead specimen of a Large-spotted Genet was collected Avifauna A total of 81 bird species were detected within the study area. A complete bird list is included as an addendum to Appendix C. The majority of the species detected can be categorised as generalists, which can persist in degraded habitats such as those found within the study area. This can be determined by the relatively high number of species that are seed eaters. A relatively low number of raptors were encountered during the survey Herpetofauna Five herpetofaunal species of importance were identified as target species during the desktop survey of the study area, they are: Python sebae (Southern African Python), Crocodylus nilotica (Nile Crocodile), Xenocalamus transvaalensis (Transvaal Quill-Snout Snake), Kinyxs natalensis (Natal Hinge-back Tortoise) and Cycloderma frenatum (Zambeziflap shell turtle). Ten species of reptile were directly observed from the study area although none of the target species from the desktop survey were found during the sampling period. However, local information gathered represents that two of the listed target species, Python sebae and Crocodylus nilotica periodically occur in and around the Nacala Dam area. Only two amphibian species, namely Amietophrymus maculates (Flat Backed Toad) and Ptycaden oxyrhyncus (Sharp-nosed Grass Frog) were recorded despite strong sampling efforts. A full explanation of these sampling efforts is described in the Specialist Terrestrial Ecological Specialist Study (Appendix C). The lack of amphibians is ascribed to the extreme human pressures in and around the Nacala Dam site and the timing of the sampling. Amphibian diversity is an excellent environmental indicator of a Wetland system, the lack of 47

62 diversity in the study area therefore reflects the extreme human pressures through subsistence farming, subsistence hunting and pollution on the Nacala Dam. As a result of the aforementioned subsistence agriculture, there is very little pristine riparian vegetation around the study area. Amphibian species therefore have no breeding habitat or any protection against predators, which resulted in the small numbers collected AQUATIC FAUNA General Overview A component of the Ecological Flow Requirement Study (Appendix D) included the assessment of the aquatic fauna that occur in the Muecula River Fish The following fish species were sampled during the Ecological Water Requirement Determination Study, Oreochromis mossambicus (Mozambique Tilapia), Tilapia rendalli (Redbreast Tilapia), Pseudocrenilarbrus philander (Southern Mouthbrooder), Clarias gariepinus (Catfish), Anguilla mossambicca (Longfin Eel), Barbus viviparous (Bowstripe Barb), Barbus radiates (Beira Bard) and Barbus trimaculatus (Threespot Barb). None of these sampled fish species can be classified as endemic, protected or endangered. It is expected that these fish numbers will be affected drastically due to the human impact of overfishing in the Nacala Dam. The full results of this survey are included in Annexure 3 of the EFR specialist study included as Appendix D Aquatic invertebrates The following invertebrate taxa were sampled during the Ecological Water Requirement Determination Study, Oligochaeta, Potamonautidae, Baetidae, Caenidae, Leptophebiidae, Coenagrioniidae, Gerridae, Notonectidae, Veliidae, Ecnomidae, Dysticidae, Gyrinidae, Chironomidae and Simuliidae. The diversity and abundance in the sampled taxa is relatively low which is indicative of a total river system that is under severe ecological pressure. The presence of Benthic Diatom growth on rocks and other hard surfaces indicate limited grazing by macro-invertebrates which is consistent with the lack of sampling of these species. The full results of this survey are included in Annexure 3 of the EFR Determination Study attached in Appendix D HYDROLOGY Nacala Dam is fed by the Muecula River Catchment, which is estimated to cover approximately 135.8km 2. The mean annual runoff of the catchment into Nacala dam is estimated at 11.66mcm/a (Jeffares & Green, 2010). The Nacala Dam catchment area (with its outlet at the Nacala Dam Wall) is bordered by the N12 road in the south and a well developed District Road in the north. A small sand track runs down the eastern boundary of the catchment. Access into the catchment is limited to a few small sandy tracks through dense vegetation in most places. The catchment conditions are considered to be largely homogenous. Only minor changes in soil characteristics, land use and vegetation were 48

63 noted. A summary of the main findings of the hydrological specialist study, as well as the water quality analyses of two water quality samples taken at the Nacala Dam are included as Appendix E Yield Hydrology The purpose of the yield hydrology analysis is to assess the water resource capability (or yield) of Nacala Dam, both currently and after the FSL is raised by a minimum of 2m. Furthermore, it also assesses the impacts of making releases to support downstream environmental flow requirements (EFR) and the possible long-term loss of available storage in the dam as a result of sedimentation. A summary of the scenarios used during the yield analysis that was undertaken is provided in Table 6-4. Table 6-4: Summary of Yield Analysis Scenarios (Jeffares & Green, 2010) # Name Nacala Dam characteristics EFR (3) Sediment allocation Live storage Average to live Raised FSL (1) req. storage (4) (m) (mamsl) (million Class (million (million m 3 % MAR (2) ) m 3 /a) m 3 ) A Present % B +2m % C +2m&EFR_C % C D +2m&EFR_C&Sed % C E +2.25m % Notes: (1) Full supply level, shown in metres above mean sea level (mamsl). (2) Mean annual runoff (MAR), which equals 11.7 million m 3 /a (3) Desktop Class C environmental flow requirement (EFR). (4) Sediment allocation to live storage over a planning period of 50 years. A summary of the results obtained from the yield analysis is provided in Table 6-5. Table 6-5: Summary of Yield Analysis Results (Jeffares & Green, 2010) # Name HFY (1) (million m 3 /a) 1:20 (95 %) Yield (million m 3 /a) at indicated RI (2) (and annual assurance of supply) 1:50 (98 %) 1:100 (99 %) 1:200 (99.5 %) Difference at 1:50 A Present B +2m C +2m&EFR_C D +2m&EFR_C&Sed E +2.25m Notes: (1) Historical Firm Yield, based on an analysis over a 50-years period, from 1956 to 2005 (hydrological years). (2) Recurrence Interval of failure, in years, based on a long-term stochastic yield analysis of year generated streamflow sequences. 49

64 Based on the results from the yield analysis, it is recommended that Nacala Dam FSL is raised by 2m as this would significantly improve the yield available from the system. Raising the dam by another 0.25m, however, provides little benefit and should therefore not be considered Environmental Flow Requirements The rehabilitation and raising of the Dam requires the assessment of the EFR of the Muecula River. Releases from the Nacala Dam for environmental purposes are an integral part of the protection of the environment in the river downstream of the dam. The objective of the EFR study is to determine the optimum flow releases from the dam to maintain a desired ecological state of the river downstream. Due to the Muecula River having insufficient flow for the initial part of the study, an EcoStatus Level III determination was completed as an interim measure (Appendix D). The EFR approach aims to give the river a present ecological class based on the site conditions and ecological diversity data obtained during a one-off site visit. These ecological data gathered during the site visit, namely fish, aquatic invertebrate, geomorphological and riparian vegetation, were used to classify the Present Ecological State (PES). The PES outcomes are used to determine a Recommended Ecological Class (REC) for releases from the Nacala Dam. The EFR hydrology was undertaken using the Desktop Support System model (DSS) and the REC. In this case, the Muecula River had a PES of a Class C, with the final REC also being a Class C. The C Class REC was used in the DSS to simulate the EFR. The C Class EFR was simulated to be % (2.497Mm 3 ) of the mean annual runoff. The recommended EFR C Class, implemented with the correct flow release timing, was considered sufficient. The results of the EWR determination, including the maintenance low flows (base flow) and the maintenance high flows (floods and freshettes) are provided in Figure 6-3, while the annual figures is provided below. C Class EFR = Mm 3 /ann = 21.4 % MAR Releases from the dam to support a downstream Class C EFR would cause a decrease in yield for a 2m raised dam from 6.0 million m 3 /a to 4.3 million m 3 /a. The implementation of the EFR has a significant impact on the yield of the system and consideration should be given to postponing its implementation until alternative sources of water are available to augment water supplies. 50

65 16 Class C EWR Natural flows Nacala Dam Simulated Streamflow Time-Series 14 Monthly flow (million m 3 ) Year Figure 6-3: Simulated natural stream flow time-series plotted against the C Class desktop EWR time-series Sediment Yield Analysis Calculation of the sediment yield transported through the catchment and deposited at the outlet is important when investigating a storage structure. The sediment deposited in the dam will decrease its live storage, and hence its lifespan, by decreasing the volume of water it can hold. It is necessary to take this into consideration when sizing the storage structure. To determine the amount of sediment that will be deposited annually, the available bathymetric survey data (2001 and 2009) were used along with the Rooseboom method. The final V 50 value for use in the yield analysis of the Nacala Dam is: Nacala Dam V 50 = 86 % 2.17 Mm 3 Nacala Dam V 50 = 1.86 Mm 3 The long-term impact of sedimentation is significant and should be considered in the timing and sizing of possible future augmentation schemes Design Flood hydrology A review of the design flood hydrology was undertaken in order to determine the peak discharge figures to be used in the design of the new spillway and the freeboard of the raised embankment. The Safety Evaluation Flood (SEF) is the flood hydrograph, which after routing through the reservoir system may bring the dam to the point of failure but the resulting damage, although possibly substantial, must not be such as to cause failure of the dam (SANCOLD, 1991). The flood data were selected based on the type of flood causing rainfall system that is present in the Nacala region. In this case the Nacala region receives a majority of its flood causing rainfall from tropical cyclones. The SEF value of 1 530m 3 /s and 51

66 the Recommended Design Flood (RDF) value of 734m 3 /s were adopted for use used in the design stage of the Nacala Dam project (refer to Section 5.4.1) GEOHYDROLOGY The area surrounding the Nacala dam has several scattered communities. The purpose of this hydrocensus was to ascertain the water sources being used by the communities surrounding the dam. The hydrocensus data were obtained through field verification of the communities that surround the Nacala Dam. The investigation identified the following water sources: Six boreholes. Three stream/ river abstractions. A shallow-dug well. Stand-pipe with two widgets A wetland abstraction point. The only water that is supplied to the communities from the Nacala Dam is from the dual widget standpipe. The rest of the surrounding communities rely on the alternate sources listed in Table 6-6. The associated resource sheets are included in Appendix F. Table 6-6: Community Water Sources identified during Hydrocensus Resource Name/Number Resource Type Latitude Coordinates Longitude Borehole 1 (BH 1) Hand Pump - Afridev 14 43' 03.5' ' S 40 20' 06.6'' E Borehole 2 (BH 2) Hand Pump - Afridev 14 39' 06.7' ' S 40 22' 07.2'' E Borehole 3 (BH 3) Hand Pump - Afridev 14 38' 39.3' ' S 40 27' 10.2'' E Borehole 4 (BH 4) Hand Pump - Afridev 14 41' 08.2' ' S 40 25' 37.4'' E Borehole 5 (BH 5) Hand Pump - Afridev 14 42' 22.3' ' S 40 26' 30.8'' E Borehole 6 (BH 6) Hand Pump - Afridev 14 42' 38.1' ' S 40 27' 04.3'' E Shallow Dug Well Well 14 42' 30.7'' S 40 26' 53.8 '' E Stream 1 Small pools of water 14 40' 42.5'' S 40 21' 06.1'' E Stream 2 Small pools of water 14 38' 47.2'' S 40 22' 25.1'' E Widget Widget dual standpipe 14 43' 19.1'' S ' 58.5'' E Wetland Wetland 14 42' 46.2'' S 40 34' 04.7'' E Mucuela River River 14 45' 38.0'' S 40 34' 42.9'' E The borehole sources are all Afridev handpumps positioned amongst the communities. They have varying levels of concrete structures to protect the borehole for becoming contaminated by stagnant water that results from spillages at the source. These concrete structures were generally in good condition and would be achieving their purpose in their current state. In most cases the boreholes are located short distances from the community households, livestock and in some cases informal latrines. The soils are sandy, and thus fairly permeable, which increases the contamination risk when the source is close to potential pollutants. Two of the stream sources (Stream 1 and Stream 2) and the hand-dug well had badly discoloured water. The sources appear to be used for all purposes, including washing, bathing, drinking and 52

67 stock watering. They have no form of protection and with the level of usage are thought to be very poor source for community use. The wetland and the Muecula River sources are of a better quality than the other stream sources due to their size and nature. However, these sources are not considered to be good due to the all purpose usage and level of contamination (visually dirty, soap scum, etc). In addition to this the area immediately below the Nacala Dam was found to be used as a place for humans to defecate. This drastically increases the risk of cholera outbreaks as communities were found to be reliant on the Muecula River for drinking water. Some of these sources dry up in the dry season and leave the communities with little to no potable water source in the near vicinity. Water security is non-existent in this area, in spite of the dam being close to it. It is recommended the Nacala Dam Rehabilitation and the Nacala Water Supply Programme considers providing a sustainable and clean source of potable water for the communities surrounding the dam THE SOCIO-ECONOMIC ENVIRONMENT Magisterial Structure Nacala Dam is located in Nampula Province, with the capital being Nampula City. The province is divided into 20 districts of which the Nacala-A-Velha District is relevant to this study (Figure 6-4). The Nacala-A-Velha District is further divided into Nacala-a-Velha (Sede) Locality. Nacala is an important economic centre of the northern region of Mozambique. The project area falls into the Moilete Bairro, which has a typical bairro leadership of a president or chefe, vice president or cabo, secretary or regulo and council members Population Demographics Preliminary results of Census 2007 (Instituto Nacional de Estatística, 2007) indicate a total population of 4, in the Nampula Province. A breakdown by gender is 2, and 1, for females and males respectively a near 50/50 split. Population numbers for the province between Census 1997 and 2007 is 3, and 4, respectively (Instituto Nacional de Estatística, 2007). The present population of Nacala is approximately 300,000: Nacala-A-Velha District has a total population of and Nacala Port District has a population of Like the rest of the country, Nampula has a very young population. 47.9% are under 15 years old, 49.5% are aged between 15 and 64, and only 2.7% are aged 65 and above. As in many sub Saharan countries, women are marginalised in terms of economic and political power. Although women in Mozambique carry out the majority of agricultural work, they have limited control over the economic resources they generate. Women are dependent on male family members, or the discretion of community leaders for access to land. Gender discrimination in Mozambique has been exacerbated by the civil war, when women were submitted to displacement, insecurity and the breakdown of social services and support. 53

68 Figure 6-4: Location of Nacala A Velha District 54

69 Community and Household Structure The community and household structure of the village located adjacent to the dam is characteristic of rural villages in Mozambique. Such villages have concentrated numbers of households within a defined area which shows a sharp transition to true rural scattered households in the village outskirts. This linear settlement is due to the Communal Village Programme of the FRELIMO Government that was carried out in the 1970s and 1980s. Typically machambas (rotational subsistence agricultural fields) are located outside the villages and vary from small homestead gardens to 1ha fields located on the outskirts of the village. The local village has developed in a linear fashion along the N12. Transport corridors in Mozambique play a vital role in terms of economic development and the N12 may play a vital role in the development of the town. Households or families tend to be centred on the homestead, which are the physical structures that make up the living area occupied by the household. The homestead is generally made up of a primary household with a number of secondary structures including kitchens, toilets and secondary residential units. Typically machambas (rotational-based subsistence agricultural fields) are located at the homestead or outside the villages, and may vary from small homestead gardens to large mutli-hectare fields located outside of the villages. Households or families tend to be centred on the homestead (Figure 6-5). The homestead is generally made up of a primary household with a number of secondary structure including kitchens, toilets and secondary residential units. Figure 6-5: Typical homestead structures The local villages have developed in a linear fashion along the N12. Transport corridors in Mozambique play a vital role in terms of economic development and the N12 may play a vital role in the local development. 55

70 Livelihoods and Economy Subsistence agriculture is primarily aimed at producing basic foods for households with any surplus food being sold at local markets. At a regional level the dominant crops include cassava, maize, beans and seasonal crops. Location, soil quality and water are the driving factors in terms of crop type. The greater population around the dam have dry land machambas, which are away from the dam and rely on ground water. Very few households have access to the coveted wet land machambas, which are around the dam and along the small inlets that feed into the dam (Figure 6-6). There are about 30 dam/river machamba owners affected by the proposed project. All have larger portions of land that have been given to them by the local bairro administration. The machamba owners divide their land into small portions and pay people to work on each portion. The work includes cleaning and clearing of vegetation, but not planting. Only family members plant, tend and harvest their crops. Clearing and cutting normally happens in February and March, for both seasonal reasons and financial reasons. People who work on these dryland machambas usually need money at this time of the year, due to their own machambas not producing enough food to feed their families during these months. The large dam/river machambas produce all year round. The average size of one of these large dam/river machambas is 1.1ha, with a total of approximately 213ha under cultivation in the busiest season. Most farmers have four or more of these plots. During the dry season and when the dam level is low there are about 235 people who plant very small areas of land in the dry river beds that form tributaries to the dam, but these people operate on a year-to-year basis, and are opportunistic farmers. They all have machambas of their own elsewhere. During the dry season they plant tomatoes and onions in the river machambas, or dry river and dam inlet beds, in order to sell, and plant cassava, maize, and peanuts on their own plots. Through discussion with local farmers it was estimated, very roughly, that 1 acre per adult person was required for food security and cash to purchase daily necessities. Land is regarded by the local landowners as their most precious possession. It is their only security in an otherwise economically insecure environment. The main animal husbandry practices in the area are chicken and duck rearing, but some people also have goats. Fish seems to be a relatively unimportant part of the local diet. As a result of poor agricultural returns, the commercialisation of charcoal has become an important livelihood strategy in the area for those people who have dry land machambas and face crop failure. Some interviewees labelled charcoal production as a lifesaver. Charcoal is produced solely for sale and is not locally consumed. The level of exploitation of wood for charcoal clearly has a significant effect on the natural resource base. 56

71 Formal labour in the immediate vicinity of Nacala Dam is likely to be limited. As with much of Mozambique, migration of males to local, regional and international centres is likely to be common. Remittances received by local families form a major component in terms of cash income Land-Use The project area is comprised of a mosaic of different land uses. There are both extensive and intensive agricultural areas with patches of natural vegetation punctuated by mango and cashew nut trees in and around the homesteads. Subsistence agriculture is the dominant land-use. No households are located in the inundation area. However the linear nature of the village is an issue in the development of any new spillways and the road deviation. Figure 6-6: Images of machambas located along the dam reservoir margin Gender While men and women will both be affected by the project, women could bear a disproportionate burden. The expected negative impacts of the Nacala Dam Rehabilitation Project on women include dislocation, loss of property and land, disruption in income source, loss of client/ marketing base for products, heightening of social tensions/ conflicts, and increased vulnerability to HIV/AIDS and STDs for women and girls. The expected positive impacts on women include additional employment opportunities in the project works of unskilled jobs; increased sources of income generation; enhanced vocal contribution of women in projects such as these; and improved access to and use of socioeconomic infrastructure by women and girls Seasonal Calender Based on information collected during the SIA (Appendix G), the following is evident: January, February, March and April are difficult months for the local population. There is a lack of food, which needs to be compensated for with collection of wild foods and purchasing of food. In this period sickness (malaria, diarrhoea) is perceived as particularly prevalent. 57