Tanzania - River Basin Management and Smallholder Irrigation Improvement Project : environmental assessment (Vol. 1 of 11)

E968 Volume 1 :~ ~~~~ j MINISTRY OF AGRICULTURE AND FOOD-SECURITY RIVER BASIN MANAGEMENT AND SMALLHOLDER IRRIGATION IMPROVEMENT PROJECT (RBMSIIP) SMALLHOLDER IRRIGATION IMPROVEMENT COMPONENT MAHENGE IRRIGATION SCHEME ENVIRONMENTA4L AUDIT --AFT TEPCT October 2003 I~~~ ~ Ii ,--@.i e.ls s. s~ lS p'^i- , - g1; e,,Z;, -t j '>2,' 'l2''?'''- f' ''ii. L?f2;f '?- U!'ei lP'r-'1 ??l7 2 i- Nk :; '  ACKNOWLEDGEMENT The team wishes to acknowledge with thanks the contributions of various staff members of the Ministry of Agriculture and Food Security's Directorate of Irrigation and Teclnical Services, during the different stages of the preparation of this report: the Project Coordinator of Smallholder Irrigation Improvement Project, Mr. Masija; the Head of Environmental Unit Cell, Mr.Simukanga, and other staff. The team also extends its appreciation to the District Officers, in particularly the ilTigation technicians who are in charge of the eight schemes, at Arumeru, Moshi Rural, Simanjiro, Korogwe, Iringa Rural and Mbarali Districts. Thanks also go to the scheme management committees, farmers and other stakeholders of the eight schemes and the community members who actively participated in the discussions and helped to provide information that was very useful during the preparation of the Environmental Audit. The team appreciates to more than 50 people who participated in data collection and analysis, especially the facilitators, research assistants, enumerators, water and soil staff, data analysts, etc. Last but not least, our appreciations go to ERC's internal staffs who directly or indirectly contributed with enthusiasm to the EA reports.  Table of content ACKNOWLEDGEMENT ...................................................................I TABLE OF CONTENT .................................................................. II EXECUTIVE SUMMARY ...................................................................V LIST OF TABLES AND FIGURES .................................................................. IX LIST OF ABBREVIATIONS ...................................................................x I BACKGROUND .I 1.1 INTRODUCTION . . . 1.2 UNDERSTANDING OF THE STUDY . . . 2 1.2. I Objective of the Study .2 1.3 STRATEGIC APPROACH . . . 2 1.3.1 Ecosystem Approach .2 1.3.2 Farmzing System Approach .2 1.3.3 Participato7y Approach .2 1.4 METHODOLOGY . . . 5 1.4.1 Consultation .5 1.4.2 Analytical Tools .5 1.5 LIMITATIONS . . . 6 2.1 THE PHYSICAL ENVIRONMENT . . . 8 2.1.1 Location .8 2.2 BIOPHYSICAL ENVIRONMENT . . .11 2.2.1 Clinmatic .11 2.3 SOCIO-ECONOMIC ENVIRONMENT . . . 15 2.3.1 Population .15 2.3.2 Occupation! land use .15 3. DEVELOPMENT PROGRAMMES AND STAKEHOLDERS ............................... 18 3.1 SOIL EROSION CONTROL AND AGRO-FORESTRY PROJECT (SECAP) ..... 18 3.4 STAKEHOLDER'S ROLE . . . 19 4.1 NATIONAL POLICIES ......... .. 21 4.1.1 National Environmnent Policy of 1997 .21 4.1.2 Agriculture Policy 1997 .21 4.1.3 Land Policy of 1995. 21 4.1.4 Water Policy of 2002 .22 4.1.5 Forest Policy of 1998 .22 4.1.6 Wildlife Policy of 1998 .22 4.1.7 Energy Policy of 2002 (Draft) .22 4.2 LEGAL FRAMEWORK ....................... 22 4.2.1 Environment Legislation .23 4.2.2 NEMCAct no. 19 of 1983 .23 4.2.3 Land Act no. 4 and Village Land Act no. 5 of 1999 .23 ii  4.2.4 Wildife Act 1974 (with amendinents of 1978~)..........................23 4.2.5 Water Acts of 1974 ..............................................24 4.2.6 Forest Act 19 74.................................................24 4.2.7 The Town and Country Planining Ordinanice, Cap 378 of]1956 ............24 4.2.8 Local Government Act (District anzd Urban Authorities) Acts of 1982.......24 4.2.9 Land Use Planniing Commission Act of 1984.....................I.....24 4.2.10 The Land Acquisitions Act of 1967 ..................................25 4.2.11 By-Laws ......................................................25 4.3 NATIONAL STRATEGIES........................................... . 25 4.3.1 Government Development Visioni 2025...............................25 4.3.2 Poverty Reduction Strategy Paper (PRSP) of 2000 .....................25 4.3.3 Ruiral Sector Developnment Strategy (RDS) of 2000 .....................25 4.3.4 Agricultural Sector Developmnent Strategy (ASDS) of 2001 ...............26 4.4 COMPLIANCE WITH WORLD BANK, SAFEGUARD POLICIES ............ 26 5.0 TOOLS AND TECHNIQUES USED IN ASSESSING AND ANALYZING ENVIRONMENTAL AND SOCIAL IMPACTS.................................28 5.1 INTRODUCTION...................................................28 5.2 IMPACT ASSESSMENT .............................................28 6.0 CONSULTATIONS WITH COMMUNITY AND FARMERS ...............29 6.] INTRODUCTION .................................................29 6.2 MAJOR ENVIRONMENTAL AND SOCIAL ISSUES IDENTIFIED BY STAKEHOLDERS: AS PRESENTED BY MEN.................................29 7.0 IDENTIFIED ENVIRONMENTAL AND SOCIAL IMPACTS...............32 7.1 INTRODUCTION...................................................32 7.2 UPSTREAM ANT) DOWNSTREAM IMPACTS...........................33 7.2.1 Demographic trend (population chaniges)..............................33 7.2.2 Catchinent degradation ...........................................33 7.2.3 Water- quality on downstream users..................................34 7.2.4 Socio economic impacts on dowvnstream users..........................35 7.3 IRRIGATION SCHEME LEVEL IMPACTS..............................35 7.3.1 Sand at intake structuire...........................................35 7.3.2 Reduced water availability for irrigation..................................36 7.3.3 Soil quality.....................................................37 7.3.4 Water quality. ..................................................38 7.3.5 Waterborne diseases .............................................39 7.3.6 Water and sanitation.............................................40 7.3.7 Drinking water quality and sanitation................................40 7.3.8 Fertilizer- and pesticides ..........................................4] 7.3.9 Socio-econonmic: positive and negative impacts of villages withini the scheme 41 8.1 INTRODUCTION...................................................42 8.3 IRRIGATION LEVEL ...............................................43 9.0 ENVIRONMENTAL AND SOCIAL MANAGEMENT PLAN (ESMP) .......45 9.1 INTRODUCTION...................................................45  I I 9.3 SUMMARY OF MAJOR ENVIRONMENTAL IMPACTS AND IDENTIFIED MITIGATION MEASURES ................................................................. 46 9.4 DESCRIPTION OF ELEMENTS OF MONITORING PROGRAM ....................... 47 10. CONCLUSIONS AND RECOMMENDATIONS CONCLUSION ........................ 58 Positive impacts ................................................................... 59 10.2 RECOMMENDATIONS ................................................................. 59 1v  EXECUTIVE SUMMARY The Government of Tanzania (GoT) through the Ministry of Agriculture and Food Security (MAFS) has taken various initiatives to improve agricultural sector in the country. One of these initiatives is undertaking the River Basin Management and Smallholder hiTigation Improvement Project (RBMSIIP); in context with which, is the Smallholder Irrigation Improvement Component (SIIC). Among others, the need to undertake the RBMSIIP arose out of a nation-wide realisation that the ecosystems of country's river basins (especially those of the Rufiji and the Pangani Rivers) are not being properly managed, leading to extensive environmental degradation and loss of potentialities of these vital ecosystems. Moreover, it was also realised that in view of the above- mentioned loss of potentiality, smallholder traditional irrigation schemes are the worst affected; hence the need arose to undertake also the SIIC. Support to smallholder traditional irrigation improvement and rehabilitation is, therefore, one of the major components of this RBMSIIP programme. The SIIC component focuses on improving management of water resources and crop husbandry practices in existing smallholder iTrigation schemes. This can be achieved, among others, through improvement of natural resources, land and water, during implementation of the rehabilitation and upgrading of irrigation schemes.) SIIC is geared at improvement of water management in smallholder iiTigation schemes to ensure sustainable use of land and water resources and ultimately yield increase with minimal environmental degradation. Under the auspices of the SIIC both the Scheme Environmental Assessment (SEA) as well as an Environmental Audit (EA) was carried out for the Mahenge Irrigation Scheme. Among others, the assessment and the audit were based on the Initial Environmental Assessments (IEE) studies carried out by the Environmental Cell Unit (ECU) of the Irrigation Section of the MAFS. This report presents the findings of the study. The objective of the study was identifying changes that have taken place before/after scheme improvement, assessing and quantifying thereto environmental and social impacts, also duly preparing an environmental and social management plan as well as developing an environmental and social management and monitoring system. According to the ToR the expected outputs of this study are two in one interrelated reports i.e. covering both E nvironmental Audit (EA) a s well a s S cheme E nvironmental Assessment (SEA), a nalysing e .g. s ocio- economic, socio-cultural and engineering factors in order to provide quantitative information. Furthermore, the report incorporates an assessment of compliance of the scheme's improvement to the Tanzanian policy and legislation framework, as well as the World Bank's relevant environmental safe guard policies (especially on OP 4.01). Different methodologies were employed to cairy out the task, including the following: * Desk review of recommended documents * Questionnaire administration to key stakeholders * Participatoiy Rural Appraisal (PRA) At different stages of the study the following approaches and analytical tools were applied * Participatory data collection * Key informant interview * Trend analysis * Geographical information system Describing the location of the scheme, the study found that the Mahenge irrigation scheme lies down-stream of the Lushoto highlands about 17 km north-east of Korogwe township. Its coordinates are latitude 50 001 South and longitude 380301 East, and are at an altitude of about 300m above mean sea level. It comprises the following villages: Kwamnndolwa, Lombei, Mianzini, Kerenge, Lusungu, Kwandulu, and Darajani. Villages around the Mahenge irrigation scheme have a total population of -------- people. The main ethnic groups in the scheme area are Wabondei, Wasambaa, Wapare and other smaller groups. The majority of these are agriculturalists. Few are livestock keepers. v  The land use in the adjacent villages of Mahenge scheme is mainly irrigation as well as rain-fed cultivation and grazing. The source of irrigation water for the Mahenge scheme is the Mkole/Bululu River, which unfortunately is not gauged. During design stage of the scheme there existed 37 years of river flow record of the Lwengera River at Korogwe ganging station. This was analysed and used to estimate river discharged at the Mahenge scheme. Dependable discharge I in 5 dry year water available at the Mahenge scheme was at peak May/June/July/August (0.38, 0.50, 0.47, 0.38) cumecs but was lowest in Nov/Dec/Jan/Febr (0.14, 0.14, 0.13, 0.12) respectively. Water abstractions by upstream users for domestic purposes, irrigation and livestock are likely to impact on the quality and quantity of water available to the scheme. Poor farming practices, especially cultivation of crops close to the riverbanks, is increasing silt load in the river and causing siltation of the irrigation stiuctures. The a vailability o f good d omestic water supply, c oupled w ith good s anitation a t M ahenge will c onsiderably reduce d ownstream water p ollution from d omestic u ses. D rained water from t he s cheme a rea i s I ikely t o b e contaminated from activities carried out in the scheme area, including application of agro-chenmicals, and sharing irrigation water with livestock. The on-farm activities will thus form the main source of pollution downstream. Conflicts over water use have been recorded in the study area, especially in the dry season when river flows are at the lowest. In the past say 10 years, fuel wood was obtained in the nearby forests. Deforestation for firewood, opening of new farms and uncontrolled wild fires have led a much decrease in forest areas. With the irrigation structures improvement and prospects for higher income eamings from i-rigated agriculture. there is greater loyalty to the leadership of Water Associations. Since most of the people are irrigators and members of the associations, the latter has greater influence beyond irrigation matters. The following are some of the positive effects: * Water availability has improved with more areas obtaining water than used to be in before improvement. * Strengthening the existing Water Users Association. * Temporal employment opportunities were created during the construction phase. * Some farmers have attended on farm training and exchange visits to other areas to share experience with other fanmers as well as learning new skills. * The project has brought about improvement in water availability distribution and management. * Crop production has improved a great deal A summary of identified impacts differentiated at up-stream, down-stream and within scheme levels for resulting from Chapter 7 and appropriate mitigation measures are summarized in the Environmental and Social Management Plan as follows: ENVIRONMENTAL AND SOCIAL IMPACTS MITIGATION MEASURES Up-stream impacts: Category :Environmental Management: - Demograhpic trend (population changes) * Promoting agro-forestry agricultural - Catcluhment degradation practices, coupled with afforestation and or reforestation program, * Strengthening enforcement of abstraction regulations Category: Enhancement of social- economic activities: vi  * Promoting environmental consciousness in all social -econonmlic activities, * Strengthening mechanisms for controlled acquisition and of land use- related social-economic practices, Downstream impacts: Category: Environmental Management: * Establishment of mechanism for - Reduced water quantity resolution of water conflicts. - Increased incidences of waterbome diseases Poor water quality Category: Enhancement of social- economic activities: * Promoting irrigation agriculture as a potentially useful socio-economic activity for all age groLups and gender * Preparing and implementing a participatory land use plan (i.e. PLUM) Category: Improving health situation * Promoting awareness on waterbome diseases, as well as HIV/AIDS * Improving availability of health, water and sanitation services. Irrigation scheme level impacts Category: Environmental Management - Sand at intake structure - Reduced water availability for irrigation Promoting up-stream soil and water - Poor soil and water quality conservation activities and environmental - Fertilizers and pesticides use protection program in general, - Increased incidences of waterborne Establishing effective water management diseases system, namely: e.g. controlled allocation and distribution of water * Promoting/providing education on appropriate irrigation practices on application of IPM and ISFM * Establishing enforcement mechanisms on abstraction rights Category :Revisiting engineering designs and/or construction stages * Reviewing designs and construction to address arising siltation/sedimentation problems * Establishing modalities for rehabilitation of destroyed structures The monitoring program comprises the following attributes: water quality, groundwater, soil conservation. biodiversity, crop diseases, afforestation, socio-economic and health indicators vii  Additionally, the environmental audit main conclusions and recommendations are: In up-stream areas of the scheme, the key issues constraining sustainability are increased soil erosion coupled with lack of soil and water conservation activities as well changes ofthe river's hydrological and hydraulic regime. In within-scheme areas the constraints are general poor soil fertility coupled with land hoarding practices .In down-stream area sustainability is mainly constrained by inadequacy of skills/knowledge of the farmers on appropriate ilTigation practices. One of the main recommendations is most of the identified mitigation measures are related with local community-based e ffective s tructural - organization. This means t herefore t hat most o f t he measures c an b e implemented by local government authorities themselves with financial and teclnical assistance of funded projects e.g. RBMSIIP, NGOs and CBOs. viii  List of Tables and Figures Tables Table 2.1 Estimated Rainfall Magnitude for specific Return Periods Table 2.2 Water resources Table 2.3 Distance for fetching water Table 2.4 Soil data Table 2.5: Farm size (acres) ownership of farmers (%) Table 7.1: Summary of key environmental and social/impacts for Mahenge Table 7.2: Population data in upstream, downstream and Mahenge (irrigation) area Table 7.3: Downstream - Lwengera Darajani Table 7.4: liTigation level - Mahenge Table 7.5: Water analysis results Table 7.6: Water efficiency at Mahenge Table 7.7: Soil Sites and Results Table 7.8: Water Analysis Results Table 7.9: Disease prevalence in the Mahenge area Table 7.10: Water supply Table 7.11: Fertilizers used in Mahenge Table 7.12: Pesticides, insecticides, and herbicides used in Mahenge Table 9. 1: Environmental and social impacts mitigation measures Table 9.2: Monitoring Plan Table 9.3: The Environmental and Social Management Plan (ESMP) Table 9.4: Implementation plan time schedule Figures Figure 1. I Basic Approach to the Study Figure 2.1 Farm size (acres) ownership (%) Figure 3.1 Organization structure for Kumekucha Mkulima cooperative society Maps Map 2.1: Mahenge irrigation scheme: Location map Map 2.2: Map of analysed water sample locations Map 7.1: Mahenge catchments area land use/vegetation maps Map 7.2: Mahenge soil sample locations Digital Elevation Models DEM 2.1: Digital elevation model 2D DEM 2.2: Digital elevation model 3D Plates Plate 7.1: Dredged sediments prepared for sell tx  List of Abbreviations NMA National Meteorological Agency MWLD Ministry of Water and Livestock Development a.m.s.l Average mean sea level SCAPA Soil Conservation and Agro-forestry Project SIRSC Shamima Irrigation Rural Savings and Credit Society DALDO District Agricultural and Livestock Development Officer WEO Ward Executive Officer VEO Village Executive Officer WUA Water Users Association NGO Non Govenmmental Organization CBO Community Based Organization NEMC National Environmental and Management Council PO-RALG Presidentss Office--Regional Administration and Local Government EIA Environmental Impact Assessment WMA Wildlife Management Areas NLUC National Land Use Commission LDC Less Developed Countries PRSP Poverty Reduction Strategy Paper RDS Rural Sector Development Strategy ASDS Agriculture Sector Development Strategy IPM Integrated Pest Management TPRI Tropical Pest ResearchInstitute TMA Tanzania Meterology Agency URT United Republic of Tanzania UNDP United Nations Development Programme FAO Food and Agriculture Organization MWL Ministry of Water and Livestock ERC Environmental Resources Consultancy CDTF Community Development Trust Fund DED District Executive Director EA Enviromnental Audit ECU Environmental Cell Unit GIS Geographical information systems IEE Initial Environmental Examination KIA Kilinianjaro Intemational Airport MAFS Ministry of Agriculture and Food Security NIDP National Irrigation Development Plan PRA Participatory Rural Appraisal RBMSIIP River Basin Management and Smallholder Irrigation Improvement Project SIIC Smallholder Irrigation Improvement Component SPSS Statistical Package for Social Science software ToR Tenns of reference UCLAS University College of Land and actectral studies ZIO Zonal Irrigation Office GTZ German Agency for Technical Cooperation SECAP Soil Erosion Control and Agro-forestry Project UMKUMTA Tanzania Partnership for Child Development x  I xi  1 BACKGROUND 1.1 INTRODUCTION The Government of Tanzania, through the Ministry of Agriculture and Food Security (MAFS), has undertaken various initiatives to improve the agriculture sector in the country. One of these initiatives is the River Basin Management and Smallholder Irrigation Improvement Project (RBMSIIP). The Smallholder Irrigation Improvement Component (SIIC) is included within the scope of RBMSIIP. RBMSIIP was developed in response to a water shortage crisis prevalent in many parts of the country. Water demands often exceed available resources; this is especially true in the Pangani and Rufiji basins. Support to smallholder traditional irrigation improvement and rehabilitation is one of the major components of this project. SIIC focuses on improving the management of w ater resources and crop husbandry practices in existing smallholder irrigation schemes. This is achieved through, among other things, the improvement of natural resources (land and water) during implementation of the rehabilitation and upgrading of irrigation schemes. The SIIC undertaking supports the objectives of the National liTigation Development Plan (NIDP) which was formulated and adopted in 1994. The plan includes a management and decision-making framework that is based on the comprehensive ranking of schemes within each management unit (river or drainage basin). Under NIDP the order of priority for irrigation development is as follows: * Improvement/rehabilitation of Traditional Smallholder irrigation Schemes; * Water Harvesting Technology; * Opening of New Smallholder Schemes; * Large Scale Irrigation Schemes for Private Sector. SIIC focuses on the improvement of water management in smallholder irrigation schemes to ensure the sustainable use of land and water resources. Ultimately, SIIC aims to facilitate increases in crop yields while minimizing environmental degradation. According to World Bank guidelines, the irrigation schemes in the Rufiji and Pangani basins are classified as Category B. Under this category, no major adverse environmental impacts are permitted and mitigation measures must be incorporated into the scheme design, implementation and operation. Under the auspices of the SIIC, a feasibility study was carried out that resulted in the preparation of the Project Implementation Plan for 1996/97 - 2001/02. This plan, produced in October 1996, contains an assessment of enviromnnental issues together with proposed environmental mitigation measures. Under World Bank advisement, the Environmental Cell Unit (ECU) of the Ministry of Agriculture and Food Security conducted an Initial Environmental Examination (IEE) of the irTigation schemes. The IEEs were used as t he b asis f or t he S cheme Improvement Assessment Studies. T he c onsultants, i n c ollaboration with E CU, have been charged to conduct environmental audits in seven Category B sites: Ruanda Majenje, Igomelo, Mangalali, Nyamahana, Soko, Kambi ya Tanga, and Mahenge. An additional site, Lemkuna, only required the development of an Environmental and Social Management Plan. This report is focused on presenting the findings of the environmental audit that was conducted for the Mahenge Irrigation Scheme. This report draws heavily on intensive field observations by the study team. Discussions were held with farmers and other local people, village and district officials, and project staff A review of various existing documents was also conducted in the preparation of this report. 1  1.2 UNDERSTANDING OF THE STUDY 1.2.1 Objective of the Study The objective of the study is to get a better understanding of the present environmental conditions and relevant impact areas (environmental audit) within the scheme. Increased awareness will allow for improved monitoring of both negative and positive changes over time and will assist in the formulation of more effective mitigation measures. T he e nvironmental a udit will a lso b e t he b asis f or t he p reparation o f a n e nvironmental a nd s ocial management plan and monitoring system. Specifically, the study will undertake the following: * Assess and quantify baseline environmental and social conditions * Assess and quantify environmental and social impacts * Conduct environmental audits in order to comply with existing Government of Tanzania and World Bank environmental and safeguard policies * Prepare an environmental and social management plan * Develop an environmental and social management and monitoring system * Conduct public consultations 1.3 STRATEGIC APPROACH The consultant's environmental audit of the Mahenge irrigation scheme was characterized by three approaches: ecosvstem,fa7rning system and participatowy. The basic approach of the study is illustrated in FIigure I -1. 1.3.1 Ecosystem Approach In view of the fact that the project activities are wholly based in a rural area, potential conflicts between the project and the environment are likely to arise. Thus, issues pertaining to the use of natural resources (e.g. livestock grazing, agriculture, inigation, water source protection, agro-forestry, etc.) have to be studied. In applying the ecosystem approach, the consultant not only focused on the Mahenge irrigation scheme but also on all the ecosystems upstream and down stream that impact the environmental and social characteristics of the area. To accomplish this, the study sought an understanding of all activities taking place within the irrigation scheme's water catchment area. River pollution, sedimentation, flash floods, deforestation, destabilization of riverbanks, erosion, salinity, land degradation, and waterbome diseases (among others) are all contributing to degradation of the catchment area. In suggesting mitigation measures, sustainable practices for the use of water and land resources must be adopted to prevent and control environmental and social problems. 1.3.2 Farming System Approach On the ilTigation scheme level, a farming system approach was used to describe and analyse environmental and socio-economic conditions. Issues related to soil contamination, water pollution, the use and dangers of pesticides and fertilizers, health, and others have been identified. It is clear that the ilTigation activities will transform village life and the whole farming system in the Mahenge area. The success of the proposed mitigating measures will, therefore, depend on community involvement, improvement of the socio-economic situation, capacity building, and proper upgrading, maintenance and operation of the irrigation infrastructure. The latter should take into account the local environment as well as the prevailing institutional, economic and social conditions. 1.3.3 Participatory Approach A participatory approach was adopted in preparation for the environmental audit. This entailed seeking information/experience from stakeholders (i.e. farmers, district and regional officers, RBMSIIP and other institutions who have been involved in the project). In order to ensure effective participation and cooperation it was necessary to inform stakeholders prior to the audit of the environmental and socio-economic problems to 2  be addressed. Their inputs have contributed to the development of more realistic and appropriate mitigation measures. 3  BASIC APPROACH TO THE STUDY Figure 1.1 So-coo IEE of eight schemesi Mitigation Measures g: C ; 'ci,) Environmental & Social ~ ~ ~ ~ nsutat p strearen n- rmncinlt y Focus groups, r.~ ~ ~ tctnn leve Interviews , nv ro me Manaement Plan Socio-economic ) ( socio-economic ) farmerq Management Plan ~ ~ ~ ~ arm .~~~~~~~~~~~~~~~~~~P.n IF~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Monitor-ing system  1.4 METHODOLOGY The methodology follows Tanzanian policy and legislation and the World Bank's policies on environmental assessment (OP/BP 4.01 and related policies and guidance documents). Available reference documents were reviewed for purposes of identifying pertinent environmental and social issues. Information was obtained on the Mahenge irTigation scheme before and after construction as well as during operation. Several meetings were held with SIIP project staff. In particular, the ECU team, which was involved in the Scheme Environmental Assessment, was consulted to discuss background and potential issues. Subsequently, a ten-day field mission was conducted in August by the study team and members of ECU. The team was used to: 1) complete further fieldwork at various sites in the Mahenge irrigation scheme, 2) collect additional information, 3) work with the irrigation scheme management team, and 4) to liaise with the various stakeholders including the district officials. During the field visits, the Public Consultation and Disclosure Plan for disseminating the results of the Draft Environmental Audit were developed with the ECU staff. 1.4.1 Consultation Public consultations took place in two phases. The first phase took place during the Environmental Audit (EA) preparation process. This initial stage allowed for the identification of the key environmental issues and involved the gathering of information on stakeholder concemns and views of potential environmental and social impacts. During the secondly phase, consultations allowed stakeholders to review findings and give their comments. 1.4.2 Analytical Tools The following methodologies were applied in the process of the study: * Participatory data collection * Key informant interviews * Socio-economic and environmental analysis * Trend analysis of river flow and rainfall * Water and soil quality analysis * Geographical information systems (GIS) Participatory Data Collection Participatoiy Rural Appraisal (PRA) involves problem analysis, ranking, proposal planning, role assigning and timing. The role playing consisted of a facilitator who played the role of an advisor on the different matters raised during the workshop (those which the team was not informed about or aware of). In the final analysis, a Logical Framework Approach workshop (also known as ZOPP) produced the Environmental Action Plan for the irrigation scheme. Key Informant Interview In addition to group discussions, information was also obtained from key informants. These were generally staff from the Zonal Irrigation Office (ZIO), the District Executive Director (DED), farmers of the Igomelo scheme, village officials (including village leaders), and others (agriculture and irrigation officers who are residents in the community). Any inconsistent information was cross-checked to ensure accuracy. Various officials conducted the crosschecking of information while members of the study team facilitated the group discussions. Socio-econoniic and Environment A total of 106 household questionnaires (sample size) have been administered using the random sampling method. This represents. Percent of households of the study area (upstream, down stream and scheme level) 80 percent (80 questionnaires) of selected sample size has been administered at Mahenge village (scheme level), where as 10 percent (10 questionnaires) has been administered at Kerenge and Kwanmdolwa villages (upstream 5  village) and 10 percent (10 questionnaires) have been administered at Lwengera Darajani village (dowrnstream village). Qualitative data related to socio-economnic and environment from the scheme was collected and analysed using SPSS (Statistical Package for Social Science) software. Trend Analysis of River Flow and Rainfall An investigation was conducted upstream and downstream on rivers that feed the scheme. Both statistical and visual interpretations of variability analysis were applied. To further reveal any existence of severe abstraction or flow regime changes, variability analysis was done month to month. Any possible causes for the change in the flow regime were quantified. In this regard, annual rainfall variability for stations in or around the study area was noted. Thu-ee approaches were followed to tackle the impacts problem: * Visual interpretation - Understanding and interpreting the a inual time series and percent deviation time series from the annual mean. * Testing randonmess on the annual and monthly time series data - This test indicates that if the null hypothesis tested for randomness is accepted, no flow regime change prevails in the record; otherwise, it shows the flow regime is changed or there is a likely impact on the river upstream or downstream. * Testing of breaks - At times a break or jump may be observed in the time series of flow. If, for example, a huge volume of water is suddenly diverted to an irrigation area, segments before and after the diversion can have different means. Subsequent sections provide scheme level variability analysis and interpretation of the results for both flow and rainfall. The flow and rainfall data were collected from various sources. Rainfall data were collected partly from Tanzania Meteorology Agency (TMA) and partly from the Ministry of Water and Livestock Development (MWL). Flow data were partly collected from the Ministry of Water and Livestock (MWL) and partly from previous reports. Water and Soil Analysis Water and soil samples were analysed at the laboratory of the Department of Environmental Engineering, University College of Lands and Architectural Studies (UCLAS) and Mlingano Soil Laboratory. Procedures and analysis were done according to the International Standards of Water and Soil Analysis. Geographic Information System (GIS) Overlay maps and GIS were used to analyse sensitive/significant/relevant features of the irrigation scheme area. Attributes a nd features that were mapped a nd a nalysed i ncluded water b odies, I and u se p attems, v egetation cover, and cultural structures. The technique involved the physical overlaying of individual topographic maps to provide a composite picture of the overall environmental and social situation. Using ArcView 3.1, analysis was carried out to link spatial and non-spatial data. 1.5 LIMITATIONS Data quantification proved a difficult exercise due to the following reasons: (i) There was insufficient baseline data related to environmental and socio-econoTmic parameters. (ii) Updated meteorological and hydrological data were not available. (iii) Most studies carried out by RBMSIIP are dealing with Pangani and Rufiji river basins not specifically with sub-catchment areas like Mahenge river basin. Catchment degradation studies conducted by RBMSIIP for Pangani and Rufiji basins were qualitative. These studies were more an overview papers, 6  and did not include measurement or simulation models. It should be highlighted that the dangers of reaching conclusions without quantification and sufficient scientific evidence. (iv) Time and resources allocated are not adequate to investigate most of upstream and downstream impacts. For example, process of digitising maps took more than three weeks. The same with water and soil analysis and linking socio-economic and environmental data to GIS. 7  2. BASELINE CONDITIONS OF THE IRRIGATION SCHEME AREA 2.1 THE PHYSICAL ENVIRONMIENT 2.1.1 Location The Mahenge irrigation scheme is located in Kwamdolwa ward, Magoma division Korogwe Rural district of Tanga region It lies about 17 Km north east of Korogwe Township. On the globe it also lies at latitude 50 00' South and longitude 38 30'East. Mahenge scheme is situated at an altitude of approximately 300m above sea level.  Map 2. i . Mvlahenge irrigation scheiuc: Location map 445r000 44 7,j 0 4500[I 452500 45500Q0 . t A