Conference Papers

Ever since the oil, financial and food crises of 2008, sub-Saharan Africa has witnessed a marked increase in large-scale investment in agricultural land. The drivers of this investment are varied and include growing food, water and energy insecurity as well as social and economic interests of investors and recipient countries. The shape of these investments and their eventual outcomes are equally influenced by the existing land and water governance systems in the host countries. Based on fieldlevel research conducted in Ghana and Mali which covered six large-scale agricultural investments, this paper analyzes the current land and water governance systems in these two countries through the lens of land and water acquisition and initial outcomes. It highlights missed opportunities for sustainable and equitable large-scale agricultural land investments due to uncoordinated governance systems and failure to rigorously apply detailed rules and regulations that are already in place. It offers suggestions for revamping land and water governance to promote large-scale investments that will lead to equitable distribution of benefits and sustainable management of natural resources.

Water is absent in the ‘Voluntary Guidelines on the Responsible Governance of Tenure of Land, Fisheries and Forests in the Context of Food Security’ (FAO, 2012). This paper explored whether and how the people-centred approaches and the human rights values that underpin this document can be better applied in the water sector and how more recognition of the land-water interface can support this. This is elaborated for participatory approaches in which people, especially the rural and peri-urban poor, better oversee the many interdependencies of natural resources and their multiple uses than the compartmentalised public sector. Further, human rights values are discussed for the development of land-bound water infrastructure, tracing the upcoming debates about a core minimum water service level that includes small-scale productive uses. Lastly, entitlements to land and to naturally available water resources are compared. While the water sector should replicate the current strong recognition of customary land rights to customary and informal water entitlements, an important difference is discussed as well: states are water regulators in a public interest. In this capacity, they should also to protect water entitlements by the vulnerable in negotiations about large-scale land-based investments through procedural and water prioritization arrangements.

Although there has been a considerable effort to reduce soil erosion and improve land productivity in Ethiopia, farmers’ investments in SWC remain limited. There is a long and rich tradition of empirical research that seeks to identify the determinants that affect farmers’ investments in SWC practices. Nevertheless, the results regarding these determinants have been inconsistent and scattered. Moreover, the impacts of different SWC practices have not been reviewed and synthesized. Thus, this paper reviews and synthesizes past research in order to dentify determinants that affect farmers’ investments in SWC practices, and to also assess the impact of SWC practices within the framework of ecosystem services, particularly in relation to provisioning and regulating ecosystem services. The review identified several determinants that affect farmers’ investments in SWC practices, which are categorized into two groups: (i) factors that are related to farmers’ capacity to invest in SWC practices, and (ii) farmers’ incentives to invest in such practices. Farmers’ investments in SWC are limited by both the capacity to invest and incentives from their investments related to land improvement. The review also showed that farmers’ capacities to invest in SWC practices and their incentives for making such investments have been influenced by external factors, such as institutional support and policies. This suggests that creating enabling conditions for enhancing farmers’ investment capacities in SWC practices, and increasing their incentives for making such investments, is crucial. The review and synthesis showed that the impact of most SWC practices on provisioning ecosystem services (e.g., crop yield) is negative, which is mainly due to the reduction of effective cultivable area due to soil/stone bunds. However, these practices were very effective in regulating ecosystem services, such as soil erosion control, soil fertility improvement and surface runoff reduction.

The study examined whether access to spate irrigation leads to better nutrition outcomes. The results showed that there is an overall improvement in the study sites compared to the 2011 DHS study. As far as households with access to spate irrigation are concerned, weight-for-height z-scores indicated that 8.2% of the children had prevalence of global acute malnutrition; 8.2% of them had moderate acute malnutrition. None of the children had severe acute malnutrition. The weight-for-age results indicated that 27.5, 17.6 and 9.8% of the children showed prevalence of underweight, moderate underweight and severe underweight, respectively. The height-for-age z-scores showed 56.5, 30.8 and 21.7% of the children had prevalence of stunting, moderate stunting and severe stunting, respectively. On the other hand, households without access to spate irrigation indicated that as far as the weight-for-height z-scores of children are concerned, there were no children (boys and girls) with prevalence of global acute malnutrition; weight for-age z-score showed that 13.6, 10.2 and 3.4% of the children had prevalence of underweight, moderate underweight and severe underweight, respectively. The height-for-age z-scores showed that 45.5, 25.5 and 20.0% of the children had prevalence of stunting, moderate stunting and severe stunting, respectively. The anthropometric measures, thus, showed the nutritional outcomes of users were worse-off than of nonusers of spate irrigation. This happens in the face of better income and consumption expenditures, mainly nonfood, for users compared to nonusers. This underlines the importance of nutrition education alongside efforts to improve access to irrigation. Moreover, multisectoral collaborations are needed between the health, agriculture, water, social protection, education, gender and other sectors to improve the nutrition outcome of children.

The study examined whether the use of spate irrigation in drought-prone areas of Ethiopia reduced poverty. Each of about 25 users of indigenous and modern spate irrigation schemes and an equal number of corresponding nonusers from the same peasant associations in Oromia and Tigray regional states were interviewed. The survey found that the poverty level of the spate irrigation users was significantly lower than that of the nonusers in terms incidence, depth and severity. Access to improved spate irrigation has led to reduced poverty, measured by all poverty indices, compared to traditional spate. Finally, the dominance test showed that the poverty comparison between users and nonusers was robust. From the study, it can be concluded that the use of spate irrigation in areas where access to other alternative water sources is limited, either by physical availability or by economic constraints, can significantly contribute to poverty reduction, and that modernizing the spate system strengthens the impact.

Flood-based farming is among the potential options in ensuring access to water for crop and livestock production for small-scale farmers in the arid and semiarid lowlands of sub-Saharan Africa, and Ethiopia in particular. Flood-based irrigation while inexpensive is rooted in tradition in many rural communities which is in contrast to many other irrigation types which are unavailable (in terms of water source, technology or capacity) or are costly to develop. Spate irrigation has been practiced in different parts of Ethiopia for many decades, but it was only recently that it gained the government’s attention. This study was conducted through a review and informal discussion with the objectives of documenting the current status, trends and prospects of spate irrigation in the country and the associated challenges, taking cases of selected schemes in different regional states. The study revealed that spate irrigation is expanding either through improvement of traditional schemes or by developing new ones. Neither the traditional nor modern schemes are free of challenges. The traditional schemes suffer from floods that damage their diversion structures, while poor design and construction of diversion structures have led to the failure of new ones. A range of socio-technical improvements in the planning, implementation and operation of schemes is proposed, including the design of headworks and canals consistent with the size and nature of expected flows, structures to minimize sedimentation, building capacity of farmers and district officers, and monitoring and improving the management that currently adversely impacts the performance of the schemes. Consulting farmers at every stage of the development, and building the capacity of engineers to deal with the unique nature of spate flows are the most likely interventions to ensure successful agricultural production using spate irrigation.

This chapter examines key institutional issues that are important to the recognition and sustainability of irrigated vegetable farming in Ghanaian cities. It assesses the informal nature of the business and examines current roles being played by relevant agencies directly or indirectly linked to urban vegetable farming and urban wastewater management. The chapter also looks at relevant bylaws, strategies and policies that have implications for the recognition of informal irrigation and/or the adoption of safety measures for risk reduction in irrigated vegetable farming. It also suggests options to facilitate the institutionalization of irrigated urban agriculture.

This chapter presents approaches tested in Ghana to mitigate wastewater irrigation-related risks for consumers and farmers from microbial contamination. The recommended interventions follow the WHO approach concerning multiple barriers along the food chain. Factors that could support the uptake of safety measures are discussed.

Access to debt financing (credit) is crucial to the development of urban agricultural production, processing and marketing activities. This chapter is based on a 2009 study 1 carried out in Accra to assess the practices of institutions and programs that could finance urban agriculture as well as the existing bottlenecks and opportunities in financing. Information is based on surveys involving 179 respondents sampled from financial institutions; urban farmers (not limited to vegetable farmers), traders and processors; literature reviews, stakeholder mapping; focus group discussions; key informant interviews; and a validation workshop.

The chapter presents the process and results from a project implemented in Accra by the Resource Centres on Urban Agriculture and Food Security (RUAF) Foundation to strengthen farmers’ organizations for innovative irrigated vegetable farming and marketing. One hundred urban farmers were organized into eight producer groups and trained on technical and organizational innovations along the vegetable value chain towards improved yield and income. Training was delivered through Urban Producer Field Schools (UPFS) on topics ranging from integrated plant production and protection principles, food safety and risk-minimization in wastewater use for irrigation to value addition for marketing. Farmers were also engaged in organized marketing, targeting niche markets.

Contamination levels of water and crops which exceed common standards are only a first indication of human health risks. This chapter shows estimates of human health risks from consumption of wastewater-irrigated vegetables based for example on dose-response modeling. The chapter focuses on human health risks and risk perceptions of microbiological and chemical contaminants such as heavy metals and pesticides.

This chapter shows results obtained from analyzing samples of vegetables taken at the farm gate and from selling points in Accra, Kumasi and Tamale. Microbiological data are based on a total of about 1,500 vegetable samples taken from different sampling points along the vegetable distribution chain – farm gates – and from different categories of sellers in Accra, Tamale and Kumasi. Fecal coliforms and helminth eggs were mainly used as the fecal contamination indicator organisms. For chemical contaminants, heavy metals and pesticides in irrigation water and vegetables were analyzed, while estrogens were used as an example for emerging contaminants.

This chapter describes the different irrigation methods and nutrient application practices used by urban vegetable farmers. Data are based on surveys conducted in Kumasi, Accra and Tamale. Recent relevant publications are also reviewed.

This chapter presents findings from studies conducted in Accra, Kumasi and Tamale aimed at assessing the quality of irrigation water used by farmers in and around the cities. Samples for laboratory analysis were taken from sources of water used for irrigation. Microbiological, chemical and other emerging contaminants are presented.

This chapter provides qualitative and quantitative information on the distribution pathways of irrigated vegetables, with a focus on lettuce, produced in Kumasi and Accra from the farm to the consumer. The data from a survey carried out in 2005 show the contribution of irrigated urban farming and the size of the beneficiary group in Accra, which is also the group at risk from crop contamination which has been quantified.

This chapter explores some of the financial and economic aspects of urban and peri-urban agriculture in Ghana. Cost-benefit analysis comparisons were made of farm finances of common rural, peri-urban and urban farming systems. Substudies also tried to quantify benefits for society and to cost externalities related to soil nutrient depletion, pesticide use and urban malaria.

The chapter describes the major sites of open-space vegetable farming in Ghana’s main cities. It also presents the principal cropping systems and characteristics of urban farmers involved in irrigated vegetable production.

This chapter serves as an introduction to the book and provides brief information about urbanization in West Africa, and in Ghana in particular, the general role of urban agriculture and the common use of polluted irrigation water. It describes our focus on irrigated smallholder vegetable production and our understanding of the terms ‘urban‘, ‘peri-urban’ and ‘wastewater’. The chapter reflects on some of the key challenges of the farming system, its dynamic and resilience. It also gives an overview on the structure of the book, the origins of the data and the main objective of this publication.

Wastewater use in agriculture is a complex phenomenon since it transcends typical sectoral and geographical policy and planning boundaries, and is influenced by opinions and perceptions. Planning for wastewater use typically requires the involvement of a number of government agencies covering health, water, sanitation, agriculture and irrigation, as well as researchers, community groups and the private sector. Where wastewater use is already taking place spontaneously and unofficially, how can these stakeholders come together to improve the management of the system to maximize the livelihoods benefits while minimizing impacts on health and the environment? One option is the formation of multi-stakeholder platforms, which provide a space for stakeholders to share opinions and seek negotiated solutions in an open and ‘level’ environment. How effective these are, what outcomes can be expected, and how they can be improved are all questions that are still being asked. This chapter presents three case studies in which multi-stakeholder processes were used to improve wastewater management for urban agriculture. Although differences were observed, there were several cross-cutting lessons. A critical factor is the starting point, including an agreed definition of the problem to be addressed, negotiated goals and a management structure that is acceptable to all stakeholders. When multi-stakeholder processes are externally initiated, as with those reviewed here, it is essential that project priorities are commensurate with local priorities. Finding an institutional home and anchor agency an improve long-term sustainability but care must be taken in considering how this impacts on existing power structures. Participation and representation greatly influence the effectiveness of the process and much may need to be done to support this, for example by strengthening local community groups. A factor that appears to significantly improve participation and engagement is having tangible outputs, which demonstrate to stakeholders the potential of multi-stakeholder platforms.

This chapter addresses the importance of understanding farmers’ knowledge and perceptions on health-risk and risk-reduction measures for the development of mutually acceptable risk-management strategies. Drawing on studies from different countries, the chapter shows that it is not realistic to expect high risk awareness. In cases where farmers are aware of health risks, they assess mitigation measures in view of their overall impact on work efficiency and crop yield rather than only the potential health benefits to be gained. The chapter asserts that for on-farm risk-reduction measures to be successful, it is pertinent that farmers’ needs and constraints are incorporated into the formulation of recommended practices. This might happen through indigenous processes but can be supported through farm-based participatory approaches where farmers and scientists work together in developing risk reduction measures. An important first step is the identification of mutually accepted problem indicators. Where health benefits for farmers and consumers are not sufficient reasons for the adoption of safer practices, other triggers have to be identified as well as appropriate communication channels for effective outreach.

This chapter discusses the implementation challenges of the WHO Guidelines on safe wastewater use pertaining to the adoption of the so-called ‘post-treatment’ or ‘non-treatment’ options, like safer irrigation practices or appropriate vegetablewashing in kitchens. Due to limited risk awareness and immediate benefits of wastewater irrigation, it is unlikely that a broad adoption of recommended practices will automatically follow revised policies or any educational campaign and training. Most of the recommended practices do not only require behaviourchange but might also increase operational costs. In such a situation, significant efforts are required to explore how conventional and/or social marketing can support the desired behaviour-change towards the adoption of safety practices. This will require new strategic partnerships and a new section in the WHO Guidelines. This chapter outlines the necessary steps and considerations for increasing the adoption probability, and suggests a framework which is based on a combination of social marketing, incentive systems, awareness creation/education and application of regulations. An important conclusion is that these steps require serious accompanying research of the target group, strongly involving social sciences, which should not be underestimated in related projects.

In developing countries urban wastewater management often fails to cope with increasing wastewater generation. Financial, technical and institutional limitations force authorities to discharge substantial amounts of untreated or partially treated wastewater into surface waters. Consequently, uncontrolled use of polluted water is increasingly common in the downstream peri-urban areas. Although wastewater use bears a significant risk on human health, such use is also productive and an asset for many. Agricultural use of wastewater is a strong manifestation of the urban-rural connection and transfers a waterborne risk from the wastewater disposal system to the food chain, requiring a paradigm shift in the approaches applied to risk minimization. Conventional models for urban wastewater treatment and management are based on top-down, mechanically driven approaches that do not, or do not sufficiently, consider the links between the social, economic and health aspects. This situation is understandable from historical and technological points of view, but does not provide innovative solutions to current problems in developing country cities. A different approach is required, one that rethinks conventional wastewater system design and management. By adopting a systems approach to analysing both the water and food chains, one discovers the interactions of different stakeholders that treat and use (or abuse) water, the impacts on overall productivity and the risks. Governance systems to manage wastewater use in agriculture must incorporate decentralization to accommodate thinking at the bottom layer, encourage stakeholder engagement and provide coordination and policy cohesion for managing risks jointly from both the water and food chains.

Interventions proposed and implemented for the mitigation of diarrhoeal diseases associated with wastewater reuse in agriculture have received little, if any, comparative assessment of their cost-effectiveness. This chapter assesses the costs, outcomes and cost-effectiveness of the so-called ‘treatment’ and ‘non- or post-treatment’ interventions as well as a combination of these for wastewater irrigation in urban Ghana using an approach that integrates quantitative microbial risk assessment (QMRA), disability-adjusted life years (DALYs) and cost-effectiveness analysis (CEA). The cost-effectiveness ratios (CERs) for the treatment and non-treatment interventions assessed ranged from US$31/DALY to US$812/DALY averted. Risk-reduction measures targeting farming practices and the basic rehabilitation of local wastewater treatment plants were the most attractive interventions with a CER well below the threshold of US$150/DALY, sometimes considered as the upper limit for a health intervention to be cost-effective in developing countries. All combinations associated with the basic rehabilitation of the treatment plants, with either on-farm or post-harvest interventions or both, resulted in CERs within the range of US$40/DALY to US$57/DALY. However, the CERs for the construction of a new wastewater treatment plant either as an independent intervention or in combination with on-farm and post-harvest interventions were unattractive in view of health-risk reduction for wastewater irrigation. Although attractive, the CERs of non-treatment options are largely dependent on compliance (adoption) by farmers and food vendors. In this regard, the CER increased by almost fivefold when the adoption rate was only 25 per cent by farmers and food vendors; but was attractive as long as adoption rates did not fall below 70 per cent. On the other hand, the success of the treatment option depends on the functionality of the treatment plants which is not without challenges in a country like Ghana. Thus, this chapter stresses the need for a balanced risk-management approach through a combination of treatment and non-treatment interventions to hedge against failures that may affect CERs at any end. While this chapter provides a contribution to the debate on interventions for health-risk mitigation in wastewater irrigation, more case studies would be useful to verify the data presented here.

Post-harvest interventions are an important component of a multiple-barrier approach for health-risk reduction of wastewater-irrigated crops as recommended by the 2006 edition of the WHO Guidelines for safe wastewater irrigation. This approach draws on principles of other risk-management approaches, in particular the hazard analysis and critical control point (HACCP) concept. Post-harvest measures are of particular importance as they can address possible on-farm precontamination, and also contamination that may occur after the crops leave the farm. Key factors influencing microbial contamination along the farm to fork pathway are basic hygiene and temperature management. Both factors are, however, hardly under control in most developing countries where microbial contamination and proliferation are supported by low education, limited risk awareness, rudimentary technical infrastructure and unenforced regulations. In the face of these challenges, the most successful strategies to enhance food safety will involve interventions at multiple control points along the production chain, with emphasis on local safety targets and innovative educational programmes fitting local knowledge, culture and risk perceptions. The WHO (2006) recommended health-based targets for risk reduction in wastewater irrigation provide the required flexibility for risk mitigation in line with the concept of food-safety objectives (FSO).

There is a significant imbalance between the number of publications describing potential and actual environmental and health impacts from chemically contaminated wastewater, and reports outlining concrete options to minimize the related risks where conventional wastewater treatment is not available. This gap applies more to inorganic and organic contaminants than excess salts or nutrients. This chapter outlines some of the options available that could be considered in and around the farm, looking at heavy metals, salts, excess nutrients and organic contaminants. The emphasis is placed on low-cost options applicable in developing countries. While such measures can reduce negative impacts to a certain extent, it remains crucial to ensure that hazardous chemicals are replaced in production processes; industrial wastewater is treated at source and/or separated from other wastewater streams used for irrigation purposes; and fertilizer application rates and related possible subsidies adjusted to avoid over- fertilization.

This chapter presents farm-based measures that have been developed and tested in the informal irrigation sector to reduce microbiological health risks for consumers from wastewater irrigation of vegetables commonly eaten uncooked. The measures target poor smallholder farmers or farmer associations in developing countries as part of a multiple-barrier approach for health-risk reduction along the farm to fork pathway. Measures discussed include treatment of irrigation water using ponds, filters and wetland systems; water application techniques; irrigation scheduling; and crop selection. In addition, the chapter highlights some practical strategies to implement these measures, based largely on field experiences in Ghana. Although most measures discussed do not fully eliminate possible health risks, they can significantly complement other pathogen barriers. Which measures fit, either alone or in combination, will depend on local site characteristics and practices. Further studies are required to develop new measures or adapt them to other irrigation practices and systems in developing countries.

Recently, the application of excreta-based fertilizers has attracted attention due to the strongly increasing prices of chemically produced fertilizers. Faecal sludge from on-site sanitation systems is rich in nutrients and organic matter, constituents which contribute to replenishing the humus layer and soil nutrient reservoir and to improving soil structure and water-holding capacity. Hence, it represents an important resource for enhancing soil productivity on a sustainable basis. However, there is little in the scientific literature about the performance of treatment technology allowing recovery of nutrient resources from human waste. This paper reviews the state of knowledge of different processes that have been applied worldwide. Their pathogen removal efficiency as well as nutrient and biosolids recovery performances are assessed. The chapter outlines the gaps in research for further development.

The volume and extent of urban wastewater generated by domestic, industrial and commercial water use has increased with population, urbanization, industrialization, improved living conditions and economic development. Most developing-country governments do not have sufficient resources to treat wastewater. Therefore, despite official restrictions and potential health implications, farmers in many developing countries use wastewater in diluted, untreated or partly treated forms with a large range of associated benefits. Aside from microbiological hazards, the practice can pose a variety of other potential risks: excessive and often imbalanced addition of nutrients to the soil; build-up of salts in the soils (depending on the source water, especially sodium salts); increased concentrations of metals and metalloids (particularly where industries are present) reaching phytotoxic levels over the long term; and accumulation of emerging contaminants, like residual pharmaceuticals. As these possible trade-offs of wastewater use vary significantly between sites and regions, it is necessary to carefully monitor wastewater quality, its sources and use for location-specific risk assessment and risk reduction.

In and around urban areas pollution of natural water bodies is on the rise. As a result, wastewater irrigation is an increasingly common reality around most cities in the developing world. For reasons of technical capacity or economics, effective treatment may not be available for years to come; therefore, international guidelines to safeguard farmers and consumers must be practical and offer feasible riskmanagement options. This chapter provides an introduction to microbiological hazards. These can be addressed best in a step-wise risk assessment and management approach starting with wastewater treatment where possible, and supported by different pathogen barriers from farm to fork. A major change in the most recent WHO Guidelines for the safe use of wastewater, excreta and greywater in agriculture and aquaculture (WHO, 2006) agriculture is the focus on a holistic approach to achieving health-based targets, instead of prescribing irrigation waterquality threshold levels that are often unattainable. The health-based targets should not be read as absolute values but as goals to be attained in the short, medium or long term depending on the country’s technical capacity and institutional or economic conditions. Local standards and actual implementation should progressively develop as the country moves up the sanitation ladder. While healthrisk assessments are recommended to identify entry points for risk reduction and health-based targets, the Guidelines also offer shortcuts in situations where research capacities and data are constrained.

After introducing terms and terminology of wastewater, sludge and excreta use, the chapter highlights their global drivers and significance using examples from different parts of the developing world. It is useful in the discussion to differentiate between unplanned use of wastewater resulting from poor sanitation, and planned use which tries to address matters such as economic or physical water scarcity. Both types of wastewater use can have significant socio-economic benefits but also institutional challenges and risks which require different management approaches and, ideally, different guidelines. This diversity makes the current WHO Guidelines, which try to be global in nature, complex to understand and apply. Whilst planned reuse will remain the norm in countries that can afford treatment, most countries in the developing world are likely to continue to use non- or only partially treated wastewater, for as long as sanitation and waste disposal are unable to keep pace with urban population growth. However, there are options to link urban faecal sludge and wastewater management with urban food demands or other forms of resource ecovery that provide opportunities to safely close the nutrient and water loops.

Farmers in rural Ethiopia live in a climate-related shock-prone environment. The major source of climate shock is the persistent variation in the amount and distribution of rainfall. The dependence on unreliable rainfall increases farmers’ vulnerability to shocks while also constraining farmers’ decisions to use yieldenhancing modern inputs, exacerbating the vulnerability of households to poverty and food insecurity. As a response, the Government of Ethiopia has embarked on massive investment in low-cost agricultural water management technologies (AWMTs). Despite these huge investments, their impact remains hardly understood. The main focus of this paper was to explore whether access to selected AWMTs, such as deep and shallow wells, ponds, river diversions and small dams, has led to a significant reduction in poverty and, if they did so, to identify which technologies have higher impacts. The study also calculated the net present value of the selected AWMT, to assess which of the AWMTs are worth investing in given that they have the promise of reducing poverty. In measuring impact we followed different approaches: mean separation tests, propensity score matching and poverty analysis. The study used a unique dataset from a representative sample of 1,517 households from 29 Peasant Associations (Kebeles) in four regions of Ethiopia. Findings indicated that the estimated average treatment effect on per capita income was significant and amounted to USD 82. Moreover, there was 22% less poverty incidence among users of AWMTs compared to nonusers. The poverty impact of AWMT was also found to differ by technology type. Accordingly, deep wells, river diversions and micro-dams have led to 50, 32 and 25%, respectively, reduction in poverty incidence compared to the reference, i.e., rain-fed systems. Although, the selected AWMTs were found to contribute to poverty reduction, we found that ponds, deep wells and small dams were not attractive from a social cost-benefit analysis perspective, implying that choices need to be made considering their relative financial viability and poverty reduction impacts compared to other available options that could improve rain-fed agriculture. Finally, our study identified the most important determinants of poverty, on the basis of which we made policy recommendations: i) build assets (AWMT, livestock, etc.); ii) human resources development; and iii) improve the functioning of labor markets and access to these (input or output) markets for enhanced impact of AWMT on poverty.

It is the belief of many analysts that agrarian countries like Ethiopia that depend on rain-fed agriculture are significantly vulnerable to rainfall variability, the risk which tends to aggravate with global climate change. Consequently, it is believed that future increases in food supplies and economic prosperity depend heavily on effective agricultural water management. It is with this in mind that the use of low-cost technologies for rainwater and runoff control, storage, water lifting, conveyance and application have become more widespread in Ethiopia since the recent drought of 2002/2003. A range of technologies are currently used with varying levels of impacts. This paper outlines an inventory, characterization, suitability and upscaling aspects of Agricultural Water Management Technologies (AWMT) in Ethiopia. Particular characteristics of each of the technologies, their suitability for a given environment, and the necessary conditions for their successful adoption and scaling up are identified. Furthermore, a variety of combinations of technologies used for control or storage, lifting, conveyance and application of rainwater are documented. Suitability of a technology in a particular environment depends on many factors, such as, the nature of technical complexity, the existing institutional and individual capacity to implement, the costs and benefits, etc. Technical considerations include implementation (set up), operation and maintenance, affordability and environmental impact. The results of a ranking exercise of the technical complexity of a given technology are presented. Concerns related to waterborne and water-related diseases due to stagnation, water quality and possibility of mosquito breeding are discussed. Households in some parts of Ethiopia, who have practiced improved agricultural water management suitable to their local conditions, have managed to diversify their incomes through beekeeping, livestock, intercropping cash crops with food crops and setting up shops, hotels and flour mills in the nearby towns or villages. Therefore, AWMT at smallholder level meet the intended purpose, provided that they are suitable and adaptable to the local circumstances. The question is which of the technologies are suitable to which area under what socioeconomic conditions?

Ethiopia’s economy and majority of the people’s livelihoods are dependent on agriculture. To develop the socioeconomy of Ethiopia and eradicate poverty, the policy and interventions should focus on agriculture as an entry point. In line with this, the government, bilateral and multilateral donors, NGOs and various institutions share the concepts and priorities identified in the “Plan for Accelerated and Sustained Development to End Poverty (PASDEP).” There are key challenges that need to be strongly addressed on transforming agriculture by overcoming a multitude of problems including biophysical and water management issues to help achieve the targets of PASDEP and sustainable socioeconomic growth in Ethiopia. This particular paper aimed at addressing the water management challenges that Ethiopia has faced in the past and is facing today, and to stimulate ideas on how to manage water resources to meet the growing needs for agricultural products, to help reduce poverty and food insecurity, and to show how water can be used as an important entry point to transform its socio-economy and contribute to sustainable development and the environment. The issues discussed will focus on innovations, policies and technologies that enable better investment and management decisions in water use, particularly focusing on agriculture and irrigation but also briefly looking into other water-related subsectors such as hydropower, water supply, watershed, drought and flood management as well as other biophysical aspects. It has also been attempted to make the paper suitable for decision-makers rather than scientists, in order to raise useful ideas for dialogue and further discussions, studies and researches. The paper, therefore, does not claim exhaustiveness. The target audiences of this paper are the people who make the investment and management decisions in water and water management for agriculture, and other subsectors - agricultural producers, water managers, investors, policymakers and civil society. The paper has benefited from the review of key policy and strategy documents of Ethiopia, outputs of various outcomes of research, civil society meetings and workshops, data and information available in government institutions, and global knowledge. The key major issues that are discussed in the paper include the following: Socioeconomic development challenges of Ethiopia, viewed from a water resources perspective., The water resources endowment, development extent, potentials and economic/socioeconomic development linkages., Water-related innovations and agriculture., Water-related interventions in various agro-ecologies., Policy and strategy actions needed. This paper should also be viewed with other components such as river basin growth pole/corridor concept, institutional reform and research capacity building. It focuses on analyzing key problems and associated interventions, and can be applicable in the contexts of the current situation and the future possib

The environmental services related with agricultural water are increasingly acknowledged as a critical factor for farming development in South Asia. However, little attention is given to the demand side linked with the preservation of these services. To this aim, we conduct a stated preference approach for the elicitation of farmers’ preferences towards the economic value rendered to environmental services related with agricultural water. The research is based on an extensive survey in selected clusters of India, Pakistan and Nepal. The case studies are situated along Indo-Gangetic basin due to more evidential linkages between environmental services and irrigation. The findings depict a highly agreeable stance of Indian and Nepalese farmers for the contribution to environmental services while the majority of Pakistani are opposed to such a contribution. However, they almost all agree on the type of the assessment approach while the agreeable Pakistanis offer the highest contributions. The association of the economic assessment with key wealth indicators and socio-demographic elements depicts the high significance of household size.

The Indo-Gangetic Basin encompasses most of the fertile landholdings in South Asia. However, low agricultural productivity is observed in the four riparian countries - India, Pakistan, Nepal and Bangladesh - by nailing down rural welfare. Accusations are directed at the inability of water supply sector to ensure high productivity rates and security of subsistence farmers. However, little is known about the demand side and farmers’ perceptions towards the effects of water use on agricultural productivity. To this aim, we conduct an economic assessment through a stated preference approach on crucial institutional and environmental related parameters of agricultural water that could enhance productivity potential. Also, vital socio-demographic elements are examined as influential factors. The analysis is based on an extensive research survey accomplished in selected clusters along the Indo-Gangetic Basin.

Agricultural water use in agrarian economies is often state subsidized for the enhancement of agricultural productivity while poverty alleviation is also targeted. The Indian agricultural dependent states offer representative examples of undervalued irrigation services mainly sourced by canal networks. However, the current inefficient operation of canal irrigation systems diverts water demand to private initiatives by significantly increasing economic value of agricultural water. The additional recent acknowledgement of economic value encompassed in supportive ecological services enhances the request for reevaluation of agricultural water. The paper attempts to assess the value of irrigation and related ecological services in representative backward clusters of Bihar state in Eastern India. The effects on different landholding groups are analyzed by giving particular emphasis to marginal landholders.

Water use and landholding factors are widely acknowledged as major determinants of agricultural development in agrarian regions of the Indo-Gangetic basin (IGB). High attention is mainly given to irrigation policy while land is often apprehended through soil productivity aspects. However, the nexus between land scale and water consumption in respect to the economic implications of agricultural development is poorly elaborated. To this aim, this paper examines the economic effects of water use and landholding scale to farming in agricultural communities of IGB area. The research is based on an extensive survey conducted in representative areas of Pakistan, India and Nepal situated along the IGB basin. The results signify that the economic viability of marginal and small landholders and water users is threatened when the study focuses on the land scaling effects to farming. Practical recommendations towards the rescheduling of irrigation and land use policies are introduced.

Irrigated agriculture in Central Asia can only be developed through increase of crop yields and reduction of water volumes applied per unit of agricultural production. Thus to improve agricultural production, proper agronomic measures and irrigation schedules have to be developed considering local conditions. To assess existing water productivity, 9 farms have been selected along South Fergana Canal. A Soil-Water-Air-Plant (SWAP) model has been applied for the same fields to predict potential water productivity.

The significance of environmental services related with irrigation is increasingly acknowledged as a critical factor for agricultural productivity in South Asia. However, little is known about farmers’ willingness to contribute for the preservation of these services. To this aim, we conduct a stated preference approach for the elicitation of farmers preferences towards the economic value attributed to environmental services related with agricultural water use. The research is based on results from an extensive survey in selected clusters of India, Pakistan and Nepal. The case studies are situated along Indo-Gangetic basins due to the presence of more evident environmental problem linked with irrigation. The findings present a highly agreeable stance of Indian and Nepalese farmers towards the contribution to the environmental services while the majority of Pakistani is opposed to such a contribution. However, they all agree on the type of the assessment approach. The association of the economic assessment with key wealth indicators and socio-demographic elements depicts the high significance of household size.

The dynamics of aquatic resources in the canals of Bac Lieu Province, in southern Vietnam, are detailed and synthesized in this study. Nekton and eight environmental parameters were monitored in this province between 2004 and 2006, at 14 sites sampled three times a year. The study area, located along the coastal zone, is characterized by a variable environment subject to saline, freshwater and acidic pulses. The spatiotemporal dynamics of aquatic resources and their relationships with environmental parameters are detailed. The dominance of either freshwater or estuarine fauna, the dynamics of assemblages and the catches of fishers appear to be largely influenced by the management of sluice gates built along the coastal zone.

The BayFish–Bac Lieu model presented in this chapter is a Bayesian model that aims to identify optimal water control regimes and trade-offs between water uses in order to improve management of water-dependent resources in the inland coastal area of Bac Lieu Province, Mekong Delta, Vietnam. The model was developed between 2004 and 2007 and integrated local databases, outputs from the Vietnam River Systems and Plains (VRSAP) model and stakeholder consultations. The model facilitates analyses of the consequences of different water management scenarios (quantitative and qualitative) on rice, fish, crab and shrimp production in the province. However, beyond production, trade-offs between household income, food security or environmental protection were also identified during the model development process. Subsequently, the BayFish–Bac Lieu model allows detailing of: (i) annual production probabilities in the case of a baseline scenario; (ii) outcomes of four different sluice gate operation modes; and (iii) trade-offs between household income, food security and environment outcomes for each scenario. The model shows that through improved shrimp farming and fish production, total household income benefits directly from open sluice gates allowing saline intrusion. However, this has the opposite effect on rice production, and on food security. Results suggest that a suitable compromise involving at least one sluice gate open at all times should be adopted for optimized outcomes.

The precise estimation of surface runoff from rainfall is critical for water resource management. In the recent past, remote sensing and Geographic Information System (GIS) technologies have been widely used in the estimation of surface runoff from watersheds, and from agricultural fields in particular. This is due to the inherent ability of remote sensing to capture spatial heterogeneity of surface parameters such as land use and land cover. This could lead to better performances of surface runoff simulation models. Surface runoff volume/rate estimation involves quantifying the amount of rainfall exceeding infiltration and initial abstractions which must be satisfied before the occurrence of runoff. The widely accepted SCS curve number method was employed to calculate surface runoff, using a combination of remotely-sensed land use/land cover and hydrometrological data in the Punjab canal command areas. Land use/Land cover maps for four cropping seasons, Rabi 2004-05, Kharif 2005, Rabi 2006-07 and Kharif 2007 were derived using red and near infrared bands of MODIS 8 day products. The existing soil map was reclassified into hydrological soil groups and rainfall data were interpolated using the inverse distance method to represent the spatial rainfall values of each canal command. The results show that CN values vary from 70 to 95 during the study period. The highest CN value of 94.4 is during the Kharif 2005 season. Meanwhile the runoff-coefficient is changing from 0.01 to 0.25 and 0.01 to 0.43, respectively, during Rabi 2004/05 and Rabi 2006/07. During Kharif 2005 and Kharif 2007, the runoff-coefficient varied from 0.01 to 43 and 0.01 to 0.45, respectively. The study shows that the SCS curve number method can be used for runoff estimation with the help of remote sensing products and GIS technologies from catchments where gauging data is not available.

Climate is changing world-wide, and the science community in Sri Lanka has come up with ample evidence to suggest that the country’s climate has already changed. During 1961-1990 the country’s mean air temperature increased by 0.016 0C per year, and the mean annual rainfall decreased by 144 mm (7 %) compared to the period 1931-1960. In addition, mean annual daytime maximum and mean annual night-time minimum air temperatures increased. However, the bigger question of national importance is what Sri Lanka’s climate will look like in 50 or 100 years and how prepared is the country to face it. Apart from the Intergovernmental Panel on Climate Change (IPCC) projections at the coarse global scale, few studies have attempted to project future climate scenarios for Sri Lanka and to identify climate change impacts on agriculture, water resources, the sea level, the plantation sector, the economy and health. Vulnerability and adaptation to climate change are the least studied areas. This paper reviews the status of climate change research and activities in Sri Lanka with respect to future climate projections, impacts, climate change mitigation and the country’s ability to adapt, and identifies existing knowledge gaps. Messages emerging from this review suggest that Sri Lanka’s mean temperature during the North-East (December-February) and South-West (May-September) monsoon seasons will increase by about 2.9 0C and 2.5 0C, respectively, over the baseline (1961-1990), by the year 2100 with accompanying changes in the quantity and spatial distribution of rainfall. Extreme climate events are expected to increase in frequency. These changes will bring about widespread impacts on the country’s agriculture and economy For example, an increase of 0.5 0C in temperature can reduce rice yield by approximately 6%; extended dry spells and excessive cloudiness during the wet season can reduce coconut yield resulting in annual losses between $32 and $73 million to the economy. Pilot studies in the Galle District suggest that sea level rise could inundate about 20 % of the land area of Galle’s coastal District Secretariat Divisions. Adaptation measures already undertaken in the agriculture sector include the development of low water consuming rice varieties and the use of micro-irrigation technologies. Tools have been developed for predicting seasonal water availability within the Mahaweli Scheme and annual national coconut production. However, Sri Lanka is yet to undertake a comprehensive national study on the vulnerability of her water resources and agriculture to climate change. The formulation of detailed and reliable future climate scenarios for the country is therefore, urgently required.

Water is a multiple use resource. Increasing scarcity and competition from various sectors is an important dimension to be considered in its management. Understanding the value of water to different water uses is, therefore, necessary to assist decision-making in water allocation among sectors. Although water used in agriculture can be valued using production function approaches, such direct valuation methods are not available for the environmental uses of water. This paper uses non-market valuation methods to estimate the economic value of a committed flow through a unique ecosystem, the Yala Protected Area Complex (YPC). The Yala Protected Area Complex is an important wildlife refuge situated in south-eastern Sri Lanka. Its large land extent, undisturbed nature, and abundance and diversity of fauna contribute to its uniqueness. The fact that the YPC is also the most visited national park in Sri Lanka is partially a result of this uniqueness. However, maintenance of the park’s ecosystem depends on the flow of the Menik Ganga. This flow is regulated by the Veheragala Reservoir Project, and there is now discussion of reducing flow into the park by about half of the current level. The proposed plan ensures dry season flow into the YPC and, therefore, has been deemed acceptable. However, there is a possibility that farmers will demand further water releases during the dry season which could in turn endanger the planned downstream water releases. So there is a potential trade-off between environmental and irrigation uses of water. A willingness to pay (WTP) survey was conducted in ten districts in Sri Lanka during the fourth quarter of 2008 to estimate the WTP of the general population of the country towards maintaining this important environmental resource. In the hypothetical market presented, participants were told of the need for financial contributions from the general public to ensure the release of a minimum downstream flow commitment of 50 MCM. Participants were also informed of how this flow would enhance the ecosystem of the YPC. A single bound dichotomous choice contingent valuation approach was used as the elicitation format. Nonobligatory voluntary contributions were solicited towards a trust fund that could be used to ensure release of the required quantity of water downstream during dry months. According to the results of a binary logistic regression, income, age, and religious attachments are important factors affecting the decision to contribute to environmental flow maintenance to the YPC. Sixty-five percent of respondents were willing to pay something to ensure the maintenance of an adequate environmental flow in the YPC. The estimated mean WTP for water releases to enhance the YPC is Sri Lankan Rupees (SLR) 435 per year. Over the requested payment horizon of 10 years, the present value of aggregate WTP from the Sri Lankan population to enhance the ecosystem of the YPC is SLR 12 billion. This quantity greatly surpasses the present

Assessment and provision of Environmental Flows (EF) is important for the protection of aquatic ecosystems. EF are a set of discharges of a particular magnitude, frequency and timing that are necessary to ensure a certain range of benefits from a river. Such flows need to be scientifically determined and economically justified. Limited exposure to the concept of EF exists in developing countries. This paper gives two recent relevant example studies, which were conducted by IWMI, with foci on EF Assessment (EFA) and valuation of EF benefits in the Walawe and Menik Ganga river basins located in a semi-arid zone of southern Sri Lanka. The Walawe example illustrates the simple method for estimation of EF. The EF are approximated at two sites along the main stream of the Walawe River, which are located below the two main reservoirs. A desktop method is used, which is based on simulated, unregulated daily flow time series and their flow duration curves. The study also illustrates how the required hydrological information can be generated for the locations where EF assessment is intended – quickly and in conditions of limited observed data. The second Menik Ganga example is used as a case study to evaluate the costs and benefits of environmental water allocations. The EF components evaluated include the water needs for religious festivals, and the requirements of the Yala National Park, the Pilinnawa coastal wetland and grasslands, and the Yala Fisheries Management Area (YFMA) off the coast. Almost all estimates are based on use values of EF such as marketed goods and recreation. The paper intends to stimulate discussion and further research in the fields of EF assessment and economic valuation.

Wetlands are habitats with temporary or permanent accumulation of water. The degradation and loss of wetlands is more rapid than that for other ecosystems, and wetland-dependent biodiversity in many parts of the world is in continuing and accelerating decline. They have been confirmed to deliver a wide range of critical and important services vital for human well-being. Therefore, it is clear that sound wetland management is now expected to not only consider conserving the ecological integrity of the ecosystem but also to pay specific attention to the well-being of local people, thereby contributing to poverty alleviation. Wetlands, both fresh and marine, have a multitude of benefits, in addition to environmental benefits, such as for agriculture, flood control, water purification, fisheries and recreation. For the maintenance and sustainability of wetlands the crucial requirement is water – a resource that has multiple demands and competition. The main competitor for the water resource around the world is agriculture for food production, a basic requirement for human survival. Therefore, in a situation of wetlands versus food production, the balance tips towards food production without considering the adverse consequences to the wetlands or adequately appreciating the benefits from achieving a balance. This is where Integrated Water Resource Management (IWRM) should be adopted to facilitate this process and enable wetland management and agricultural management to fit into the picture along with the other multiple uses of water. Integrated Water Resource Management should be of considerable interest for Sri Lanka, being a country which has agriculture very high on the agenda. The country is also home to a range of wetlands including 103 distinct river basins and 42 lagoons, which support a multitude of functions and services to people. The relationship between agriculture and wetlands in Sri Lanka is complex. The proliferation of village level water storage structures (small tanks) has created an unusually large number of man-made wetland habitats that add significantly to the natural wetlands that are concentrated mainly in the coastal belt. The absence of an integrated approach to water resource development however, continues to erode natural wetland systems. Two major problems, which concern downstream fisheries and livelihoods, are high levels of agricultural pollution, especially through the excessive use of fertilizers, and modifications to the hydrology. The objective of this paper is to review the work of the International Water Management Institute (IWMI) on wetlands and agriculture in Sri Lanka, to look at the competing water demands between water for wetlands and water required for agriculture, keeping in mind the requirements for nature as well as the sustainability of livelihoods. The paper will address some impacts of agriculture on wetlands, the consequences for livelihoods and the benefits of adopting the IWRM approach, building a

The demand and use of water resources is permanently increasing, while the quality of water is dropping and the availability of water in the context of climate change is becoming uncertain. To meet these growing problems it is necessary to carefully assess the existing water stocks and future trends in a country. The accuracy of such an assessment highly depends on the quality of data and information used. In other words – we cannot manage what we do not measure. In most developing countries, the lack of readily accessible and quality controlled data is the major obstacle for scientifically-based assessments on water resources, water development planning and evaluating the status and trends of water resources. Sri Lanka too faces similar obstacles. Recently IWMI initiated the development of a prototype system for managing national water resources data and information, which can be accessed online by various users and interested stakeholders. The data and information in the system is being organized in modules to provide user-friendly access. The ‘overview’ module includes information on topography, soil, land use, land cover, river network and settlement patterns. The ‘water availability’ module contains data on various components of the hydrological cycle, including rainfall, runoff, evaporation, ground- water, river basin characteristics, per capita water availability and trends, and water scarcity. The ‘Demand and use’ module focuses on the factors that affect demand, such as population growth, sectoral demand, irrigation requirements and withdrawals. The ‘water quality’ module provides information on salinity, water quality constituents and Water related diseases. The ‘governance and management’ module contains information on institutions, legislation and finances in the Sri Lankan water sector. The ‘disaster and risk’ module focuses on the characteristics of floods, land slides, tsunami etc. Finally, the ‘climate change’ module covers the impacts of climate change on rainfall, salinity and sea level rise to guide adaptation planning. The system is designed with a view to facilitate assessments of water resources at various administrative (e.g., province, district) and hydrological (e.g., river basin) units. The map-based interface ensures quick access to available data and allows the date to be downloaded and displayed. The system is currently a ‘work in progress’ and only an illustration of what can be achieved. It is envisaged that by cooperating with national agencies, the system will be enhanced into a unified platform for maintaining and sharing data by various participating agencies and will be used to conduct a systematic assessment of water resources in Sri Lanka. By developing a comprehensive and national water audit, Sri Lanka may provide as an example to other developing countries too.

Agriculture development has been the main strategy for the socioeconomic development in the country since time immemorial, even though its contribution to GDP has been declining recently. Successive governments of Sri Lanka since independence have invested heavily in the irrigated agriculture sector to address the food security concerns of the country. The continuous investment in irrigation was required to address problems such as spatial and temporal variations in monsoonal rainfall in the country, which has a serious negative impact on food production and livelihoods of people. The need for pursuing irrigation development and management has become more important in the country in the face of rapid population growth and increasing food prices in the world market. In this context, managing irrigation schemes for productivity increase is becoming increasingly important and different irrigation management models have also emerged through attempts made in this direction by countries including Sri Lanka, where irrigation plays a leading role in food production and nation development. Farmers’ active involvement in irrigation management, especially operation and maintenance (Oamp;M) and decision-making as well, has been identified as a key requirement to attain productivity goals and the sustainability of irrigation systems. This paper aims at reviewing participatory irrigation management approaches adopted in medium and major irrigation systems in Sri Lanka with a view to identifying their past and present trends and future directions. The review will contribute to an improved understanding by policymakers, managers of irrigation schemes and farmers of the role of participatory irrigation management, its past and present including institutional structures, responsibilities and performance and the directions it should take to meet future challenges as a dynamic institutional mechanism. As all the medium and major irrigation schemes in the country are jointly managed by farmers and government agencies, the inferences drawn from the review would be important for the agencies and farmers alike to introduce necessary changes in their programs to address future needs and requirements.

The issue of scale has become paramount for the effective evaluation of WSD programs. Shile terms vary from state to state, the following definitions have been adopted for this study and are deemed appropriate for Andhra Pradesh. Micro scale - less than 1500 hectares; Meso scale 1500 - 10000 hectares; Macro level over 10000 hectares (including basin level investigations). There is a need for a meso-scale benefit and cost evaluation of the WSD programs so that unintended impacts are avoided and that the implementation of programs is improved. Operating at a meso-scale will also provide more effective opportunities to link and address micro and macro scale biophysical and institutional issues. This project will integrate environmental, economic, social, equity and dimensions at meso levels to help ensure that WSD contributes positively to the Indian governmentapos;s sustainable livelihoods goal and provide the foundations for a resilient and sustainable WSD. Success will not only be determined by spatial scale (e.g. micro versus meso) but will also be determined by the disciplinary scale of analysis (e.g. focusing on short term economic efficiency alone runs considerable risk of ignoring longer term trends in natural and social capital). This paper describes early progress on developing such an evaluation model.

Wastewater irrigation is a widespread and growing phenomenon that carries varying degrees of risk. Whether spontaneously practiced in urban and periurban agriculture or planned as part of water reuse programmes, food and fodder production using untreated sewage or treated effluent can have serious human health implications for farmers and consumers, and can irreversibly degrade the environment. In low-income countries water pollution is often the result of inadequate wastewater collection and treatment, and unplanned release to receiving water bodies. Making wastewater irrigation safer depends on a location-specific combination of different pathogen barriers including, where possible, appropriate wastewater treatment. Ensuring that these strategies work in an integrated, mutually supportive manner requires a multi-sectoral paradigm shift in the common approach of wastewater management for disposal. Additionally, it is crucial to continue research (especially in developing countries) on the types and severity of risk, locally feasible mitigation options, the cost-effectiveness of safer wastewater irrigation practices compared to other interventions against diarrhoea and facilitating the adoption of ‘non-’ or ‘post-treatment’ options. This concluding chapter presents an outlook for wastewater irrigation by integrating the major findings of the present volume, synthesizing key elements of the current global status and challenges of sanitation and wastewater irrigation with emphasis on the WHO Guidelines. It also highlights wastewater-governance opportunities with the greatest potential to support safe wastewater irrigation that simultaneously address the combined challenges deriving from the global sanitation, water and food crises.

Wastewater use in agriculture is a complex phenomenon since it transcends typical sectoral and geographical policy and planning boundaries, and is influenced by opinions and perceptions. Planning for wastewater use typically requires the involvement of a number of government agencies covering health, water, sanitation, agriculture and irrigation, as well as researchers, community groups and the private sector. Where wastewater use is already taking place spontaneously and unofficially, how can these stakeholders come together to improve the management of the system to maximize the livelihoods benefits while minimizing impacts on health and the environment? One option is the formation of multi-stakeholder platforms, which provide a space for stakeholders to share opinions and seek negotiated solutions in an open and ‘level’ environment. How effective these are, what outcomes can be expected, and how they can be improved are all questions that are still being asked. This chapter presents three case studies in which multi-stakeholder processes were used to improve wastewater management for urban agriculture. Although differences were observed, there were several cross-cutting lessons. A critical factor is the starting point, including an agreed definition of the problem to be addressed, negotiated goals and a management structure that is acceptable to all stakeholders. When multi-stakeholder processes are externally initiated, as with those reviewed here, it is essential that project priorities are commensurate with local priorities. Finding an institutional home and anchor agency an improve long-term sustainability but care must be taken in considering how this impacts on existing power structures. Participation and representation greatly influence the effectiveness of the process and much may need to be done to support this, for example by strengthening local community groups. A factor that appears to significantly improve participation and engagement is having tangible outputs, which demonstrate to stakeholders the potential of multi-stakeholder platforms.

This chapter addresses the importance of understanding farmers’ knowledge and perceptions on health-risk and risk-reduction measures for the development of mutually acceptable risk-management strategies. Drawing on studies from different countries, the chapter shows that it is not realistic to expect high risk awareness. In cases where farmers are aware of health risks, they assess mitigation measures in view of their overall impact on work efficiency and crop yield rather than only the potential health benefits to be gained. The chapter asserts that for on-farm risk-reduction measures to be successful, it is pertinent that farmers’ needs and constraints are incorporated into the formulation of recommended practices. This might happen through indigenous processes but can be supported through farm-based participatory approaches where farmers and scientists work together in developing risk reduction measures. An important first step is the identification of mutually accepted problem indicators. Where health benefits for farmers and consumers are not sufficient reasons for the adoption of safer practices, other triggers have to be identified as well as appropriate communication channels for effective outreach.

This chapter discusses the implementation challenges of the WHO Guidelines on safe wastewater use pertaining to the adoption of the so-called ‘post-treatment’ or ‘non-treatment’ options, like safer irrigation practices or appropriate vegetablewashing in kitchens. Due to limited risk awareness and immediate benefits of wastewater irrigation, it is unlikely that a broad adoption of recommended practices will automatically follow revised policies or any educational campaign and training. Most of the recommended practices do not only require behaviourchange but might also increase operational costs. In such a situation, significant efforts are required to explore how conventional and/or social marketing can support the desired behaviour-change towards the adoption of safety practices. This will require new strategic partnerships and a new section in the WHO Guidelines. This chapter outlines the necessary steps and considerations for increasing the adoption probability, and suggests a framework which is based on a combination of social marketing, incentive systems, awareness creation/education and application of regulations. An important conclusion is that these steps require serious accompanying research of the target group, strongly involving social sciences, which should not be underestimated in related projects.

In developing countries urban wastewater management often fails to cope with increasing wastewater generation. Financial, technical and institutional limitations force authorities to discharge substantial amounts of untreated or partially treated wastewater into surface waters. Consequently, uncontrolled use of polluted water is increasingly common in the downstream peri-urban areas. Although wastewater use bears a significant risk on human health, such use is also productive and an asset for many. Agricultural use of wastewater is a strong manifestation of the urban-rural connection and transfers a waterborne risk from the wastewater disposal system to the food chain, requiring a paradigm shift in the approaches applied to risk minimization. Conventional models for urban wastewater treatment and management are based on top-down, mechanically driven approaches that do not, or do not sufficiently, consider the links between the social, economic and health aspects. This situation is understandable from historical and technological points of view, but does not provide innovative solutions to current problems in developing country cities. A different approach is required, one that rethinks conventional wastewater system design and management. By adopting a systems approach to analysing both the water and food chains, one discovers the interactions of different stakeholders that treat and use (or abuse) water, the impacts on overall productivity and the risks. Governance systems to manage wastewater use in agriculture must incorporate decentralization to accommodate thinking at the bottom layer, encourage stakeholder engagement and provide coordination and policy cohesion for managing risks jointly from both the water and food chains.

Interventions proposed and implemented for the mitigation of diarrhoeal diseases associated with wastewater reuse in agriculture have received little, if any, comparative assessment of their cost-effectiveness. This chapter assesses the costs, outcomes and cost-effectiveness of the so-called ‘treatment’ and ‘non- or post-treatment’ interventions as well as a combination of these for wastewater irrigation in urban Ghana using an approach that integrates quantitative microbial risk assessment (QMRA), disability-adjusted life years (DALYs) and cost-effectiveness analysis (CEA). The cost-effectiveness ratios (CERs) for the treatment and non-treatment interventions assessed ranged from US$31/DALY to US$812/DALY averted. Risk-reduction measures targeting farming practices and the basic rehabilitation of local wastewater treatment plants were the most attractive interventions with a CER well below the threshold of US$150/DALY, sometimes considered as the upper limit for a health intervention to be cost-effective in developing countries. All combinations associated with the basic rehabilitation of the treatment plants, with either on-farm or post-harvest interventions or both, resulted in CERs within the range of US$40/DALY to US$57/DALY. However, the CERs for the construction of a new wastewater treatment plant either as an independent intervention or in combination with on-farm and post-harvest interventions were unattractive in view of health-risk reduction for wastewater irrigation. Although attractive, the CERs of non-treatment options are largely dependent on compliance (adoption) by farmers and food vendors. In this regard, the CER increased by almost fivefold when the adoption rate was only 25 per cent by farmers and food vendors; but was attractive as long as adoption rates did not fall below 70 per cent. On the other hand, the success of the treatment option depends on the functionality of the treatment plants which is not without challenges in a country like Ghana. Thus, this chapter stresses the need for a balanced risk-management approach through a combination of treatment and non-treatment interventions to hedge against failures that may affect CERs at any end. While this chapter provides a contribution to the debate on interventions for health-risk mitigation in wastewater irrigation, more case studies would be useful to verify the data presented here.

Post-harvest interventions are an important component of a multiple-barrier approach for health-risk reduction of wastewater-irrigated crops as recommended by the 2006 edition of the WHO Guidelines for safe wastewater irrigation. This approach draws on principles of other risk-management approaches, in particular the hazard analysis and critical control point (HACCP) concept. Post-harvest measures are of particular importance as they can address possible on-farm precontamination, and also contamination that may occur after the crops leave the farm. Key factors influencing microbial contamination along the farm to fork pathway are basic hygiene and temperature management. Both factors are, however, hardly under control in most developing countries where microbial contamination and proliferation are supported by low education, limited risk awareness, rudimentary technical infrastructure and unenforced regulations. In the face of these challenges, the most successful strategies to enhance food safety will involve interventions at multiple control points along the production chain, with emphasis on local safety targets and innovative educational programmes fitting local knowledge, culture and risk perceptions. The WHO (2006) recommended health-based targets for risk reduction in wastewater irrigation provide the required flexibility for risk mitigation in line with the concept of food-safety objectives (FSO).

There is a significant imbalance between the number of publications describing potential and actual environmental and health impacts from chemically contaminated wastewater, and reports outlining concrete options to minimize the related risks where conventional wastewater treatment is not available. This gap applies more to inorganic and organic contaminants than excess salts or nutrients. This chapter outlines some of the options available that could be considered in and around the farm, looking at heavy metals, salts, excess nutrients and organic contaminants. The emphasis is placed on low-cost options applicable in developing countries. While such measures can reduce negative impacts to a certain extent, it remains crucial to ensure that hazardous chemicals are replaced in production processes; industrial wastewater is treated at source and/or separated from other wastewater streams used for irrigation purposes; and fertilizer application rates and related possible subsidies adjusted to avoid over- fertilization.

This chapter presents farm-based measures that have been developed and tested in the informal irrigation sector to reduce microbiological health risks for consumers from wastewater irrigation of vegetables commonly eaten uncooked. The measures target poor smallholder farmers or farmer associations in developing countries as part of a multiple-barrier approach for health-risk reduction along the farm to fork pathway. Measures discussed include treatment of irrigation water using ponds, filters and wetland systems; water application techniques; irrigation scheduling; and crop selection. In addition, the chapter highlights some practical strategies to implement these measures, based largely on field experiences in Ghana. Although most measures discussed do not fully eliminate possible health risks, they can significantly complement other pathogen barriers. Which measures fit, either alone or in combination, will depend on local site characteristics and practices. Further studies are required to develop new measures or adapt them to other irrigation practices and systems in developing countries.

Recently, the application of excreta-based fertilizers has attracted attention due to the strongly increasing prices of chemically produced fertilizers. Faecal sludge from on-site sanitation systems is rich in nutrients and organic matter, constituents which contribute to replenishing the humus layer and soil nutrient reservoir and to improving soil structure and water-holding capacity. Hence, it represents an important resource for enhancing soil productivity on a sustainable basis. However, there is little in the scientific literature about the performance of treatment technology allowing recovery of nutrient resources from human waste. This paper reviews the state of knowledge of different processes that have been applied worldwide. Their pathogen removal efficiency as well as nutrient and biosolids recovery performances are assessed. The chapter outlines the gaps in research for further development.

The volume and extent of urban wastewater generated by domestic, industrial and commercial water use has increased with population, urbanization, industrialization, improved living conditions and economic development. Most developing-country governments do not have sufficient resources to treat wastewater. Therefore, despite official restrictions and potential health implications, farmers in many developing countries use wastewater in diluted, untreated or partly treated forms with a large range of associated benefits. Aside from microbiological hazards, the practice can pose a variety of other potential risks: excessive and often imbalanced addition of nutrients to the soil; build-up of salts in the soils (depending on the source water, especially sodium salts); increased concentrations of metals and metalloids (particularly where industries are present) reaching phytotoxic levels over the long term; and accumulation of emerging contaminants, like residual pharmaceuticals. As these possible trade-offs of wastewater use vary significantly between sites and regions, it is necessary to carefully monitor wastewater quality, its sources and use for location-specific risk assessment and risk reduction.

In and around urban areas pollution of natural water bodies is on the rise. As a result, wastewater irrigation is an increasingly common reality around most cities in the developing world. For reasons of technical capacity or economics, effective treatment may not be available for years to come; therefore, international guidelines to safeguard farmers and consumers must be practical and offer feasible riskmanagement options. This chapter provides an introduction to microbiological hazards. These can be addressed best in a step-wise risk assessment and management approach starting with wastewater treatment where possible, and supported by different pathogen barriers from farm to fork. A major change in the most recent WHO Guidelines for the safe use of wastewater, excreta and greywater in agriculture and aquaculture (WHO, 2006) agriculture is the focus on a holistic approach to achieving health-based targets, instead of prescribing irrigation waterquality threshold levels that are often unattainable. The health-based targets should not be read as absolute values but as goals to be attained in the short, medium or long term depending on the country’s technical capacity and institutional or economic conditions. Local standards and actual implementation should progressively develop as the country moves up the sanitation ladder. While healthrisk assessments are recommended to identify entry points for risk reduction and health-based targets, the Guidelines also offer shortcuts in situations where research capacities and data are constrained.

After introducing terms and terminology of wastewater, sludge and excreta use, the chapter highlights their global drivers and significance using examples from different parts of the developing world. It is useful in the discussion to differentiate between unplanned use of wastewater resulting from poor sanitation, and planned use which tries to address matters such as economic or physical water scarcity. Both types of wastewater use can have significant socio-economic benefits but also institutional challenges and risks which require different management approaches and, ideally, different guidelines. This diversity makes the current WHO Guidelines, which try to be global in nature, complex to understand and apply. Whilst planned reuse will remain the norm in countries that can afford treatment, most countries in the developing world are likely to continue to use non- or only partially treated wastewater, for as long as sanitation and waste disposal are unable to keep pace with urban population growth. However, there are options to link urban faecal sludge and wastewater management with urban food demands or other forms of resource ecovery that provide opportunities to safely close the nutrient and water loops.

This unit provides an introduction to the key concepts and issues associated with managing water for ecosystems. ‘Aquatic ecosystems’ is a wide term that includes a range of inland, coastal and marine ecosystems but for the purpose of this module we will concentrate on inland and coastal aquatic ecosystems. Section 1 begins by outlining the natural resources provided by ecosystems and linkages with poverty by identifying the interdependencies and the importance of water. Section 2 details the ecology of aquatic ecosystems and their structure, processes and biodiversity. Section 3 takes a further step and describes the ecosystem services provided by these ecosystems. Section 4 looks at the over-exploitation of the services provided by aquatic ecosystems and how this can lead to ecosystem degradation. The final section concludes the unit by summarising scenarios and management response options. This unit includes an extended listing of recommendations for further reading with brief commentaries on each. These can extend study for the core topics of this unit but also cut across many of the topics covered in earlier units, given the linkages and interdependencies between water for nature and other human uses of water. Students should review the commentaries on these readings but only use this extended listing of reading as a resource to pursue specific interests as far as time allows. Concentration of study on the unit text and recommended Key Readings is sufficient for the examinations. Unit aims: To introduce the concept of natural resources with water being an important resource that supports both the livelihoods of the rural poor and aquatic ecosystems, whilst understanding their inter-linkages and interdependencies; To introduce key concepts of aquatic ecology by describing the variations and structure, the processes, species and genes, and inter-linkages; To introduce the concept of ‘ecosystem services’ in the context of aquatic ecosystems and to describe the role these play in maintaining the resource as well as supporting livelihoods of the rural poor; To provide an understanding of the key drivers of degradation and impacts on aquatic ecosystems and to describe available assessment tools and identify management approaches.

This unit provides an introduction to the key characteristics of fisheries and aquaculture and the distinctions between them. It looks at their significance in farming systems and the water requirements involved. It proceeds to discuss the methods and tools available to assess water requirements for fisheries and aquaculture. The final sections of the unit look at the trade-offs for water allocation for fisheries and aquaculture and introduce perspectives on water governance and associated implications for water policies related to fisheries and aquaculture. Unit aims: To define and explain the nature of fisheries and aquaculture and the differences between them in relation to water resource management; To highlight the importance of fisheries and aquaculture to livelihoods; To explain the basis for assessment of fisheries and aquaculture water requirements in terms of quantity and quality; To present existing methods for assessing water needs in fisheries and aquaculture; To present existing methods for assessing water needs in fisheries and aquaculture; To introduce water resource management options for fisheries and aquaculture and related governance and policy implications.

This unit provides an introduction to large-scale and formal irrigation systems. The first section introduces large-scale irrigation systems and looks at their role in poverty alleviation. The section analyses the positive and negative implications in the context of social, economic and environmental needs. Section 2 describes the types of irrigation systems based on governance and water sources and key implications of various irrigation system types. The following section deals with irrigation management by providing guidance on the management steps, design and assessment tools. It also looks at different options for irrigation financing such as water pricing. Section 4 explores investments in irrigation – types of investments, drivers for investments, priorities and social and environmental considerations. Unit aims: To introduce the linkages between investments in large-scale irrigation and poverty and to discuss possible positive and negative outcomes; To introduce standard irrigation system typologies based on governance and to understand the different types of water resources utilised; To introduce the steps and considerations involved in irrigation management, introduce basic assessment tools and discuss the main issues behind irrigation financing and water pricing; To provide an understanding of the different types of investment, when and where they are applied and how they are prioritised.

This unit provides an introduction to some of the key elements of the role and importance of water resources in smallholder agriculture. The first section introduces the basic concepts at the farm level by looking at farm productivity and the role of men and women which is essential in understanding the linkages between the livelihoods of the people and poverty alleviation. Section 2 explores water management concepts and issues in smallholder rainfed agriculture, including a range of practices that show promise in best supporting livelihoods and utilising available resources. Rainfed agriculture is critically important, as most rural poor depend solely on rain as their water source and there are many means to upgrade the performance of these systems. Some of these ways require a small amount of irrigation. Section 3 leads into small-scale irrigation. This section summarises and provides the differences between individual versus community based systems including management styles and key considerations in the design and management of these systems. In Section 4, the multiple uses of water, the use of water for household and industrial uses as well as farming, at the farm and household level are presented. Multiple uses of water provide an ideal way of obtaining more benefits per unit of water. Unit aims: To introduce and explain the linkages between small-scale water resource management in agriculture, food security, livelihoods and poverty; To identify the important roles of both men and women in small-scale farming and water management systems; To introduce key concepts of rainfed agriculture in the context of the ‘blue–green water’ continuum and identify the strengths of and constraints to different methods of rainwater water management; To introduce the concept of irrigation in small-scale agriculture and to look at the two main ways of managing it: individual compared to community based management; To introduce the concept of multiple uses for water by rural households and to describe some of the key uses in detail; To provide a basic understanding of multiple uses of water and the approaches available to manage them; To assess the importance of fisheries and livestock production as competitors for water with irrigated crop production.

This unit provides an introduction to the key concepts, challenges, perspectives and issues associated with the governance of water resources. Section 1 presents an introduction to the specific challenges of managing water and the issues that frame institutional and policy responses to water resource governance. Section 2 introduces local and community scale water governance systems as a way to improve the access, efficiency and distribution of water through the active participation of water users. It uses the case of Irrigation Management Transfer (IMT) to highlight important issues in local water governance. Section 3 evaluates the limitations of local governance and introduces alternative and complementary mechanisms designed to address those limitations by operating at ‘higher’ scales. It examines how the simultaneous use of governance mechanisms across scales can take advantage of each mechanism’s positive attributes while overcoming its limitations. Section 4 examines how factors beyond the water sector including trade policy, increasing appreciation for the environment and urbanisation impact water governance. The section thus highlights how successful water governance requires a broad understanding of not only water but the larger political economy in which water is used.

This unit is concerned with key concepts of assessment and management at scales from the water user to the river basin. The first section outlines the various scales of assessment of water resources and discusses the relationship between the various scales. Section 2 focuses in on the river basin scale and presents a number of key tools for understanding and assessing water resources at this scale. This section describes development trajectories of river basins and provides an overview of key issues which affect river basins. Section 3 introduces the new and prevalent water management paradigm of river basin management. Challenges and a general critique are provided in this section and a typology of river basin management models is presented. Section 4 focuses on Integrated Water Resources Management (IWRM); reviewing the evolution of the concept of integrated approaches, providing a description of IWRM and a definition, and evaluating critically the concept as an operational approach.

This module is about water resources management. It is therefore necessary to understand what water resources are. This unit provides a general introduction to the terms and concepts that help us to understand water resources and their various forms and movements through our systems. What is the hydrological cycle and what does this mean for availability, use and management of water? This section provides an introduction to all aspects of input, storage, changes in state, use and output of water through our land, water and atmosphere systems, with special attention paid to the inclusion of groundwater as a water resource. This important background information on water resources is vital for being able to address the management aspect of the moduleapos;s title.

This paper attempts to identify and evolve a method for valuing and estimating the net gains from domestic and industrial water supply from the interbasin transfer schemes contemplated in the National River Link Project (NRLP). An existing interbasin transfer (IBT) scheme, namely Indira Gandhi Nahar Project (IGNP) and a proposed IBT scheme namely Polavaram- Vijaywada (PV) Link Canal were chosen for detailed analyses. Secondary data were used for identifying the region and the populations that benefited from the schemes. Economic gains arising out of water supply to the actual or potentially benefited areas were estimated. The estimation involved assessment of current costs incurred by the people in the area, in terms of both paid-out costs and time spent in fetching water. The saving in time was valued at market wage rates prevalent in the area and paid-out costs were assessed in terms of current market prices, ignoring the administered prices involved. The gains to urban populations were assessed by estimating the reduction in energy costs incurred by municipal authorities in undertaking the supply. Amortized capital costs for putting necessary hardware for distributing water from the IBT schemes as well as operation and maintenance (Oamp;M) costs of running these schemes were netted from the gains to obtain the figures for net economic gains. More indirect benefits such as reduced drudgery or improved educational performance as well as reduced health expenditure were recognized but were all ignored to ensure greater robustness in the estimates. Only net gains to the society were considered and hence gains arising out of creation of industrial estates within the commands were ignored since similar gains could also be obtained by locating these estates elsewhere. The net economic gains are seen to depend on both demographic features of the region and its ecology. Desert-like conditions of the IGNP-benefited areas tend to make the gains from domestic water supply schemes large, while similar gains in the Polavaram-Vijaywada areas are smaller. The net economic gains are of a significant order and would seem to indicate that, at least insofar as the dry areas of the country are concerned, these can perhaps exceed the gains due to increased agricultural production and hence could perhaps justify the creation of the schemes by themselves.

Groundwater exploitation in hard-rock India is leading to high distress amongst farmers. Various water conservation schemes have been tried and piloted, but no idea has scaled up to the national level. An idea of revitalizing groundwater use, individual as it is, and if still individual-based, could possibly succeed. Recharging through dug wells is one such thought. After mass movements in Saurashtra in the mid-1990s, no effort has been made to promote the idea nationally, till now. The current national program on artificial recharge of dug wells hopes to do so. But this idea can succeed only if farmers see any value in it and try to make it successful. A survey of 767 farmers owning dug wells in 10 districts of India shows that there is immense potential in, yet constraints to, dug-well recharge. A comparison of dug-well recharge with the average annual natural recharge over hard-rock areas of 116 mm shows that there is almost an equal potential in recharging groundwater irrigated areas through dug wells. Surveyed farmers also expect a great increase in water availability, especially during the dry seasons. However, farmers are wary of this recharged water flowing across to their neighbors. They expect to gain around 30% from their recharged water, but agree that there would be a common gain by recharging groundwater together with their neighbors. The farmers’ estimated cost of Rs 10,000 for the recharge structures is not such a big constraint, nor is siltation, for which they suggest numerous innovative solutions. Managing dug-well recharge locally is critical. Should it become mandatory for farmers to apply in groups of 10, as our sampled farmers suggest? Should the national program be structured such that farmers are transferred the subsidy and they can construct the structures in April or May as they unanimously prefer to do? Instead, should the policy be to promote local businesses around recharge, so as to harness the experience of well drillers, who also operate during the same summer months? More such tuning is needed over implementation of the dug-well recharge program to create demand from farmers, catalyze enterprises locally around recharge and establish monitoring programs to measure the benefits from the first upcoming season in 2009 over lakhs of recharge structures.

For millennia, India has been using surface storages and gravity flow to irrigate its crops. During the last 40 years, however, India has witnessed a decline in gravity flow irrigation and the rise of a booming “water-scavenging” irrigation economy through millions of small, private tube wells. For India, groundwater has become at once critical and threatened. Climatic change will act as a force-multiplier; it will enhance the criticality of groundwater for drought-proofing agriculture and simultaneously multiply the threat to the resource. Groundwater pumping with electricity and diesel also accounts for an estimated 16-25 million tonnes of carbon emission, 4-6% of the country’s total emission. From the point of view of climatic change, India’s groundwater hot spots are western and Peninsular India. These are critical for mitigation of, and adaptation to, climatic change. To achieve both, India needs to make a transition from surface storages to “managed aquifer storage” as the comerstone of its water strategy with proactive demand and supply-side management components. In doing this, India needs to learn intelligently from the experience of countries like Australia and the USA that have long experience in managed aquifer recharge.

Few large irrigation projects in India have been as elaborately planned as the Sardar- Sarovar Project (SSP), incorporating as it did the lessons of decades of irrigation project design and management. The project was to blaze a new trail in farmer-participatory irrigation project design and management with water user associations (WUAs) building their own distribution systems. However, as it unfolds, the institutional reality of the project is seen to be vastly different from its plans. If SSP is to chart a different course from scores of earlier large irrigationprojects, it must invent and put into place new rules of the irrigation management game.

Water, a critical component of food, livelihood and economic security, has always received a central place in India’s investment portfolios. The investment in water transfers of the National River Linking Project (NRLP) is one of the biggest proposed in recent times. When and if completed, the NRLP forms a gigantic water grid covering most of South Asia. It envisages transferring 174 billion cubic meters (Bm3) of water across 34 river links and will cost about US$120 billion (2000 prices). The proposed plan has aroused a large interest in recent public discourses. Hydrological feasibility, financial viability and social cost are the issues that dominate these public dalogues. This paper analyzes the cost and benefits of eight river links in the peninsular component, which include the main subcomponent of linking rivers of Mahanadi, Godavari, Pennar and Cauvery. Irrigation is the main beneficiary in this component and, en route, these links or canals account for 85% of the total water transfers to irrigation and domestic and industrial sectors in the command areas. However, our analyses show mixed results of financial viability of individual links. The main reason for this is low net value-added benefits from additional irrigation over and above the existing level of cropping and irrigation patterns. The proposed cropping patterns of these links generate much less net value-added benefits than the existing cropping and irrigation patterns. To make these links financially viable, they need to include high-value cropping patterns that, at least, generate as much benefit per unit area as fruits and vegetables. Although some individual links show less than desirable net benefits, taken together the Mahanadi-Godavari-Pennar-Cauvery subcomponent gives a higher internal rate of return of 14% compared to a discount rate of 12%, and a high benefit-cost ratio of 1.3. However, many unknown factors or unavailable information in this analysis can alter the estimates of financial benefits and costs.

Before indigenous practices and institutions can be evaluated, they first have to be identified, described and characterized. This tool describes the methods used to answer a specific question: “Which indigenous practices, legal frameworks and institutions are most conducive to equitable, win-win, and pro-poor investments within sub-Saharan African transboundary basins”? It describes case studies on transboundary issues and local water governance institutions from the Volta amp; Limpopo Basins.

Using mutually agreed indicators facilitates communication among the key stakeholders and is helpful when planning new small reservoirs. Indicator definitions chosen from the literature should be tailored to local conditions to take into account of the field experience of local experts. Planners should pay special attention to the development and use of impact indicators, including those defined together with the community as being most efficient in measuring change. This tool based on a case study conducted in Morocco demonstrates how this may be done.

Some rural populations are dependent on small reservoirs for their water supply and are concerned about the quality of this water for direct consumption and other uses. Chemical and biological water quality measurements can be made to ascertain the suitability of water for different uses. Water “suitability” of course, depends on the use for which it is intended. This tool describes selected methods for assessing the suitability of reservoir water quality.

One of the health risks of small reservoirs is the potential for increased transmission of water-related diseases, in particular, parasitic infections dependent on water-based “vectors”. The design, use, and management of reservoirs all influence their suitability as breeding grounds for disease vectors. This tool describes the use of selected methods to help stakeholders understand the ecological preferences of vector organisms in relation to small reservoirs. This is an important step in identifying management options for environmental disease control.

This tool uses standard biomedical methodologies to determine infection rates for key water-related (or “reservoir-related”) diseases including schistosomiasis and other intestinal parasites, and malaria. In any particular locale there may be a completely different set of priorities with regard to reservoir-related health issues. Therefore, it is always wise to check with local health personnel about priorities, and to sample local communities’ perceptions with respect to reservoir-related problems. For diseases and infections not described in this tool, local health professionals, literature, and the internet provide good starting points.

This tool describes the use of school surveys, an important tool that supports both participatory and biomedical research. When epidemiological studies are carried out at the same time, a local quantitative relationship between measured and reported infection rates can be established and the questionnaire can be applied in a larger area to assess prevalence at the level of the reservoir cluster or river basin. Such questionnaires can be adapted for other diseases and to fit varying local circumstances.

This tool contains guidelines intended to reduce the health risks and increase the health benefits from small reservoirs. Guidelines are structured in a step-wise manner, beginning with the identification of relevant health issues and concluding with small reservoir design and operation for improved human health. The guidelines focus on: major water-related diseases associated with small reservoirs in Africa, the added value of community participation in health impact assessment, opportunities to mitigate risks and improve human health through better planning and operation of small reservoirs, and improved planning, design, and management options.

Methods for estimating runoff that have been developed for temperate climates may not be suitable for use in the monsoonal climates of Africa, where there is a distinct dry season in which soils dry out to a considerable depth. Water balance models have been shown to better predict river discharge in regions with monsoonal climates than alternative methods based on rainfall intensity, or on the USDA-SCS curve number. This tool can be used to develop a simple water balance model for predicting river discharge.

The outcome mapping tool presents an approach to assist planners to monitor the implementation, adoption, and changes in attitude and behaviour of the stakeholders. Outcome Mapping is a participatory planning, monitoring and evaluation methodology which focuses on the contribution of a program to changes in the actions and behaviours of the ‘boundary partners’. Applied to knowledge and learning strategies, Outcome Mapping facilitates communication and has a number of potential other benefits.

This tool will assist those planning research on or interventions for small reservoirs systems to use Impact Pathways Analysis to develop a plan to better bring about desired outputs, outcomes and impacts. By helping make explicit the links between project activities or program interventions on the one hand, and partner roles and inter- relationships on the other. The likelihood of achieving greater better impacts may be improved. How the Impact Pathway Analysis was found useful in the Small Reservoirs Project is presented.

In transboundary river basins, like the Blue Nile, conflicts over the use of water resources are growing and recent advances in sustainable resource management recognizes the need for approaches that coordinate activities of people dependent on a common resource-base to realize sustainability and equity. Payments for Environmental Services (PES) are a component of a new and more direct conservation paradigm and an emerging concept to finance conservation programs by fostering dialogue between upstream and downstream land users. Those kinds of approach are particularly useful if applied in basins where irrigation schemes are emerging and the service life of reservoir and irrigation canals, in downstream areas are threatened by the sediments moved from upstream region. Here we report the results of our study on the determinants of Willingness to Pay (WTP) and Willingness to Compensate (WTC) for improved land and water management practices in the Blue Nile Basin (Gumera and Koga watersheds). A total of 325 sample households were selected using a multi-stage sampling technique, and a structured and pre-tested questionnaire was used to collect data from the sample households. We applied Contingent Valuation Method (CVM) to elicit WTP using monetary and material payment vehicles. Our results showed that more households are willing to pay in labor than in cash. The mean WTP for improved land and water management was estimated at US$1.06 and US$1.3 months-1 household-1 for upstream and downstream farmers, respectively. Besides, 83.56% of the sample farm households showed WTC the upstream farmers in cash. However, the aggregate WTP falls far short of the estimated investment cost needed for ecosystem restoration. Among others, the number of livestock, size of arable land, access to education and credit by the sample farm households were identified to positively influence sample farmers’ WTP for restoration of ecosystem services and downstream farmers’ WTC for improved ecosystem regulation services. Therefore, institutions and policy measures that enhance environmental education, reduce poverty and foster stakeholders’ cooperation must be promoted. Prospect of Payments for Environmental Services in the Blue Nile Basin: Examples from Koga and Gumera Watersheds.

Transboundary water resource governance is premised on equitable water and water-related benefit sharing. Using the case of the Blue Nile (Ethiopia and Sudan), we explore the conceptual issues that need consideration in the crafting of cross-border cooperation within the water sector. First, drawing on global experiences with transboundary water management, we evaluate how upstream and downstream concerns are addressed by transboundary water management institutions. Second, we explore the kinds of institutional design and the issues which need to be considered to result in ‘win-win’ scenarios for both upstream and downstream users, as well as the mechanisms of benefit sharing negotiated amongst different stakeholders. Third, we examine ways of addressing equity and livelihoods in transboundary institutional arrangements. Finally, we attempt to assess how transboundary institutions can address broader historical, political and economic issues and their implications for sustainable transboundary water governance. This paper raises key issues that need to be addressed in establishing transboundary governance institutions.

Land and water institutions play a vital role in managing and sustaining land and water resources as well as enhancing economic development and poverty alleviation efforts. While a lot has been done in terms of understanding the micro-determinants of farmers’ decisions in land and water conservation, there is little attempt to understand the broad macro-institutional and organizational issues that influence land and water management decisions. The objective of the study was to assess institutional arrangements and challenges for improved land and water management in the Ethiopian part of the Blue Nile Basin (Tana and Beles subbasins). Focus group discussions and key informant interviews were held in Amhara and Benishangul Gumuz regions with important stakeholders such as the bureaus of Agriculture and Rural Development, Water Resources Development, Environmental Protection and Land Use Administration (EPLUA), National Agricultural Research Systems, and important NGOs, operating in the area of land and water management, and selected community members. As the major findings in this study, we outlined major land and water-related institutional arrangements that are currently in place and their design features, in order to identify those institutions related to superior performance. We highlighted major institutional and policy gaps and actions that are required to respond to emerging issues of environmental degradation, upstream/downstream linkages and climate change. Such analysis of institutions and their design features provides useful insights and contributes to the debate on institutional reform for improved land and water management in the Blue Nile Basin, in general. By doing so, it identifies the gaps in institutional arrangements and policies and potential remedies.

Gully formation and upland erosion were studied in the Debre-Mewi Watershed in the Gilgil Abay Basin south of Lake Tana. Gully erosion rates were found to be equivalent to over 500 tonnes/ha/year for the 2008 rainy season when averaged over the contributing watershed. Upland erosion rates were twentyfold less. Gully formation is accelerated when the soils are saturated with water as indicated by water table readings above bottom of the gully. Similarly, upland erosion was accelerated when the fields were close to saturation during the occurrence of a rainfall event. Height of the water table is an important parameter determining the amount of erosion and should, therefore, be included in simulation models.

The Soil Water Assessment Tool (SWAT) is a watershed model widely used to predict water quantity and quality under varying land use and water use regimes. To determine the respective amounts of infiltration and surface runoff, SWAT uses the popular Curve Number (CN). While being appropriate for engineering design in temperate climates, the CN is less than ideal when used in monsoonal regions where rainfall is concentrated into distinct time periods. The CN methodology is based on the assumption that Hortonian flow is the driving force behind surface runoff production, a questionable assumption in many regions. In monsoonal climates water balance models generally capture the runoff generation processes and thus the flux water or transport of chemicals and sediments better than CN-based models. In order to use SWAT in monsoonal climates, the CN routine to predict runoff was replaced with a simple water balance routine in the code base. To compare this new water balance-based SWAT (SWAT-WB) to the original CN-based SWAT (SWAT-CN), several watersheds in the headwaters of the Abay Blue Nile in Ethiopia were modeled at a daily time step. While long term, daily data is largely nonexistent for portions of the Abay Blue Nile, data was available for one 1,270 km2 subbasin of the Lake Tana watershed, northeast of Bahir Dar, Ethiopia, which was used to initialize both versions of SWAT. Prior to any calibration of the model, daily Nash-Sutcliffe model efficiencies improved from -0.05 to 0.39 for SWAT-CN and SWAT-WB, respectively. Following calibration of SWAT-WB, daily model efficiency improved to 0.73, indicating that SWAT can accurately model saturation-excess processes without using the Curve Number technique.

Methods for estimating runoff that have been developed for temperate climates may not be suitable for use in the monsoonal climates of Africa, where there is a distinct dry season during which soils dry out to a considerable depth. This has a distinct effect on runoff generation that is not captured by “the temperate climate” models. The scope of this tool is to develop a simple water balance method for predicting river discharge. Water balance models have been shown to better predict river discharge in regions with monsoonal climates than alternative methods based on the United States Department of Agriculture-Soil Conservation Service (USDA-SCS) curve number. The latter is an empirical-based model developed in the USA that does not apply to monsoonal climates with distinct dry and wet periods.

Rapid land use change due to intensive agricultural practices in the Ethiopian Highlands, results in increasing rates of soil erosion. This manifested in significant impacts downstream by reducing the storage capacity of reservoirs (e.g., Roseires, Sennar), and high desilting costs of irrigation canals. Therefore, this paper aims to provide a better understanding of the process at basin scale. The Soil and Water Assessment Tool (SWAT) was used to model soil erosion in the upper catchments of the Blue Nile over the Ethiopian Plateau. The SWAT output forms the input sediment load for SOBEK, a river morphology model. The two models integrated using the principles of the Open Model Interface (OpenMI) at the Ethiopia-Sudan border. The Nash-Sutcliffe coefficient was found to be 0.72 and 0.66 for results of SWAT daily sediment calibration and validation, respectively. The SOBEK results also show a good fit of the simulated river flows at Roseires and Sennar reservoirs, both for calibration and validation. The results of the integrated modeling system showed 86 million tonnes/year of sediment load from the Upper Blue Nile, while SOBEK computes on average 19 Mm3/year of sediment deposition in the Roseires Reservoir. The spatial variability of soil erosion computed with SWAT showed more erosion over the northeastern part of the Upper Blue Nile, followed by the northern part. The overall exercise indicates that the integrated modeling is a promising approach to understand soil erosion, sediment transport, and sediment deposition in the Blue Nile Basin. This will improve the understanding of the upstream-downstream interdependencies, for better land and water management at basin scale.

The Blue Nile (Abbay) Basin lies in the western part of Ethiopia between 70 45apos;-120 45apos; N and 340 05apos;-390 45apos; E. The Blue Nile region is the main contributor to flood flows of the Nile, with a mean annual discharge of 48.5 km3. Soil erosion is a major problem in Ethiopia. Deforestation, overgrazing, and poor land management accelerated the rate of erosion. The SWAT was successfully calibrated and validated for measured streamflow at Bahir Dar near Kessie and at the border of Sudan for flow gauging stations, and for measured sediment yield at Gilgel Abbay, Addis Zemen and near Kessie gauging stations in the Blue Nile Basin. The model performance evaluation statistics (Nash–Sutcliffe model efficiency (ENS) and coefficient of determination (r²)) are in the acceptable range (r2 in the range 0.71 to 0.91 and ENS in the range 0.65 to 0.90). It was found that the Guder, N. Gojam and Jemma subbasins are the severely eroded areas with 34% of sediment yield of the Blue Nile coming from these subbasins. Similarly, the Dinder, Beshilo and Rahad sub basins only cover 7% of sediment yield of the basin. The annual average sediment yield is 4.26 t/ha/yr and the total is 91.3 million tons for the whole Blue Nile Basin in Ethiopia.

Land degradation is a serious threat in the Gumera watershed which is reflected in the form of soil erosion. Erosion is a major watershed problem causing significant loss of soil fertility and productivity. Increased sediment loads that shorten the useful life of the reservoir, the lives of other water-related structures, and increase the cost of maintenance and sediment remediation are off-site impacts of erosion. To develop effective erosion control plans and to achieve reductions in sedimentation, it is important to quantify the sediment yield and identify areas that are vulnerable to erosion. In recent decades, several simulation models have been developed in order to estimate, quantify, enhance understanding of spatial and temporal variability of erosion, and identify areas which are high contributors of sediment at micro-watershed level and over large areas. We used SWAT (Soil and Water Assessment Tool) to predict sediment yield, runoff, identify spatial distribution of sediment, and to test the potential of watershed management interventions in reducing sediment load from ‘hot spot’ areas. The tool was calibrated and validated against measured flow and sediment data. Both, calibration and validation results, showed a good match between measured and simulated flow and suspended sediment. The model prediction results indicated that about 72% of the Gumera watershed is erosion potential area with an average annual sediment load ranging from 11 to /ha/yr 22 tons exceeding tolerable soil loss rates in the study area. The model was applied to evaluate the potential of filter strips with various widths to reduce sediment production from critical micro-watersheds. The investigation revealed that implementing vegetation filter strips can reduce sediment yield by 58 to 74%.

The riparian countries of the Nile have agreed to collaborate in the development of its water resources for sustainable socioeconomic growth. Currently there is significant potential for expansion of hydropower and irrigation in the Blue Nile River in both Ethiopia and Sudan. However, the likely consequences of upstream development on downstream flows have not been fully assessed and the water resource implications of development in both countries are unclear. Against this background, the Water Evaluation And Planning (WEAP) model was used to provide an assessment of both the current situation and a future (2015) scenario. The future scenario incorporated new irrigation and hydropower schemes on the main stem of the Nile and its principal tributaries. Data for all existing and planned schemes were obtained from the basin master plans as well as from scheme feasibility studies. Water use was simulated over a 32-year period of varying rainfall and flow. Preliminary results indicate that currently irrigation demand in Sudan is approximately 8.5 Bm3y-1 for 1.16 million hectares (mha). This compares to a total irrigation demand in Ethiopia of just 0.2 Bm3y-1. By 2015, with many existing schemes being extended in Sudan and new schemes being developed in both countries, irrigation demand is estimated to increase to 13.4 Bm3y-1 for 2.13 mha in Sudan and 1.1 Bm3y-1 for 210 thousand hectares (tha) in Ethiopia. The flow of the Blue Nile is estimated to decline from an average of 46.9 Bm3y-1 to 44.8 Bm3y-1 at the Ethiopia-Sudan border and from a current average of 43.2 Bm3y-1 to 36.2 Bm3y-1 at Khartoum (including evaporation from all reservoirs). Although total flows are reduced, greater regulation results in higher dry season flows at both locations.

The purpose of this study is to simulate water allocation for major activities (existing and planned) in the Abbay Basin using up-to-date water allocation and simulation models. The model, MIKE BASIN, is used to gain an insight into the potential downstream consequences of the development of physical infrastructure and water abstraction in a number of different future development scenarios. Seventeen irrigation projects covering an area of 220,416 hectares (ha) of land have been selected from different gauged catchments of the sub-basin in addition to 4,800 megawatt (MW) hydropower projects on the main stream of the study area (Ethiopian part of Blue Nile). From the analysis, the total water extracted for these irrigation projects was estimated to be 1.624 billion cubic meters (BCM) annually. A reduction in the border flow volume as a result of the implementation of these irrigation projects under the reservoir scenario is 3.04% of the estimated mean annual flow of 50.45 BCM. Similarly, from the analysis, the total power generated due to the development of the major hydropower projects on the main stream, having an installed capacity of 4,800 MW, is 18,432 gigawatt hours (GWh) per year. This implies, while these interventions provide significant opportunities with respect to interventions and energy generations, their impact on downstream water availability is minimal.

Lake Tana is a natural reservoir for the Blue Nile River which has huge potential for hydropower and irrigation development. Water resource development is being encouraged by the government to stimulate economic growth and reduce poverty. In this study, the Water Evaluation And Planning (WEAP) model was used to simulate planned hydropower and irrigation development scenarios. Simulation of water demand and estimated downstream environmental flows was conducted for a 36-year period of varying flow and rainfall. Based on the simulation results, water availability for the different proposed irrigation and hydropower schemes was determined. The likely impact of future water resource development on water levels of the lake was assessed based on the simulation results of three development scenarios. The simulation results revealed that, if the full future development occurs, on average, 2,207 GWhy-1 of power could be generated and 548 Mm3y-1 of water could be supplied to irrigation schemes. However, the mean annual water level of the lake would be lowered by 0.33 meters (m) with a consequent decrease of 23 km2 in the average surface area of the lake. Besides having adverse ecological impacts, this would also have significant implications for shipping and the livelihoods of many local people.

With its total area of about 200,000 square kilometers (km2), which is 20% of the country’s land mass, and accommodating 25% of the population, the Upper Blue Nile Basin (Abbay) is one of the most important river basins in Ethiopia. About 40% of agricultural products and 45% of the surface water of the country are contributed by this basin. However, the characteristic-intensive biophysical variation, rapid population growth, land degradation, climatic fluctuation and resultant low agricultural productivity and poverty are posing daunting challenges to sustainability of agricultural production systems in the basin. This calls for technological interventions that not only enhance productivity and livelihoods in the basin, but also bring about positive spillover effects on downstream water users. In this study, the farming systems in the basin have been stratified and characterized; and promising agricultural water management technologies, which may upgrade the productivity of smallholder rainfed agriculture while improving downstream water quality, have been identified. As a consequence, supplementary and full irrigation using rainwater and drainage of waterlogged soils are recognized as being among the promising agricultural water management technologies that can be easily scaled-up in the basin. The magnitude of the impacts of these technologies on the productivity of the upstream farming systems and the concomitant effects on the downstream water flow and quality are under investigation, assuming an assortment of scenarios.

Climate is changing world wide, and the science community in Sri Lanka have come up with ample evidence to suggest that the country’s climate has already changed. During 1961- 1990 it’s mean air temperature has increased by 0.016 0C per year (higher than the global average of 0.013 0C), and mean annual rainfall- decreased by 144 mm (7%) compared to the period 1931-1960. In addition, mean annual daytime maximum and mean annual night-time minimum air temperatures increased. However, the bigger question of national importance is what Sri Lanka’s climate will look like in 50 or 100 years and how prepared is the country to face it. Apart from the IPCC projections at the coarse global scale, few studies attempted to project future climate scenarios for Sri Lanka and to identify climate change impacts on agriculture, water resources, the sea level, the plantation sector, the economy and health. Vulnerability and adaptation to climate change are the least studied areas. The paper reviews the status of climate change research/activities in Sri Lanka with respect to future climate predictions, impacts, mitigation and adaptation, and identifies existing knowledge gaps. Messages emerging from this review suggest that Sri Lanka’s mean temperature during the North-East (December-February) and South-West (May-September) monsoon seasons will increase by about 2.9 0C and 2.5 0C respectively, over the baseline (1961-1990), by the year 2100 with accompanying changes in the quantity and spatial distribution of rainfall. Extreme climate events are expected to increase in frequency. These changes will bring about widespread impacts on the country’s agriculture and economy. For example, a 0.5 0C increase in temperature can reduce rice yield by approximately 5.9%; extended dry spells and excessive cloudiness during the wet season can reduce coconut yield so that annual losses can range between $32 and $73 million. Pilot studies in the Galle District suggest that sea level rise could inundate about 20% of the land area of coastal district secretariat divisions. Adaptation measures already undertaken in the agricultural sector include development of low water consuming rice varieties and use of micro-irrigation technologies. Tools have been developed for predicting seasonal water availability within the Mahaweli Scheme and for predicting annual national coconut production. However, Sri Lanka is yet to undertake a comprehensive national study on the vulnerability of its water resources and agriculture to climate change. Formulation of detailed and reliable future climate scenarios for the country is and urgent need in this regard.

To evaluate the impact of a small-scale irrigation scheme on the level of malaria transmission in a semi-arid area, entomological studies were conducted in Zeway area, Central Ethiopia. Larval and adult anophelines were sampled during the dry and short-rainy seasons from irrigated and non-irrigated villages. Overall, significantly higher density of Anopheles larvae were found during the dry season in the irrigated village (Mean = 38.3 larvae/100 dips) than the non-irrigated village (7.4 larvae/100 dips). Canal leakage pools, irrigated fields and irrigation canals were the major sources of Anopheles mosquitoes. Larval and adult Anopheles pharoensis and An. arabiensis, principal malaria vectors in Ethiopia, were more abundant in the irrigated village than the non-irrigated village throughout the study period. Hourly light trap catches revealed that peak indoor and outdoor biting activities of An. arabiensis and An. pharoensis occurred during the early period of the night before the local inhabitants retire to bed. The majority of blood-engorged An. arabiensis (0.78) and An. pharoensis (0.69) had fed on humans, suggesting that their highly anthropophilic nature in Zeway area. Plasmodium falciparum infection rates of 1.02% and 0.54% were determined for An. arabiensis and An. pharoensis, respectively, in the irrigated village. This study demonstrated that due to poorly maintained irrigation structures, the irrigation scheme created conducive breeding grounds for malaria vector species, particularly during the dry season. Consequently, the period of malaria transmission might possibly extend from seasonal to year-round, involving the dry season. Proper water management coupled with environmental management such as source reduction could reduce vector abundance and hence malaria transmission in the irrigation schemes.

Irrigated production is far from satisfactory in the country. The countryapos;s irrigation potential is estimated at 3.7 million hectare, of which only about 190,000 hectare (4.3 percent of the potential) is actually irrigated. The aim of this paper is to identify the impact of small-scale irrigation on household food security based on data obtained from 200 farmers in Ada Liben district of Ethiopia. Different studies revealed that access to reliable irrigation water can enable farmers to adopt new technologies and intensify cultivation, leading to increased productivity, overall higher production, and greater returns from farming. In the study area also about 70 percent of the irrigation users are food secure while only 20 percent of the non-users are found to be food secure. Access to irrigation enabled the sample households to grow crops more than once a year; to insure increased and stable production, income and consumption; and improve their food security status. The study concludes that small-scale irrigation is one of the viable solutions to secure household food needs in the study area but it did not eliminate the food insecurity problem.

Irrigation development is seen as one of the means to reduce poverty and promote economic growth. While a lot of effort is exerted towards irrigation development, little attempt is done to quantify the contribution of irrigation to national income in Ethiopia. This study is an attempt to quantify the actual and expected contribution of irrigation to the Ethiopian national economy for 2005/06 cropping season and 2009/10 using adjusted net gross margin analysis. Our results show that irrigation in the study sites generates an average income of about USD 323/ ha. This compares to the calculated gross margin for rainfed which is USD 147/ha. This indicates that after accounting for annual investment replacement cost net gross margin from irrigation is more than twice higher than gross margin from rainfed agriculture. On the contribution of irrigation to national economy, in 2005/06 smallholder irrigated agriculture contributed about 262.3 million USD. This accounts for about 4.46 percent of the agricultural GDP in 2005/2006 and 1.97 percent of the total overall GDP. The total income earned from large scale schemes is estimated to be about 74.0 million USD. This accounts for about 1.26 percent of the agricultural and 0.5 percent of the total GDP respectively. Overall, the contribution of irrigation to agricultural and total national GDP was about 5.7 and 2.5 percent during the 2005/06 cropping season. As a result of expansion, by the year 2009/2010 the expected contribution of smallholder managed irrigation to national economy, assuming that exiting cropping pattern, and the average gross margin values for different crop categories are still valid, is expected to increase from USD 262.3 million in 2005/2006 to about USD 414.2 million in 2009/2010, which accounts to about 5.5 percent of the agricultural GDP and 2.3 of the overall GDP for the same year. On the other hand, the contribution coming from the large scale sugar growing estates in 2009/2010 is estimated to be USD 217.5 million which amounts to 2.9 and 1.2 percent of the agricultural and overall GDP respectively. Similarly the contribution coming from large scale commercial farms growing crops other than sugar cane is expected to increase to USD 35.8 million in 2009/2010 which accounts to 0.4 and 0.2 percent of the agricultural and overall GDP respectively. This implies that large scale commercial farms will contribute about 3.3 and 1.4 of the agricultural and overall GDP respectively. In summary, our results indicate that under conservative estimates the future contribution of irrigation to agricultural and overall GDP will be about 9 and 3.7 percent respectively. When some of the assumptions related to cropping pattern, input and output prices, 128 and efficiency levels are relaxed, the contribution of smallholder managed irrigation to agricultural and overall GDP will vary between 4 to 6 and 1.8 to 1.9 percent respectively. Similarly, the contribution from large scale irrigation to agricultur

This article presents the finding of a study undertaken to assess the status-quo and significant environmental impacts of two selected large-scale irrigation on natural resources in Ethiopia. Main focus is on the environmental impacts of irrigation on natural resources with special emphasis on soil quality, water quality and downstream impacts, hydrology and potential interference with ecosystems. For this purpose two schemes were selected. Wonji/Shoa Sugar Plantation is located in the Upper Awash Basin and Finchaa Valley Sugar Estate located in the Blue Nile Basin. It is well known that irrigation projects can have several adverse environmental impacts that may threaten the sustainable production of agricultural goods, which is of major importance and interest in Ethiopia since it contributes 44 percent to Ethiopia’s GDP, employs 80 percent of the labor force, and provides a livelihood to 85 percent of the nearly 80 million population (Awulachew, 2006, Government of Ethiopia, 2006, UNDP, 2006). Irrigation projects inter alia can have potential impacts on the hydrological characteristics of aquifers, quality of downstream water bodies, quality of soils and ecosystems. The most prominent results and environmental impacts of the selected case study sites could be summarized as follows. In general the irrigation water is of good quality, but the electric conductivity is unfavorable to the adjusted sodium ratio, which leads in some instances to soil crusting and has a negative impact on infiltration rate. In Wonji/Shoa the groundwater table has risen due to improper irrigation management and seepage of reservoirs. In Fincha a valuable ecosystem has been destroyed due to the establishment of the scheme and increased migration.

This paper examines the institutional arrangements that facilitate irrigation management and the present state of irrigation management and establishes where problems have occurred in the operation of Gibe-Lemu and Gambela-Terre Small-scale irrigation systems. The study employed the case study approach to tackle the research. Key informant and expert interview, desk review of different documents produced about the projects, group discussion, direct observation and structured interview schedule were used to collect data. The study proved the proposition that the government has uncritically supported the irrigation systems. Enabling legal system of land and water rights, strong woreda level state irrigation agency, support services (irrigation extension) and wellestablished water users associations through which purposes of irrigation are achieved were not adequately planned and put in place. These shortcomings undermined irrigation management, ultimately risked feasibility and sustainability of irrigated agriculture. Findings revealed poor record of accomplishment, in spite of the difference between the two systems, in managing water distribution in terms of the three most important performance indicators: adequacy, reliability and equity in water distribution. Water related conflicts are rampant but not settled yet. In addition, results indicated that irrigation had positively impacted irrigators’ livelihoods in terms of diversification and intensification of crop production, household income, housing and employment generation and this social effect of irrigation was significantly different between irrigation systems (due to difference in the institutional and socioeconomic context of the two irrigation systems) and locations within irrigation systems. Nonetheless, many irrigators did not maintain these positive changes for long. The constraints were scarcity and unreliability of water and management and socioeconomic problems. These, in turn, were mediated by lack of: a) clearly defined and well enforced institutions of land and water rights; b) technical problems in design and construction; c) inadequate institutional capacity of the local state irrigation agency to coordinate and support decentralized management of irrigation; d) policy related problems; e) inadequate organization of users for self management; and f) problematic social relation of power among water users. Finally, the paper draws a number of conclusions, using the theoretical notions like context, social requirement for use, social effects and social construction, about policy options and requirements in the readjustment of the surveyed irrigation systems and in the design of irrigation projects of these types.

Water scarcity became a common phenomenon in Ethiopia with drought frequency of at least once in three years while the country owns a large irrigation potential that should be exploited sustainably. Various national and international institutions are currently engaged in developing small scale irrigation (SSI) schemes for poverty alleviation. A monitoring and evaluation exercise was conducted in 2004 and in 2006 in four administrative regions of Ethiopia, namely Tigray, Southern regions, Oromia and Amhara, to assess the benefits and associated environmental effects of SSI investments of the International Fund for Agricultural Development (IFAD). A combination of participatory Mamp;E tools namely, individual interviews, group discussions, key informants, review of relevant documents and field observations were used. The mission was supported by an in depth pre-mission socio-economic survey in three representative irrigation schemes. Data from the sites indicated that 50 % of the respondents had improved food security and higher income, while 26% of the respondents did not see any change on their livelihoods. Crop yield under irrigation was by 35% to 200% higher than under rain fed conditions, with much higher benefit obtained from high potential areas and in farms where external inputs (fertilizer, improved seeds and pesticides) are accessible. The positive effect was more visible with horticultural crops. There has been also a shift towards improved varieties with access to irrigation. Farmers replaced early maturing but low yielding varieties with high yielding varieties. Crop diversification increased significantly, in some sites from three to about 15 species, although this decision making process did not favour legumes. The apparent effect was on crop rotation, intercropping and land management with in the order of 79, 42 and 35%, respectively. On the other hand, there is a decline in number of livestock per household, but an increased number of draught oxen. The decline is associated with reduced grazing area due to conversion of dry season fallow to vegetable fields and an increase in area enclosure in the sloppy landscapes. The shift from cereal to vegetable-dominated cropping increased the competition for water between downstream and upstream users and between resource rich and poor farmers. The impact of irrigation schemes should be evaluated better on long term benefits than short term fixes, as farmers initiated long term investments like planting perennial fruits, bought calves and other retail trade investments. The communities would benefit most from further integration of livestock into the schemes by adopting feed sourcing strategies for dairy and fattening. The paper also presented best-bets for improved irrigation management in Ethiopia.

The study examined the extent and nature of market oriented production in irrigated compared to rainfed systems in Ethiopia. By doing so the paper identifies the role of irrigation in market-oriented production, while at the same time highlighting the main constraints to market oriented development. Our results indicate that irrigation contributes significantly to increases in market participation, volume of marketed produce and, hence, income, by inducing shifts in farmers’ cropping mix. The impact of commercialization of production on household food security is not direct and immediate mainly because of failures in the food market. While irrigation enhances market production, there are series of factors that pose serious constraints to market production. Land size, oxen holding, access to market and means of transport were found to be important determinants of market oriented production calling for policy interventions in land markets, access to productive assets and infrastructure development and policy measures to improve the performance of agricultural markets. The study also found education has market promoting effect in terms of increasing the probability of participation and volume of sale. Increased support to education can, thus, help in the long-term to transform traditional subsistence agriculture into more market-oriented agriculture. Finally there are unobserved site specific effects, related to location and other covariates, which influence market participation and volume decisions.

The purpose of the undertaken study was to evaluate the impact that the modern Hare river irrigation scheme had on household food security as well as on lifestyle changes of the population in the study site Chano Chalba. This was done on the basis of the FAO food security pillars access to food, availability of food, utilization of food and the overall factor of food stability. RRA tools were used to conduct a before-after comparison, considering a ten years period. The quantitative data was analysed using SPSS and/or Excel and simple statistical measures such as cross tabulations, frequencies, percentages and means gave a visible overview of the outcomes. The modern irrigation scheme did not affect the livelihood and food situation directly but indirectly through other modernizations that came with and after the construction of the modern main canal, e.g. road, merchants, agricultural office, health centre, drinking water points, school, electricity etc. The major trigger was the introduction of a new banana type so that farmers changed from food crops to cash crops to earn a higher income. Following, the wealth situation of the population ameliorated but less food crops are produced and people become more dependent on the local market. The infrastructure of the study site developed in a positive way but still education, especially on food issues, are needed to have a sustainable repercussion and to secure people’s health and food situation. Further positive changes on the food situation could be able if the higher income was utilized more efficiently and if the construction of the modern irrigation scheme had been more appropriate and by incorporating the farmer’s requests.

The regional government of Tigray has invested in millions of Birr to develop irrigation schemes as a strategy of poverty reduction. The study was based on a representative sample of 613 farm households (331 irrigators and 282 non-irrigators) drawn using three stage stratified sampling with probability proportional to size. The main aim of this paper is to study the impact of irrigation on household income, therefore, to contribute to the scant literature on irrigation-poverty reduction nexus in Ethiopia, which policy makers can use it as an input to make informed policy decisions in their future endeavors. We found that farming income is more important to irrigating households than to non-irrigating households, while off-farm income is negatively related with access to irrigation. We also found that irrigating households’ average income is above the regional average, while non-irrigating households’ average income is 50 percent less than the average income of irrigating households. Although there can be other factors, which may contribute to the difference in income, these results are in line with our expectation and supports the decision of the Tigray government to use irrigation as a poverty reduction tool. We have used a stochastic dominance analysis and found that the results are consistent. This result differs from a previous study by Pender et al. (2002), which argues that irrigation has less impact in agricultural yields than expected, reducing returns to investment in modern irrigation.

Recently, there has been very little irrigation development in sub-Saharan Africa. The main reasons cited for this lack of interest in developing irrigation in sub-Saharan Africa is that irrigation projects are expensive and perform poorly compared to projects from other regions. However, when classified into success and failure projects, the sub-Saharan Africa success projects’ investment costs are not significantly higher than from other regions. African countries like Ethiopia, which has embarked on an agricultural led development program, aspire to use irrigation as a development strategy with small scale irrigation playing a key role in rural development. This study evaluates the financial performance of small scale irrigation using O amp; M and investment recovery, and the ability to replicate the investments. It is concluded that the systems are financially viable and provide a low cost development option for rural areas.

Ethiopia is an agrarian society in a land of drought and floods. Agricultural production, which is the source of livelihood for eight out of ten Ethiopians, is extremely vulnerable to climatic conditions. The causes of rural poverty are many including wide fluctuations in agricultural production as a result of drought, ineffective and inefficient agricultural marketing system, under developed transport and communication networks, underdeveloped production technologies, limited access of rural households to support services, environmental degradation and lack of participation by rural poor people in decisions that affect their livelihoods. However, the persistent fluctuation in the amount and distribution of rainfall is considered as a major factor in rural poverty. Cognizant of this reality the successive Ethiopian governments and farmers have made investments in small scale irrigation schemes. This paper aims to assess the efficacy of these investments in reducing poverty based on data obtained from a survey of 1024 farmers drawn from four major regional states of Ethiopia. The Foster, Greer and Thorbecke poverty measures were used to compare the incidence, depth and severity of poverty among groups of farmers defined by relevant policy variables including access to irrigation. In order to explore the correlates of rural poverty and their quantitative significance, logistic regression model was estimated. The main conclusion of the study is that the incidence, depth and severity of poverty is affected more by the intensity of irrigation use (as measured by the size of irrigated area) than mere access to irrigation. Alternatively, there seems to be an economy of scale in the poverty irrigation relationship.

This research was conducted to introduce the concept of evaluating the countries large scale irrigation systems and using the IWMI’s minimum set of indicators for the same purpose. This was done by selecting two irrigation systems in the Upper Awash Basin. NuraEra state and Wonji estate farm were selected for their relatively better organization and management, nearness to weather station and their representative nature of the large scale irrigation systems in the country. The necessary primary and secondary data to calculate the nine indicators were collected which are measurement of canal capacity and pump capacity, and total yields, farm gate prices of irrigated crops, area irrigated per crop per season or per year, crop types, production per season or per year, incomes generated from water fee and cropping pattern. The indicators used are output per cropped area, output per command area, output per irrigation diverted, output per water consumed, relative water supply, relative irrigation supply, water delivery capacity, financial self sufficiency and gross return on investment. The result of the analysis shows that the ratio of RWS, RIS and WDC for NuraEra are 4.8, 6.6 and 1.4, for Wonji estate 1.36, 1.4 and 0.77 respectively. The four agricultural indicators; output per cropped area, output per command, output per irrigation supply and output per water consumed are in the order of 21017.44, 23791.21, 0.74 and 2.3 for NuraEra and 20074.97, 13916.03, 1.4 and 1.2 for Wonji, respectively. NuraEra spent 0.36 percent of its income in the year of analysis and that of Wonji is 0.17 percent for operation and maintenance of the delivery system. FSS was 100% for both of the farms. And gross return on investment was 84.7% for NuraEra and 76.8% for Wonji.

The water users located at the upstream of the irrigation system have more access to water than those located at the downstream of the system. Moreover, the irrigation activity of tail-enders is seriously affected in both water scarce and water abundant periods due to under and over irrigation respectively. Not only water but also the situation of landholding affects the productivity and income of the farming community. The goal of this study was to assess the spatial variation of irrigation performance and to evaluate its effects in terms of performance of agricultural production (intensification and productivity), income and resources base as well as the environment. Across-system performance assessment study sponsored by International Water Management Institute (IWMI) was done on the basis of simple illustration of the approach followed for the assessment and different levels of water accessibility along the canal reaches. The level of availability of irrigation water or accessibility to the farm is affected by the proximity of the farm to the water source or to the water carrying canals. The study confirmed that as one gets away from both the water source and the canal the accessibility of water becomes less and less, unless proper system for water allocation is in place and practiced. In view of that, six zones can be differentiated based on the condition of water accessibility. These are highly accessible, moderately accessible, less accessible, very less accessible, poorly accessible and water scarce zones. Sometimes the tail-end, which is characterized by water scarce zone, is also found to be affected by water logging. Since, available water and demand for water are not continuously monitored and managed, the situation outlined paves the path for potential conflicts among water users in response to visible livelihood differences. Despite disruption of downstream users from irrigating their field, significant loss of scarce resource by the upstream users have resulted in detectable environmental threat such as water logging, sodicity (10.44meq/l, k (H.C.) 0.00279cm/hr) and salinity problems in the area.

Crop production is a function of water, nutrient, climate and soil environment. Provided that all other requirement are satisfactorily for proper growth and production, rainfall rarely meets the time with required amount of water application for plant growth. As a result average yield of agricultural crops under rain-fed agriculture is low compared to irrigated agriculture. This study assesses irrigation and rain-fed agriculture system in connection to its potential productivity under existing practice. While the rain-fed areas considered in this study are the aggregate at the national level, five systematically selected Medium and large scale irrigation schemes were selected based on cropping patter, geographic and agro ecological representation These are Fincha’a, MAAE, Metehara, Sille, and UAAIE which are located at three river basins, viz, Nile (Abbay), Awash and the Rift valley basins. Data were collected using pre-formulated checklists, through series of interviews and discussions; and from published and unpublished documents. The result indicated that crop production was undulating under rain-fed agriculture and as a result the performance of rain-fed productivity remained low and stable for most crops. Although crops grown by smallholder private farmers are different, cereals occupy about 74 per cent followed by pulses and oil seeds with small proportion. During the last one decade, the maximum and minimum cultivated land by small-holder peasant farmers at the national level was 10.7 and 6.6 M ha, respectively. Increased cultivable area by private small-holder farmers could not seem to contribute to the increased production. Total irrigated land by private peasant farmers ranged between 66 and 147 thousand hectares for the last one decade. During the last decade the area under irrigation was steadily increasing for most of the large scale schemes. Particularly Fincha’a and Metehara farms are significantly increasing while MAAE farm has shown only a slight increase. At UAAIE farm, crop production shows a decreasing trend. Productivity of banana at Sille farm was decreasing despite its increasing in land area.

Although performance evaluation of irrigated agriculture has gained momentum since late 1980s worldwide such attempt is rarely carried out in Ethiopia. The aim of this study was to assess the performance of 7 irrigation schemes some of which are expected to contribute much to the national economy. Sugar cane is grown by three of these schemes whereas cotton is grown by three schemes and the remaining single scheme grows tobacco. With regards to management types both government agency and community managed schemes are considered. The scheme level values of water supply performance indicators show that there was no constraint of water availability and supply at scheme level. In general, schemes that grow sugar cane were found to have attained higher outputs per units of land and water used which ranges from 7794 – 10834US$/ha and 0.24 – 0.55 US$/m3 respectively. On the other hand, whether state farm or community managed, schemes that grow cotton have shown low output per units of land and water, i.e. 310 – 385 US$/ha and 0.01 – 0.05 US$/m3 respectively. Large productivity performance differences have been observed between irrigation schemes with same cropping and management types. From scheme level performance values it is not simple to identify the area where and what is going wrong which is responsible for low performance. Generally, problems casing low productivity derive both in management and deterioration of physical structures. Hence investment on improvements of physical structures, management and operation of the system at all levels will bring substantial improvement in the performances of cotton producing schemes.

This paper first looks in to the background on major challenges of Ethiopia with respect to poverty. It discuses the root cause of poverty and its vicious cycle nature, the interlink of population growth, the scarcity of land and natural resources, the extension of agriculture in to marginal land, the decreasing productivity, inability to invest and deepening of poverty and further aggravation as a result of various shocks such as drought, flood, war, etc. The paper also looks in to the importance of the broad agricultural water management in general and irrigation in particular with respect to increasing productivity and capability to break the vicious cycle and opportunity to reverse in to virtuous cycle that can help eradicate poverty and develop the poor economy. The paper also looks in to how poor management of water resources and impacts of variability of rainfall and related drought affecting the socio-economy and the overall wellbeing of the country to the extent that significant population became dependent on imported food. Results of broad assessment of water resources, database of irrigation development and potential, characterization by typology and major performance in Ethiopia are presented. Key water resources information related to each of the 12 river basins in Ethiopia is summarized. Details of existing irrigation and future potential are also captured in the paper. A geographic information system (GIS) database describing irrigation by typology, region and location, scheme size, type of structures, water source, number of beneficiaries, investment cost, etc, are some of the important attributes of the database. In addition, schemes that are operational and failed are identified in the database. Based on the broad database, performances of the schemes are highlighted. Furthermore, the various sites that are used in the detail study and the selection criteria for the impact of irrigation on poverty and environment project and the specific characteristics of these sites are described.

The following paper explores the possible inter-linkage of the Ganges and Brahmaputra River Basin and analyzes its effect on future water allocation between the upstream country, India, and the downstream country, Bangladesh. We find that water transfer from the Brahmaputra River could be mutually beneficial for both countries. However, the only possible motivation for the richer upstream country, India, to agree to transfer water to the poorer downstream country, Bangladesh, is political altruism. Using a political economy model we find that, if there is a good political relationship between India and Bangladesh, then India could be altruistic toward Bangladesh and transfer more water downstream. Changes in political altruism factor, however, could entice India to exercise unilateral diversion, in which case simulations predict that Bangladesh would incur large environmental damages. Political uncertainty may also result in unilateral diversion of water by India, and could prevent agreement on water transfers from the Brahmaputra. We therefore explore the conditions under which Bangladesh could accept an Indian proposal to transfer water from Brahmaputra, despite political uncertainty.

Development of irrigation can result in negative environmental and human health impacts. Irrigation undertaken without full consideration of these impacts can have serious adverse repercussions, not only undermining the investment but also worsening poverty and contributing considerably to peoples’ suffering. The impacts are strongly inter-linked because it is changes in the environment that cause changes in health. Furthermore, mitigation measures that reduce environmental damage often improve health outcomes. In the past, research into impacts, and the development of impact assessment methodologies, has focused primarily on large scale, capital intensive, schemes. However, small scale and less formal water management interventions, which are increasingly prevalent in sub-Saharan Africa, can also have significant environmental and health impacts. This paper summarizes the findings of a study of environmental and health issues associated with all scales of irrigation in sub-Saharan Africa. It is not a compendium of data, but rather provides an overview and framework for understanding policy and programming issues. It is recommended that a pragmatic approach to address current environmental and health planning includes three levels of implementation: i) strategic planning at the national and regional level; ii) full environmental and health assessment for government and donor funded projects; and iii) development of simplified tools for impact assessment relevant to community led, NGO and small private projects.

Municipal sewage water vehicles a wide variety of emerging organic pollutants. Some can be of natural origin, but they are mainly considered as anthropogenic. After secondary biological treatment, organic pollutants may not completely degrade (as pharmaceuticals), or give metabolites more persistent than parent compounds (as alkylphenols), or react during sewage treatment process to be reactivated (as hormones, pharmaceuticals). Some of these contaminants have been shown to act as endocrine disruptors. In reclaimed waters, they have been detected at levels of ng to g/l. In arid and semi-arid countries, effluent reuse is often promoted as an alternative water resource to meet agricultural water needs and to protect receiving waters and public health. Occurrence of emerging organic contaminants in reclaimed water and irrigated soils have been always overlooked in these regions. Even though, and depending on their physico-chemical properties, hydrophobic chemicals may accumulate at variable depth while the more polar ones may be transported through soil column and may reach groundwater. According to laboratory and field experiments, aquifer contamination should be of concern in some cases. Plant uptake of organic chemicals from irrigated soils have been investigated. Available data shows that contamination through uptake is of little concern for most toxic compounds.

Since the 1850s, the Krishna basin has seen an increasing mobilization of its water resources and a dramatic development of irrigation, with little regard to the limits of available water resources. This progressively led to the closure of the basin: surface water resources are now almost entirely committed to human consumptive uses; the increasing groundwater abstraction negatively affects the surface water balance by decreasing base flows, and the discharge to the ocean continues to decrease. The lower Krishna basin, located in Andhra Pradesh, is a deficit sub-basin; it depends highly on inflow from the upper basin and on upstream water uses. It is the first part of the Krishna basin to face the adverse consequences of any hydrological changes. It is also the region of the basin where most of the available water is depleted by human consumptive uses. In times of drought, it is the first region to face severe water shortages and to witness a spatial re-distribution or re-appropriation of water. Taking place on the basis of current political, institutional and geographical forces, this re-appropriation of water raises socio-political questions of sectoral and regional water apportionment within the lower Krishna basin and may be at the origin of conflicts between water users. This paper identifies two main drivers to the lower Krishna basin closure: (i) a long-term trend towards decreasing water availability with a declining surface water inflow due to water development in the upper basin and (ii) a local water over-commitment due to uncontrolled development of private groundwater abstraction and short term management decisions, both at the farmer and command area levels, in the large irrigation projects of the lower Krishna basin. In 1996/2000, 80% of the lower Krishna basin net inflow was depleted and discharge to the ocean amounted to 17.9 km3/yr, defining a moderately modified ecosystem. During the drought of 2001/2004, likely to forecast the future waterscape of the lower Krishna basin, all indicators point to further water resource commitment with a depleted fraction amounting to 98% of the net inflow, a lack of discharge to the ocean and the shrinkage of surface irrigated agriculture. This paper illustrates that local users and managers participate to a large extent in the shifting waterscape of the lower Krishna basin. At the basin scale, this paper shows that both the intra-agriculture and the inter- sectoral distribution of water are being reshaped. In the agricultural sector, the strong political divide among the three regions of Andhra Pradesh and the need to balance rural development among those regions are two of the main driving forces of a shifting agricultural water use. If surface water distribution among large irrigation projects tends to be to the advantage of the politically influent coastal region; the uncontrolled groundwater development mainly benefits the dry upland regions of Telangana and Rayalaseema and is tantamount t

Productivity decline occurs in many agronomic systems due to loss of soil organic matter and a consequent decline in soil fertility. This is pronounced in light textured soils, which even in their pristine state can have low levels of fertility. High temperatures and leaching conditions in tropical environments further exacerbates this poor fertility. In order to facilitate agronomic production on these soils, significant amounts of organic or inorganic fertilizers are required to maintain economic yields. However, the inherent low cation exchange capacity (CEC) of these soils limits their ability to retain nutrients such as Ca2+, Mg2+ and K+. The addition of inorganic fertilizer is often beyond the means of resource poor farmers and has the potential negative impact on the environment due significant leaching losses associated with the high hydraulic conductivity of light textured sandy soils. This paper reviews results from field experiments designed to assess the efficacy of bentonite (high-activity clay with a high CEC) additions on improving crop productivity and reducing nutrient loss. A number of field trials were established on light-textured soils in Northern Australia, Northeast Thailand and Hainan Province in China. Treatments and crop species (including sugarcane and various forage crops) differed at each of the study locations and included a range of rates (from 10 to 60 t ha-1), different application methods (broadcast, banded and slotted), and in some trials a comparison with other commonly used field amendments (e.g. various organic materials and termite mound material). These field trials demonstrated significant increases in crop biomass and yields associated with clay additions. Additional glasshouse studies support the observed increases in biomass observed in the field trials, and suggest that the yield increases were due to a combination of increased water-holding capacity, nutrient availability and reduced nutrient loss. These results support the notion that degraded light textured soils can be highly productive if intrinsic properties are addressed through clay additions.

In the Ecuadorian Cordillera, the hardened volcanic ashes (cangahuas) account for 15% of the cultivated area. The soil resulting from the fragmentation of these materials, generally by heavy machinery, shows an apparent stable millimetric structure. However, this new structure is highly susceptible to disintegration under rain, because it contains no organic matter and has a sandy-silt composition with very little mineralogical clay, and the material itself is readily eroded. In consequence we studied the evolution of soil aggregate stability in two factorial experiments during five cultivation cycles with two kinds of soil preparation and five fertilization treatments. Rainfall simulation was implemented before and after three cycles of cultivation to asses the soils structure evolution and its erodibility. The cultivated plots had flat surfaces and the rainfall simulation tests were conducted after the harvest on bare surfaces. Surface soil crusting occurred rapidly within the cultivated plots when compared to the recent tilled cangahua. Runoff and soil loss were generally higher on plots with lower structural stability, generally with higher clay content. The aggregate stability was not influenced by either kind of soil preparation, nor by large additions of manure (80 t ha-1) or green fertilizers (10 t ha-1), nor by growing a perennial grass. The variation in the aggregate stability seemed to depend on the components inherited from the original volcanic material: in the plots with larger clay content, and with swelling clay minerals, the aggregates were less stable than those composed of isometric fine silt particles. In agreement with the structural stability measured in a laboratory, organic matter inputs increase the soil porosity but had no effect on the structural stability and resistance to crusting, and thus to runoff and to erosion. For these soils, no tillage and a permanent soil cover (pasture) would be the best agricultural option.

Waste acid bentonite is a byproduct from vegetable oil bleaching that is both acidic (pH lt;3.0) and water repellent (hydrophobic). These materials are currently disposed in landfills and are an environmental hazard due to the aforementioned properties. A study was undertaken using three different sources of waste oil bentonites collected from processing plants within the Bangkok metropolitan area. These wastes included soybean oil bentonite (SB), palm oil bentonite (PB) and rice bran oil bentonite (RB), each of which was co-composted with rice husk, rice husk ash, and chicken litter in order to eliminate their acid reactivity and hydrophobic nature. The chemical and physical characteristics of acid activated bentonites before and after bleaching and the co-composted materials after addition to a degraded light textured soil were assessed and are reported herein. The organic carbon (OC) content, pH, exchangeable cations and cation exchange capacity (CEC) of the waste oil bentonites increased significantly after the co-composting phase. In addition, the hydrophobic nature of these materials as measured using the Water Drop Penetration Test (WDPT) decreased from 10,800 seconds to 16-80 seconds after composting. Furthermore, when these composted materials were incorporated into a degraded light textured sandy soil positive impacts to soil physical attributes in terms of specific surface area, total porosity and available water content for crop growth were observed. The results from this study demonstrate the positive impact of the waste products when modified through composting on the physical and chemical properties of a light textured sandy soil.

In the Sahel, sandy soils are widespread and support not only most of pearl millet production, the major staple crop in the region, but also forage production for livestock. Parent sediments of these soils have an aeolian origin and hence are prone to wind erosion. However, the clay content, albeit very low, results in the formation of crusts during rainfall, thus leading to runoff and water erosion. Squall lines, major rainfall events of the rainy season, are usually preceded by intense wind. Wind and water erosion is thus closely associated both in time and in space, but they are rarely studied simultaneously. Erosion measurements were carried out during two years (2001, 2002) on a small catchment of grazing land (1.4 ha) at Katchari, Burkina Faso, typical of the Sahel area under 500 mm annual rainfall. Wind erosion occurred at the onset of the rainy season, when soil cover is the lowest, from May to 15th of July, before vegetation growth. Water erosion occurred throughout the rainy season, but some intense events produced most of the total annual erosion. Wind caused the largest sediment fluxes leading to both erosion (up to 20 Mg ha-1 yr-1) and deposits (up to 30 Mg ha-1 yr-1) according to the area of the catchment. Water erosion is one order of magnitude lower than wind erosion, and is more intense where wind erosion is the highest. Thus the same area is eroded both by wind and water. Conversely, in areas where there are aeolian deposits, water erosion is low and these areas correspond to fertile islands where vegetation grows. At this study scale, there is no land degradation, but intense dynamics leading to a high spatial variability typical of the Sahelian environment. On this uncultivated area, the dynamics were similar to those recorded in other Sahelian cultivated millet fields.

Acidification of soil profiles from legume and N fertilized crops is a serious sustainability threat. Under tropical conditions of Northeast Thailand and Northern Australia, acidification to gt;90 cm has been recorded in Stylosanthes and Leucaena based pasture systems. Acidification has also been measured in other Australian cropping systems fertilized with urea or ammonium forms of N. The major processes contributing to what could be termed anthropogenic acidification are removal of base cations in the harvested product and leaching below the root zone of nitrate from ammonium and urea N fertiliser or legumes resulting in an accumulation of protons in surfaces horizons. If prophylactic applications of lime are not undertaken, acid generation in surface horizons will progressively move down the profile inducing subsoil acidification. Subsoil acidity is often difficult to correct using conventional applications of liming products. Field experiments with pastures on Acrisols in Northeast Australia (two sites) and Northeast Thailand (one site) compared the rates of alkalisation or acidification from N applied as nitrate or as urea (Australia) or ammonium sulphate (Thailand). Soil pH increased where N was applied as nitrate and decreased where N was applied as urea or ammonium sulphate. At one of the sites in Australia, regular applications of N as nitrate at 350 kg N ha-1 year-1 were made to irrigated Digitaria melanjiana cv Jarra. This significantly increased soil pH (1:5 0.01 M CaCl2) by up to 0.5 units to a depth of 0.90 m over a period of 4 years when compared to bare soil. The alkalisation of the profile was equivalent to 2.7 t/ha of calcium carbonate distributed evenly down the profile. Urea at the same rate of N decreased soil pH at 20-50 cm by 0.2 units. Similar but smaller changes were measured at the other Australian site (Brachiaria decumbens) and the site in Thailand (Andropogon gayanus cv Carimagua (Gamba grass). Treatment effects at these sites were restricted by time (1 year) or seasonal conditions that limited the number of N applications that could be applied (290 kg N/ha over 3 years) at the Thai site. The research has clearly demonstrated that nitrate N fertilizer can rapidly correct soil acidity down the soil profile to 0.9 m and this is attributed to the release of alkali from roots as nitrate is taken up. Such a strategy may be an effective approach to addressing subsoil acidification where surface applications of lime are ineffective and profile modification is cost prohibitive.

Over the past 4 decades there has been considerable expansion in the plantation forestry along the eastern seaboard of South Africa. In particular there have been significant increases in eucalypt, and to a less extent, pine plantations on soils of a light sandy texture along the Zululand coastal plain. These soils are characteristically dominated by sands with low clay and organic matter contents, have low cation exchange capacity and water holding capacity. Pedogenesis and selected chemical attributes of a 49-year-old stand of Eucalyptus grandis and Pinus elliottii established on these sands were compared. Changes in soil pH, exchangeable cations, organic carbon, extractable Fe and Al and the surface charge characteristics were investigated. Evidence of the development of bleached A2e horizon within the surface 0-5 cm depth interval under E. grandis was confirmed through the development of surface charge fingerprints, changes in organic carbon and Fe and Al mobilization for each of the pedogenetically distinct horizons. Such development was not observed under the P. elliottii stand, suggesting that this pine species has had less impact on the soil. It is argued that the rate of A2e horizon development is not dissimilar to that observed under native forest ecosystems in Australia, although considerably slower that those observed under reclaimed sand mining operations. Whilst these systems appear to be relatively stable due to no clear felling and timber product extraction, this could drastically change with the introduction of short-term rotations of fast growing clonal plantations, questioning the long-term sustainability of these production systems on these light textured sands.