Water resources and the way they are managed are central to improving livelihoods and to sustainable development. The challenge of meeting greater human needs for water from finite freshwater is a growing concern, along with threats from climate change, such as uncertain rainfall and water availability, affecting rainfed and irrigated agriculture. The implications for food security and nutrition are severe, through the impact on food systems, from agricultural production – including rainfed and irrigated crop production, livestock, inland fisheries and aquaculture – through food processing to households and consumers.

This report addresses two main water challenges affecting agriculture and food production: scarcity and shortages. Water scarcity refers to a physical lack of freshwater, which can seriously affect production and productivity in irrigated agriculture. Water scarcity is not just about inadequate freshwater but also inadequate infrastructure and institutional capacity to ensure equitable access to water services, such as drinking water and irrigation. Shortages through inadequate rainfall – in volume and timing – limit crop production in rainfed agriculture and livestock production on pastureland. Other water risks include natural hazards, such as flooding, where the problem is excess water (see Glossary for definitions of terms related to water).

While freshwater resources are finite, demand for water to meet basic human needs for food, drinking water and sanitation continues to grow. This includes water for irrigated agriculture, but also for broader food systems, including food processing. These needs cover domestic drinking water, and water for sanitation and hygiene (WASH). Sustainable management of water resources must reconcile these with the need to maintain aquatic ecosystem goods and services, which in turn depend on groundwater and river flow. Preserving water resources and using them sustainably is not just a question of volume; water quality is also a major and growing problem.

Rainfed agriculture is facing greater challenges from inadequate rainfall. The impacts can take several forms, including droughts, floods, and extreme rainfall and weather events. Precipitation anomalies on grazing lands are also a threat to livestock production.

The dual challenge of growing freshwater demand leading to increasing water scarcity, and the risk of drought or inadequate rainfall on rainfed areas leading to water shortages, is the focus of this report. The last time The State of Food and Agriculture addressed water issues in a comprehensive way was in 1993 (Box 1). What is striking, more than 25 years later, is the extent to which the contents of that edition are valid and relevant today. The challenges of managing water resources still remain, suggesting that they have not yet been sufficiently addressed. However, if the 1993 edition emphasized the consensus that “the growing water scarcity and misuse of freshwater pose serious threats to sustainable development”, there is even greater urgency today to address the problem. While the 1993 edition focused on the challenges of limited supplies and competing demands for freshwater in irrigated agriculture, the 2020 edition broadens the scope to cover water-related challenges in rainfed agriculture, including pastoral systems. It takes into account forestry, inland fisheries and aquaculture, and recognizes the importance of restoring and maintaining environmental flows and ensuring environmental services of water-related ecosystems.

Many of the challenges related to water resources feature prominently in the 2030 Agenda for Sustainable Development (2030 Agenda). Water is closely linked to several of the Sustainable Development Goals (SDGs) and a critical determinant of their success. Sustainable Development Goal 6 (Ensure availability and sustainable management of water and sanitation for all) covers all the key dimensions of water availability and management, including equitable access to drinking water, improved quality, increased water-use efficiency, integrated water resources management and protection of water-related ecosystems. Achieving SDG 6 is expected to generate several other economic, environmental and social benefits, and thus also contribute to other SDGs, not least SDG 2 (End hunger, achieve food security and improved nutrition and promote sustainable agriculture). Progress towards SDG 2 depends critically on achieving SDG 6, given that food and agricultural productivity are highly dependent on water and ecosystems to deliver services that, in turn, depend on maintaining environmental flows. Ending hunger and malnutrition also demands access to safe drinking water (SDG Target 6.1) as well as equitable sanitation and hygiene (SDG Target 6.2). Productive agricultural systems (SDG Target 2.3) require adequate availability (SDG Targets 6.4 and 6.6) and good-quality (SDG Target 6.3) water resources. Improved water management could have wide implications for various SDGs, while progress towards other SDGs could help achieve SDG 6. Figure 1 summarizes the potential linkages between SDG 6 and other SDGs. The column on the left refers to those expected to be mainly affected by SDG 6, while the column on the right describes which SDGs are most likely to have an impact on SDG 6.

FIGURE 1

Water and relevant targets of the Sustainable Development Goals (SDGs)

Back

Water resources are under increasing stress and degradation owing to population pressure and unsustainable consumption and production. Climate change exacerbates these factors and is expected to alter rainfall patterns, hydrological regimes and the availability of freshwater. Water scarcity and shortages are closely related to the hydrological cycle (Box 2). They derive from the growing mismatch between human demand for water and finite resources from the hydrological cycle in the form of renewable freshwater and rainwater failing to enter freshwater systems. They are increasingly a limiting factor for agriculture across small-, medium- and large-scale production systems. Scarcity and shortages also limit environmental services and ecosystem functions, essential to sustain water-related systems and human livelihoods; hence, the environment can no longer be considered a residual water user.

BOX 2

The hydrological cycle and agriculture

Water is a renewable resource, circulating on the planet in a continuous state of flux. The hydrological cycle diverts water from the oceans through the atmosphere and back to the oceans overland and underground (see figure). The mass of water in the hydrological cycle is essentially constant; water is not created or destroyed in any of the natural hydrological processes, with minor increases in annual global availability in response to higher temperatures under climate change.

THE HYDROLOGICAL CYCLE

Back

Freshwater refers to water on the earth’s surface in glaciers, lakes and rivers (surface water), and underground in aquifers (groundwater). Available freshwater is rare; 99 percent of water is either saline (97 percent of all water being in the oceans) or frozen (2 percent in ice caps and glaciers). Most of the remainder (1 percent) is groundwater with minute proportions in freshwater lakes, soil moisture, rivers and biological systems.

Rainfed agriculture relies on precipitation water that does not run over the surface in the form of streams (and subsequently rivers and lakes) or soak down to enter groundwater reservoirs or aquifers. Irrigated agriculture relies on drawing freshwater from surface water or groundwater sources in competition with other sectors and human activities.

Certain aspects of the hydrological cycle are critical:

• ▸ There is essentially one water resource, and only a systemic approach to water can ensure its proper management. Interlinkages between surface water, groundwater and soil moisture content are critical. Groundwater and surface water are part of the same resource and cannot be regarded as alternative sources. Promoting efficient water use in a specific domain without understanding the impact on systemic water balances may lead to unexpected or undesired results. For example, groundwater capture and recharge in alluvial plains can reduce flows in rivers.

• ▸ Water should be managed at the level of hydrological systems: basins, catchments and aquifers. Water management in one part of a system will have impacts on others. Intensifying agricultural water use upstream in a river basin can affect surface water and groundwater downstream.

• ▸ There are limits to the cleansing and dilution of pollutants in aquatic ecosystems. In the past, when disposing of effluent, many towns and cities relied on the self-cleansing and dilution potential of rivers and coastal waters. However, this was possible only where population density and related industries were minimal. In many places, these diluting functions have reached their limits, and such practices must now be carefully regulated.

• ▸ Water-related ecosystems, which deliver many environmental services, depend on the maintaining of groundwater levels and flow regimes in river systems. It is essential to recognize environmental flow requirements (see Glossary).

SOURCES: FAO. 1993,¹ and FAO. 2012.²

Back

Population growth is a key driver of scarce freshwater resources as rising population drives increased demand for water for different human uses. Human pressures on water also increase as per capita incomes grow and societies become increasingly urban, leading to dietary changes and greater water demand from households, industry, energy and services. These trends also imply increasing challenges for rainfed agriculture, called on to meet greater demand for food resulting from continuous population growth and rising incomes. Climate change exacerbates the challenges associated with these drivers, which may jeopardize rainfall patterns and increase the risk of extreme weather events.³ Extreme weather events and fluctuations in water availability can also trigger food price volatility, which can further exacerbate food insecurity and malnutrition. Small Island Developing States (SIDS) are vulnerable to climate-stressed groundwater resources, which affect both food prices and reliance on food imports.^4,5 When it comes to water scarcity, population growth outweighs the impacts of climate change.^6,7

FIGURE 2

Per capita renewable freshwater resources by region, 1997–2017

Back

Looking at the average amount of water per person can indicate freshwater availability, but it can oversimplify the situation in specific countries. Averages at the regional and even country level may not be meaningful in large countries with major regional differences. In many countries, scarcity is not an issue at the national level, but there may be serious water shortages in specific areas and watersheds. Brazil is a case in point. On average, it is estimated that, for every Brazilian, there are almost 42 000 m³ of renewable freshwater annually.^8,11 While parts of the country where most economic activity occurs (including irrigation) may suffer high water stress and usage, the Amazon Basin contains a large volume of water, but very little is used by people. Therefore, annual water supply per capita ignores local factors determining water access and the fact that different countries and regions use different amounts of water.

Growing competition for water resources

Population growth trends are expected to increase pressure on water resources for agriculture and other uses, including industrial and domestic. Figure 3 depicts total water withdrawals. These have kept pace with population and economic growth, rising dramatically over time, particularly since the middle of the twentieth century. While the pace of growth has slowed in recent decades, the rise continues. Agriculture is still by far the largest water user, accounting for more than 70 percent of global withdrawals of water, which are continuing to increase. Agriculture has faced greater competition from other sectors, as industrial and municipal withdrawals have grown more rapidly, particularly since the middle of the twentieth century. In the past decade or two, industrial withdrawals have declined, while municipal withdrawals have increased only marginally since 2010. Agricultural withdrawals have continued to grow at a faster pace, although more slowly since 1980, and the share of agricultural withdrawals has increased slightly since 2000.

FIGURE 3

Global sectoral water withdrawals

Back

Figure 4 combines total water withdrawals and population in 2010 and 2017. In the past decade, depending on the region, per capita water withdrawals have been stable or slightly decreasing – a result of population increasing faster than water withdrawals, or at the same pace. Considerable regional differences exist, with Central Asia having the largest water withdrawals per capita, reaching almost 2 000 m³ per person in 2017. This is followed by Northern America, where the average person withdrew more than 1 300 m³ of freshwater in 2017. In sub-Saharan Africa, this value barely reaches 130 m³ per person, in large part owing to economic constraints to accessing freshwater. Water withdrawal ratios also vary significantly by income level (Box 3).

FIGURE 4

Total water withdrawals per capita by region, 2010 and 2017

Back

BOX 3

Competing demands for water are determined by country income level

One feature of the growing demand for water is increased competition among all users. Looking at water withdrawal ratios by income group and country classification can provide a general picture of the extent of this competition. The figure below shows the breakdown of sectoral water withdrawals by income level, whose ratios can vary significantly. They range from 91 percent, 2 percent and 7 percent for agricultural, industrial and municipal water, respectively, in low-income countries to 43 percent, 41 percent and 16 percent, respectively, in high-income countries. As populations and incomes expand, and the impacts of climate change are increasingly felt, competition for water is expected to intensify,^18,19 especially in low-income and lower-middle-income countries.

In least developed countries and landlocked developing countries, agriculture also represents around 90 percent of total water withdrawals. In SIDS, the share of agricultural withdrawals is lower, accounting for about 60 percent of total withdrawals.

Sectoral water withdrawals by income and country classification, 2017

Back

Back

Figure 4 captures water withdrawals across regions but cannot take account of local water access and competition between sectors. Rising demand from agriculture and other sectors is leading to competition for scarce freshwater, increasing the risk of conflict among local farmers and other water users up to the international level in the form of transborder conflicts. Competition and disputes over land and water exist in countries with acute scarcity and limited access to water. In the Sahel pastoralist region, overgrazing and severe pasture degradation led to limited or no fodder production in 2018. As a result, pastoralist households embarked on migration two months early, leading to higher concentrations in certain areas and conflict between farmers and herders.¹³

Landlocked developing countries and least developed countries are particularly affected by potential international conflicts. They often share cross-border water resources, e.g. Lake Chad, Lake Victoria and the Nile River, with competition over water, such as for irrigation, along with the impact of pollution.¹⁴ These countries also rely heavily on inland fisheries as providers of animal protein, nutrients and vitamins.¹⁵ Less-formal sectors such as fisheries are frequently forgotten, partly because it is difficult to demonstrate their true economic value and their ability to compete with economically powerful stakeholders such as energy and irrigation.¹⁶ Competition among sectors also manifests itself along the Nile River, where Ethiopia is seeking to meet its electricity needs through construction of the Grand Ethiopian Renaissance Dam on the Blue Nile River, but Egypt fears a threat to its main source of irrigation water. International talks among water and irrigation ministers from Egypt, Ethiopia and the Sudan, with observers attending from South Africa, the United States of America and the European Union aim to prevent international conflict.¹⁷

The impacts of dietary change on water use

Competition for water is expected to grow as a result of changing dietary patterns. The observation that diets change as countries develop economically is well recognized and associated with increasing wealth, access to cheaper food, expansion of global food markets and urbanization.^22,23 Dietary changes include a shift in preferences from unprocessed cereals towards highly processed foods, livestock products and high-value crops, such as fruits and edible oils, whose consumption is expected to continue increasing, especially in low-income and lower-middle-income countries. Such changes influence future agricultural water demand because, as reflected in Table 1, livestock products and oils require more water than do cereals, starchy roots, fruits and vegetables.²⁴

TABLE 1

The water footprint of selected food products

Back

Table 1 considers the average annual water footprint of selected food products based on Mekonnen and Hoekstra (2012), using the total volume of water (rainwater, surface water or groundwater) directly or indirectly to produce the product.²⁴ This is useful for policy in water-scarce regions when considering the benefits of specializing in some products rather than others, local production versus imports, the water-related impacts of consumption patterns, etc.²

Table 1 highlights the complexity of water-related impacts of diets. The fourth column shows that livestock products require substantially more water for one tonne of product, and per calorie, than do crops. The only exception are nuts, which, after beef and goat meat, consume the most water per tonne. Assessing the water requirements for protein, Table 1 shows that producing one gram of protein for milk, eggs and chicken meat is in the same order of magnitude as for pulses. For beef, the water requirement is considerably higher, indicating that differences across livestock production are also important, while butter and oil crops have a relatively small water footprint per gram of fat. In purely “accounting” terms, from a freshwater perspective, it is often more efficient to obtain calories, protein and fat through crop products than through livestock. These are averages over all types of water use, across production systems and regions where nutritional challenges differ greatly. In low-income countries, the quality of proteins and bioavailability of nutrients from different foods will be crucial to avoiding malnutrition. High-income countries increasingly overconsume livestock products, putting additional pressure on water resources. A meta-analysis of 63 publications on the water footprint of various diets in high-income countries found that reducing consumption of animal-based foods in Western diets could reduce water use by 18 percent.²⁵

While studies based on global averages provide interesting insights, experts in environmental assessments of livestock production have questioned them. Estimates are often very context-specific and cannot be generalized because of differences in feed used between and within species and production systems. Part of the water footprint of animal production in Table 1 is associated with rainfall on pastureland, often not convertible to cropland, thus making livestock the only option for using rainfall for food production, improving water-use efficiency.²⁶ Studies also usually consider population-level intake of different foods, but do not examine dietary requirements of specific groups, such as children, women or the elderly. The conclusions of these studies should be viewed with caution, and any guidance should be context-specific and consider the dietary status of a population, and specific water constraints faced by producers, combined with the viability of different land uses.

Table 1 does not include seafood as there is very little analysis of water use in its production. Fish are an important source of proteins, healthy fats and nutrients, playing a crucial role in nutrition.¹⁵ The seafood industry is very diverse, with vastly different water use, in particular, but not only, between aquaculture and capture systems. In China, the blue and green water (see Glossary) footprint of freshwater aquaculture associated with feed and evaporation ranges from 3 349 m³ to 21 215 m³ per tonne of product.²⁷ For marine aquaculture, levels are much lower and only associated with feed. For capture fisheries, consumptive freshwater use is negligible, but adequate water is still essential. For inland fisheries, which provide dietary diversity and underpin food security and nutrition in some areas, water volumes and timing depend largely on context and species.

Rising scarcities and climate change risk greater inequality in water access. This, in turn, can undermine livelihoods, resilience and food security and nutrition through the share and quality of water allocated for WASH, agriculture, food production and ecosystem functioning, and exacerbate unequal distribution among people and sectors.³¹ The human rights dimension of water access is important and was recognized by the United Nations General Assembly in 2010.³² While the right to water focuses primarily on water for drinking, sanitation and other personal and domestic use, it extends to food and agricultural production in its interactions with other human rights, notably the right to food – of particular importance for rural women and indigenous peoples.

Rural access to water is particularly uneven owing to physical and/or economic constraints for small-scale farmers. Small farms of less than 2 hectares make up the majority of farms both worldwide (84 percent) and especially in low-income and lower-middle-income countries.³³ They are more vulnerable to water constraints because of limited access to irrigation technology and rainwater harvesting options. In Southern Asia, where more than 60 percent of farms are small,³³ Li et al. (2011) found drought to be a major constraint to crop yield.³⁴ Improving access to water for agriculture and better management are important poverty alleviation tools.^35,36

Small-scale farmers in irrigated and rainfed settings face barriers to irrigation equipment and water harvesting. In sub-Saharan Africa, water is present but scarce without the capital to access it,³⁷ although expanding small-scale irrigation can be profitable and benefit between 113 million and 369 million rural people.³⁸ Many factors impede uptake of irrigation technologies, including tenure and access to finance and credit.³⁹ Water harvesting improves crop yields in semi-arid regions of Africa and Asia, but small-scale farmers with limited market access may be reluctant to invest in water harvesting owing to low returns and an average payback of 4–5 years.⁴⁰ To further expand access to water, farmers and service providers need the skills to design, operate, maintain and repair irrigation technologies and systems, as their misuse will result in water and yield losses.⁴¹

Women also face severe constraints in access to natural resources, especially water, despite constituting up to half the agricultural workforce in low-income countries.⁴² They often lack rights to the land they farm, and water to irrigate their fields. Women also lack influence over the use of natural resources, including water. Their labour burden exceeds that of men, as they have more unpaid household responsibilities, such as water and fuel collection and food preparation. Fetching water can be dangerous for women and girls, exposing them to the risk of violence. Irrigation can allow women greater participation in income-generating, caregiving and social activities. Water professionals, extension staff and decision makers still fail to perceive women as farmers⁴³ and often overlook the knowledge, workload and needs of women and the most vulnerable groups. General Recommendation No. 34 of the Committee on the Elimination of Discrimination against Women considers women’s access to land and water to be fundamental human rights.⁴⁴

Strong governance and water allocation, such as for irrigation and hydropower that engage different users, are essential in order to address competition and tensions between sectors, and to ensure reliable, high-quality water flows. In many countries, as indicated in the 2015 report by the High Level Panel of Experts on Food Security and Nutrition, decisions in water-use sectors are often taken by separate departments with “little consideration for the cumulative impacts of water.”³¹ Governance must balance the need for more efficient water use with equitable access that respects the human right to water. The notion of allocative efficiency is concerned with how much wealth a given natural resource base can produce, while equity relates to how the wealth is distributed in society.⁴⁵ Reconciling efficiency and equity may not be easy owing to weak entrenched water policies, such as underpricing or unregulated use.⁴⁶ Markets and efficiency considerations may dominate, favouring those who use water to produce the greatest economic returns, trading off equity against efficiency.^47,48 Agriculture can invoke its multiple functions beyond commodity production to important social, cultural and environmental aspects. Increasing agricultural water efficiency, equity and productivity will be key to providing sufficient quality food for everyone, while respecting environmental flow requirements that sustain ecosystems, and the human livelihoods and well-being that depend on them. Yet, it has been estimated that 41 percent of current global irrigation occurs at the expense of environmental flow requirements.⁴⁹ Reconciling irrigation with environmental flows will thus be pivotal for attaining the 2030 Agenda.

If water were abundant, managing demand would be less challenging, as it could be met at little cost. With greater scarcity, use creates increasing rivalry, as one user limits its potential use by others. Water should be recognized as an economic good that has value and a price,⁵⁰ as well as vital for the ecosystems upon which all depend. Its unique characteristics – essential, non-substitutable, finite and a human right⁵¹ – have made this difficult (Box 4), and water must be managed from economic and social standpoints. Its allocation cannot be left to market forces alone. However, this does not imply that as a basic human right, water must be free, a common misinterpretation.

There is a need for fair pricing that aims at cost recovery, a primary goal, but ensures access for the poor, along with meeting environmental requirements.⁵² A reasonable price sends out a clear signal to users that water must be used wisely. Policies may offer cross-subsidies (one group of consumers pays more to lower the price for another group) for equity reasons, or water use may be subsidized (e.g. for irrigation). A well-functioning, efficient, equitable and sustainable market depends on these criteria. Governments have prime responsibility in this.

As water becomes scarcer and demand grows, the policy focus has shifted from increasing supply towards economic, legal, institutional and other interventions to manage demand (Box 1). Management can deliver additional water to meet society’s needs, while addressing the causes of problems, such as pollution and over-exploitation of aquifers. Solving water scarcity in agriculture requires controlling supply with vigorous demand management.

The concept of food systems can be useful for understanding the relationship between food security and nutrition, food production and consumption, and water. A food system encompasses the entire range of actors in the production, aggregation, processing, distribution, consumption and disposal of food products that originate from agriculture, forestry and fisheries, and parts of the broader economic, societal and natural environments in which these activities are embedded.⁵⁹ A sustainable system delivers food security and nutrition for all, without compromising the economic, social and environmental bases that generate food security and nutrition. Sustainable and equitable water management is essential to food systems, to achieving food and nutrition security, and to ending hunger.

Global attention has focused primarily on water quantity, but water quality is also important from a food-security perspective. Pollution affects the availability of freshwater for economic activities,⁶⁰ including food production.^61–63 Polluted water affects health and well-being through food safety and health risks.⁶⁴ It also undermines the sustainability of fisheries, land and ecosystems, including the ability to provide food security and nutrition.³¹ (For a further discussion of water quality, please refer to the In Focus: Agriculture, water pollution and salinity.)

The following subsections look at different components of the food system, to highlight the entry points through which water management affects food security and nutrition. Beyond the food system, an increasingly important source of competition for water is the water–energy–food nexus, and biofuel production (Box 5).

Water at the centre of primary production

Agriculture accounts for about 70 percent of water withdrawals worldwide, but about 90 percent in low-income and lower-middle-income countries (see figure in Box 3). Increasing scarcity of freshwater and growing competition, particularly in arid and semi-arid regions, is a sharp constraint on agricultural production. Rainfed agriculture is the primary source of global production, representing more than 80 percent of land under cultivation (see Chapter 2) and 60 percent of global crop production.¹⁹ Increasing productivity in rainfed agriculture can reduce pressure on scarce freshwater from irrigation. This involves increasing the productivity of rainwater, although the water-related challenges facing production systems – rainfed and irrigated – are largely, but not wholly, different.

Rainfed agriculture is completely reliant on rainfall. With climate change causing precipitation and temperature changes,⁸⁵ rainfed agriculture is highly vulnerable to the challenges of water management. There is a need to harness the water resource potential through water harvesting, soil moisture conservation and supplementary/deficit irrigation, as well as a need to make better use of water.⁸⁶ Improved rainwater management and farm practices can help retain water in the soil. A lack of rainfall also affects irrigated agriculture – as irrigation water comes from rainfall – but farmers with access to irrigation have more influence on volumes and timing to manage soil moisture more effectively. An additional dimension is linked to forms of aquaculture and livestock production, whereby the water productivity of aquaculture and livestock depends on efficient and sustainable use of water in crop production, as explained in the following sections.

Water for livestock production

Water in the livestock sector can be divided into direct use (service and drinking water) and indirect use (production of feed, fertilizer, pesticides and other inputs).⁸⁷ Precipitation patterns are critical for land under permanent meadows and pastures grazed by livestock, much of it not convertible to cropland because of climate, slope, soil depth or other factors. Mottet et al. (2017) estimated that livestock graze about 2 billion hectares of meadows and pastures.²⁶ In dryland areas, such as the Sahel, livestock may be the only option for turning sparse and erratic biomass into edible products. Precipitation patterns also play a major role in increasing soil carbon storage. Manure can increase water-use efficiency in arable lands, enhancing resilience, yields and soil carbon storage.⁸⁸

As the sector uses a large share of agricultural land, either as pastureland or for feed production, it also consumes large amounts of water. An integrated approach is crucial to improving water productivity and the efficiency of all food production sectors. Reducing the amount of irrigated feed and animal water consumption are the two main strategies to reduce livestock’s impact on water scarcity.⁸⁹ Other factors influencing water consumption are animal species and breeds, and the moisture content and production of feed. A major challenge in global or regional assessments of livestock water use is the very large diversity of production systems.⁸⁹ The Livestock Environmental Assessment and Performance (LEAP) Partnership has recently developed assessment guidelines that take into account a wide range of conditions.⁸⁷

Water for inland fisheries

Sustaining inland fisheries requires limiting adverse impacts from other sectors on water. This requires adequate environmental flows, water quality and habitat conservation. Different flow requirements among fish species will lead to changes in species assemblages and, hence, fish catches.⁶⁷ Conversion of a river to a reservoir may well cause a complete shift and, often, the elimination of some aquatic fauna. To maintain inland fisheries and mitigate losses, it may be necessary to replace lost species with others better adapted to a standing-water environment.⁶⁸

Water and forests

Water management challenges and solutions related to food go beyond primary agriculture and must be considered at the broader landscape level. Forests are an integral component of the water cycle and can be crucial in sustainable water management and water-related ecosystems, such as the return of rainfall to the atmosphere, which helps to stabilize and extend crop growing seasons. Moisture retention and release by forests, even in dry periods, is essential in areas affected by water scarcity and drought. Forest restoration in dryland areas in Burkina Faso, for example, has helped restore the productivity of degraded land for agriculture and offered a means to diversify food sources, thereby enhancing food security.⁹⁰ Given the importance of forests for the water cycle, water-related benefits from forests are best ensured through a holistic, comprehensive and integrated landscape approach. Forest–water relationships are spatially dependent. Their extent and location within the landscape can produce a range of water-related environmental benefits. Forests in upper catchments provide not only local but landscape benefits, often delivering high-quality water downstream. At the basin scale, major forested areas in some of the world’s largest basins, such as the Amazon, Congo and Yangtze river basins, are important sources of water vapour for areas downwind and, therefore, crucial to rainfed agriculture. Moisture evaporated from land may fall up to 5 000 km downwind.⁹¹

Water use along the food supply chain – critical for food safety and water quality

Little is known about total water use by the food processing industry. The industrial sector accounts for less than 20 percent of water withdrawals worldwide (Figure 3), but this figure is about 40 percent in high-income countries (see the figure in Box 3). As food processing is a subsector of the industrial sector, its water withdrawals are much smaller than those of agriculture. Research on water use in food processing tends to be product-specific, such as on tomato sauce, juice or potato products,^92,93 identifying the most water-intensive processing steps rather than the quantity of water used at various levels. The manufacturing food industry is water-intensive. It uses potable water and generates a significant amount of wastewater per unit of product, more than 70 percent of which is discharged.⁹⁴ The quantity for a particular food product depends on a range of factors: the origin of the product (animal or plant); processing conditions (dry or wet); type of processing (minimally processed, fully cooked or dried); the technology; cleaning procedures; and recycling activities. The volume and strength of effluents also vary significantly.⁹⁵

Water quality is crucial for food production and transformation. Food processing can require water for a number of operations, such as washing, evaporation, extraction and filtration⁹⁶ and, many, if not most, food-borne illnesses can be traced back to poor-quality water in food production, processing and preparation.³¹ While quality water is essential to deliver nutritious, safe food, the sector does generate wastewater.⁹⁶ Improper disposal of effluents into land and water ecosystems also harms the quality of water itself.^96–98 Water waste carries contaminants such as nitrogen, oxygen-depleting substances and pathogens, which make their way into lakes and rivers.⁹⁹ This reduces water quality, affecting biodiversity, and lowering fish production and quality.¹⁰⁰

Without proper treatment, disposing of contaminants into water may expose humans to them, and limit access to safe, drinkable water, especially for the most vulnerable people. People are also affected by eating contaminated food products, such as fish.^101,102 To address water pollution and protect ecosystems, wastewater treatment technologies (such as digesters or activated sludge processes) are needed to avoid discharge into water resources.⁹⁷

As manufacturing demand for water increases, equally important are water savings in food processing, often the main driver that motivates food companies to support water conservation programmes. Cultural and operational changes are among the first-line approaches, with little capital investment resulting in water reductions of up to 30 percent.⁶¹ Examples include awareness and monitoring programmes, and taps that automatically shut off when not in use. Other options can achieve more significant water reductions, in the range of 50–80 percent, depending on the technology.^103,104 However, capital investment is higher, and consideration needs to be given to the impact of the changes on finished product quality and safety.⁶¹ Internal strategies to increase water efficiency and productivity include: (i) reduced use through consumption analysis (water mapping); (ii) improved planning; (iii) water recycling; (iv) reuse after treatment; and (v) equipment and plant layout design.⁹⁵

Water use by consumers – the link between water access and food security and nutrition

Safe and reliable WASH practices are a basic necessity for human development and a healthy life. Lack of access to safe and clean water for WASH is a key underlying cause of malnutrition, particularly in children. Diarrhoeal disease is directly linked to a poor WASH environment, particularly in low-income countries, where access to clean water is a major issue. According to the World Health Organization (WHO), in most low-income countries, diarrhoea is the third main cause of child death, after acute respiratory infections and malaria, as well as of deaths across all age groups.¹⁰⁵ In a poor WASH environment, food that is eaten may pass through the body without being absorbed owing to diarrhoea or other enteropathy. Water-related diseases undermine productivity and economic growth, reinforcing deep inequalities and trapping vulnerable households in cycles of poverty.^106,107

When access to household water sources is limited, irrigation water sometimes fills the need. Although some studies have shown household use of irrigation water can lead to positive effects on WASH and nutrition, the quality is not always sufficient for human consumption, with possibly adverse health effects.^108–110 This is particularly true where irrigation water for domestic consumption is unplanned. There may be benefits when multiple uses are incorporated into the irrigation system; for example, the overall time that household members, often women, spend collecting water decreases, freeing them for other productive activities and caregiving, leading to better nutritional outcomes.¹⁰⁸ The importance of WASH for human health, well-being, and food security and nutrition is further discussed in the In Focus: Improving access to safe drinking water in rural areas.

This chapter has emphasized the urgency of addressing increasing water shortages and water scarcity, as well as unequal access to water across stakeholders, and laid out the main challenges to ensuring sustainable and inclusive water management. It has highlighted the role of management along the entire food supply chain for the purposes of food security and nutrition. From this overview, it is clear that agriculture occupies an enduring and central role in managing water, and that water remains a binding constraint for many small-scale producers. Therefore, the report places the main emphasis on water management in agriculture – the main user of water globally and in most countries – covering both irrigated and rainfed agriculture as well as livestock production systems, inland fisheries and aquaculture. It balances the dual agendas of water access in agricultural production and ensuring economic, social and environmental sustainability.

Chapter 2 looks at trends and patterns in water shortages and water scarcity, affecting irrigated and rainfed agriculture, respectively, and presents an overview of the effect on different production systems. It uses an indicator of water stress as a proxy for scarcity of freshwater affecting irrigated cropland, and an indicator of severe drought frequency as a proxy for water shortages owing to inadequate rainfall, affecting rainfed cropland and pastureland. It shows the first spatially disaggregated representation of SDG Indicator 6.4.2 on water stress, and links it to irrigated production systems. Chapter 3 looks at agriculture water management strategies and technologies in irrigated and rainfed agriculture, livestock production systems, inland fisheries and aquaculture, while Chapter 4 focuses on governance and institutions for improved water management. Chapter 5 presents the overall policy framework for improved governance of water resources, and draws conclusions and policy implications.

As discussed in Chapter 1, the right quantity and quality of water are central to food security, nutrition and health for all. Water is also the lifeblood of ecosystems, upon which all humans depend. As water becomes scarcer, further competition and disputes among users are likely, as are inequalities in access to water, mainly affecting the rural poor and other vulnerable populations. The 2030 Agenda reflects growing concern over water scarcity and misuse in SDG Target 6.4, calling for greater water-use efficiency and sustainable withdrawals. Severe droughts, exacerbated by climate change, cause water shortages, affecting crop and livestock yields, especially for the rural poor.

Thanks to efforts by FAO, monitoring progress towards SDG Target 6.4 is now possible through SDG Indicator 6.4.2 on the level of water stress; and this chapter presents new spatial estimates for irrigated areas. As water shortages is the primary constraint to agricultural production and productivity in rainfed areas, the chapter assesses the impact of recurring drought on rainfed cropland and pastureland. Agriculture is the world’s largest water user, and most of the poor depend on it for their livelihoods, food security and nutrition. Those engaged in different agricultural production systems also face different water-related challenges and opportunities. The chapter sheds new light on the global distribution of the main agricultural systems – irrigated, rainfed (low- and high-input), and pastureland – and briefly discusses their vulnerability and exposure to water risks. The chapter then discusses how climate change exacerbates water shortages and scarcity. It also introduces governance, institutional frameworks and the policy environment of responses to water shortages and scarcity. It ends with a review of water quality issues from agriculture and presents possible policy responses and management strategies.

Water shortages are driven primarily by biophysical factors (e.g. rainfall), reflecting a lack of water of acceptable quality, while scarcity arises from water shortages and the multitude of factors driving water demand (e.g. population increase), depicted through different indicators. This report draws on two indicators: FAO’s historic drought frequency indicator and SDG Indicator 6.4.2 on the level of water stress to measure water shortages and scarcity in rainfed and irrigated areas, respectively.

FIGURE 5

Historical drought frequency on rainfed cropland, 1984–2018

Back

FIGURE 6

Historical drought frequency on rainfed pastureland, 1984–2018

Back

FIGURE 7

SDG Indicator 6.4.2 – Level of water stress on irrigated areas, 2015

Back

FIGURE 8

Contribution of the agriculture sector to the level of water stress, by basin, 2015

Back

If areas with high (in addition to very high) severe drought frequency or water stress are also considered, the number of people affected increases to 3.2 billion, of whom more than 40 percent (1.4 billion) live in rural areas. This estimate may be a global assessment of the future potential impacts of climate change on water constraints. Water in these areas is likely to be a constraint to agricultural livelihoods and for most households, and unless demand and user practices change or alternate water resources are found, people may be driven to migrate. Georeferenced reviews of studies have concluded that drought, dry spells, precipitation variability and weather extremes do influence migration, mainly through effects on agricultural productivity.⁵ Orderly and regular migration can contribute to economic development and improve livelihoods. However, it can be disruptive during a crisis. Male outmigration may increase the domestic burden for women, shifting responsibilities in the home, with women taking on additional burdens such as caring for livestock.⁶

In terms of hectares affected, 128 million hectares of rainfed cropland and 656 million hectares of pastureland face frequent droughts, while 171 million hectares of irrigated cropland are subject to high or very high water stress. This means that about 11 percent of rainfed cropland and 14 percent of pastureland experience severe recurring droughts, while more than 60 percent of irrigated cropland is highly water stressed. More than 62 million hectares of cropland and pastureland experience high to very high water stress and drought frequency, affecting about 300 million people.

Heterogeneity in water constraints within and across regions

The wide range of colours in Figures 5–7 within and across countries highlights the need to employ spatial datasets when measuring water constraints. These can show differences at subnational level, information that national-level assessments may hide but which is essential in order to identify hotspots and the most appropriate interventions. Some Andean countries (Argentina, Bolivia [Plurinational State of], Chile and Peru) and the dry corridor in Central America (El Salvador, Guatemala, Honduras and Nicaragua) are a case in point. In Peru, while the national level of water stress is very low (about 1 percent),⁹ Figure 7 shows that the coastal area of the Pacific, with very low runoff, is extremely water stressed. This is also where most people live and economic activity occurs (including irrigation and mineral development),⁹ making the average estimate of water stress irrelevant in policy support information. For country-level data on the area subject to drought or water stress for different production systems, see Tables A1 and A2 in the Statistical Annex.

The same area can have distinct levels of water stress and drought frequency – with the latter depending on the map layer used (cropland or pastureland) – emphasizing the need for multiple indicators and distinguishing production systems. Most countries in the Sahel region report no water stress, but Figures 5 and 6 report medium to high likelihood of severe drought there. Most vulnerable communities live in drought-prone areas and are highly dependent on agriculture for their livelihoods and food security and nutrition. Those relying on livestock are particularly vulnerable, as it takes a long time to rebuild herds decimated by drought.¹² Drought causes almost 90 percent of all damage and loss to livestock.¹³

The probability of severe drought is also likely to impact irrigated areas, owing to decreased water supply and quality. In Tajikistan, the 2011 drought severely affected irrigated agriculture, as water levels in the Nurek reservoir fell sharply. As a result of low rainfall, production of wheat, barley and rice in irrigated areas fell by at least 75 percent compared with previous years.¹⁴ Irrigation systems relying on open water resources (rivers, lake and reservoirs) are also more vulnerable to drought, which reduces the quantity of surface water delivered. In Africa, where about 80 percent of irrigated systems rely on surface water,¹⁵ aquifers must act as primary buffers against drought. To derive a more comprehensive picture of the water challenges facing these countries, water stress and historical drought frequency are better understood when put together.

Facing multiple water challenges – defining country profiles

Figure 9 brings together the characteristics of a country’s agriculture sector and associated water challenges, displaying country profiles to frame the water constraints for each country and to identify appropriate solutions. The figure illustrates the share of rainfed and irrigated cropland subject to high or very high drought frequency or water stress, respectively, for selected countries. There are cut-off points of 33 percent for both indicators to give a sense of the gravity of the challenge in the two dimensions. However, it is where countries appear along the continuum that matters most.

FIGURE 9

Placement of selected countries based on the share of rainfed and irrigated cropland experiencing high to very high drought frequency or water stress, respectively

Back

Countries in the first quadrant (top right) of Figure 9 face the dual challenge of high incidence of severe drought frequency and water stress. Of the selected countries, 11 are in this situation, all in Northern Africa and Asia. For nine of them, 100 percent of their irrigated land suffers from high or very high water stress. For these countries, sound water accounting (see Glossary), clear allocation, the adoption of modern technologies and a shift to less-water-demanding crops with less irrigation will be necessary, along with investment in increasing water supplies, such as through desalination.

Other countries, without the dual challenge of drought and water stress, may have more options. Many countries report a relatively low incidence of severe drought but high water stress (upper-left quadrant). Policymakers may choose to focus on shifting irrigated production towards water conservation – including water-saving crop methods and a change in planting dates and cultivars – or investing in non-conventional sources, such as desalinated water. This requires removing barriers and creating an enabling environment through legislation and regulation to facilitate financing to scale up implementation (further discussed in Chapters 4 and 5). For countries with a small amount of cropland experiencing severe drought and water stress (bottom-left quadrant), water challenges may still be a concern but are likely at the subnational level. Countries with low access to irrigation and a small share of irrigated cropland may indicate no water stress, but that does not mean water is not scarce. They have the potential to expand irrigation either through infrastructure to extract more surface water and underground water, or by drawing on rainfall (e.g. through harvesting systems, small dams, reservoirs, etc.). Africa’s agricultural water remains comparatively underdeveloped, despite viable potential to expand irrigated areas. At least 1.4 million hectares could be developed using existing or planned dams for hydropower, and at least 5.4 million hectares would be viable for small-scale irrigation.¹⁶ This depends on financing, energy sources and prices, and labour availability (see Chapter 3).

One broad observation from Figure 9 is that, in terms of affected share of hectares, high water stress is an issue for more countries than is high incidence of severe drought. However, the rainfed cropland area in many countries is much larger than the irrigated area. Hence, even a small proportion of rainfed area at risk of drought can translate into millions of hectares. Figure 10 compares the share of rainfed and irrigated cropland under high or very high water constraints. In South Africa, despite irrigated areas being proportionately under more stress (Figure 9), in terms of hectares, the rainfed area at risk of drought is twice that of irrigated areas under water stress. Therefore, Figure 9 needs to be interpreted only for the production system to which it applies – irrigated or rainfed cropland – large or small, as it may be.

FIGURE 10

Share of water-constrained cropland by production system, for selected countries

Back

Figure 10 further indicates that water constraints alone do not drive countries’ policy priorities. In Viet Nam, all affected cropland is rainfed, although more than one-third of its total cropland is irrigated. Irrigated agriculture plays a very important role in the country’s socio-economic development for poverty reduction, food security and nutrition, gender equity in rural areas, and improvement to cropping patterns and the environment. For these reasons, in recent decades, Viet Nam has invested heavily in new infrastructure and the rehabilitation of existing irrigation.¹⁸

Considerable variation exists in agricultural production systems

BOX 6

Land productivity in irrigated and rainfed agriculture in sub-Saharan Africa

Agricultural productivity is complex as output depends on a range of different inputs, including land, labour, fertilizers, chemicals and irrigation. A recent study by the World Bank highlights how irrigation predictably leads to a fall in the overall volatility of agricultural output, raising cropping intensity and encouraging the cultivation of high-value crops.²⁸ Irrigation is an important source of global agricultural output growth.^28,29

This box examines differences in land productivity – value of crop production per hectare of land cultivated* – between irrigated and rainfed agriculture using household survey data in rural areas of Ethiopia, Kenya, Malawi, Rwanda, Uganda and the United Republic of Tanzania between 2004 and 2014. As expected, irrigated areas are more productive (see the figure in this box), except in Ethiopia.

Land productivity values in irrigated and rainfed areas, 2004–2014

Back

Across the six countries, Ethiopia reports the lowest percentage of households using irrigation (9 percent), after Uganda and the United Republic of Tanzania. Almost half the irrigated area in Ethiopia relies on traditional forms and only a negligible amount uses high-tech systems, such as sprinkler and micro-irrigation.³² The mix of crops can also help explain higher rainfed productivity. In Ethiopia, high-value crops such as coffee, oilseed and pulses are mostly rainfed,³³ while industrial crops such as sugar cane, cotton and fruit are mostly irrigated.^32,33 Both farm systems produce vegetables and cereals; however, teff – arguably the most important cereal crop in Ethiopia – is predominantly rainfed and more valuable than other cereal crops.^33,34 This finding suggests irrigation alone does not determine higher productivity and, depending on the level of other inputs (including crop varieties and irrigation services), irrigation may provide only marginal benefits relative to rainfed agriculture.

Back

Even within irrigated and rainfed settings, there are different production systems and a continuum of technologies from full irrigation to full rainfed production.²⁵ While some farmers practise rainwater management to enhance production – diverting, capturing, storing or reapplying rainfall instead of simply allowing it to flow without intervention – others may not. Not all farmers who irrigate their fields do so the same way, some irrigating more frequently and intensively than others. They may use different techniques and extract water from varied sources, which may influence its quality.²⁶ (See In Focus: Agriculture, water pollution and salinity.)

These differences are crucial determinants of successful production and likely to become more relevant as water shortages and scarcity increase. It is important to distinguish between separate production systems, which may be affected differently and have varied capacities to respond to water constraints. This report distinguishes between three systems delineated by water supply and farmers’ inputs, based on the SPAM dataset by IFPRI: (i) irrigated; (ii) high-input rainfed crop production; and (iii) low-input rainfed crop production.²⁷ For further discussion on the SPAM methodology, see Box 7.

Different production systems are an indicator of the level of a country’s agricultural development as well as its ability to address water constraints. In countries with more land under high-input rainfed and irrigated production, farmers have greater access to modern inputs and infrastructure, including irrigation, and crops can tolerate higher temperatures with higher yields and greater stability.^24,28 Based on Figures 5 and 7, Figures 11 and 12 display the relative share of each production system and incidence of water shortages and scarcity in each world region, income grouping and country classification. The bar colouring indicates the level of water shortages or scarcity in each system.

FIGURE 11

Share of cropland by production system and level of water shortages and scarcity, by region

Back

FIGURE 12

Share of cropland by production system and level of water shortages and scarcity, by income level and country grouping

Back

Production systems, type and extent of water shortages and scarcity vary considerably across different regions (Figure 11). Central Asia stands out as facing recurring agricultural drought on more than half of its low-input rainfed cropland, and almost all of its irrigated areas are under high or very high water stress. Northern Africa and Western Asia are similarly challenged in both dimensions, and irrigated farming systems face water-stress conditions in all Asian subregions.

High-income countries, such as in Europe and Northern America, have a considerable amount of cropland under high-input rainfed production. They have temperate climates and the highest public expenditure on agricultural research and development (R&D) and investment as a share of gross domestic product (GDP).³⁹ Agriculture is also highly capital-intensive and efficient.³⁹ Conversely, in sub-Saharan Africa, more than 80 percent of cropland is rainfed with low-input levels, while only 3 percent is irrigated or equipped for irrigation. Capital intensity and agricultural research are much lower than in high-income countries.³⁹ Farmers – particularly women – have difficulty accessing irrigation equipment, mechanization, and improved seed and fertilizer, and/or they lack the skills and technology to retain water in the soil. Despite these challenges, a relatively small share of rainfed cropland in sub-Saharan Africa suffers frequent drought.

Not all low-income and lower-middle-income countries lack access to irrigation and modern inputs (Figure 12). For example, countries in Southern Asia employ modern inputs on, and irrigate 40 percent of, their cropland despite many having a low level of development. Most irrigated areas are under high or very high water stress. In these water-scarce countries, water productivity R&D is important, coupled with sustainable production to maintain soil moisture and supplemental irrigation to overcome increasing dry spells during plant growth. There is also the potential to engage in virtual water trade to reduce usage and depletion of water resources (Box 8). In countries with little incentive to use irrigation more efficiently to save water, public policies – through, inter alia, improved access to extension services, credit and technology – will shape those incentives. Managing competing demands for water is also key, particularly in lower-middle-income countries with a large irrigated area under water stress, and where urbanization is likely to continue, and expanding cities, industries and tourism may take priority for water supply. This will reduce the water available for irrigated, urban and peri-urban agriculture, such that crop production will compete with growing demand from other users for land and water,²⁴ with greater reliance on food imports likely. Given that a significant share of urban water is non-consumptive, its reuse in agriculture after treatment has great potential, particularly in water-scarce countries.⁴⁰

For countries sharing similar characteristics and constraints in their development efforts, least developed countries have an almost equivalent allocation of production systems as those in the low-income group – i.e. heavy predominance of low-input rainfed production and a low share of cropland under irrigation (Figure 12). The minimal irrigated area is already under high or very high water stress. This is a challenge shared by landlocked developing countries, with the added concern that more of their rainfed farming systems suffer drought, leaving them particularly vulnerable to climate change effects. Up to 95 percent of their total food derives from domestic production,⁴⁹ and almost 70 percent of their cropland uses low levels of inputs, highlighting the opportunity and necessity for agricultural transformation. Not having an outlet to the sea makes access to technologies, markets, information and credit more difficult and costly.^50,51

SIDS also share unique geographical, economic and social circumstances as a result of their isolation or limited natural resources. Their land area and remoteness limit agricultural production, with low diversity of agricultural commodities, and increase import dependence.^52,53 These countries use more irrigation as well as high inputs in rainfed settings, partly because some SIDS are working to improve irrigation, groundwater extraction and rainfall catchment.⁵⁴ They have very few issues with recurring droughts or water stress. However, with climate change and overuse of natural resources, they are under threat from sea-level rise, coastal erosion and less freshwater for agriculture.⁵² As a result of climate change, rainfall is projected to steadily reduce in the Caribbean and Pacific SIDS, a serious problem for the sustainability of rainfed systems.⁵⁵

Heterogeneity in input use, irrigation and management practices can also be significant within regions and countries, affecting farmers’ capacity to cope with water shortages and scarcity. The World Bank’s Living Standards Measurement Study – Integrated Surveys on Agriculture (LSMS-ISA) explores variations of within-country input and irrigation use that macrolevel statistics mask. In Ethiopia, the share of households using chemicals ranges from 16 percent to 55 percent by region (compared with a national average of 40 percent). This large spread also applies to inorganic fertilizer, with ranges from 20 percent to 70 percent (60 percent nationwide).³⁵ Spatial datasets also illustrate the heterogeneity of input levels across and within regions (see Figures A1 and A2 in the Statistical Annex).

Various factors explain this heterogeneity. They include input and output prices, market access, investments in infrastructure and agricultural extension services. Policies should start by supporting farmers – via secure land and water tenure, credit and extension services – to reduce water-related risks. In Bangladesh, more-secure tenure rights, improved access to agricultural extension and electricity facilitate drought mitigation.⁵⁶ Given that one of the main obstacles to addressing water challenges is the ignoring of gender issues and women’s access to natural resources, the Grameen Bank in Bangladesh gives small loans to poor women, to help make decisions on allocating resources under changing economic and climate conditions.⁵⁷

Extreme water shortages or scarcity affect almost 1.2 billion people globally. Climate change will add to this problem through increased water stress and recurring droughts, placing additional stress on agricultural systems that already have to satisfy rising demand from population growth and dietary changes. Both the livelihoods and the food security and nutrition of rural and urban communities are at risk. The rural poor are the most vulnerable⁶¹ owing to their high dependence on natural resources, limited resilience and protection against climate-related risks and shocks, and power imbalances over access to natural resources such as water and land.

Multimodel assessments have explored how climate change might affect future global water risks. One study found that climate-driven changes in evaporation, precipitation and runoff would result in a 40 percent increase in the number of people who will have to survive on less than 500 m³ of water per year, considered “extreme” water scarcity (see Chapter 1).⁶² Another study found that an additional 0.8 billion to 3.9 billion people will experience water stress by 2050.⁶³ The authors found that exposure to water scarcity would increase steeply with a temperature rise of up to 2 °C above pre-industrial levels in many regions (including Northern and Eastern Africa, Arabian Peninsula and Southern Asia) and then stabilize by 4 °C. The authors’ assumption was that beyond this point, there would be no further areas where precipitation would decrease significantly.

Climate change will also play a strong role in water shortages. A recent study finds that 129 countries will experience increased drought mainly owing to climate change.⁶⁵ Drought is likely to become more frequent and severe by the end of the twenty-first century in some parts of Southern America, Western and Central Europe, Central Africa and Australia.⁶⁶ Drought can produce negative economic growth, and the consequences for human development and women’s empowerment may be long-lasting or even permanent. In sub-Saharan Africa, women exposed to drought in early childhood are significantly less wealthy as adults, have reduced adult height and receive fewer years of formal education.⁶⁷ A great concern is that these impacts can be transmitted across generations, with children of women affected by drought more likely to have low birth weight. Climate change also affects flood hazards. Dankers et al. (2014) found an increase in flooding owing to climate change over more than half the global land surface.⁶⁸

Although there is uncertainty on their location and magnitude, the effect of these changes on water availability will have a sizeable impact on crop yields for rainfed and irrigated areas.⁶⁹ Direct climate impacts on heavily irrigated regions could see reversion of from 20 million to 60 million hectares of cropland from irrigated to rainfed management.⁷⁰ Freshwater in other regions could ameliorate these losses, but will require substantial infrastructure investment (e.g. supplemental irrigation). Trade may be an adaptation measure to climate change with policy ramifications (Box 8).⁷¹ Climate change also affects freshwater ecosystems, fish and other aquatic populations that have low buffering capacity and are sensitive to climate-related shocks and variability.⁷² Exceptionally, climate change effects can be beneficial to inland fisheries (e.g. for some native and exotic fish species).

Water management will be key to equipping people and societies to make adjustments across systems, sectors and scales to withstand, recover from and anticipate the impacts of climate change.⁷³ There is a need for more scientific information and data at the local level to be included in multi-stakeholder decisions.⁷⁴ The evidence for climate change may be enough to define approaches or investment levels.⁶¹ Where uncertainty poses challenges on the action to be taken and where to focus investments, the best water management options are robust, the “no regrets” type of policies. These demonstrate satisfactory performance across a range of possible futures, and make agricultural production more resilient to future impacts, alongside equitable and inclusive measures.⁶¹ A good example is contingency planning to adapt to droughts of varying intensity and duration. If complemented by flexibility, this approach will retain the ability to respond to future events, changes in climate and hydrology patterns, and residual risk.⁷³ Recognizing that most climate change impacts are likely to alter the water cycle, climate-smart agriculture strategies – guiding actions to re-orient agricultural systems to support development and food security and nutrition in a changing climate – should be viewed through a water lens.

This chapter has shown how almost one-sixth of the world’s population live in areas with very high severe drought frequency or very high water stress. Water requirements will only increase owing to population and economic growth, dietary changes and climate change. Thus, there is a need to adapt water and sectoral policies, as well as management strategies, to use water in ways that meet the needs of people and the environment today, tomorrow and beyond. This is a significant governance challenge, involving important trade-offs and opportunities.

The most appropriate solution for one farmer, country or region may not be the same as that for another, as situations vary widely across production systems – rainfed and irrigated – and analysis and proposals for improvement can be highly specific. In irrigated settings, the water scarcity challenge will require both supply management, with selective development and use of unconventional water resources (seawater desalination, brackish water and reuse of wastewater), and vigorous demand management, with actions to optimize existing supplies.⁷⁵ Demand management requires recognition of the economic value of water along with cost recovery, although with concern for affordability and security of the human right to water and food, particularly for the poor. There is also a need to address water supply through conservation of water-related ecosystems. In rainfed systems, on-farm conservation to increase infiltration and water storage in the soil may be the most relevant option to increase production. Water harvesting and storage systems can also contribute to increasing water availability and agricultural production at household and community levels, and to overcoming drought.⁷⁶

The most appropriate mix of supply and demand management will depend on local conditions, and it is unlikely that a single set of options can be the optimal solution.⁷⁶ Nor is a particular option desirable in all contexts. Policy options and related strategies will largely be shaped by elements such as a country’s level of development, water constraints, and the governance, political, socio-economic and cultural structures.^75,77 Various stakeholders view water scarcity differently, and they implement different adaptation and mitigation strategies as a function of their power and capacities. A critical concern is to ensure environmental flows, ecosystem services and non-consumptive use of freshwater, often not considered owing to a lack of proper economic valuation.⁷² Supporting necessary water management strategies calls for an inclusive enabling environment based on a set of mutually supportive policies and a comprehensive legal framework with coherent incentives and regulatory measures, such as secure land and water tenure. It also means creating and strengthening institutions and mechanisms that transcend traditional boundaries between sectors.⁷⁵ Governance mechanisms are needed for cross-sectoral coordination and policy coherence, involving a variety of users and stakeholders to identify key trade-offs and synergies, and for efficient, sustainable and equitable water resources management. Water demand and supply strategies should also have a financing strategy to cover the necessary investment.

Figure 13 illustrates how these dimensions come into play. The challenge of greater water shortages and scarcity (first circle, starting from the bottom) calls for integrated water management and technologies (second circle). These include, inter alia, desalination, pollution control and greater water-use efficiency, conditioned by technical planning and investment economics at the organizational and management levels. In turn, these are influenced by the institutional and legal framework (third circle) – encompassing water rights, licensing, regulations, incentive measures and the institutional set-up – and the overall policy environment (fourth and last circle) – including societal choices, priorities, sectoral policies (e.g. agriculture, municipalities and industry) and trade-offs.⁷⁶ Chapter 3 reviews available technologies and agriculture water management strategies (second circle) to adapt to increasing water shortages and scarcity. The latter dimensions in the third and fourth circles are discussed in more detail in Chapters 4 and 5.

FIGURE 13

Placing water shortages and scarcity responses within the broader policy context

Back

This chapter has shown that almost 1.2 billion people live in areas with issues of severe water shortages or scarcity in agriculture, putting their lives and livelihoods at risk. Water constraints vary spatially and over time; some countries and regions are more vulnerable than others. The majority of these 1.2 billion people live in Southern Asia, where about 80 percent of the population in countries such as Pakistan and Sri Lanka live in affected agricultural areas. Other parts of Asia and Northern Africa are also disproportionately affected.

This chapter has further traced different dimensions of water shortages and scarcity – recurring droughts and water stress – and how they impact the agriculture sector and different population groups, depending on the extent to which they rely on irrigation or rainfall and employ high levels of inputs. The severest challenges are very high drought frequency and very high water stress in rainfed and irrigated agriculture, respectively. Challenges are particularly severe in low-input rainfed agriculture, which tends to be the dominant production system in low-income countries and among poor and vulnerable groups. It is likely that the additional food to satisfy future demand will come from increasing productivity on existing land. As populations and economies grow, consumption patterns move towards more water-intensive foods, and the impact of climate change deepens, adaptive technical solutions will be needed to improve water productivity in rainfed and irrigated settings while protecting environmental flows (see Chapter 3). In turn, this will require the adoption of appropriate institutions and incentives (presented in Chapter 4). In some cases, there is potential to engage in virtual water trade to reduce water use and depletion of water resources.

Chapter 2 has shown that numerous regions are experiencing severe water constraints from drought or water stress. Population growth, rising incomes, increasing urbanization, dietary changes and climate change may exacerbate water risks, affecting production systems in ways yet to become apparent. Ensuring that agriculture and food systems meet the needs of a rising population in an inclusive and sustainable manner will require major transformations. These may involve technical change and innovation but will also be widely influenced by governance, institutional frameworks and the policy environment (further discussed in Chapters 4 and 5). This chapter reviews technologies and management methods to address water shortages and scarcity in agriculture, and achieve food security and nutrition sustainably. It assesses options for different production systems – rainfed or irrigated cropland, livestock, inland fisheries and aquaculture – with distinct water challenges in mind. The chapter concludes by examining the role of aquaculture in reducing water constraints and ensuring a sustainable food system.

Almost one-sixth of the world’s population lives in areas with very high water stress or severe drought frequency, threatening economic growth, food security and nutrition, and livelihoods. These challenges must be addressed alongside climate change, which will exacerbate water shortages and scarcity, and negatively impact agricultural production, especially in low-latitude and tropical regions.^1–3 More sustainable management of irrigated areas is critical, but water management in rainfed cropland and pastureland areas is also an important part of the solution. Yield-improvement opportunities exist in both irrigated and rainfed systems, and across crops and geographical locations.^4–6

Improved water management is crucial to reducing yield gaps. Adoption by farmers will depend on, inter alia: (i) water accessibility; (ii) water risk; (iii) level of uncertainty under a changing climate; (iv) cost of other inputs; and (v) net benefits of water management strategies. Secure but limited water access incentivizes farmers to improve water-use efficiency and reduce usage. The greater the water risk, the more farmers are encouraged to change water use and management. Changes may also involve varying other inputs, including labour and energy. The cost, and associated net benefits, will ultimately influence the decision to adopt new water management strategies.⁷

Not all water risks can be addressed by farmers alone or depend exclusively on farmers’ decisions. Some will rely on public-sector intervention and initiatives. Small yield variations owing to erratic precipitation can be addressed through normal on-farm business decisions, but more catastrophic water risks that cause great damage may require government involvement.⁸ Farmers may not understand the current status and future trends in water supply and demand. Public investment in water accounting – the systematic assessment of water status and trends – and dissemination of results together with awareness-raising campaigns are vital for policies on water risks, climate change and engaging farmers in sustainable water use (see Chapter 4).^9,10 Governments can also play an important role in removing barriers, such as low market access, that deter farmers from managing water resources.

The following sections review technical options and farmer management strategies in rainfed and irrigated agriculture. There is no clear demarcation between rainfed and irrigated systems, and managing water includes a spectrum of options – from entirely rainfed to fully irrigated conditions, to supporting livestock, forestry and fisheries, and interacting with important ecosystems.¹¹ Figure 14 depicts water management options along the spectrum from fully rainfed (green) to fully irrigated (blue). The grading from green to blue refers to practices where farmers use both rainfall and irrigation water, and are not fully reliant on rainfall or irrigation, but somewhere in between.

FIGURE 14

Agricultural water management along the spectrum from rainfed to irrigated

Back

The continuum starts from farmers in fully rainfed settings who apply on-farm conservation to store rainwater in the soil (see Water conservation box in Figure 14). Along the continuum, farmers in rainfed areas capture rainwater or manage runoff (from a surface source or an aquifer) for supplemental irrigation to enhance crop production. This additional freshwater has other uses in integrated aquaculture and livestock systems. (For further discussion on the role of aquaculture and integrated farming systems, see the In Focus: Aquaculture in the context of sustainable water use in food systems) In fully irrigated systems, farmers have access to affordable surface water or groundwater (see predominantly blue boxes). Drainage is an important supplement across the whole continuum. Farmers in rainfed settings may minimize drainage to the water table by increasing root water uptake. In irrigated systems, when farmers apply too much water, drainage will determine the water table and soil salinity. (See the In Focus: Too much water? Flooding, waterlogging and agriculture.)

Innovative water management practices should aim at (i) reducing water consumption in agriculture to increase water available to other users and (ii) improving production systems’ resilience to growing water shortages and scarcity. Water management should be combined with better agronomic practices (drought-tolerant varieties, proper crop planting, etc.), improved environmental sustainability through reduced sediment loads and pollutants, improved soil health, reduced surface runoff, and increased recharge to shallow groundwater. Investments need to be economically, socially and culturally viable, calling for strong institutions and governance to guarantee equitable distribution of benefits, enhanced food security and nutrition, and sustainable livelihoods. The Principles for Responsible Investment in Agriculture and Food Systems endorsed by the Committee on World Food Security can serve as framework to guide stakeholders on any type of agricultural investment.¹²

Rainfed production dominates agriculture, covering about 80 percent of total cropland (see Figure 11). Farmers, particularly small-scale farmers, have limited influence over the amount and timing of water.¹³ The main challenge is to manage and adapt to weather variability, temperatures and rainfall patterns. Global analyses estimate that extreme weather events affecting rainfall and temperature can explain 18–43 percent of yield variation for key crops, including maize, rice, soybean and wheat.¹⁴ As water shortages increase, and population and economic growth accelerate, there will be pressure on all agricultural systems, especially rainfed ones, to use water more productively. Chapter 2 further distinguished between low-input and high-input rainfed production systems. While the challenge of addressing water shortages remains the same in both categories, what differs is their capacity to address it. Farmers in high-input systems can more easily invest in improved water management and agronomic practices to ensure the most efficient use of scarce rainfall.

Yields in rainfed agriculture remain lower than those in irrigated areas (Figure 15), and substantial yield gaps persist globally and regionally.^5,15 Such gaps are expected to largely mirror the classification of low-input and high-input systems. There is great opportunity to increase yields in Africa, Eastern and South-western Europe, and parts of Asia, where gaps are largely due to a combination of water and nutrient shortages.^{5, 15, 16} In temperate regions, such as Western Europe and Northern America, where a substantial amount of cropland is rainfed and largely high-input (see Figure 11), yields of cereals often exceed 6 tonnes per hectare, against a global average of 4 tonnes per hectare.¹⁷ In Central and Western Europe, supplemental irrigation maintains yields during dry summers.¹⁸ Yields in Eastern Europe remain lower, suggesting that unlocking the vast potential of the region will depend on new agricultural water management and technological change.

FIGURE 15

Vegetable yields by region, 2012

Back

While some countries in tropical areas often exceed 5 tonnes per hectare for cereals, others do not surpass 2 tonnes per hectare. This suggests that the biophysical constraints causing low yields in rainfed farming, particularly in tropical low-income countries, can be overcome, inter alia, by appropriate water management, combined with best agronomic practices.

Making best use of rainfall for improved rainfed crop productivity

There are two broad strategies for increasing yields in rainfed agriculture: (i) collecting or harvesting more water, infiltrating it into the root zone; and (ii) conserving water by increasing plant uptake capacity and/or reducing root-zone evaporation and drainage losses. Where the issue is excess water, strategies focus instead on relocating practices to divert it. Figure 16 illustrates options, described along a continuum from production fully dependent on rainfall to situations in which farmers rely partly on supplemental irrigation.

FIGURE 16

Main water management practices in rainfed agriculture

Back

Key to making the best use of rainwater are soil and water conservation technologies – first box on the left in Figure 16 – which control the water available to a crop by affecting the water content in the root zone. Terracing, agroforestry, contour cultivation and conservation agriculture can modify and enhance soil-water content to retain moisture and prevent erosion.²¹ Organic mulching, a natural or artificially spread layer of plant residues or other organic materials on the surface of the soil, can also minimize evaporation. As residues decay over time, they increase the water-holding capacity of soil, improving efficiency.²² Organic mulching also provides soils with nutrients and restricts weed growth by blocking light penetration of the soil surface, contributing to increased water efficiency.^22,23

A distinction is often made between in situ water harvesting, which refers to the capture of local rainfall on farmland, and ex situ water harvesting, which refers to rainfall capture outside the farm. Ex situ water harvesting uses water to mitigate dry spells, protect springs, recharge groundwater, enable off-season irrigation and permit multiple uses.²¹ These practices include surface microdams, subsurface tanks, ponds, and diversion and recharging structures. Communities or individual farmers usually manage these systems, and they require information, training and awareness raising to properly implement and maintain these practices.²⁴ For example, in Tigray, a water-constrained region in northern Ethiopia, the government has prioritized different ex situ systems, the majority run by individual farmers. These have helped increase crop and livestock productivity, crop diversification and access to water points.³⁰ However, outcomes depend on farmer and stakeholder participation during planning, implementation and utilization.³¹ In the Sahel, FAO is implementing the “One million cisterns” programme to promote rainwater harvesting and storage systems for vulnerable communities.³² The objective is to allow millions of people in the Sahel, especially women, access to safe drinking water, enhance agricultural production, improve food and nutrition security, and strengthen their resilience.

Water collected through harvesting can be later applied as supplemental irrigation when rainfall is scarce (Box 9). In situ water harvesting covers different technologies – microcatchments, bunds, broad-beds and furrows – as well as management options such as tillage or adding organic matter.

Combining water conservation and harvesting can be highly effective. Rost et al. (2009) estimate that a 25 percent reduction in evaporation and a 25 percent collection of runoff could increase crop production by 19 percent.³⁸ Jägermeyr et al. (2016) have shown that soil moisture conservation alone could boost global rainfed kilocalorie production by 3–14 percent.³⁹ The authors also found that a combination of in situ and ex situ water harvesting could further increase kilocalorie production by 7–24 percent. Under the ambitious scenario (all measures combined, including irrigation expansion), this could increase global kilocalorie crop production by 41 percent.

Access to cost-effective rainwater management and supplemental irrigation technologies can give farmers in rainfed holdings the security to invest in fertilizers and high-yielding varieties. Aside from water management, the performance of a crop is the result of inherent attributes (i.e. genetic gains, as with improved varieties) and agronomic practices, including various inputs. Without agronomic practices, in situ water harvesting and soil and water conservation may generate only marginal, if any, crop yield gains.^40,41

Water relocation is another important supplement to water harvesting and conservation (last box on the right in Figure 16). Farmers combine harvesting and conservation with drainage to avoid floods during heavy rainfall, while terracing systems can also work as drainage structures on sloping cropland.

Almost 20 percent of global cropland is suitable for water harvesting, and for soil and water conservation, with hotspots in large parts of Eastern Africa and South-eastern Asia.⁴² Water harvesting in these cropland areas can increase production by 60–100 percent. These practices may reduce surface and groundwater flows; therefore, water accounting should precede any implementation. In many rainfed areas, efforts towards sustainable rainfed production have been in place for decades. In Ethiopia, public investments, farmer in-kind contributions through labour and international development inputs have gone into soil and water conservation for more than 40 years. As a result, about 20 percent of the country’s cropland employs terracing.⁴³ The extent of cropland under improved management practices at the local and global levels remains unknown. Global data are also scarce for agricultural areas equipped for surface and subsurface drainage.

Irrigation is important for adapting to climate change as well as increasing land and water productivity. Irrigated areas occupy only about 20 percent of total cropland (see Figure 11), but generate more than 40 percent of total production in terms of value.⁴⁴ In some areas, irrigation contributes to more than half the value of agricultural production. This is the result of higher productivity in irrigated areas relative to rainfed agriculture, and higher and more stable yields with more intensive cropping, as well as cultivating higher-value crops.⁴⁴ The scope for efficiency gains and for increased land and water productivity is considerable. The challenge is how to improve performance without compromising sustainability.

Increasing water productivity in irrigated agriculture

Making more productive use of irrigation water can produce more crops with less water, by either increasing crop yield, reducing seasonal evapotranspiration, or achieving a combination of both. Globally, there is a large disparity in water productivity among crops (Table 2), reflecting large variation in yield, nutritional outcome and US dollars per litre of water consumed. Figure 17 illustrates the economic water productivity of irrigated cereals, the green patches indicating high water productivity, with less water per unit of value, while the yellow-red fields represent low productivity.

TABLE 2

Global average water productivity of selected food categories

Back

FIGURE 17

Economic water productivity of selected irrigated crops, by region

Back

Water is one of several inputs when producing a commodity, and some agroecological zones are better suited to certain crops than are others. For wheat, the most water-consuming crop in Figure 17,⁴⁵ almost all regions report low economic water productivity. The only exception is parts of Europe, where wheat accounts for half of total cereal production in terms of value.¹⁷ A similar pattern emerges for barley, where besides Europe and some parts of China, the red patches in other regions suggest low productivity. For maize, high-income countries in Northern America and Europe are highly productive, while low-income and low-middle-income countries in Asia, South America and sub-Saharan Africa report lower water productivity. This is a concern in Africa, where food insecurity and malnutrition are substantially higher,⁴⁶ and maize represents more than one-third of total cereal production in terms of value.¹⁷ For rice, a different pattern emerges, as Asia and South America are as productive as parts of Europe and Northern America. In Asia, rice accounts for almost two-thirds of total cereal production,¹⁷ and is central to the livelihoods of millions of small-scale farmers.

Better access to inputs, efficient irrigation, improved crop varieties, and better soil and water management can explain higher water productivity for most crops in high-income countries of Northern America and Western Europe. In contrast, in addition to operating under conditions of poor soil and poor water management, farmers in sub-Saharan Africa may have limited access to high-yielding crop varieties, fertilizers, pesticides, mechanization and markets. Variability in crop water productivity within regions and countries is due to a range of factors, including: (i) climate conditions, such as evaporation, amount and timing of rain and/or irrigation water, and air temperature; (ii) soil properties, texture and organic matter content; (iii) crop cultivars, as crop varieties and cultivars have different crop yield and water needs; (iv) soil and water management practices, which influence the amount of water available in the soil, or the ability of roots to extract it and reduce soil evapotranspiration; and (v) other agronomic practices, such as timing of crop sowing or planting and fertilizer application.^47–49

Despite considerable improvements in water productivity, gaps remain between actual and attainable yield per unit of water. Figure 18 shows actual water productivity (blue) and productivity gaps (grey), in economic terms, for irrigated crops by region. Australia and New Zealand, Europe, and Northern America have the smallest water productivity gaps, while Latin America and the Caribbean, Northern Africa, Western Asia, and sub-Saharan Africa have the largest water productivity gaps for most crops. While closing yield gaps can promote food security and nutrition in most countries, some may be more relevant than others.⁵¹ Farmers and policymakers may prioritize those crops where economic gains are likely to be greatest.

FIGURE 18

Actual economic water productivity and water productivity gaps for selected irrigated crops, by region

Back

For example, Europe has one of the largest water productivity gaps for sorghum and wheat, partly from climate change.⁵² While wheat accounts for half of cereal production in terms of value, sorghum production is negligible.¹⁷ Sub-Saharan Africa, on the other hand, exhibits the highest water productivity gaps for barley and wheat, while that for sorghum is smaller compared with other regions. Sorghum and wheat account for almost one-third of African cereal production in terms of value, while barley reaches 3 percent. These findings suggest closing water productivity gaps for wheat in Europe and sub-Saharan Africa might bring the greatest economic benefits and improve food security and nutrition, especially in the latter region. The costs of closing these gaps must be considered, especially for wheat in Europe, where water productivity is already very high compared with that of other regions.

Different irrigation for different contexts

No single irrigation system is best for all situations, and when deciding, farmers must bear in mind several factors: soil, water and climatic conditions; crop types; financing possibilities; energy prices and sources; labour; application efficiency; economies of scale; and the depth from which the water is pumped, etc.⁵³ The three main irrigation methods are surface irrigation, sprinkler irrigation and micro-irrigation (e.g. drip). In surface irrigation, water flows over the soil by gravity. Sprinkler irrigation applies sprinkles or sprays of water droplets. Micro-irrigation involves frequent small applications by dripping, bubbling or spraying, and usually only wets a portion of the soil.⁵⁴ A fourth method is subsurface irrigation, which applies water below the soil surface to raise the water table into or near the plant root zone.⁵⁴ Table 3 shows some advantages and disadvantages of various irrigation systems.

TABLE 3

Typical strengths and weaknesses of irrigation systems

Back

Farmers’ decisions on investments in irrigation depend on associated costs. Studies on those costs and benefits can be useful. In Texas, the United States of America, Amosson et al. (2011) studied five common irrigation systems,⁵³ discovering furrow irrigation requires less capital than other systems but is less efficient and more labour-intensive. Centre-pivot systems (referred to as moving sprinkler systems in Table 3) are more efficient and reduce field operations to offset additional costs. Low-energy, precision application is a type of centre-pivot irrigation that generates the greatest benefits. For most crops, owing to high investment and small efficiency gains, subsurface drip irrigation may be limited to land where pivots cannot be installed.

In sub-Saharan Africa, where large-scale irrigation projects often underperform in relation to investment, small-scale farmers develop and expand their own irrigated land.⁵⁵ Small-scale farmer-led irrigation systems can have lower unit costs than those managed by government agencies^56,57 and offer much higher internal rates of return (28 percent) than does large-scale, dam-based irrigation (7 percent).⁵⁸ They also improve yields and income, and reduce risks from climate variability (Box 10). Governments should support these initiatives by, inter alia, removing market barriers, and promoting affordable and appropriate credit facilities to enable small-scale farmers to embrace the initiative. Governments should also enact regulations to ensure these initiatives are environmentally sustainable.⁵⁵

In Asia, large-scale state-funded surface irrigation schemes are in decline for a variety of reasons, including poor maintenance by governments. Many were not set up to properly cater to farmers’ needs and have failed to provide sufficient water for crops.⁵⁹ Efforts to rehabilitate them are constrained by poor service provision and a lack of effective management. As a result, farmers are tapping directly into groundwater. While this has helped boost farmers’ efficiency and productivity gains, it has also placed excessive pressure on groundwater.⁶⁰ Addressing these issues will require modernizing old irrigation schemes, as well as coherent, effective and feasible policies, investment and interventions.

An agronomic practice with positive influence on water productivity is deficit irrigation, which ensures optimal water use. Deficit (or regulated deficit) irrigation is a way of maximizing water productivity.⁶⁵ The crop is exposed to a level of water stress either during a period or throughout the whole growing season. Any yield reduction will be insignificant compared with the benefits through diverting saved water to other crops.⁶⁶ Studies reveal higher water savings for fruit trees compared with herbaceous crops, for which there is almost always some yield penalty. Among other field crops, cotton and grain sorghum are suitable for deficit irrigation.⁶⁶ Other advantages of deficit irrigation include fewer fungal diseases and less nutrient loss, controlled sowing dates and improved agricultural planning.⁶⁷ As crop responses to water stress vary considerably, deficit irrigation requires precise knowledge of soil-water and salt budgeting, as well as crop behaviour.^65–68

Investing in sustainable irrigation for improved livelihoods and the environment

The traditional assumption has been that increasing irrigation efficiency through modern technologies, such as drip irrigation, leads to substantial water savings to be released for other uses.⁶⁶ While the farm-level benefit may be substantial, when properly accounted for at basin scale, total water consumption by irrigation tends to increase, reducing return flows to other users, including the environment. With increased irrigation efficiency, much of the water previously “wasted” by inefficient irrigation returns to the system via groundwater recharge, rivers and drainage networks, and is often reused for irrigation.³³ In addition, as modern irrigation incentivizes farmers to switch to higher-water-consuming crops, expand cropping areas or increase cropping intensity, this raises farmers’ incomes but also water consumption.^69–73 Without a water allocation system, new irrigation often leads to higher water consumption at the basin level. This is documented, for example, in the Indus Basin in Pakistan,⁷⁴ and in Andalusia, southern Spain.⁷¹

None of this is to recommend inefficient irrigation, but rather promote measures such as limiting water use while improving rural livelihoods (see Chapter 4). One study estimated that integrated water management (the integration of rainwater management with irrigation upgrades) could increase global kilocalorie production by 10 percent, while still respecting environmental flow requirements.⁷⁵

In addition, advanced irrigation technology brings important benefits that must be promoted as it (i) often saves labour; (ii) allows precise and economic application of fertilizers and chemicals; (iii) minimizes leaching of nitrates and other pollutants; (iv) reduces pumping costs and saves energy; and (v) allows the farmer to diversify into higher-value crops, increasing production value (Box 11).⁶⁶ If adoption remains low, this is mainly due to a lack of awareness of these benefits, among other economic and structural constraints. To be sustainable, investments in advanced irrigation technology must include robust water accounting; a cap on extractions; assessment of uncertainties; valuation of trade-offs; and better understanding of the incentives and behaviour of irrigators (see Chapter 4).⁷⁶

Water management is most effective when combined with optimal use of inputs and good crop management. The efficiency of a limited resource is at its best when all other inputs are at their optimum.⁸³ Improved water management should be combined with correct management of other inputs. Modern high-yielding crops are crucial in raising water productivity. During the green revolution, modern crop varieties, with increased irrigation and agrochemicals, played a major role in increasing yields of major crops. Soil nutrient status also has major effects on crop water productivity. Sadras (2004) demonstrated this for wheat crops in the Mallee region, Australia, where water and nitrogen accounted for a proportion of the gap between attainable and actual water productivity.⁸⁴

Several integrated approaches allow farmers, particularly on small-scale rainfed farms, to improve productivity sustainably.²⁵ These combine best practices with improved soil and water management that intensifies production through integrated soil fertility management, greater water-use efficiency and crop diversity. Box 12 illustrates the importance of crop management for yield, evapotranspiration and water productivity.

Some critical primary crop and nutrient management factors include:

• ▸ timely crop planting and harvesting to match rainfall, multicropping when possible to utilize soil moisture and recover soil nutrients, and shifting the planting season to periods of low evaporation;^{68, 85, 86}

• ▸ plant spacing and row orientation, involving optimum planting density (the amount of space between plants) and high stand uniformity;

• ▸ selecting crop varieties with high yield potential and/or that are resistant to drought and/or grow faster under canopy cover;^87–89

• ▸ spatial allocation and zone crop management, identifying and excluding fields that deliver consistently lower yields to help improve average crop water productivity;⁸⁶

• ▸ nutrient management, as soil nutrient status affects crop water productivity, weeding and pests.

Conservation agriculture

Conservation tillage can improve soil-water storage, soil quality and crop yield, and reduce evaporation.^96–100 Livestock on improved pastures derived from crop–pasture rotations based on conservation agriculture produce more meat per unit of pasture and with less greenhouse gas (GHG) emissions.¹⁰¹ The impacts on water productivity depend on context and effects on evapotranspiration and yields.^50,102 Conservation agriculture may face challenges in sub-Saharan Africa and Southern Asia, where crop residues are used as livestock feed or household fuel.^103–105 Other challenges include increased weeds and additional labour when herbicides are not employed, affecting women in particular.¹⁰⁶ The success of conservation agriculture often depends on identifying agroecological regions and soil types where it can be readily adopted. Developing site-specific packages and educating the farming community and general public about benefits will also help.

Conservation agriculture can also contribute to making agricultural systems more resilient to climate change. In many cases, it has reduced farming systems’ GHG emissions and enhanced their role as carbon sinks.^101,107 Climate-smart irrigation agriculture is another important option for adaptation to climate change. It focuses on improving productivity and profitability of existing irrigation, enhancing farmers’ resilience to climate change.¹⁰⁸ Box 13 estimates the potential benefits of implementing the improved management strategies described in this chapter.

BOX 13

Putting it all together – the potential for enhancing rainfed and irrigated crop production

Based on the rainfed and irrigated production systems in Figures 5 and 7, it is possible to estimate the percentage of cropland that can benefit from increased yields from different types of irrigation and water management technologies and practices. (For a breakdown by country of the share of cropland under each production system with water constraints, see Table A2 in the Statistical Annex). Projected yield improvements are based on investments to expand irrigated areas, irrigation rehabilitation, and the potential adoption of the following technologies and management practices: (i) drip irrigation; (ii) sprinkler irrigation; (iii) water harvesting; (iv) drought-tolerant varieties; (v) heat-tolerant varieties; (vi) conservation tillage; (vii) integrated soil fertility management (i.e. combining chemical fertilizers, crop residues and manure/compost); and (viii) precision agriculture (for a definition, see section Making innovation, communications and technology work for all).

The analyses in the figures in this box indicates what could be attained by 2030 based on the percentage of cropland using that technology according to projections of IFPRI’s International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT). A more detailed description of this modelling exercise and an overview of IMPACT are presented in the Technical Annex.

Under the projections, investment in irrigation rehabilitation and modernization is slightly greater with high water stress than with low water stress, as under high stress, investments can have higher returns. The expected investment in drip and sprinkler irrigation is also greater in irrigated settings with high water stress. Where water is plentiful, investments may not be profitable; where water is scarce, adoption offers farmers better control and application efficiencies to grow higher-value crops and achieve higher yields. To make sure investments translate into water savings for a watershed, they should be contingent on water accounting and allocations (see Chapter 4). Investments must also be accompanied by socio-economic analysis, considering local requirements and conditions.

Water harvesting and drought-tolerant varieties were modelled for rainfed production only. The projected adoption rate is higher in low-input rainfed production systems, indicating this could benefit small-scale farmers. As for drought-tolerant varieties, the projected percentage of areas is substantially higher in rainfed areas with high drought risk under both high- and low-input use.

Growing heat-tolerant varieties benefits all areas, rainfed or irrigated. Increased drought frequency is correlated with higher evaporation and temperatures, although the benefits may be greater in regions subject to frequent droughts and particularly relevant for low-input systems. Conservation tillage benefits irrigated and rainfed cropland and, for rainfed systems, has more scope in low-input systems facing droughts, indicating small-scale farmers could benefit. Integrated soil fertility management can benefit all areas, in particular, those with low water stress, but no clear pattern emerges across the different profiles. Under the projections, precision agriculture is the most profitable option and therefore the most adopted in irrigated systems with good control over water.

Percentage of cropland area to benefit from investment in selected technologies and management practices by 2030

Back

The investments, technologies and management practices assessed could provide benefits in all production systems with different water constraints. Although these will not resolve water shortages and scarcity on their own between 2020 and 2030, they can have a substantial impact for millions of farmers in irrigated and rainfed systems. Positive impacts vary significantly across countries, highlighting the importance of tailoring water management to irrigated and rainfed systems, to local capacities and conditions, and to water challenges.

Back

Animal products have lower water productivity compared with crops in terms of kilograms of product per cubic metre of water (see Table 4 relative to Table 2). Crop productivity ranges from 0.12 kg/m³ for nuts to 5.49 kg/m³ for sugar, while animal products range from 0.07 kg/m³ for beef to 1.05 kg/m³ for milk. After milk, the highest water productivity is reported for eggs and tilapia. Depending on the production system, the water productivity of tilapia can vary considerably. For instance, when cultured in fed aerated ponds, its water productivity is lower.¹¹⁰ In fisheries and aquaculture, calculating water consumption is less straightforward than for cropland and livestock, as the former considers feed, energy, and level of circulation and discharge. For further discussion on water use by fisheries, see the In Focus: Aquaculture in the context of sustainable water use in food systems.

TABLE 4

Global average water productivity of selected animal products

Back

In calorific terms, crops generally have higher water productivity than do animal products. From a protein perspective, tilapia reports the highest value in Table 4 and is more efficient than American catfish. Milk, eggs and chicken report relatively high values. Economic water productivity (in terms of US dollars per cubic metre of water) is often greater for animal products than for crops, with the exception of fruits, vegetables and starchy roots. Global demand for livestock products is rising (as is also that for animal feed), potentially a burden on freshwater resources. There is a need for further improvements in water productivity for animal products.

Options for livestock production systems

Livestock production makes use of different systems with varied water-use patterns. For feed, livestock may rely on grazing and/or feed from either rainfed or irrigated production. In mixed production, livestock consume crop residues and by-products, and produce manure to fertilize crops. More than one-third of the planet’s ice-free land is used for pasture.¹¹⁴ Livestock graze on about 2 billion hectares of pastures and meadows, two-thirds of which are not suitable for crops. In these areas, livestock production is the only way of transforming rainfall into food. Besides using a large share of agricultural land, livestock production also uses large amounts of water.¹¹⁵ Unlike cropland, livestock are often not considered subject to agricultural water management, even with many opportunities to improve water productivity and environmental performance. Livestock are also a strong asset for resilience as they buffer the impact of drought on agricultural outputs and farmers’ livelihoods through, inter alia, animal mobility, disease control and animal health, feed and drink management, and stratification of production to reduce grazing pressure in arid areas.¹¹⁶ In many pastoral societies, mobility is a key strategy for accessing dispersed grazing and water over large areas, which is particularly important during severe droughts.¹¹⁷

In pasturelands, proper control of the grazing season, intensity, frequency and distribution can improve vegetation cover, reduce soil erosion and maintain or increase water quality and availability.¹¹⁸ Animal management includes improving animal health and careful animal husbandry.^115,119 Diets can also meet the dual challenge of increasing the sector’s water productivity and conserving water through improved management and closing the yield gaps of feed crops. A study in Santa Catarina, Brazil, in 2001–2011 found that nutritional strategies could reduce the water footprint of swine by 18 percent, and increase water productivity – in nutritional terms – by more than 20 percent.¹²⁰ Another study in northern Germany found that increasing milk yield, combined with grass and maize silage-based feeding, substantially raised water productivity on dairy farms relative to pasture and concentrate feeding.¹²¹ In mixed crop–livestock farming systems, choosing feed types carefully, improving feed quality and sourcing, increasing feed water productivity and grazing management can raise water productivity.^119,122 These practices improve land- and water-use efficiency and significantly reduce GHG emissions.

The effective use of stored water in tanks and reservoirs, rainfall and marginal quality water for livestock is key, given that much water in livestock farming is for animals.¹¹⁵ Reducing the amount by water-efficient drinking devices (e.g. water bowls and bite-type drinkers), and maintenance and repair of water troughs to eliminate leaks, are important conservation strategies. Beyond changes to animal diets and drinking systems, other options include shade on waiting yards or feed yards, and regulating the temperature in animal housing.¹¹⁵ Managing cleaning, high-pressure washers or recycling can also reduce consumption and vulnerability to shortages, and water from alternative sources alleviates pressure on water-scarce sources. Attempts to improve agricultural water productivity must recognize differences among systems and optimize resource use by their components.¹²² Taking institutions, policies and gender into consideration can lead to successful uptake of interventions.¹¹⁹

Linking agricultural landscapes and ecosystem functions

Agricultural production systems are major drivers in a range of desirable and undesirable environmental changes. Rainfed cropland and pastureland can substantially affect biodiversity and water quality.¹²³ Some water strategies can have negative impacts. Decentralized measures, such as rainwater tanks and storm-water harvesting, even if small, can have a negative impact on a catchment’s water balance when not combined with other solutions (e.g. restoration of upstream ecosystems). Large programmes of small-scale water harvesting, such as local basin management in the State of Andhra Pradesh and other parts of India, have substantial impacts on overall hydrology and availability of water downstream,¹²⁴ and can seriously affect the productivity of river fisheries. However, evidence is mixed, and there is a need for new modelling tools and field data collection.^125,126

Improved agricultural water management can also lead to desirable environmental changes. In the Kothapally watershed in southern India, for example, agricultural water interventions have reduced sediment loads to the rivers, with large positive impacts on in-stream river ecology and the lifespan of reservoirs.¹²⁵ Appropriate water management can also substantially reduce GHG emissions. For example, reducing or interrupting periods of flooding is one of the most promising techniques for reducing rice-related emissions, as it lowers bacterial methane production and thus methane emissions.^127,128 Several approaches take account of the relationship between agricultural landscapes, resource use and ecosystem functions. Nature-based solutions are inspired and supported by nature, and use or mimic natural processes to contribute to improved water management. They can involve conserving or rehabilitating natural ecosystems and/or enhancing or creating natural processes in modified or artificial ecosystems.¹²⁹ They can have positive cascading effects for agriculture, biodiversity, food security and the environment. However, despite increasing recognition, their broad implementation still faces some challenges. There are calls for a paradigm shift to view forests, peatlands and other ecosystems as regulators of freshwater from site to continental scales with a landscape approach across many stakeholders (Box 14). Enabling conditions place nature-based solutions at the same level as other water management options. These may include redirection of investment, payment for ecosystem services, and sustainable agricultural practices and policies that support these solutions.¹²⁹

Runoff management, and sediment and erosion control

An undervalued benefit of agricultural water management is the effect on surface water runoff retention and sediment control. Retention systems’ capture of runoff and extreme rainfall not only reduces water shortages during drought, but also flooding, and they are useful for biomass production and nutrient retention.¹³⁵ Sediment control aims at alleviating erosion and sedimentation, such as loss of valuable topsoil – which reduces the productivity and the water-holding capacity of land – and infrastructure damage (e.g. to hydropower stations and wastewater treatment plants). Sedimentation may also degrade water quality through discharge into streams, lakes and coastal zones, reduce the water storage capacity of reservoirs, and aggravate flood damage.¹³⁶

A study in Ethiopia showed that water harvesting and soil and water conservation, such as bunds and conservation agriculture, had significant benefits in terms of retained runoff and reduced sediment loss by 45–90 percent.⁴¹ In Southern Africa, sediment and surface runoff were reduced by 80 percent and 60 percent, respectively.⁴⁰ A meta-analysis by Joshi et al. (2008) covering more than 600 microwatersheds in India reported an average runoff reduction of 45 percent, and 1.1 tonnes per hectare of retained topsoil.¹³⁷ The study also showed a positive relationship between participation and benefits from watershed development, highlighting the importance of stakeholder participation in preventing actions of one group of farmers from adversely affecting another group. The use of strips of grass, shrubs and trees is another soil and water conservation practice, a nature-based solution that, in addition to retaining moisture and preventing erosion on slopes,²⁵ can significantly reduce sediment loss.¹³⁸ Planting along waterways can greatly improve water quality for fish. In the Zarqa river basin, Jordan, sustainable rangeland management has resulted in increased edible biomass, carbon sequestration and/or sediment stabilization.¹³⁹

These findings are not easily scaled up to watershed level and beyond.¹⁴⁰ There are large data gaps for tropical and subtropical agricultural regions, as well as micro- to meso-scale watersheds (from 0.01 km² to 100 km²).¹⁴¹ There is a lack of long-term landscape monitoring across all regions and production systems, something that would be especially valuable in low-income and least developed countries where agriculture is under rapid transformation.

Managing agricultural nutrient loadings

Agricultural production can interfere with natural cycles of nutrient elements – nitrogen and phosphorus – leading to concerns about water degradation from excess nutrient loadings and eutrophication. These problems are expected to intensify as a result of population growth and wealth generation. Growth is faster in low-income countries, with a projected increase of up to 118 percent for nitrogen and up to 47 percent for phosphorus.¹⁴² These are the countries with most population growth, driving food demand and agricultural production. Ensuring food security and nutrition and environmental sustainability will require addressing agricultural pollution.

Water management, such as vegetation strips, infiltration ditches/basins and human-created wetlands, can contribute by retaining excess nutrients, especially nitrogen and phosphorus (the most common water pollutants), thus reducing non-point pollution load, also known as diffuse pollution.¹³⁸ While these technologies have varied efficiency, often dependent on design and local landscape, they are widely applied in agricultural production systems in Europe and Northern America.

The integration of aquaculture within agricultural systems can help retain excess nutrient loadings and improve water quality.¹⁴³ In some systems, the presence of fish aids rice–fish culture, nutrient cycling and circulation. These reduce pesticide use and related costs, suppress weed growth in rice fields, and improve soil fertility. However, this may add complexity to the management of these systems. For more information on water pollution from agriculture, see In Focus: Agriculture, water pollution and salinity.

In the face of growing demand, the use of non-conventional water sources, such as treated wastewater and desalinated water, is gaining momentum. Most human water activities produce wastewater, potentially recoverable for secondary uses such as in agriculture. If all this water were recovered, it would substantially reduce pressures on freshwater and alleviate scarcity, provided accounting assessments ensured the return flow was not serving an environmental function.

Water reuse

Wastewater is predicted to increase considerably with population growth and urbanization. On average, high-income countries treat about 73 percent of their wastewater. The figure drops to 54 percent in upper-middle-income countries and to 28 percent in low-middle-income countries. Globally, about 80 percent of wastewater is released without adequate treatment.^144,145 In 2019, 7.5 million m³/day of new water reuse capacity was forecast. China dominates this total (3.7 million m³/day), followed by the United States of America (880 000 m³/day) and India (680 000 m³/day).¹⁴⁶ Most is tertiary and/or advanced wastewater treatment. This is part of a broader trend towards advanced treatment driven by industrial demand for higher-quality water, and from agricultural users.

Although definitive numbers on water reuse in agriculture are hard to find, about 10 percent of the total global irrigated land area receives untreated or partially treated wastewater, more than 30 million hectares in 50 countries.^144,147 For decades, the most significant benefit of water reuse in agriculture has been that of decreased pressure on freshwater sources.¹⁴⁸

The circular economy has brought a different perspective on water reuse in agriculture, proposing a model where the value of products, materials and resources is sustained for as long as practical and waste reduced or even eliminated.¹⁴⁹ Treated wastewater is readily available for agriculture, including irrigation. Water reuse for irrigation brings more certainty that water will be available throughout the year, even during dry spells. Nutrients can be recovered from sewage sludge (biosolids) and reused as fertilizer, as widely practised in many countries.¹⁵⁰ In Europe, more than one-quarter of sewage sludge produced in 2017 was used in agriculture.¹⁵¹ A final benefit is energy recovery, such as biogas production from waste treatment at the farm level.

When treated according to the end users’ needs (fit for purpose), wastewater is a realistic option for non-conventional sources of water, nutrients and energy for agriculture. Reusing water in agriculture from fit-for-purpose treated wastewater is a “win-win” situation as it is based on improved sanitation (collection systems), treatment facilities, reuse of chemical elements (nitrogen and phosphorus) and making water available for higher-value uses. However, in some countries, using treated wastewater to irrigate food crops is still not culturally acceptable. With strong communication channels, government regulations and the involvement of stakeholders would help to change negative perspectives about the use of non-conventional waters for food production. Moreover, assessment of water quality criteria, potential environmental impacts and regulatory issues need to be resolved to foster best practices and implementation.

The current policies for using reclaimed water are highly fragmented, and in many countries incomplete, which tends to inhibit development.¹⁵² There is a need to develop both policy and planning frameworks for governments, municipalities and water resources groups to develop recycled wastewater as a future supply for irrigated agriculture. Training and capacity-building programmes can promote technology uptake through local and international streams, taking into account local needs and conditions. Removing barriers and creating an enabling environment will require appropriate legislation and regulations to make finance available for their adoption.

Desalination

Desalination covers the removal of dissolved solids (predominantly inorganic salts) and other dissolved contaminants from several sources, including seawater, brackish water (surface water and groundwater), and irrigation drainage. Aristotle, in his famous Meteorologica (written in about 350 BCE), described distillation to remove salts and other compounds to produce freshwater. Since then, desalination has become a major option for urban water supply, especially in desert and drought-prone regions. Owing to almost unlimited seawater, desalination is an attractive solution to the age-old challenge of its abundance despite being undrinkable.¹⁵³ There are approximately 16 000 desalination plants, producing about 100 million m³/day of drinking water for 5 percent of the world’s population, of whom 48 percent are in the Near East and North Africa.^154,155 Since 2018, more than 400 desalination projects have been contracted worldwide, with 4 million m³/day in new capacity in the first half of 2019.¹⁴⁶

The main way to produce freshwater has been distillation, where saline water is distilled into steam and then condensed into pure water. The 1950s brought the development of membrane processes, such as electrodialysis and reverse osmosis. In electrodialysis, an electric current separates salts in water. In reverse osmosis, pressure forces water through a semi-permeable membrane that extracts most of the salts.¹⁵⁶ Unlike distillation, modern membranes use very little energy to produce freshwater, although a major environmental problem has been disposal of salts removed from water.¹⁵⁷

The main obstacle to desalination has always been the cost. Its application in agriculture has been limited to a small number of areas, for certain high-value crops, and needing government subsidies in capital costs.¹⁵⁶ Over the last decades, however, desalination has become much more efficient and cost-effective thanks to rising demand, technology improvements, reductions in costs and energy use, increase in plant size to large and mega capacity sizes, and more competitive project delivery.¹⁵⁸ A 2008 study showed a consistent reduction in desalination costs over nearly three decades, and estimates that large-scale desalination plants are capable of producing water in the range of USD 0.5–2.0/m³, depending on plant size.¹⁵⁹ Similarly, a more recent study estimates that the cost of desalinated water varies between USD 0.5–1.5/m³.¹⁶⁰ In terms of cost, brackish-water desalination is more suitable for agricultural production than is seawater. Membranes and renewable technologies such as solar power have made desalination more feasible, especially for high-value cash crops such as greenhouse vegetables. Farmers welcome it as the process removes salts (especially sodium and chloride) that damage soils, stunt plant growth and harm the environment.¹⁶¹

Several countries, such as Australia, China, Mexico, Morocco and Spain, are now using desalinated water profitably for agriculture. Dévora-Isiordia et al. (2018) calculated the cost of desalination (USD 0.338/m³) and its economic use in agriculture in Sonora, Mexico.¹⁶² They concluded that, in order to ensure its viability, farmers should choose high-yield crops with profitable cost–benefit ratios, such as vegetables (e.g. tomatoes and chillies), and apply drip irrigation. Integrated agri-aquaculture farms are testing the integration of saline water into farms using salt-tolerant crops.¹⁵² Policies and regulations have a powerful role in boosting both through public projects, enabling the private sector and knowledge exchange.¹⁵² Public–private partnerships also reduce investment risks.

Water desalination can have negative impacts on the environment (e.g. brine disposal of residues from desalination and GHG emissions). Although there are technology and management options to reduce such impacts, there is a need for standards and impact assessment studies (local and regional),¹⁵⁶ as well as for brine disposal research and continuous monitoring of effluents.

With agriculture increasingly becoming knowledge-intensive, and farmers having to make more complex decisions on land and water, on which crops to produce and how, and on where to buy their inputs and sell their outputs, information needs will only become greater. The localized nature of agriculture means information should be tailored to each context.¹⁶³ Information and communication technology (ICT) has great potential to increase agricultural productivity and preserve natural resources, including water.

The term ICT is an umbrella covering anything from radio to satellite imagery, mobile phones to exchange information via messaging services, and electronic money transfers.¹⁶³ In India, Nano Ganesh, an irrigation automation system, allows farmers to switch their water pump on and off remotely and obtain information on water and electricity usage. It also allows them to time irrigation to meet crop water requirements. About 20 000 farmers used this device in 2015, and the estimated benefit–cost ratio was 6:1.¹⁶³ Use of this system can bring additional income-generating opportunities, such as through installation, repair, training and demonstrations, with job opportunities for women.

Precision agriculture comprises other ICT tools, including Global Positioning System (GPS), satellites, sensors and aerial images, that provide farmers with site-specific information to make management decisions.^163,164 Determining soil and crop conditions – while minimizing impacts on wildlife and the environment – is at the root of precision farming. Although concentrated in high-income countries, some precision tools have great potential in low-income countries. Many of these applications have been limited to large-scale farming, but there are opportunities for small-scale farmers. Wireless sensor networks – a group of small sensing devices, or nodes, that capture data – are a case in point. Not only is the technology fairly cheap (some units cost less than USD 100), but it can operate on batteries and alternative energy, crucial for low-income countries.¹⁶⁵ Wireless sensors can also be used in aquaculture to monitor oxygen, tidal currents, temperature, fish behaviour and water conditions. AKVA, a Norwegian firm specializing in commercial fish farming, uses sensors with a built-in camera to detect uneaten feed in fish cages.¹⁶⁶ With this information, sensor signals can stop the release of feed, allowing for more specific care and feed purchase. The sensors can also adapt to the accurate feeding rate of the fish over time.¹⁶³

Satellite technology is another tool that can capture, manage and analyse data relating to crop productivity and field inputs. However, the initial costs and technical requirements are a problem for small-scale farmers. Efforts to be inclusive and effective must focus on the full range of capacities and resources required by small-scale producers. An example of satellite information is FAO’s recently developed Water Productivity Open-access Portal (WaPOR), a publicly accessible database using satellite data (Box 15).¹⁶⁷

BOX 15

Water Productivity Open-access Portal (WaPOR) – remote sensing for water productivity

FAO’s WaPOR platform offers operational and open access to a water productivity database and thousands of map layers. It allows for direct data queries, time series analyses, area statistics and data download of key variables associated with water and land productivity.¹⁶⁹ By providing near-real-time pixel information for all of Africa and the Near East, WaPOR opens the door for service providers to help farmers achieve more reliable yields and better livelihoods. At the same time, authorities have information to modernize irrigation schemes, while government agencies can enhance efficient use of natural resources.

The figure in this box shows the spatial variation of water productivity measured by WaPOR. The yellow-green patches have high water productivity, with low water consumption per crop produced and fields that yield at least 1 kg of product per cubic metre of water. The orange-red fields are underperforming, with low water productivity, possibly owing to poor agronomic practices. To improve red areas, green areas can be analysed and referenced for scaling up.

Gross biomass water productivity, 2019

Back

Back

Advances and the global spread of ICT tools, such as geospatial statistical methods, have made it possible to gather, analyse and share data more effectively, as well as visualize and understand what this information means for agriculture.¹⁶³ The array of sensors in smartphones has expanded to include barometers and thermometers that can collect hyperlocalized weather information. Small-scale farmers with mobile phones are beginning to benefit from improved tools. However, access to data remains a challenge.

Both the public and private sectors have important roles in helping to bridge these gaps. Integrating ICT into national programmes, creating an enabling environment, and designing digital systems that are compatible and easy to use can help improve access. One example is the Global Open Data for Agriculture and Nutrition initiative, launched in 2013, which advocates for open-data and open-access policies in the public and private sectors. Another example is Open Ag Data Alliance, launched in 2014, which aims to help farmers access and control their data.¹⁶³ Launched in 2008, Digital Green enables extension agents and peer farmers to upload videos online to share knowledge on improved agricultural practices. As of June 2020, the organization had reached 1.8 million small-scale farmers in India – 90 percent of them women – across 15 200 villages.¹⁶⁸ The FAO Dimitra Clubs seek to empower rural communities, especially women and young people, using mobile phones and radio stations to share information. There are age asymmetries in ICT access as young people tend to adopt more readily, which can be turned to advantage and used as a learning tool within communities.

Meeting future demand for food without further undermining the environment is possible but will require transformations in water management. This chapter has explored technological options and new water management practices to address water shortages and scarcity in irrigated and rainfed cropland, livestock, inland fisheries and aquaculture, and to improve agricultural production, food security and nutrition, and climate resilience in a sustainable way. Some key points emerge.

First, although rainfed agriculture predominates, substantial yield gaps in rainfed crop systems persist. Combined with agronomic practices, improved water management has major potential to increase yields, especially in sub-Saharan Africa, Eastern Europe and parts of Asia, where yield gaps are largest, taking into account local needs and conditions.

Second, while irrigated areas have higher and more stable yields compared with rainfed agriculture, substantial gaps remain in irrigated agriculture, suggesting major scope for improvement, particularly in sub-Saharan Africa, Northern Africa and Western Asia, and Latin America and the Caribbean. Investments are required in water accounting and allocation; efficient irrigation; high-yielding and resilient crop varieties; adequate fertilizer and pesticides; and improved soil and water management. Non-conventional sources can also ease pressure on freshwater resources.

Third, animal production uses significant amounts of water, especially for feed, and therefore holds great promise for increased water productivity. For livestock, options include better use of pasturelands; improved animal health and animal husbandry; effective provision of feed and drinking water; and the integration of crop, livestock and aquaculture systems.

There is also a need for integrated approaches to improve productivity in rainfed and irrigated areas and environmental sustainability, tailored to the capacities and resources of producers. These include conservation agriculture and nature-based solutions, such as agroforestry and soil and water management that intensifies production sustainably. Fourth, ICT has a role for farmers in making complex decisions on land and water resources.

Water management strategies mean strengthening intersectoral institutions and mechanisms that effectively involve users and stakeholders, with concern for affordability and the human right of access to water, particularly for the most vulnerable. Finally, water demand and supply strategies require finance for essential and responsible investment. These dimensions are discussed in more detail in the following two chapters.

Chapter 3 presented water management options for reducing water risks and improving productivity in rainfed and irrigated cropland, livestock systems, and inland fisheries and aquaculture, while ensuring environmental sustainability. Their relative potential will depend on a series of factors, including local agroclimatic conditions, water shortages and scarcity, agricultural production systems and the benefits of different strategies. It will also depend on external factors, including global trade and climate change, as well as governance, institutional frameworks and the policy environment.

This chapter focuses on the need for effective governance and strong institutions to guarantee sustainable and effective use of water and equitable distribution of benefits. It provides an overview of the opportunities, challenges and impacts of existing tools and measures to manage water scarcity, including water pricing to control demand and recover costs, as well as allocation tools, such as water rights and quotas, to protect the resource and its quality, and to ensure equitable access. The chapter goes beyond irrigated systems, and reviews options for water governance of rainfed crops, livestock, inland fisheries and aquaculture, and the impact of excess water in agriculture. The overall policy framework is presented in Chapter 5.

Figure 13 shows that reducing water shortages and scarcity will require major transformations involving technological change and management innovations, influenced by the overall political, institutional and legal framework. Water issues typically involve multiple stakeholders (e.g. watersheds across multiple administrative regions or even country borders) and institutions, and there are often political economy considerations and conflict over the roles of public and private actors.

Safeguarding the contribution of water to food security and nutrition will involve significant governance challenges from local to broader levels (Box 16).¹ Institutions at various levels will need to address the continued degradation of soils in irrigated areas, the deterioration of freshwater ecosystems and sustainable water use. Strong political will, discussion and cross-sectoral collaboration will be needed to negotiate increasing competition for freshwater resources, including between agriculture and cities. Policymakers and regulatory agencies should be informed on the needs, operational capacity and importance of different sectors, especially regarding those groups of people who lack sufficient political leverage (e.g. fishers).^{2, 3} In collaboration with FAO, Jordan is improving national, regional and local capacity to cope with water scarcity, especially that of farmers and livestock breeders, as a result of an improved knowledge of water use in agriculture and capacity needs to develop water harvesting and irrigation technologies.⁴

Devolution to provincial or district government further exacerbates the complexity of water governance, resulting in the need for horizontal and vertical decisions across water, agriculture and land institutions.¹ Improved coordination and integration should be achieved vertically from the sectoral and river-basin level through irrigation systems and households, and horizontally across sectors (agriculture, households and industries). Furthermore, some of the world’s dry areas are becoming even drier, and precipitation more variable and extreme, calling for robust and flexible water management as well as innovative technologies and finance to develop new water resources.

Fragmentation and conflict remain part of water governance systems. Control over land and water is important when establishing political allegiance, with implications for less powerful groups. Water tenure is particularly insecure for small-scale farmers and other vulnerable groups, such as women, youth, migrants and indigenous populations. Appropriate water management strategies, governance, innovations and policies can go a long way towards ensuring that water usage is inclusive, equitable and sustainable. Recognizing that water accounting and auditing should be central to any programme to address the challenge of water shortages and scarcity, the following section highlights their role in water resources management and improved governance.

The subsequent sections review tools and strategies to improve governance and manage water constraints and competition in agriculture. Acknowledging that managing scarcities and competing demands encompasses allocating and managing freshwater withdrawals, governance options are first assessed for irrigated agriculture. The chapter then focuses on water governance in rainfed crop production, livestock systems, aquaculture and inland fisheries.

Effective water risk management must be based on sound water accounting – the systematic study of the hydrological cycle and the status and future trends in water supply, demand, accessibility and use.⁹ Water accounting is vital as a resource baseline for any policies and interventions aimed at tackling water scarcity, especially in agriculture.¹⁰ Without understanding water endowments, societies risk excessively optimistic estimates of water and subsequent over-allocation of water rights, causing serious shortages during drought. Future climate change is likely to further invalidate the hydrological assumptions on which water rights have been based.⁹

However, water accounting will only make a difference if it forms part of a broader process of improving governance. Auditing goes one step further than water accounting by placing trends in water supply, demand, accessibility and use in the broader context of governance, institutions, public and private expenditure, legislation and the wider political economy.¹¹ Combining accounting with auditing can provide the basis for more realistic, sustainable, effective and equitable water management.

Despite information being critical, government departments – such as agriculture, sanitation and the environment – rarely share a common information base.⁹ Incorrect understanding of water volumes and distribution often underestimates pressure on resources and decreasing water availability. Water accounting and auditing are necessary for policy coherence and a common information base acceptable to stakeholders’ planning or decisions. Eight countries in the Near East and North Africa region use water accounting and auditing to consume less water and use it more productively.¹² In Iran (Islamic Republic of), water accounting and auditing have highlighted issues of water-use efficiency on farms in conveyance, groundwater depletion, and the disparity between availability and government recommendations. In Jordan, water accounting has highlighted issues related to water quality, and suggested the benefits of adding small amounts of irrigation through water harvesting.

Water accounting and auditing are not free of challenges. First, the dynamic nature and uncertainty of both the physical processes of water and societal responses – including water stocks, depletion and replenishment rates, the condition of infrastructure, and user demand – make the long-term measurement of water resources particularly challenging. Therefore, water management plans need to be problem-focused and dynamic.⁹ Second, in low-income countries, where infrastructure and institutions are weaker, and large irrigation systems service many small-scale farmers, measuring water use can be costly and a major constraint to water management. Third, the need to allocate water for environmental flows requires more detailed understanding of hydrological and ecosystem needs, often beyond the capacity of irrigation engineers and water managers, and cost–benefit models. Water accounting is an iterative process, with continual improvements needed in order to increase comprehensiveness and accuracy.

Compared with water accounting, water auditing requires societal information – qualitative and quantitative – and ensuring that well-motivated personnel have the necessary training.¹¹ The managing and collecting of water information requires resources, skill and patience, as it is often fragmented, sourced from different organizations and of variable quality. The overall cost of water accounting and auditing programmes varies enormously with, for example, the scale and ambition of the programme, the cost of contracting an implementation team, and the need to collect primary and secondary information. Advances in cyber technologies (e.g. remote sensing, drones, online information bases, and GPS-enabled smartphones) reduce costs and provide information even in remote areas without biophysical and societal monitoring networks or programmes. They are also strengthening global and regional databases with free information, involving more scientists.¹¹

Because water accounting and auditing depend on context, there are different approaches and no standard methodology. In 2017, FAO published a sourcebook that is a good starting point for any organization to: use water accounting and auditing for the first time; combine water accounting with auditing; or review, and possibly refine, water accounting or auditing already in place.¹¹

Water should be treated as an economic good with a value and a price. Insecure water rights, inequalities, inappropriate subsidies and poor cost recovery undermine water infrastructure and investments in water projects. These can lead to unproductive water use and excess irrigation.¹³ Coupled with agricultural support – i.e. policy transfers linked to production, such as price support for high-water-using crops (e.g. rice) or subsidies for irrigation technology or fuel – they can also lead to overuse and misallocation. In India, price supports for rice and input subsidies have caused excess water use and environmental degradation.¹⁴

Many mechanisms and tools manage scarcities and competing demands. They include allocation tools and incentives, including water rights and quotas; tradable permits; licences; reform of social protection systems; and other measures, including water quality and protection regulations.¹ The choice of tools and social and legal systems (both formal and informal) can affect water availability and quality for agriculture, food security and nutrition, and access to water for poor, vulnerable and marginalized populations. Regulations with high compliance costs increase the risk of degradation and illegal groundwater pumping.¹⁵

Water allocation ranges from identifying national priorities and allocation between countries in shared river basins, to individual basin-level users (Box 17).¹ Badly adapted tools can disrupt existing systems. In times of severe drought and water stress, market tools may prioritize sectors offering the highest economic value (such as cities and industries), restricting water for agriculture.^{1, 16} The challenge is to prioritize water for food production as well as the basic needs of poor and vulnerable populations.

Where river health deteriorates owing to flow disturbances, it is important to restore flows to meet environmental needs and maintain species abundance and diversity, supporting other river ecosystem services.³ Although politically challenging, most high-income countries, and some low-income ones, now have environmental flow regulations.^{3, 17}

The role of water tenure, land tenure and water rights

Discussion about allocation, reallocation and equitable delivery of water services takes place around water rights, associated with land rights. A water right is a legal right to extract and use water from a natural source, such as a river, stream or aquifer.²⁰ There are distinct types of water rights, just like relationships under the heading of water tenure, including annual licences (to use water based on command and control), supply contracts, and agency control (legal power for an irrigation agency to use water).¹⁰ Because of their connection to property, water rights are today a cause of controversies between countries of all income levels. In this report, water tenure (Box 18) is a broader, supplementary concept to water rights. Neither term should be confused with the human right to water emerging from international human rights law.

In a world of increasing demand, water and land tenure can be a strong building block for efficient use and secure, equitable and sustainable access to water. It allows adjustments through the market, while the price mechanism – reflecting the true value of water – incentivizes users to monitor and use water more efficiently and productively.²¹ By requiring user consent to any reallocation and compensating for any transfers, tenure empowers users and increases the economic value of water, provided that state institutions and enforcement mechanisms operate properly. This incentivizes farmers to invest in, inter alia, irrigation, land and soil management, more advanced technologies and reducing resource degradation.^{22, 23} Secure water rights can also help develop ICT, such as real-time management of irrigation systems, and water mapping through satellite technology, artificial intelligence and blockchain tools.

Traditional formal water rights (Box 18) are still relevant.¹⁰ Tied to land tenure rights, a formal mechanism and associated bureaucracy are not necessary, as a person with a land tenure right also has a water right. Landholders should assert their water rights against third parties, without enforcement by water administration. Often, traditional formal water rights are inadequate for enforcing access. Although a system of water tenure exists in most settings where water is scarce, those systems not formally recognized or grounded in law are more vulnerable to encroachments and expropriation.²⁵ Establishing rights should be transparent and secure in order to protect small-scale users, enabling them to negotiate benefits or compensation. Community-based water tenure can support indigenous peoples, local communities and women – who are often unaware or unable to assert water rights.

FAO developed the Voluntary Guidelines on the Responsible Governance of Tenure of Land, Fisheries and Forests in the Context of National Food Security to address the land–water interface.²⁶ This includes improvement of policy and legal frameworks, with the overarching goal of food security for all and realizing the right to adequate food. Young (2015) lays out a blueprint for water rights and trading (buying and selling water rights), based on the Murray–Darling River Basin in Australia.²⁷ It highlights the importance of allocating water in a transparent process, accounting for evaporative losses and environmental outcomes, including water quality and flows to the sea. This provides transparency in response to changes in the water available to each irrigator. As water tenure is context- and location-specific, the situation in Australia can be very different from that in other countries, particularly low-income countries. Small-scale users are often reluctant to register water use for fear of invoking fees. This may risk access to water as water rights regimes are rolled out in many countries.^{1, 28}

Adding to the difficulty of reform, water is often treated as a free good and generally subsidized, which impedes secure water rights. Entrenched interests benefit from existing subsidies and water allocations.²⁹ Access and tenure are often linked to political dynamics, different groups, interests and influence. Within the agriculture sector, priority may go to the most productive and largest users over small-scale producers, especially women, threatening their livelihoods and food security. This can be remedied through a user approach with equal priority on a territorial basis, considering intended use (e.g. food security and nutrition) and water productivity. This aligns with agreed principles, including the human right to water and food.^{30, 31}

Water tenure can promote policy coherence across sectors. The land–water interface is an obvious example, with the use of one resource influencing and being influenced by the other.¹⁰ Well-defined water tenure can improve irrigation technology for conveyance, diversion and metering, and the institutional frameworks of water management, especially in low-income countries. This requires a water accounting and an allocation system before investing in new irrigation. Without secure water rights, new technologies can actually increase water consumption. There can be economic gains by allocating more water to higher-value uses, such as fruits and vegetables. However, there is the risk of increasing water consumption with negative effects on small producers and women. It is also possible to improve water quality by reducing withdrawals, managing groundwater levels and sustaining baseflow in rivers (i.e. the portion of streamflow maintained by groundwater discharge).

Economic instruments – redirecting farmer incentives

Economic instruments can encourage producers to change their behaviour to achieve the desired hydrological outcome.¹⁵ Such schemes may produce revenue for the regulator (via taxes), be costly to the regulator (subsidies), or involve payments only between farmers (trading). In the absence of binding and enforced water tenure, incentive-based instruments may be difficult to implement and their outcome hard to quantify; hence, they are often used with underlying regulatory approaches for monitoring and enforcement, rather than independently.

Water market opportunities and challenges

In areas where freshwater allocations are in place, it may be possible for producers to transfer entitlements among themselves. Mechanisms include leasing and selling water rights, auctions, water banks, block pricing and water quality trading. These treat water as a good to transfer among users according to market price.²¹ Under certain circumstances and in some country contexts, markets may allocate water effectively, being economically efficient and responsive to change. When users can decide to buy or sell, those who sell, do so voluntarily, which is often not the case when a central authority reallocates or expropriates water. The market mechanism can thus reduce conflict although there is a very small number of functioning water markets with sufficient experience.³²

However, there are significant preconditions to a successful water market and equitable distribution. For example, in Chile, (new) water rights are auctioned to the highest bidder, with the expectation this will result in equitable water allocation, based on the premise that anybody can join the market.³⁶ This often hurts subsistence farmers, whose benefits are difficult to calculate in economic terms. How market rules are designed and monitored matters. In Chile, speculators hoard water-use rights, with limited registering or tracking of those rights.³⁷ One study for the Limarí river valley in Chile found that eliminating trade restrictions on water markets between districts would result in welfare gains of 8–32 percent of agriculture’s contribution to regional GDP.³⁸

In Australia, water markets in the Murray–Darling basin reduced overall benefits and imposed environmental costs owing to the over-allocation of rights. To increase efficiency and free up water for environmental flows, heavy public investments were directed into irrigation.³⁹ Analyses show it would be much less expensive and more effective to buy back excess entitlements. The cost of infrastructure subsidies is almost 2.5 times more than the cost of acquiring water.⁴⁰ Similarly, the cost of increasing environmental flows from subsidies is more than six times greater than that of direct purchases.⁴⁰ The Murray–Darling basin illustrates the benefits from water markets, and the importance of a correct sequence of reform and of the definition and quantity of water rights.

The principles of groundwater management are more complex than those governing surface systems owing to information constraints. With caps on water withdrawal in the aquifer, these markets can improve accessibility to groundwater irrigation, particularly for marginal and small-scale farmers. Negative aspects include monopoly power by local water sellers and combining water markets with electricity subsidies without usage regulations, leading to over-exploitation of groundwater (Box 19). The costs of depleting groundwater reserves can be disproportionately borne by small-scale and marginal farmers. In extreme cases, over-extraction can lead to abandonment of irrigation in many coastal areas (e.g. in Morocco and Tunisia).⁴¹

Policies to manage over-extraction usually require state funding, and regulatory and incentive-based tools. These include limits on new wells or irrigated acreage, pumping rights and permits, certification of irrigated acreage and well metering. Lower-cost metering can be achieved through proxy measurements and advanced information technology, such as remote sensing, especially in dry areas. Controlling expansion in the number of wells requires strong political will and field staff, in addition to the imposition of gradual sanctions on violators. The number of wells can be reduced by buying them back. Incentive-based tools include taxes, fees, land retirement, trading groundwater permits and cost sharing to incentivize water management. See Box 20 for two cases of general groundwater management in the United States of America.

In an in-depth analysis of groundwater management reform, Molle and Closas (2017) find that co-management by users and the state offers greater potential for success where implemented with a combination of the following factors: (i) the threat of sanctions in accordance with the law, often linked to environmental safeguards or water-sharing agreements/treaties; (ii) a severe drought or environmental crisis that makes state intervention more legitimate and acceptable; (iii) lower transactions costs; (iv) limited number of users and relative social homogeneity; (v) sufficient resources to offer incentives beyond regulations and sanctions; (vi) possibility of disaggregation of management of the aquifer into smaller parts, provided that effective regulations and incentives ensure water-use efficiency; (vii) reliable and transparent information on water resources; and (viii) establishment of agreed accountability and transparency about the rationale behind the measures, and distribution of costs and benefits.⁴¹

Overall, many surface water and groundwater market-based mechanisms are still fairly new, and water market approaches will improve based on such experiences. More firms are investing in or supporting water markets, a sign of a developing marketplace.²¹ The implementation of water market mechanisms, whether a water auction, water bank, or other forms of transferring water utilizing price, is complicated and requires specialized expertise for each location, including on socio-economic, political, legal, hydrological and environmental circumstances, or on the heterogeneity of water tenure. Given that pressures on water will continue and that the traditional approaches of developing resources are nearing their limit, experimentation and innovation in different water market approaches is likely to continue.

Water pricing – opportunities and challenges

Water pricing, charging for a water (use) right in monetary terms, can serve to recover direct (water supply and infrastructure) and indirect (environmental, social and opportunity) costs.⁴⁸ It may also help conserve water and promote more sustainable use, address scarcity problems and foster investments into alternative, less water-intensive crops or water-saving technologies. In agriculture, water pricing is difficult to implement for political, cultural and equity reasons. In many countries, there is no national price for water, as it can vary greatly within the country and for different irrigation systems. Some countries do not price water at all, despite the need for investment in infrastructure and technologies, which requires massive private and public financing.⁴⁹

In certain local and regional agricultural circumstances (e.g. a low share of water costs in proportion to overall production costs), price elasticity of water demand can be low, especially in the short term. In these cases, a higher water price may not lead to significant use reductions.⁴⁸ Incentive-based tariffs are more prominent as they deal with the way water users pay and whether the right price signals are transmitted, instead of just focusing on cost recovery. These trends reflect the devolution of water management from central governments to regional or local authorities, the increasing private-sector investment in water services and the financing of large water investments through public–private partnerships. These emphasize the importance of water pricing, but also call for strong regulation to guarantee protection of the public interest.⁴⁹

It can be very difficult to raise cost recovery from users. In most cases, even operation and maintenance costs are not recovered.⁵⁰ Robust allocation can help shift water from cereal crops towards higher-value uses, with flexibility to adjust to changing conditions.⁵¹ Encouraging payment for water management and services also requires consistent quality of water services and a clear explanation of how revenue is used to benefit users, in addition to regulations and sanctions. For a pricing scheme to deliver optimal cost recovery and sustainable use, design options such as the tariff structure and price level are crucial. Table 5 presents a summary of the main pricing methods.

TABLE 5

Water pricing methods

Back

A number of countries have included water prices in their responses to water scarcity. In Australia, accurate price signals and effective water markets are seen as essential in improving water-use efficiency and encouraging users to adjust to climate change.⁹ In Israel, the Water Commission sets the price of water using a three-tier system according to consumption (i.e. volumetric pricing, see Table 5) in order to encourage water savings. For a given allotment, farmers pay differential prices for potable water. According to one FAO report, the first 60 percent of the water allocation costs USD 0.20/m³, 60–80 percent costs USD 0.25/m³, and 80–100 percent costs USD 0.30/m³.⁵⁴ In irrigation, there is no fundamental difference between an agency setting prices, with farms then choosing how much water to use, and having the agency assign (tradable) water rights or quotas, with the farm revealing marginal costs through water-use decisions. The choice of control mode depends on its relative effectiveness. If there is any advantage to choosing price or quantity control, it is owing to inadequate or asymmetric information, uncertainty about transaction costs, or unequal sharing of risk among water users.^55–58

Several factors make volumetric pricing of irrigation water difficult to implement. First, in irrigation systems, the value of water rights has already been capitalized into the value of irrigated land. Holders see pricing as expropriation of those rights, leading to capital losses on farms.²³ Attempts to establish prices are often strongly opposed by irrigators, making it difficult to maintain an efficient price system.²³ Second, measurement and monitoring costs may be prohibitive, especially in low-income countries. Last, water scarcity is often dealt with through quota definition, with prices mainly used to regulate use at the margin, beyond the quota, rather than rationing scarce water.⁵⁹ This is particularly true for surface water, as its application to groundwater may be challenging.

Reasons for the predominance of quotas include transparency and ensuring equity when supply is inadequate.⁶⁰ Quotas can also bring use directly into line with varying resources, aligning them with information from water accounting, and leading to smaller income losses relative to price-based regulations. For example, in Greece, an increase in water prices led to serious income decreases.⁶¹ In China, a study found the price of water had to be raised substantially to generate water savings; however, the increase resulted in substantial income losses for small-scale farmers.⁶² In high-income countries, farmers can respond by reducing water on a given crop, adopting water-conserving irrigation technology, shifting to more water-efficient crops, and changing the mix to higher-value crops. In low-income countries, these options may be unavailable or too costly. Prices set high enough to induce significant allocation changes (or recover capital costs) can severely affect farmers’ incomes.^62–65

For this reason, raising water prices should occur over several years in order to give farmers time to adapt, with integrated management involving communities to make sure no one is left behind. To avoid negative effects and deliver ecosystem services, payments for them could be considered a complement to incentive pricing (see Chapter 5).⁴⁸

Quantity and price allocation can be combined. While yet to be applied, a potential allocation is water brokerage or passive market. This introduces incentives for efficient water allocation while protecting farm incomes, provided the water agency has accurate information on aggregate water demand and supply.⁶⁶ Instead of imposing volumetric water prices on farmers, this pays farmers to use less water based on the charge–subsidy approach for pollution control. If demand exceeds the base water right, users pay an efficiency price, based on the value of water in alternative uses. If they use less, the same efficiency price is paid to users instead. Base water rights establish a cap on total water use in the basin or system, allowing amounts to be maintained or reduced.⁶⁷ The passive market is distinguished from formal water markets because the buyer or seller does not have to pursue a matching seller or buyer. Instead, each farmer simply determines water use at the price set by management without reliance on a unique water market.

Collective management – bringing farmers together for irrigation management

Managing water requires local-level analysis, planning and action, for which local groups play a central role. The important contribution of water users associations to water management and governance is their ability to bring together farmers (particularly small-scale farmers) to manage a shared irrigation system. Through synergies, members can pool their financial, technical, physical and human resources to operate irrigation schemes, including other local water systems, such as a river or water basin. Through water users associations, it is easier to access credit for investment in irrigation in order to improve water management. Association members, particularly small-scale farmers, can increase their bargaining power in negotiations with large water users and regulators. However, those relying on non-consumptive water use (e.g. fisherfolk), still have little say over how resources are managed and how the costs and benefits are shared.

Case study evidence suggests water users associations have led to yield improvements,^{70, 71} more efficient use of water, increased production in a dry year⁷² and improved conflict resolution.⁷³ In Punjab Province, Pakistan, watercourse-level users associations have increased crop yields by 10 percent for farms at the tail of a watercourse, and by 8 percent for those relying on groundwater.⁷⁴ Devolution of sub-basin water management to community-based water users associations, farmers groups or other private-sector actors can also be beneficial, but the evidence is mixed (Box 21). Improvements are conditional on representing the interests of stakeholders in water users associations. For example, the exclusion of fisheries from decision-making lowers fish yields.

Some tendencies can help determine the conditions for successful water users associations. Top-down implementation has not generally worked well, as it can undermine genuine association leadership and equitable, inclusive member participation.⁷⁵ According to a review of associations in sub-Saharan Africa, they are more likely to be effective when their design and implementation involve prospective members and emphasize improved water delivery services, such that farmers’ engagement goes beyond paying fees.⁷⁵ Improved services through infrastructure and technology, and the benefits of improved inclusiveness, accountability, capacity and conflict management, all give users an incentive to pay and participate. Participation in the design can help users, irrigation managers and officials find affordable infrastructure and management solutions that include technological innovations and mechanization. Irrigation management turnovers are more likely to be successful when boards are farmer-elected, management consists of professional cadres and legal systems handle increasing complexity (Box 21).⁷⁶ It is equally important to establish clear roles and responsibilities through agreements between the irrigation agency and the water users association. The potential for conserving water is enhanced when water tenure and service objectives are clear and secure, water is priced as an economic good, and consumption is monitored at the farm and basin level with water-conserving technologies.

Given their highly variable experience illustrated in Box 21, the creation of water users associations needs to be carefully promoted to develop decentralized, community-based and inclusive organizations. Enabling conditions include social and economic context; equity dynamics; local control and enforcement of water rights, services and fees; monitoring capability; and clear legal authority. Effective associations also depend on members’ ownership, and the attitude of relevant government agencies and their accountability to water users associations as service providers.

It is essential to increase women’s engagement in water users associations and farmers organizations, where they remain under-represented and disadvantaged. The use of fixed gender quotas is one approach, as well as capacity development of skills such as communication and negotiation to encourage participation and leadership.^{77, 78} It is essential to target men to raise their awareness of gender roles that disadvantage women and, in challenging them, show how this can benefit both women and men.

Women-only groups can give women a new voice and bring many benefits. Where such groups exist alongside water users associations, they must be involved in decision-making. In Tajikistan, women have started to teach younger people about irrigation. In some instances, their role has become informally institutionalized, the community accepts them and some receive a salary.⁷⁷

Policy and governance on water resources management for agriculture remain focused on irrigation, while the framework at watershed and basin scales concentrates primarily on allocation and management of freshwater in rivers, groundwater and lakes.⁸³ Water resources management is normally under ministries for water affairs and focuses on large-scale irrigation, drinking water and hydropower. This has resulted in limited investments and innovations in governance, policy, institutions, practices and technologies to support small-scale farmers in rainfed areas and non-consumptive uses such as inland fisheries and aquaculture.

Institutions for managing water in rainfed crop production

Rainfed agriculture is facing growing challenges in terms of irregular, insufficient or inadequate rainfall. Increased climate variability is expected to further increase the frequency and severity of droughts, extreme rainfall, weather events and flooding, radically disrupting markets and increasing production risks. (For a discussion on the impact of flooding in agriculture, see In Focus: Too much water? Flooding waterlogging and agriculture.) Precipitation anomalies on grazing lands are also a threat to livestock production. Low-income countries are particularly vulnerable to water risks owing to weak institutional mechanisms and their high dependence on low-input rainfed agriculture,⁸⁴ which remains the livelihood of the majority of the rural poor.

What is needed is effective integration to promote investment in water management from rainfed to irrigated agriculture. Focusing on river-basin water planning does not emphasize sufficiently water management in rainfed areas. This usually occurs below the river basin scale, on farms of less than five hectares, with small catchments. An equally strong focus is thus needed to manage water at the watershed and basin scales.⁸³

The potential gains from water investments in agriculture are greatest when combined with other production practices, such as improved or high-yielding crop varieties, no tillage and restoration of soil organic matter. Improvements can be achieved through synergies, but ensuring the full benefits from water management also requires attention to land tenure, water ownership and market access.⁸³ As water shortages and land degradation in rainfed areas cannot be tackled through farm-level interventions alone, community-based watershed management is preferable.⁸⁵ This extends to forest conservation and restoration at the watershed level, particularly in large basins, and calls for new investment to plan and manage water for rainfed agriculture. Improved water management in rainfed agriculture also requires public investment in infrastructure and access to roads to link farmers to markets. For this to occur, farmers organizations, financial policies and other institutional arrangements need to go hand in hand with policy advances (see Chapter 5).

The management of rainwater and other investments to upgrade rainfed agriculture is receiving increased priority. In 2005, the National Commission on Farmers in India adopted an integrated watershed management approach with a focus on harvesting rainwater and improving soil health for drought-prone rainfed areas.⁸³ The following year, the National Rainfed Area Authority was established – a central agency that supports strategic plans for watershed development projects and the country’s rainfed agriculture. The agency facilitates convergence of different government projects and, therefore, acts as coordinator between all bodies, organizations, agencies and ministries involved in watershed programmes.^{85, 86} There is growing evidence of the importance of redirection of water governance and management towards upgrading rainfed agriculture, including livestock production, as explained in the following section.

Livestock management during droughts

Livestock are a key livelihood asset for pastoralist and other communities. During emergencies such as drought, livestock conditions and production can worsen dramatically owing to lack of feed and water. Livestock mortality can be high, and rebuilding herds extremely difficult. Without preventive support, longer-term impacts are possible.⁸⁷ In view of concerns that emergency interventions often fail to support pastoralists and other livestock keepers, preparedness and contingency planning as well as emergency response are paramount. National policies, regulations and institutions can influence the ability to use livestock assets in any emergency, such as drought. Veterinary services and policies on taxation, marketing and exports all have an impact on livestock-based livelihoods. However, the measures for implementing the most appropriate intervention are often lacking. A wide range of governance strategies can improve water management of livestock production, particularly during times of drought. Some of these are discussed below.

Involving community representatives and local institutions – Effective identification, design and implementation of livestock interventions requires local community involvement, particularly of marginalized or vulnerable groups who keep livestock or might benefit from access to livestock or livestock products. Community participation in targeting is an effective means to ensure fair distribution of benefits.⁸⁷ Customary or indigenous institutions can play a key role in emergency interventions and in managing natural resources, including grazing land and water. Their participation is necessary to sustain activities and contribute to livelihoods. In the United Republic of Tanzania, the Engaresero Maasai pastoralist site has established a community-based organization to manage natural resources and livestock sustainably, promote tourism, and preserve and develop the indigenous knowledge and customary law of the local community.⁸⁸

Identifying and mapping water sources, and early warning systems – In drought-prone areas, spatial data and geographical information systems for mapping water points (including groundwater) are an important step towards forming a knowledge base for mitigation and water emergency report planning.⁸⁹ A case in point is the extreme drought in Kenya in 2000, which led to the loss of up to 50 percent of cattle in certain districts. Owing to a lack of information on the location of alternative local water sources in the worst-affected areas, relief agencies remained helpless.⁸⁹ Early warning systems can anticipate emergencies and allow time for preparation and mitigation of disasters. They can also help inform emergency response.⁸⁷

Secure and flexible access to land and resources – As pastoralists use land and other resources collectively, a narrow sense of ownership (i.e. the right to control a resource completely and exclusively) does not fit with their traditions and livelihoods.⁹⁰ Pastoral property rights are understood as overlapping, often nested within a different set of rights over another resource, operating with different authorities and functions. Access to resources must be flexible enough for negotiations to accommodate different rights that often overlap. Women’s participation should also be improved in land tenure and decisions. A five-year joint programme by FAO, the International Fund for Agricultural Development (IFAD), UN Women and the World Food Programme (WFP) is advancing women’s land rights in Ethiopia, Guatemala, Kyrgyzstan, Liberia, Nepal, Niger and Rwanda through advocacy work, awareness-raising campaigns and training.⁹¹

Developing national guidelines and standards for livestock responses to water risks – In some countries, such guidelines already exist and can assist livestock projects, including policymakers and decision makers. To complement existing guidelines or develop new ones, the Livestock Emergency Guidelines and Standards (LEGS) project was created in 2005. The project is managed by a steering group, comprising FAO, the African Union, the Feinstein International Center, the International Committee of the Red Cross, and Vétérinaires Sans Frontières Europa.⁹² A global network of more than 1 500 organizations and individuals consults with a range of stakeholders. The project aims to provide rapid assistance to protect and rebuild the livestock of crisis-affected communities, and to improve the quality and livelihoods impact of livestock projects in humanitarian situations. The project has generated two main products: a handbook and a training programme. The handbook sets out standards, guidelines and tools to design, implement and evaluate livestock interventions in rapid- and slow-onset emergencies, such as flooding and drought. It covers assessment, response identification and technical areas including destocking, veterinary services, water, feed, shelter and restocking.⁹² The training programme focuses on a series of regional three-day training courses across Africa, Asia and Latin America.

Governance for integrating inland fisheries, aquaculture and irrigated systems

The impacts of irrigation on inland fisheries and aquaculture can be profound in positive or negative ways. Irrigation changes geomorphology, hydrology and land use, aquatic habitats and nutrient contents, which, in turn, affect inland fisheries. In most cases, productivity has declined because of a lack of awareness or a lack of priority being given to the impacts of irrigation on inland fisheries, and the way these systems are designed and operated.^{2, 93} Environmental impact assessments of irrigation schemes rarely recognize the existence of inland fisheries.⁹⁴ However, despite these constraints, irrigation can create opportunities for inland fisheries and livelihoods, changing the economic environment and institutional arrangements that affect how, by whom and to what extent fisheries resources can be utilized.⁹⁵

In an irrigated area of northwestern Bangladesh, rice farmers have largely replaced the Aus rice crop (produced between April and July) with fingerlings, while continuing to produce Aman (August–November) and Boro rice (December–March). There are three advantages to this: (i) fingerlings are produced at the start of the fish culture season, when demand from pond owners is high; (ii) one cycle of fish production breaks the rice production cycle, reducing pest survival (with fewer pest problems in subsequent crops); and (iii) fingerling production is far more productive than Aus rice.²

National and regional laws and policies can have a large impact on governance structures to manage water resources, and on the extent to which inland fisheries and aquaculture can be integrated within irrigation systems (Table 6). Some countries and regions encourage integration of natural resources governance, while others treat them separately. For example, in Cambodia and Sri Lanka, integrated rice–fish practices are encouraged, and community fish refuges – a fish conservation measure to improve the productivity of rice-field fisheries – have become a national policy thrust.⁹⁶ Other countries do not allow rice-field areas to be used for fisheries nor rice fields to be converted for fish culture,⁹⁷ or they specifically ban fisheries-related activities, such as that of placing fish cages in irrigation canals.⁹⁸

TABLE 6

Impact of irrigation-related governance aspects on inland fisheries and aquaculture

Back

Despite the clear linkages between its multiple functions, water at all levels is still managed today in a fragmented manner. Water-related responsibilities are dispersed across several sectors, and effective coordination is the exception rather than the norm at decision-making level, among implementing entities and across national boundaries. The behaviour of different actors in relation to water management is the result of political and policy choices by various sectors that often remain disconnected.

This chapter has recognized the need for a stronger focus on inclusive water governance as water management alone is less effective at solving problems, and different sectors (involving water, food and energy) are clearly interlinked such that no sector can operate in isolation. Solutions to water problems most often lie outside the water domain. Therefore, this chapter has examined ways to improve water governance and how such governance relates to efficiency and equity, ensuring the human right to water and sanitation, as well as to food. The different mechanisms and tools, such as water rights, market-based instruments, water tenure and water users associations, can improve access to irrigation and rainwater, particularly for marginal and small-scale farmers, while mitigating water constraints. When water is not allocated properly, when usage regulations are lacking and when prices do not reflect the true cost of water, these mechanisms can contribute to over-exploitation of surface water and groundwater resources. Often, most of the benefits accrue to larger farmers who use more water, fertilizer and energy, further exacerbating inequalities.

The chapter has highlighted the need for sound transparent water accounting and governance analysis in order to establish accountability mechanisms and transparency about the rationale behind the measures, and the distribution of costs and benefits. It is also important to promote a human rights approach to water management, with particular attention to vulnerable groups, such as small-scale producers, women and indigenous peoples. The water tenure concept can provide a holistic approach to understanding people’s relationships with water, and serve as a strong building block for equitable and efficient water use. These measures need to be combined with realistic water market instruments and the credible threat of sanctions in accordance with the law, often linked to environmental safeguards and water-sharing agreements or treaties.

The previous chapters have demonstrated how, in many parts of the world, growing water shortages and scarcity are urgent and major challenges for agricultural systems and the environment. Demographic pressure, urbanization, dietary change and climate change are expected to amplify the issues. However, despite increasing competition in the demand for water, agriculture will remain by far the largest water user, as its withdrawals of water – currently 70 percent of total withdrawals – continue to increase. The agriculture sector (crop and animal production, and forestry) manages the greater part of the landscape in water basins. Addressing water shortages and scarcity must rely on a combination of sound water accounting and auditing, suitable water technologies and water management in which the agriculture sector must play a major role. Chapter 3 has shown that there is a wide range of technical options and management strategies to align water-use patterns with different users’ needs, while also accounting for environmental flow requirements. However, the adoption of integrated technical solutions does not happen in a vacuum. Adoption and implementation are dependent on appropriate institutions and the political economy surrounding water, as illustrated in Chapter 4, and on aligning incentives for efficient and sustainable water use. This chapter considers the broadest dimension presented in Figure 13 by focusing on policy coherence and setting policy priorities.

Over the last 25 years, water governance paradigms have been shifting towards coordination, and towards decentralized, participatory and integrated approaches. The SDGs and the 2030 Agenda have given renewed impetus to the debate on the interconnectedness of multiple sectors, and refocused attention on the need for greater cross-sectoral coordination and policy coherence. In particular, SDG Target 6.4 on water use and scarcity has a strong link to SDG Target 2.4: “By 2030, ensure sustainable food production systems and implement resilient agricultural practices that increase productivity and production, that help maintain ecosystems, that strengthen capacity for adaptation to climate change, extreme weather, drought, flooding and other disasters and that progressively improve land and soil quality.”

Although it is clear that water is an increasingly scarce and finite resource, and that water shortages are a growing problem for rainfed agriculture and livestock, the integration of these concerns into policy frameworks is still slow, even within the agriculture sector. Globally, water is seriously undervalued owing to its unique properties (presented in Chapter 1). In many countries, water is not charged for at all. As prices do not reflect its true cost, water is misallocated, and there is little investment in new infrastructure and water scarcity management. Recognizing that scarcity will also generate tensions among users, this chapter starts by asserting the need to harmonize water-use policies across different sectors, subsectors within agriculture and locations. The chapter reviews policies and practices for better water resources management in agriculture, and for aligning private incentives for farmers with the overriding purpose of optimizing water use.

Having covered policy coherence and more efficient and sustainable water-use incentives, the chapter then examines opportunities for actions and investment in agricultural water management, based on the analysis and discussion of preceding chapters. Building on the challenges in Chapter 2 concerning drought risk in rainfed crop and pastureland systems, and water stress in irrigated areas, this chapter outlines policy strategies tailored to specific situations. It takes an “all of agriculture” perspective, highlighting the important role of nature-based solutions, and how the interests of inland fisheries and aquaculture are well aligned with environmental flow requirements.

Need for policy coherence across sectors

The behaviour of different actors is the result of political and policy choices in various, often disconnected, sectors. Adding to the challenge of reducing water scarcity is the need to improve coherence through coordination across various policies, legislation and fiscal measures that influence water management. Many policies can have a major impact on water supply and demand, through measures such as energy taxes, trade agreements, agricultural subsidies and poverty reduction strategies.¹ While these may have major implications for water use, they are often not taken into account (Box 22). There is a need to integrate decision-making, as different departments take decisions on irrigation and on industrial or municipal use of water with little consideration for the cumulative impacts on water demand and quality. Without this integration, water-related ecosystems are under increasing pressure from growing water demands from cities, industry and agriculture, seriously affecting their ability to deliver services essential to meeting the SDGs.

Box 22

Incentives, water scarcity and productivity in the Near East and North Africa region

In the Near East and North Africa (NENA) region, per capita renewable freshwater is less than 10 percent of the world average.⁵ High water and energy subsidies, coupled with weak monitoring and enforcement, undermine incentives for efficient water use across the region. They encourage over-exploitation and, in many countries, perpetuate a pattern of low-value uses and low water productivity.^{6, 7}

As a consequence of underpricing fuels in groundwater extraction and undervaluation of water, water extraction in most NENA countries exceeds renewable resources, resulting in depleted aquifers.^{5, 8} In agriculture, water charges do not reflect either the scarcity value of water or the delivery cost.⁹ Farmers have little incentive to save water, and tend to grow water-intensive crops if they are profitable, delaying adoption of water-saving irrigation technologies.¹⁰

Governments in the NENA region have prioritized national self-sufficiency in food staples, mainly by subsidizing cereal production through a combination of producer price-support and input subsidies as well as import controls and public procurement. Self-sufficiency in cereals to reduce import dependence has been central to agricultural policies in several NENA countries, including Algeria,¹¹ Egypt,^{12, 13} Iran (Islamic Republic of),¹⁴ the Syrian Arab Republic¹⁵ and Tunisia.¹⁶

In the absence of incentives to use water efficiently and increase productivity, and given the high irrigation requirements of these crop yields, water overuse has been the norm. This has resulted in serious depletion of aquifers, with important consequences particularly for small-scale producers.^{5, 17}

The dominance of cereal production (wheat in particular), promoted by expensive subsidy systems, entails major GDP losses compared with policies that encourage production in line with comparative advantages.¹⁷

With the region having the lowest water tariffs in the world, water-use patterns result in very low economic water productivity. Although physical water productivity levels are high compared with global trends, agriculture produces the lowest economic returns from water while accounting for almost 80 percent of the region’s water use, higher than the world average of about 70 percent.^{7, 17}

A study done by FAO has revealed that the most remunerative crops per cubic metre of water are fruits and vegetables, with economic water productivity in the range of from USD 1.07/m³ to USD 6.18/m³. Cereals, namely wheat and rice, have the lowest economic productivity, with values of about USD 0.35/m³. To date, the low cost of water, coupled with cereal production support, has decoupled water use from its economic productivity.¹⁷

An earlier study compared the economic water productivity of major crops in Egypt, Jordan and Lebanon with quantities of water used.¹⁸ The results demonstrated that Egypt’s staple irrigated food crops (including wheat, maize, sugar beet and rice), consuming most water, had the lowest economic water productivity. On the other hand, vegetables had the highest productivity, while consuming a very small share of agricultural water (see figure in this box). The study showed similar results from Karak Governorate, Jordan, where four irrigated crops – barley, wheat, olives and tomatoes – occupied 85 percent of cropland and consumed 95 percent of freshwater, but had the lowest economic water productivity, while other vegetables were more productive and consumed less than 5 percent of irrigation water.

ECONOMIC WATER PRODUCTIVITY AND WATER CONSUMPTION OF MAIN CROPS IN EGYPT, AVERAGE 2007–2011

Back

Low water tariffs and high energy subsidies, coupled with inadequate or absent metering and monitoring, have disincentivized farmers from adopting more efficient irrigation. Data from FAO reveal that conversion to modern irrigation such as sprinklers or a localized scheme has been slow, especially in low-income or highly water-scarce countries. In Egypt, Morocco and the Syrian Arab Republic, more than 70 percent of irrigated land uses surface irrigation, while more efficient schemes are almost absent in Yemen.²¹ Farmers in the NENA region are mostly small-scale farmers and lack financial incentives to invest in technology. Incentives are further weakened by land fragmentation.²²

In some cases, self-sufficiency policies for staple crops have resulted in extreme depletion of water and mass population displacement. This was the case in the Syrian Arab Republic, where policies, mostly targeted to wheat self-sufficiency, played an important role in degrading natural resources. Several studies have highlighted how government policies favouring irrigation-intensive crops (wheat and cotton) collapsed groundwater levels.^{15, 23} This limited the coping capacity of Syrian farmers when severe drought struck the Near East in 2007–2009. Conditions were further worsened in 2008 when the government lifted diesel subsidies (the main fuel used in irrigation), triggering an overnight price jump of 300 percent.^{15, 24} While the same drought had negligible impacts on other countries in the region,^{24, 25} in 2009 it displaced about 300 000 people in the Syrian Arab Republic from rural areas towards cities, leaving 60–70 percent of villages deserted in the regions of Hassakeh and Deir ez-Zor.²⁶

Back

Integrating horizontally across sectors will help reduce possible negative cross-sectoral effects of policies within each sector, thereby saving resources and reducing trade-offs.² The water–energy–food nexus is part and parcel of the need for policy coherence. Agriculture policies directly influence water and energy, when, for example, they encourage overplanting of water-intensive crops (e.g. rice) leading to excessive water and energy use to pump groundwater.³ Higher energy prices may reduce water withdrawal from aquifers with less pumping, thus reducing over-exploitation of groundwater.⁴ Affordable solar-powered pumps could significantly change this relationship by expanding groundwater extraction. Agriculture may then use even more freshwater. To avoid greater water scarcity, integrated agriculture and irrigation information systems, across other major water-using sectors, can help make effective decisions under uncertain conditions. Data services and knowledge management for the water–energy–food nexus can promote transparent and robust decisions and take into account hydrological constraints and environmental flow requirements.

Subsidies are often justified to provide public goods, as an incentive to adopt new technologies, to promote food security, to deliver income support to small-scale farmers and as a counterbalance to poor infrastructure.²⁷ As shown in Box 22, agricultural input subsidies can help raise production and profitability, but they can also promote inefficiency, and over-exploitation and unproductive use of water, with important economic and social consequences. Governments often maintain large subsidies for private goods such as energy, fertilizer and credit, displacing important public goods (e.g. investment in research, roads and education), offering incentives that promote inefficiency as well as unsustainable use of natural resources, including water. This also applies to private water use, where cheap or free irrigation water to farmers continues to distort incentives, leading to overuse and polluted water resources.²⁸ This can promote the planting of crops that need a lot of water. Subsidies on electricity and water have caused over-extraction of groundwater, causing land subsidence, salinization, and degradation of land and water. In India, where groundwater subsidies are estimated to exceed the education budget, subsidies contribute to unsustainable groundwater extraction.²⁹ When subsidies are broadly based or poorly targeted, most benefits go to larger farmers who use more water, fertilizer and energy.²⁷ Water subsidies are a considerable cost for society. In Andhra Pradesh State, India, a conservative estimate by the Global Subsidies Initiative revealed annual irrigation subsidies between 2004 and 2008 of about USD 300 million on average.³⁰ (See Box 22 for a discussion of the implications of public policies on water use in the NENA region.)

Proper incentives are a crucial component of policy coherence for sustainable water use. Managing the many water-related challenges in agriculture and in the broader economy will require a rethinking of the incentives that drive water-use decisions. It will entail taking into account the role water plays beyond agricultural production, for ecosystems more broadly and society more generally, while bearing in mind that policies that transcend water use can shape incentives.

The need for coherence is also strong across agricultural subsectors

Better integration is needed also across subsectors in agriculture. As it uses most water, agriculture is the largest beneficiary of water subsidies and policies. The impact across agricultural subsectors is very uneven, as these policies often benefit irrigated farming to the detriment of other systems such as inland fisheries and rainfed production. One example of trade-offs that illustrates the need for coordination is the relationship between irrigation and inland fisheries. Although the expansion of irrigated lands across the globe since the green revolution has brought major food-security benefits to low-income countries, these may have been partly offset by losses in inland fisheries. The 2030 Agenda can be a starting point for the multidisciplinary and inclusive dialogue needed to negotiate trade-offs and balanced solutions based on common and trusted data.³¹

Within the agriculture sector, the bulk of managed water use is in irrigated systems. Rainfed agriculture does affect the share of rainfall left after evapotranspiration that percolates as groundwater or surface water runoff. However, irrigation has a more direct impact through groundwater withdrawals that affect surface water flows and ecosystems through dams and diversions. As mentioned in the beginning of this report, around 41 percent of current global irrigation water use occurs at the expense of environmental flows requirements.³² Irrigation – where present in a water basin – thus plays a central role in water accounting, which in turn should guide sustainable water allocations. In regard to environmental flows and ecosystem services, there is a window of opportunity to implement actions to rectify earlier mistakes in the design and operation of irrigation systems, and so improve productivity and the nutritional benefits of irrigated agriculture. Actions span technical and policy interventions for more effective integration of fisheries and aquaculture in irrigated areas, covering (i) modified design and operation of delivery and storage infrastructure to improve water connectivity and flows; (ii) construction or improvement of habitat and refuge areas – i.e. constructed or enhanced natural depressions – within and around irrigated systems; and (iii) revised policies, regulation and management of irrigation systems to enable these modifications.

Integrating fish into irrigation systems can benefit from the availability of fingerlings for aquaculture. Globally, the production and distribution of huge numbers of quality fingerlings have boosted aquaculture. Fingerlings from hatcheries are now so inexpensive they can be used in great numbers to stock waterbodies, such as reservoirs, in what have become known as culture-based fisheries. Across Asia, irrigation dams are now routinely stocked with fingerlings to enhance fish production.^33–35 Mexico systematically stocks its reservoirs with fingerlings, and has established seed production centres solely for this purpose.³⁶ Recognizing a vast untapped potential, there are now international guidelines to support responsible stocking of reservoirs and other open waterbodies.³⁷

Broader coordination in agricultural strategies, beyond irrigation, will also play a role in rethinking water use. The proportion of cropland requiring irrigation may be reduced by introducing innovations that improve rainfed agriculture productivity. Similarly, forest conservation and management upstream will affect water resources downstream. This highlights the broader issue at the subsectoral level of aligning the many sectors and stakeholders that influence water management, service delivery and demand. An example that is particularly relevant for water in an agricultural context is that of non-consumptive water use and how water can be reused.

Coherence needed across locations – integrated approaches

Realigning private incentives with true costs by adjusting subsidies and prices to make water use more sustainable is important. However, it is unlikely to address the full scale of the problem, as impacts of water use by one stakeholder may affect availability to others downstream in a water basin. For this reason, this report emphasizes environmental flow requirements and water allocation systems based on water accounting as an important precondition for more sustainable water management. In turn, these allow a more integrated approach, taking into consideration different water users in a watershed, including non-consumptive use and water needed for ecosystem services.

One example of an integrated approach is irrigation scheme management that maintains food production levels as well as other environmental and ecosystem services.^{38, 39} These range from regulating functions (i.e. groundwater recharge and flood control) to provisioning services (watering small gardens and livestock, inland fisheries and aquaculture). The development of inland fisheries (whether capture fisheries or culture-based) and aquaculture in irrigation schemes is a particularly attractive option as it can offer additional production at little or no additional water service cost. Examples of positive irrigation impacts on inland fisheries are found in Sri Lanka,⁴⁰ in large reservoirs of Lao People’s Democratic Republic and Thailand for indigenous Thai river sprat,⁴¹ and in the Lake Kariba reservoir, shared between Zambia and Zimbabwe, with the introduction of the non-indigenous Lake Tanganyika sardine.⁴² Evaluating these interventions must also take into account the loss of riverine and floodplain fisheries caused by the damming of watercourses to create the reservoir.

Watershed management aims for sustainable use of resources through an integrated ecosystems approach centred on understanding the overall interactions between biotic (including humans) and abiotic factors. It is best to address inequalities among communities at the watershed level regarding socio-economic status and access to water, resources and services as a consequence of their location. Watershed management provides a framework for understanding and reconciling interconnections among various land-use systems, and for collaborative action and decision-making in the face of competing claims on resources, especially water. Based on a sound analysis of conditions and dynamic processes in the watershed, a medium-to-long-term vision will allow for the design and implementation of measures to preserve ecosystems and biodiversity, optimize resource productivity, and improve human livelihoods and well-being. Watershed management is very context-specific but also highly flexible and adaptive to different fields of application and implementation scales.⁴³

Mechanisms and tools for improved policy coherence

Rather than general subsidies on private goods, targeted subsidies on environmental services can incentivize specific goals such as new irrigation technology and environmental services by, for example, subsidizing structures to mitigate the impacts of irrigation development and dam construction. Such structures include fish-friendly irrigation and fish passages, constructed wetlands, and refuges for fish and aquatic biodiversity. As general subsidies for private goods are phased out in favour of more-targeted ones, there is the possibility of loss of income for small-scale farmers and other vulnerable populations who may not qualify for the targeted subsidy. They can be compensated for losses by using some of the funding saved, for example, with smart cards or smartphones for efficient funds transfer to small-scale farmers.²⁷ Other options are targeted loans or subsidized equipment prices for small-scale farmers to invest in practices such as drip irrigation, or to cover labour and installation costs of water harvesting structures.

Temporary subsidies during early input and technology adoption may help meet fixed costs of new technology and encourage farmer experimentation and learning during rapid technological change. Such subsidies should be temporary and phased out with adoption and appropriate use of technologies. Once in place and once they have political support, removing subsidies becomes difficult; thus, implementation requires care.^{27, 44} Promoting linkages with other programmes may be effective; for example, linking social protection programmes such as public works or cash transfers with mechanisms and/or programmes for better water use. Box 23 reveals how targeted subsidies have increased the use of solar-powered irrigation pumps in Bangladesh and India. This type of intervention may be inappropriate in areas facing water stress, as affordable solar-powered pumps may increase the risk of over-extraction of groundwater. This highlights the importance of water allocation systems based on water accounting to avoid unintended effects, whereby even water-saving technologies can lead to greater water consumption.

In the context of integrated approaches and watershed management, payments for environmental services are another targeted policy instrument with environmental and economic benefits. They consist of payments to farmers or landowners who agree to manage their land or watersheds for environmental protection, to protect water resources, reduce GHGs, or improve soil quality and nutrient status. Most existing schemes focus on reducing deforestation or improving the watershed, adopting a nature-based management perspective. These incentives are extremely important when markets fail to take into account the scarcity of natural resources and the social value of well-functioning ecosystems. Examples are found in both higher- and lower-income countries, and their success and cost-effectiveness depends on their design.^{49, 50} Evaluating these programmes to see which approaches work best can be challenging. The main challenge is that evaluations – to be rigorous – need to compare areas with payments for environmental services to other areas without payments, which can be costly.

Payments for environmental services will help sustain ecosystems where, even with an integrated approach, barriers to practices and property rights may make it difficult to address all environmental issues. There are significant positive impacts on environmental outcomes, primarily for local or subnational payments for environmental services. One example is the Rio Rural Programme in Brazil, which encourages sustainable farming systems, integrating income generation and environmental conservation in 72 municipalities of Rio de Janeiro State. The programme strengthens organization and community mobilization in 366 watersheds, developing skills and encouraging best practices.⁵¹

In general, smaller-scale programmes that are at least in part user-financed, with effective targeting criteria and strong conditionality rules, have performed better. Other factors in the success of these payments are low opportunity costs on other land uses – or payments high enough to cover these opportunity costs – limited production mobility and well-established property rights. Appropriate monitoring and sanctions, with social safeguards, also increase the probability of success. Payments are most likely to succeed where there is a clear demand for environmental services with economic value to one or more stakeholders; there are effective brokers or intermediaries; land and water rights are clear, and contracts enforceable; and outcomes can be independently monitored and evaluated.

However, improving policy coherence will need strong governance, tools and processes to manage and coordinate policy, and develop budgets and regulation. It will also require strong political commitment and leadership, cultural changes, monitoring, and learning from international experience and evidence.⁵² Specific steps can include capacity strengthening for public institutions; coordination across water, agriculture and energy ministries; improved planning and monitoring tools; and upgrading and networking department databases to synthesize data and analytical capabilities. Putting in place effective regulatory and incentive policies is an important step towards policy coherence, eliminating general subsidies so that the water, agriculture and energy sectors face the same opportunity costs when assessing the viability of policies, programmes and projects. Another frequently debated dimension is the role of international trade and how it affects water use in countries (Box 24).

The institutional and policy reforms of water management require a complex blend of public-sector, market, and civil-society action (Box 25). This is particularly relevant because of the link between agriculture and food security and nutrition, both intimately linked to water. Food security and nutrition are affected by access to clean water (see In Focus: Improving access to safe drinking water in rural areas). However, food security and nutrition are also linked to water through the many small-scale farmers and rural poor who depend on agriculture. This report shows how many people live in areas where water risks affect agricultural producers. Macroeconomic and commodity price policies that create a level playing field across sectors and commodities can enable small-scale farmers to make more-informed and less-risky water decisions, such as on water harvesting or on irrigation investment. Improving irrigation investments to include or link with other interventions that address gender, youth, health and nutrition outcomes could also transform irrigation programmes from solely increased food production towards being an integral component of poverty reduction strategies and improved food security and nutrition.⁶³ Agricultural extension, cooperatives and water users associations can include nutrition and diet in their messaging.⁶⁴ This could also be tailored for producers in rainfed areas and the water-related challenges they face. There should be greater targeting of water interventions towards women, to improve dietary quality and nutritional outcomes.^65–67 Identifying interventions that reduce women’s time burden and support their control over production could accelerate nutritional gains and increase benefits.⁶⁴

Although every country and region experiences some water risk – whether water stress, drought, flood or water quality issues – each faces different risks of varied magnitude. (For a brief overview of issues related to flooding, see In Focus: Too much water? Flooding, waterlogging and agriculture.) Choosing the most suitable water management policies will depend on the production system: irrigated, rainfed (high- or low-input production), livestock, or inland fisheries and aquaculture. Also relevant are the risks faced and the endowment, in terms of both natural resources and finance, as well as each country’s governance and capabilities. Deciding on concrete actions, interventions or policies means prioritizing objectives to direct limited resources to where they are most needed and can be most effective. Building on the spatial analysis in Chapter 2 for rainfed, irrigated and livestock production, Table 7 presents possible policies and intervention areas to reduce water shortages and scarcity in crop and livestock systems, as well as interventions and strategies for inland fisheries and aquaculture. These are elements of a portfolio of interventions for an “all of agriculture” water management strategy in parallel with intersectoral efforts to make water use more sustainable. The importance of water accounting, as a premise for sustainable water management, is a cross-cutting theme affecting all types of water users.

TABLE 7

Policy priorities for improved water management in agriculture

Back

Improved water management in rainfed cropland

Globally, this profile is relevant for all 1.2 billion hectares of rainfed cropland, but especially for the 77 million hectares and 51 million hectares of low- and high-input rainfed production systems with high to very high drought frequency, respectively. In these areas, conserving water and the balance between irrigated and rainfed agriculture receive most attention, as relying solely on rainfed agriculture involves considerable risk of drought. Water harvesting techniques (e.g. to support supplemental irrigation) can bridge short dry spells, and thus decrease risk in rainfed agriculture.⁷⁰ Although water harvesting has great potential for enabling water management strategies to be most effective, such strategies also need best agronomic practices, including improved varieties, proper crop planting and harvesting periods, and nutrient management. Where drought risk and a lack of resources constrain farmers’ investment in higher-risk and higher-return activities – making it harder to break the vicious cycle of low-input production – public interventions that invest in modern inputs will play a central role. Governments can help attenuate the effects of drought by investing in roads and market infrastructure to link farmers to their markets, and subsidize water capture and conservation, while at the same time contributing to overall agricultural development. Mobile phone apps, a cost-effective solution, can help farmers access market, financial and weather information. Where drought risk is severe, databases and information systems with drought monitoring and early warning systems will be key preventive measures. Governments can also eliminate barriers to investment through credit and extension services, or by introducing crop insurance and safety nets with alternative income sources for small-scale farmers.

Expanding water harvesting can affect the sustainability of inland fisheries and other water-related ecosystems and, consequently, the food security and nutrition status of those who depend on them. Any decision about investing in water harvesting should be based on detailed water accounting. Water harvesting that integrates agriculture systems with raising fish and other aquatic animals can be important for offsetting environmental and economic costs, adding nutritional benefits at the household and farm level, and increasing water productivity.

Realizing maximum benefits from interventions in rainfed agriculture also depends on involving farmers in developing the technology within their local community and possibly at the water-basin level.⁷¹ A new water policy framework for integrated water resources management is required in order to plan and allocate rainwater at the watershed scale, given that water policies and regulations are usually designed to allocate irrigation water and not collect rainfall.⁷¹ For the 14 million hectares of rainfed agriculture suffering very high drought frequency, governments could also remove agricultural distortions to facilitate trade in water-intensive goods in order to compensate for water deficiencies and provide food security and nutrition.

A key policy area for rainfed areas, both cropland and pastures, is drought preparedness. Drought policies should not simply be a response to disaster but a permanent concern for governments and society. Drought policies should be in place during non-drought years, when there is more time to plan and address challenges. During drought years, efforts will logically be directed towards drought response programmes. Each country policy will have its own characteristics based on local conditions; however, there are some elements common to all policies. A drought policy should have three pillars: (i) drought monitoring, forecasting and early warning systems; (ii) vulnerability and impact assessment; and (iii) drought preparedness, mitigation and response. These three pillars should be supported by cross-cutting policies involving, at a minimum, the following elements: coordination and institutional development; capacity building; finance; knowledge management, science, technology and research, and awareness; regional and international cooperation; stakeholder participation and inclusiveness; and evaluation.⁷²

Improved water management in livestock production systems

Of the total of 4.6 billion hectares of pastureland, almost 15 percent (656 million hectares) experience high to very high severe drought frequency. The livestock sector is already a major user of natural resources such as land (although often marginal lands where crop production is not viable) and water through feed and rainfed pasture. Livestock water usage should be an integral part of agricultural water-resources management, taking into account the production system (e.g. grassland-based, mixed crop–livestock or landless) and scale (intensive or extensive), the species and breeds of livestock, and the social and cultural aspects of livestock farming in different countries.⁷³ To improve insight into the demand for freshwater in a specific region and enhance the performance of individual farms and the whole supply chain, stakeholders must undertake sound, transparent water accounting, taking into account climate, agricultural practices and feed utilization. To this end, in 2012, FAO established LEAP to improve the environmental sustainability of livestock, including optimal use of water, and to identify opportunities to improve water productivity for livestock (see Chapter 4).⁷³ Monitoring systems can conduct dryland water and feed assessments to improve early warning systems and inform development strategies.

As much livestock water consumption is feed-related, higher crop water productivity is pivotal to improving the water-related environmental performance of livestock production.⁷³ The water management for rainfed and irrigated agriculture mentioned in the previous and following sections is very important. Other critical options include improved seed varieties and cropping systems for forage and feed crops, and targeted subsidies to encourage the use of crop residues and by-products as animal feed. Other important subsidies are for the restoration, sustainable management and preservation of pastureland ecosystems. Apart from feed production, most water in livestock farming is for drinking. Chapter 3 presents several water management practices for reducing the amount of animal drinking water required. Improved animal health is one important way to increase overall production, and thereby water productivity, as the animals use fodder and other water resources more efficiently.⁷³ When access to water is lacking, improvements to infrastructure (e.g. boreholes) and the preservation of traditional water harvesting, water conservation and irrigation systems (e.g. canals, terraces and wells) should be promoted. Developing innovative technologies for extensive grazing management (e.g. mobile pumps and reservoirs) will complement this strategy.

There have recently been practical innovations in integrated production systems that harness synergies between crops, livestock and agroforestry, and ensure economic and ecological sustainability, while providing ecosystem services.⁷⁴ There are multiple ways to achieve this integration. The integration can be on-farm as well as on an area-wide basis involving some specialization. This will need political will, and policy and institutional support to adopt innovations and practices linked to promising crop–livestock systems for food security and nutrition. Governments should also promote input and output market linkage for such systems, with input and output supply chains and public–private service providers for different production systems and markets.

Successful scaling up also depends on strong farmers organizations, community empowerment, and multi-stakeholder and inter-institutional approaches. This requires knowledge exchange, capacity development, and adaptive and relevant interdisciplinary research.⁷⁴ Examples include farmer field schools and farmers clubs.

Improved water management in irrigated areas

As in rainfed systems, there are many options to alleviate water scarcity in irrigated agriculture. Globally, more than 275 million hectares of irrigated cropland would benefit from improved water management. Action is particularly urgent for the 171 million hectares under high to very high water stress. The starting point for any efficient, effective and sustainable strategy on water stress and improving water resources management in irrigated agriculture should be a detailed accounting of water supply and demand. Once stakeholders have a thorough understanding of the water balance – including the hydrological and ecosystem needs for water quantity and quality throughout the year – the challenge is to introduce clear, transparent allocation systems. These will need to balance water for food production, for the basic needs of the poor and vulnerable populations, and for environmental flows. Establishing secure water rights and access to ecosystem services within river basins and aquifers will also help create security for users, promote efficient water use, and open opportunities for water markets. To encourage effective management, the totality of water rights should amount to less than current usage in the basin or aquifer. Only under such conditions is it possible to design effective water conservation measures.

Although any expansion of irrigation must be done cautiously and as part of an integrated water resources management strategy, it is clear that the rural poor can benefit substantially from irrigation. In India, irrigation had the highest impact in reducing rural poverty from 1970 to 1993, compared with adopting high-yield varieties, fertilizer application, and improving rural literacy and rural road density across 14 states.⁷⁵ Other studies in Malawi and Pakistan have shown that – if well managed – irrigation can reduce the risk of stunting among children and promote diverse household diets.^{76, 77} There is great potential to expand irrigation in some regions of the world. Between 2010 and 2050, the harvested irrigated area is projected to increase by 12 percent in Eastern Asia and the Pacific, by 35 percent in Latin America and the Caribbean, by 22 percent in the Near East and North Africa, by 30 percent in Southern Asia, and by more than 100 percent in sub-Saharan Africa.⁷⁸ The potential is even higher with appropriate policies in place. One study estimates that there is potential for at least 16 million hectares of profitable large-scale irrigation and 7 million hectares of small-scale irrigation in Africa, with a higher internal rate of return for individual and farm-community managed systems.⁷⁹ Another study has revealed an even larger potential for profitable small-scale irrigation expansion in sub-Saharan Africa, with potential of up to 30 million hectares for motor-driven pumps. This expansion could benefit more than 350 million rural people.⁸⁰ Given that many countries depend on inland fisheries for food security and nutrition and are threatened by such intensification, it is important to adopt a more holistic approach in order to offset or mitigate some of these negative impacts.

Beyond expansion, priorities for irrigation investment include rehabilitating ageing and obsolete systems and modernizing existing ones for improved water control and water-use productivity. This might involve investments in advanced irrigation technology to raise crop water productivity or reduce consumptive use of water by minimizing evapotranspiration. Other options involve producing higher-value crops from irrigation or limiting the cropped area under irrigation. However, implementation of the latter is usually more difficult and less popular.¹ Where financially viable, investing in precision agriculture allows farmers to enhance irrigation efficiency while minimizing impacts on wildlife and the environment. Another type of infrastructure worth prioritizing concerns integrated data and information systems to monitor water resources and rights. These help inform efficient water allocation systems to ensure water consumption is sustainable in the long run. Measures to enhance supply from non-conventional resources – namely, desalination and wastewater reuse – will also become more important but will need sizeable investment.

Beyond investing in irrigation systems, to make the best use of scarce irrigation water, more active crop and nutrient selection is needed in all irrigated areas – particularly highly water-stressed areas – including crop diversification to higher-value and less-water-using crops (e.g. drought-tolerant varieties). Among integrated crop management options, conservation agriculture is one of the most important for enhancing efficient water and nutrient use. Other integrated management systems should also take into account the potential of aquaculture and inland fisheries, and environmental flow requirements.

As demand for water increases, much stronger institutions are needed to guarantee equitable distribution of benefits and maintain environmental services. Water governance reforms can help resolve water-related issues of equity and efficiency, especially in highly water-stressed areas. Depending on the context, key governance reforms include coordination of policies between government agencies across the food–water–energy nexus; integration of agricultural and urban water policies where there is direct competition for water; water users associations with strong capabilities (including control of local water rights, services and charges); enforcement of measuring and monitoring; and the promotion of clear legal authority. To avoid overuse of water, strategies should also consider phasing out payments coupled to production (e.g. price support), especially for crops that require a lot of water, and begin to phase out general subsidies for water, energy and fertilizers. Policymakers should also remove agricultural trade distortions in order to facilitate trade in agricultural commodities where subsidized water gives the sector a comparative advantage.

Improved water management in inland fisheries and aquaculture

Inland fisheries and aquaculture are a valuable component of food systems and have a useful role in many development initiatives. Water use by the inland fisheries sector is inextricably linked to protecting and maintaining aquatic ecosystems. Any water development project should first consider the needs of inland fisheries and aquaculture in terms of water quantity and quality. While other sectors can use water resources such as groundwater and rainwater, inland fisheries are constrained by the availability of surface waters. Therefore, assessing how much water is available is often not enough. Equally critical features include the location of the water resources, their flow dynamics, availability, water quality and salinity, and the impacts of drivers of change and anthropogenic pressures.⁸⁴ There is a need to establish environmental flows to sustain aquatic ecosystems and incorporate valuations of water-related ecosystems into water management. Most high-income countries and some low-income ones now have strict regulations on environmental flows and water quality criteria,⁸⁵ helpful in sustaining fisheries and aquaculture. Other policy tools at the disposal of river-basin agencies include costings to allocate water for aquaculture and review incentives and policies on water-saving technologies to identify outcomes that impact inland fisheries and aquaculture, as well as nutritional outcomes. Expanding stakeholder consultation on water management to include inland fisheries and aquaculture can ensure a more balanced decision-making process for water schemes. Examples include involving aquatic experts in rehabilitating old irrigation schemes or developing new ones.

Disputes over water for irrigation and water for inland fisheries and aquaculture are often difficult to resolve owing to the different water needs for fish and crops.⁸⁵ Nonetheless, proper planning and a holistic approach to development, farming and fisheries can mitigate them. First, it is important to consider trade-offs between water use for field crops and for inland fisheries and aquaculture, and to explore potential integrated solutions that maximize outcomes, especially with nutritional benefits for poorer or marginalized stakeholders. Rice systems that integrate aquaculture into existing irrigated crop production or co-located waterbodies are excellent examples of how the two activities can coexist. There are many cases that demonstrate fish have a positive impact on rice crops, with less need for pesticides and fertilizers.

In rainfed systems, integration of aquaculture and fisheries can also create win-win situations. Integrated approaches include (i) encouraging water harvesting technologies (e.g. small ponds) that enable farm diversification and supplementary crops, such as fish, horticulture and livestock; (ii) establishing refuge areas within rainfed rice systems to sustain and encourage aquatic biodiversity; (iii) establishing and promoting community-based social systems to conserve water-related ecosystems; and (iv) looking holistically at floodplains to reconnect systems by reducing obstructions, such as those created by all-weather roads (e.g. culverts) or small weirs.

Policymakers should also look at nature-based solutions as a way to protect natural resources and improve the state and quality of water-related ecosystems. Options include restoring water channels through barriers and bottlenecks created by water management structures; managing flows and opening structures to allow fish to pass during breeding seasons and to disperse within systems; creating refuge wetlands as part of broad-scale water engineering solutions for large irrigation schemes; and enhancing integration of aquaculture into existing irrigated crop production. Environmental services need to be fully costed in food production systems, and subsidies must change to reflect this. Only then will policymakers consider changing policies and governance to promote an agroecological approach.⁸⁶

Water resources management in agriculture will be key to attaining multiple Sustainable Development Goals linked to resource-use efficiency, the environment, and sustainable food production. This edition of The State of Food and Agriculture has focused on the extent to which agriculture contributes to, and is affected by, water constraints, specifically investigating the extent of the area and the number of people suffering severe drought frequency and water stress. The objectives have been to identify different constraints that producers might face vis-à-vis water resources management, and to provide guidance on governance, policy and prioritizing the interventions presented in this chapter, keeping in mind the heterogeneity of water users within agriculture (large farms, small-scale producers, women, men, indigenous peoples and traditional communities). The report has also highlighted the fact that competition for water resources is intensifying with population growth, economic development, changing consumption patterns, water quality degradation and climate change. As a result, the issue of managing trade-offs between economic, environmental and social objectives, and balancing the interests of all water stakeholders is moving up the policy agenda. Growing pressures on water resources will favour allocation regimes that perform well across a range of conditions and can adapt to changing conditions at the lowest cost.⁸⁷ The effectiveness of any water management policy will be influenced by fragmentation and rivalry between organizations; plurality of land and water tenure regimes; power relationships underlying existing institutions; conflict of interests; and access to and use of data and information.

Alongside the main theme of the report, there are water-related topics that are extremely important but could not be covered in depth. These were either touched upon in Chapter 1 – such as water use by the food processing sector – or covered by the In Focus briefs at the end of each chapter. The topics include the importance of rural wastewater, sanitation and hygiene (WASH), water pollution and salinity as they relate to agriculture, and also floods and drainage and how these impact agriculture. Each of these topics would warrant a separate chapter.

Water shortages and scarcity need to be addressed intersectorally and at the basin level, although agriculture is the largest user globally, with almost three-quarters of all water withdrawals, thus, holding the key to addressing these issues. More than ever, it is crucial to adopt an integrated approach, taking account of the water available throughout a watershed as a function of how different stakeholders use it, and to guarantee ecosystem functions. Better integration is needed across all subsectors in agriculture – including irrigated and rainfed areas, forests, inland fisheries and aquaculture – whereby the 2030 Agenda is a starting point for the multidisciplinary and inclusive dialogue needed to manage water resources in an efficient, equitable and sustainable manner.

One of the main findings of The State of Food and Agriculture 2020 is that 1.2 billion people live in extremely water-scarce irrigated areas or rainfed areas affected by severe water shortages, and, of these, 520 million live in rural areas. About one out of six people on the planet are affected by severe water-related challenges – about 15 percent of the world’s rural population. The confluence of increasing demand for water and of precipitation variability caused by climate change provides a sense of urgency to act according to the priorities laid out in this report. Policies should incentivize investment in increasing water productivity, combined with water allocation that better balances productivity both with equitable and inclusive access to water and with environmental flow requirements. This will entail the reforming of support policies, including other relevant sectors, that have led to inefficient water use. In many cases, water allocation will need reform, which can be politically challenging. Another possibility is to rely on alternative water sources, such as desalination and water reuse, or manage water demand more carefully through a combination of interventions. Additional efforts should be invested in developing tools and technological innovations to improve information and data on water resources and agriculture, as well as interactions and trade-offs, providing models to explore future pathways and optimal policy responses that balance economic, environmental and social objectives. Governance innovations should complement these efforts in leading a major transformation of the present food system and water paradigms to accelerate progress towards sustainable development that leaves no one behind.