Aqua Appia was an aqueduct built in Rome in 312 BC. It was the first of 11 aqueducts to be built over 600 years. They provided water for irrigation, fountains and drinking, were able to fill and empty lavish baths and latrines, and kept Rome’s streets clean.
Aqueducts sprang up all over the Roman Empire to transport water to the mills, mines and farms that underpinned Rome’s prosperity. Aqua Appia channelled water to a cattle market. Access to fresh water and sanitation lay at the heart of the Roman Empire’s strength. Julius Frontinus, a first-century water commissioner, described the unique contribution in his book, De aquae urbis Romae (The waters of the city of Rome): "an array of indispensable structures carrying so many waters; compare if you will, the idle Pyramids or the useless though famous works of the Greek."
The aqueducts were built for a reason: the population was growing fast, and groundwater wells and the Tiber had become polluted. Disease was rampant. The aqueducts were both a fast solution and a long-term investment, and a few are still partly in use today.
The world of the 21st century faces far greater water challenges than Rome, though timeless lessons can still be drawn.
Water, like air and food, is our life support. It covers about 70% of the surface of our planet. However, only 2.5% of that is fresh water. It is the only fresh water in our solar system and possibly in our galaxy–in actual fact it is the same water as in Ancient Rome. There is probably plenty of it for present and future needs–the total amount of water vaporised in a year to feed the world’s population would fill a canal 10 metres deep, 100 metres wide and long enough to encircle the globe 193 times. But as the Romans eventually found out, it will be spoiled without the right management, conservation and investment.
A key challenge is to improve access to clean water. Access to clean water is a human right, but hundreds of millions of people are deprived of that right. How water resources are managed affects access rights, and conditions social and political relations throughout the world. Add in threats such as climate change–flooding, drought, ocean acidification–and pollution from the likes of cleaning products and medicines, nutrients and pesticides, and industrial and domestic effluents, and it is not hard to see how serious a challenge water policy is. Indeed, the prospect of water becoming an arena of human strife and division, even conflict, seems realer every day.
Yet, water holds huge potential for economic, social and individual betterment. As the Romans understood, it is a source of life and prosperity, and a source of opportunity for investing in humankind’s future progress.
A matter of economy
A world economy that is four times larger in 2050 than now, with over 2 billion additional people, will clearly need more water. Global water demand is projected to increase by around 55% in that time.
Water demand in OECD countries is actually projected to fall somewhat, from 1,000 km3 in 2000 to 900 km3 in 2050, thanks largely to efficiency gains and a structural shift away from water-intensive sectors. But water demand is projected to increase sharply in the emerging economies, from 1,900 km3 in 2000 to 3,200 km3 in 2050, and most of their populations will live in severe water stress zones.
Demand will double to some 1,300 km3 in the rest of the world, particularly in cities, where most of the global population lives, making water investment and governance in cities particularly crucial.
Take access again. As many as a billion people drink unclean water every day. Over 350 million in Africa do not have access to clean water, along with nearly 200 million in Asia and a similar number again in the Middle East. In Latin America, some 36 million have no access, and even in developed countries some 9 million people are without proper access. By 2050, these numbers will be higher unless action is taken.
Clearly, good governance can help resolve many of these problems. The trouble is, in our fast-moving world, policymakers struggle to keep up with rapidly expanding demand: in vast megacities, such as São Paulo, Brazil, millions of people face water supply shortages, despite Brazil’s being a water-abundant country, whereas drought is affecting the vast irrigated land of California, which is one of the world’s richest economies. Water infrastructure is creaking and leaking in developed countries everywhere: the newly created Irish Water recently estimated that at least 40% of drinking water in Ireland was leaking from the system, which would demand decades of investment to repair. Water pollution affects all countries. In richer ones, despite costly treatment to remove nutrients and pesticides to meet drinking water standards, protect fisheries and the like, pollution loads from rural and urban sources, from fertilisers to polluted run-off from streets and car parks, remain a threat to humans, animals and plants. In rural France, people’s water bills indicate if the water is safe to drink or not; in Korea, despite good water treatment, people have turned to bottled water instead.
In poorer counties, untreated water is a major killer: over three-quarters of a million people die every year from diarrhea caused by inadequate drinking water and sanitation. The UN believes that 10% of the global disease burden would be reduced by better water supply, sanitation and hygiene.
It should not be that way. On the contrary, our water systems could become the harbinger of inclusive, innovative growth. How? The answer lies in understanding and marshalling demand and supply in smart, participative and innovative ways.
Take a closer look at how that 55% increase in water demand by 2050 will be broken down. Most of it will be from a rise of 400% in demand by manufacturing, over 140% in electricity generation and 130% in domestic use.
Farming already accounts for some 70% of global freshwater withdrawals, and has little scope to expand as other activities take a higher water share. Yet we need water to produce food. Crop evapotranspiration (not including water for food processing and preparation) consumes about a litre of water to produce one calorie; an adult in OECD countries needs 2,000 calories per day. A fifth of this water is irrigation water (both ground and surface water) for agriculture.
So how can world agriculture raise production to meet higher demand–70% higher by 2050?
Not all countries face this challenge: Canadians use far less of their total water than, say, Koreans: Korea is the OECD’s most densely populated country, and its delicate water balance is a concern for policymakers. In Spain, national indicators conceal unsustainable use in some drought-prone regions; and in parts of Germany, France and the US, crop intensity saps the soil dry, demanding even more intensive treatment. Meanwhile, seasonal and local fluctuations in water tables can oscillate wildly, as destructive summer and winter flooding in the UK has shown.
Global warming is partly responsible: in hotspots like northern Africa, India, China, parts of Europe, the western United States and eastern Australia, the reduction in water for irrigation could be dramatic. A study in Chile estimates that climate change could dry freshwater flow to decrease on average in all river basins by 35% between 2041 and 2070.
Clearly infrastructure investment, innovation and efficiency in extracting, conserving and distributing water will be priorities for farming to keep up with the needs of hungrier, expanding economies and populations. Moreover, a mix of more responsive spatial and economic management, as well as stakeholder engagement, would help mitigate if not completely overcome these constraints. Different approaches may be required for different contexts. One city, Auckland in New Zealand, amalgamated its district councils to better address urban encroachment on freshwater and marine resources, whereas San Francisco, California, decentralised its water treatment systems to secure water and waste-water services.
Cities generally are an important focus of any policy action. In rural areas, water policies clash with strong lobbies, and are often tangled up in disputes over regional policy, nature conservation and local unemployment. Half the world’s population lives in cities, which frequently have the eclectic mix of political institutions, investors, civil society players and collective determination to make a difference. From San Francisco to Sydney and Auckland to Seoul, several cities are leading the way in trying out new forms of governance, innovative green technologies and tough regulation. As one OECD Observer article letter-writer pointed out, at this rate cities, not the countryside, will be the cleanest places on earth to live. Not a pipe dream, but there is a long way to go.
Energy is another heavy user of water. Water is used to cool power plants, extract fossil fuels and produce electricity. Coal, natural gas and nuclear fuel cycles require substantial water per megawatt-hour. And though water use appears lower for electricity generated by solar and wind sources than for thermoelectric generation technologies, manufacturing geothermal, photovoltaic and wind power facilities requires a lot of water. Even hydroelectric stations carry heavy water footprints, largely from evaporating reservoirs, though much of the water is recycled through the system. As this is unlikely to alter in response to water scarcity, efficiencies and better management will be key.
What can be done about such challenges? A combination of regulation, water pricing, investment, innovation and governance is needed. Regulations can draw vital red lines to prevent excessive or toxic pollution for instance, by imposing fines and even penal sentences. Some regulations, such as the requirement for filters in effluent pipes, can impose additional costs on firms, but if well designed, can encourage innovation in treatment technologies that do not hurt–and may even boost–productivity.
It is harder to arrest someone for, say, hosing the cricket pitch or taking too many showers. Water pricing can help control water consumption and generate revenue to invest back into the system. Introducing water charges is not easy politically even when stakeholders are engaged, as the Irish government has been finding out as it faces protests against its new water charge policy. The principle for charging for water is crystal clear: yes, access to clean water is a right, but it is not cost-free. Even very poor people in developing countries see paying as an assurance that treated water is cleaner than in local rivers. Again, governance and administration matter: charging can help with holding water authorities to account. Public support is best achieved at design and implementation stage, avoiding remote corporate approaches, and by showing results in terms of efficiency and hygiene.
Innovation is also vital: drip-emitter technologies and smart irrigation in farming, smart water meters and heating systems for buildings, and systems for capturing and controlling run-off and waste water. San Francisco and Tokyo now encourage alternative non-potable water sources, such as rainwater and storm water, for instance for large buildings and sports stadiums. New York is using a "green" infrastructure, notably storm-water capturing surfaces, to improve waste-water flow to its treatment plants, which handle 1.3 billion gallons of waste water on an average dry day (see OECD Observer reference below). Desalination is also an area being developed, notably in Israel (see here).
What about governance? This issue is explored in the next article; suffice it to say that flexible, forward-looking, joint innovative approaches are needed. Politics may be local, but water supply and demand rarely respect boundaries between countries, regions or sectors, and everyone has a stake. Much will depend on the level of ambition and co-operation policymakers are willing to show.
A high road to progress
There is a way forward. The first thing to do is to secure access to safe water supply and sanitation to all. The economic, social and environmental benefits would be enormous: the World Health Organization puts the cost of inadequate water supply and sanitation at US$260 billion per year; in some African countries, these losses amounted to 10% of GDP.
Steps should be taken to protect water users, the economy and ecosystems against risks of scarcity, flooding, pollution, etc.
This will require investment, with a priority given to improving resilience to water variability, such as by sharing water-use more efficiently among agricultural, energy and industrial sectors; upgrading irrigation infrastructure; improving water disaster prevention and mitigation; protecting ecosystems; and diversifying economic activity. The choice of investment should incorporate long-term plans for economic and social development, and while based on robust decision-making criteria, remain adaptable to shifting conditions.
Innovation is clearly essential, and can be promoted by policies that make wastage and pollution more costly, and coax new practices among those users who generate liabilities, such as in heavy industry or energy. Policies and institutions which bolster existing water users and current technologies can make it harder to respond to new challenges in the future, and should be addressed.
As for financing, there is no generic model, and though the public sector plays the lead role in funding water services in most countries, other sources can be tapped, ranging from major long-term institutional investors down to household investments in water-saving equipment.
The level of governance, whether local, national or transborder, will also have an effect, depending on hydrological conditions, capacities to invest, those affected, and so on. The international community has a particular role to play in assisting vulnerable regions, weaker economies, or populations with difficult hydrology and transborder watersheds.
The environment is our natural capital, and from water can spring a truly better future. Just as engineers showed remarkable foresight when planning Rome’s aqueducts, a water vision for the world would do a great service for the civilisation of tomorrow and show a commitment to the pale blue dot that is our earth. Julius Frontinus would raise a flask of aqua to that.
Xavier Leflaive of the OECD Environment Directorate advised on this article.
OECD (forthcoming), Drying Wells, Rising Stakes: Towards the Sustainable Management of Agricultural Groundwater Use, OECD Publishing.
OECD (forthcoming), Policy Approaches to Droughts and Floods in Agriculture, OECD Publishing.
Securing Water, Sustaining Growth, report for the OECD/GWP Global Dialogue on Water Security for Sustainable Growth.
Fit to Finance?, report for the OECD/WWC High Level Panel on Financing Infrastructure for a Water Secure World.
Water Policy Dialogues (NPDs) in Eastern Europe, the Caucasus and Central Asia (EECCA), Brazil, Lebanon, Mexico, the Netherlands, Palestine, Tunisia.
©OECD Observer No 302 April 2015 (article amended 12 April)