Rural and Urban Settlements

During the 20th Century, populations tended to move from rural settlements to urban ones. This shift largely reflected the continued industrialization of human societies that had begun in the latter half of the 19th Century. Along with the adjustments required to feed and house large numbers of people in more densely populated cities, came the challenge of how to provide them with adequate water for drinking and sanitation.

Water is an integral part of the infrastructure of modern cities. As cities grow, so do their water needs, requiring not only more infrastructure, but often, also an additional sources of water. New sources of water often have to be found further and further away from urban centres, particularly if there has been intensive industry in the area that poses a contamination risk. And it is not just industry that can cause contamination. Seepage from waste sanitation systems, agricultural contamination from intensive animal rearing or from use of fertilizers and pesticides, and airborne pollution, all contribute to the risk of groundwater contamination. In most developed countries, waste water is treated before being returned to the environment, but this also increases the costs of water. UNESCO has reported that every cubic metre of untreated waste water can contaminate up to 10 times its volume of clean water.

Maintaining ageing water delivery infrastructure is also a growing challenge in many large urban centres and also increases the cost of water. Because water in urban centres tends to be provided almost invisibly, there is a real risk of wastage of water. For example, in most developed countries, the water used for sanitation is the same as that used for drinking, only distributed through separate lines once it inside the house. Few people give thought to how much water is wasted simply by being thrown away, nor do they give much thought about what is thrown down the drain and its potential impact on the water. Such waste water must be collected and treated, all of which increases the cost of water itself.

As populations continue to grow and accumulate in urban centres, the demand for water and effective water delivery systems also grows. Water is not an infinitely renewable resource. More and more water removed from the water table or returned, but in a polluted form. Without concerted efforts to protect and conserve water at all levels, how can future needs in urban centres be sustained?

Through its emphasis on water, sanitation, and hygiene, the United Nations Children's Fund is working to improve health, education and economic productivity so vital to social development. Read more.

Signs of strain are already evident, even in developed countries. Subsidence due to pumping out too much of groundwater threatens Houston in the United States and Venice in Italy. Turbid water from early spring run-offs have forced the Greater Vancouver area in Canada to issue a boil water advisory for the first time this year.

But it is the developing countries, with the most rapid predicted population growth and urbanization that are most at risk. Even today, many large cities do not have adequate sanitation systems and simply discharge waste water back to the environment without any treatment. Delivery of safe drinking water is equally difficult, in crowded centres with inadequate distribution systems. The World Bank has estimated that about $600 billion needs to be invested in water delivery systems alone. The urban poor pay unreasonably high costs for water, especially in those areas without distribution systems where they must purchase water from private vendors.

Part of the solution to these challenges comes from the experiences of others. The United Nations Human Settlements Programme (UN-HABITAT) maintains a unique website of best practices in water and sanitation that demonstrate the concrete solutions being put into practice in the developing world.

Despite having less dense populations, rural settlements face unique challenges with respect to water resources. Human needs compete with those of crops and animals for the same water supplies. In developed countries agriculture tends to be more intensive- using automated equipment, irrigation, fertilizers, and pesticides to maximize yields, but production costs are also high. And the risk of failure, due to unpredictable weather particularly flooding or droughts, can have serious consequences.

In addition, intensive farming can have consequences for the safety of water in nearby communities. Failure to remove organic animal waste not only presents a risk of spreading disease, but chlorinated by-products created by the water treatment process are now emerging as a new potential risk to health.

In developing countries, agricultural practices may not be as intensive, but may also have impacts on the environment, and ultimately the people who rely upon it for their water supply. Salinization and soil erosion from poor irrigation practices risk not only the crops that grow on the land, but the stability of the soil itself.

All told, water issues in both urban and rural settlements have a significant impact on human, social, and economic development. Improved management of existing resources, conservation of water, and use of new technology will all be required to meet the growing future needs for water as modern society continues to grow and evolve.

With assistance from the International Atomic Energy Agency, Morocco is using isotope hydrology to find new sources of water.