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A number of factors present difficulties for the sustainable development of water resources, including climate change and the natural variability of the resource, as well as pressures caused by human activities.
These factors, combined, increase competition for water and lead to gross inefficiencies in how water is supplied. The fundamental problem, however, is that the long-term vision required for sustainable practices to take hold is relegated due to economic short-term gains and political considerations. Managers should ideally consider best current practices and the latest techniques in drawing up their water plans.
Scientists must persuade policy-makers of the relevance of their recommendations so that they can be implemented. Most up-to-date solutions will be required to meet the challenges of managing water resources sustainably. Increased funding for the collection of information will also be required.
There is often limited understanding of processes and interactions among the various elements of the water cycle, such as rain, snow, soil moisture, evapotranspiration, and meltwater from glaciers. This makes it difficult to develop comprehensive strategies to protect water resources. More comprehensive assessments methods are needed.
It is relatively easy, based on long-term measurements taken in many places, to predict, and find solutions for annual and seasonal differences in water flow. However, it is much more difficult to predict long-term variations over several decades. Underground water could be used during long dry spells, while surplus runoff could replenish aquifers.
However, solid information on underground water is lacking in many developing countries—especially in Asia and Africa, where monitoring programmes have been cut drastically.
Most developing countries also lack adequate monitoring of water quality, and this poses considerable public health challenges. Information on the consumption, pollution, and withdrawal of water globally is still fragmentary.
The poor quality of water and the inadequacy of supplies can have a negative impact on economic development, public health, and living conditions.
Changes to the landscape such as the growth of cities, the removal of wetlands, deforestation, construction of roads, and surface mining disrupt environmental water flows, cause ecosystem changes, and complicate water planning. They also make it more difficult to understand what local and regional impacts climate change will have on water resources—already a major challenge, given the scarcity of information.
We have a good understanding of the effects of pollution and of drawing too much water from aquifers and from rivers, lakes, and inland seas. Fighting these effects will require substantially increased funding in most developing countries.
Practices that are more sustainable are now being included in new water programmes, and these give reason for hope. More...
More attention should be paid to making better use of existing natural resources, controlling demand and reducing losses, and achieving greater efficiencies in water management.
New approaches, such as desalination and the replenishment of aquifers complement standard techniques such as storing runoff. In some very dry countries, water is drawn from the ground without being replenished.
Most water companies focus on developing infrastructure rather than on managing demand. A shift towards reducing demand will require changes in patterns of behaviour by individuals and organizations, as well as political commitment to enforce rational water management.
Countries have responded to the present situation with new laws, new techniques, and local knowledge. Regular assessments of basins and aquifers will bring economic, social, and environmental benefits.
Climate change is expected to bring more erratic weather, with greater variations in the level of rainfall, which may reduce harvests and create widespread water shortages. In order to prevent or reduce damaging consequences, we need a comprehensive approach that takes into account all aspects of the water cycle.
The most recent, integrated approaches to the management of water resources consider the relations between the water cycle and ecosystems. Such approaches need complete information and should also include in their scope social, economic, and environmental considerations.
Conservation programmes that try to reduce the demand for water differ from the standard method, under which all water is regarded as available, and promote awareness, as well as efficiency and fairness in the use of water. Conservation programmes have not been readily implemented, even though they can bring economic benefits for water supply and treatment plants, and for sewage disposal systems. They also help sustain ecosystems and reduce freshwater pollution.
Programmes that focus on managing demand emphasise steps to encourage lower consumer use and fewer leaks in water distribution networks. Such leaks can lead to the loss of from 40% to 70% of the water within the supply system.
Levels of consumer use could fall by as much as 40% once conservation measures are introduced in households. These figures suggest that, if conservation programmes were carried out more widely, some large-scale investments in plants and equipment might not be necessary.
In recent years, water resources have been looked at from the standpoint of potential use, with an eye on social equity and the health of ecosystems, among other things. These analyses require a reliable generation of water data from many monitoring stations around the world. However, investment in such stations has fallen sharply since the mid-1980s, particularly in Africa and Eastern Europe.
On most continents, the assessment of water resources is becoming less centralised and more focused on river basins. This approach will always have to face issues of competition and sovereignty, but the joint collection of information on water resources in basins shared by more than one country will benefit all sides, in terms of economic development, people’s livelihoods and the health of ecosystems. More...
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