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Climate change and the hydrological variability of water’s distribution and occurrence are natural driving forces that, when combined with the pressures from economic growth and major population change, make the sustainable development of our water resources a challenge.
5a. Driving forces and pressures
The combination of these factors commonly results in increased water use, competition and pollution in addition to highly inefficient water supply practices. These results can be traced back to the fact that most decisions in water resources management, at almost all levels, remain principally driven by short-term economic and political considerations that lack the long-term vision needed to implement sustainable development practices. Water management plans should consider the best existing practices and the most advanced scientific breakthroughs.
The scientific community has to convey more effectively its recommendations to decision-makers to enable the latter to develop and maintain multidisciplinary integrated approaches and solutions. Societies should realize that today’s water-related challenges are no longer readily solved just by using last century’s hydraulic schemes. Increased funding and resources need to be provided for the collection of detailed water data and information.
5b.State of our natural water resources
The roles and interdependencies of the different hydrological cycle components are often not fully appreciated. As a result, it is difficult to set up adequate protection and prevention strategies.
All components of the hydrological cycle should be taken into account when developing water management plans. Each component has a specific role that must be better understood. For example, rain and snow directly supply terrestrial ecosystems and soil moisture is a unique water source for both agricultural development and terrestrial ecosystems. Furthermore, glacial melting has a strong influence on water availability in many nations and as a result more comprehensive global assessments are needed.
We can substantively predict annual variability in surface runoff and have created solutions to deal with it. However, overcoming the less predictable five- to ten-year global cycles of distinctly lower and higher runoff remains a challenge. Groundwater resources could provide a valuable contribution to overcoming climate variability and meeting demands during extended dry periods. A surplus of surface water runoff during wet periods can be used to replenish aquifer systems.
However, we do not have enough data on groundwater and aquifer systems, especially in developing countries where the lack of adequate surface water resources is most extreme. This is particularly true in both Asia and Africa where there has been a dramatic reduction in water monitoring programmes.
Water quality monitoring programmes are inadequate or lacking in most developing nations; thus safeguarding human health is difficult. Despite two decades of increased international scientific attention and concern, attempts to collect, compile and gain knowledge from consumption, pollution and abstraction data and information at a global scale are still piecemeal and in relatively early stages of applicability.
5c. Impacts
Poor quality water and unsustainable supplies limit national economic development and can lead to adverse health and livelihood conditions.
Landscape modifications further complicate our understanding of and ability to predict the impacts on water resources since these changes disrupt natural hydrological and ecosystem functioning. This becomes more important when we seek to advance our understanding of the future impacts of climate change at local and regional scales. We know that detailed estimates of climate change impacts on water resources at regional or global scales are currently very problematic due to inadequate water data.
We have reached a reasonable level of knowledge towards recognizing impacts on water quality and quantity from pollution and excessive groundwater and surface water withdrawals. The focus must now be on reducing these impacts. In most developing countries, specific and well-targeted programmes should be funded to reduce impacts on water quality and quantity.
Overall, there are reasons to be hopeful as new water programmes are emerging that finally emphasize the application of more sustainable practices to reduce impacts.
Source & ©:
UNESCO,
The United Nations World Water Development Report 2 (2006)
Section 2: Changing Natural Systems,
Chapter 4 (UNESCO
& WMO, with IAEA),
Part 5. The Challenge of
Sustainable Development, p.151
The source document for this Digest states:
5d. Responses
Prevention strategies and new technologies that augment existing natural water resources, reduce demand, and achieve higher efficiency are part of the response to meet today’s increasing demands on our available water resources.
To meet current and future water demands, increased attention should be given to precautionary approaches such as innovative uses of natural supplies and new technologies. In the past we have responded by storing runoff in reservoirs, diverting flows from water-abundant to water-scarce regions, and extracting aquifer resources – methods that provided ample water where and when it was needed. These methods are likely to remain part of most water resources development strategies. Non-conventional water resources, such as water reuse and desalination, are being increasingly used and new technologies such as artificial recharge are also becoming more and more common. Capturing rain at the source through rainwater harvesting is yet another method used to increase the availability of natural water sources. In certain regions, an extreme response has been adopted. In some arid countries, where sufficient renewable water resources are not available, non-renewable groundwater reserves are being exploited to support development.
Demand management and conservation are methods that target efficiency. Conservation begins by reducing high losses from water supply distribution systems. Demand management has gone largely unaddressed since most water utilities still focus on infrastructure development rather than on conservation.
It is worth noting that industry’s approach in recent years has been to reduce wastewater and minimize the quantity of processed water needed as this method has proven to be technically feasible and economically advantageous. The demand reduction and efficiency approach should be an integral part of modern water resources management. Its applicability should be promoted while recognizing that it requires a distinct change in the behavioural patterns of institutions, utilities and individuals – a change that will require education, awareness-raising and political commitment to achieve effective implementation.
Institutional responses at different levels are also needed. Some nations have implemented new laws and regulations that point the way forward toward protecting and restoring our water sources. Many nations are adapting emerging technical practices to secure and protect their existing natural water resources and use local knowledge as part of sustainable resource development.
5e. The benefits
There will be economic, social and environmental benefits from carrying out regular Water Resources Assessments (WRAs) in all basins and aquifers in individual nations as well as regionally, where transboundary shared water resources are present.
Modern approaches to WRA are rapidly emerging and now go well beyond the traditional hydraulic and supply-biased studies carried out during the last century. WRAs have been extended to take advantage of the recently recognized benefits that come from using an integrated approach (IWRM) and including ecosystems’ services (ecosystem approach). WRAs continue to fundamentally require well-documented hydrological cycle component data – without this data the evaluation results are unreliable. To be comprehensive and assist in sustainable practices, WRAs should include well-documented user consumption and water quality requirements, accurate use data, estimates of the environmental flow volumes needed to maintain ecosystem resilience, characterization of both point and non-point sources of pollution and the quality of the receiving waters, and the extensive engagement of all water users and other pertinent stakeholders.
Providing incentives to improve demand management efficiencies has proven highly effective in augmenting natural water supplies. WRAs should consider new capacities to use non-conventional water supplies and new technologies to augment existing supplies. A comprehensive WRA must also include social and economic considerations as well as ecosystem needs and contributions.
If climate change follows the projected scenarios, we can expect more erratic weather in the future, including increased variability in precipitation, which will threaten crop yields in both developed and developing countries, while placing more than 2.8 billion people at risk of water shortage. Understanding all aspects of the hydrological cycle is critical if our society is to be able to cope with the many changes we observe.
Source & ©:
UNESCO,
The United Nations World Water Development Report 2 (2006)
Section 2: Changing Natural Systems,
Chapter 4 (UNESCO
& WMO, with IAEA),
Part 5. The Challenge of
Sustainable Development, 5d. Responses, p.153
Conserving available water and reducing demand is a necessary measure in water-short regions, especially those in arid climates. Programmes of conservation and demand reduction are referred to as water demand management (WDM). This approach differs from the traditional supply-driven method, which makes all existing water available. WDM applies selective economic incentives to promote efficient and equitable water use. It also identifies water conservation measures that are aimed at raising society’s awareness of the scarcity and finite nature of the resource.
Conservation measures have not been readily implemented, particularly where water was perceived as abundant. However, the benefits in the extended useful life of water supply and treatment plants and in the operating efficiency and duration of sewage disposal systems can be considerable in terms of higher economic return on investment. On the environmental front, conservation allows for the diversion of the unused volumes to sustain ecosystems and also lowers the pollution loadings to lakes, rivers and groundwater. Such steps lead to improved protection of drinking water sources and overall ecological balance (Environment Canada, 2005b).
WDM advocates a wide range of measures that go beyond conservation to broader sustainable resource management. It applies to the protection of water quality sources; reduction of wastage both in infrastructure leakage and by users; improvement of water allocation among competing uses, and creation of appropriate pricing mechanisms. One example of a situation where conservation measures are needed is the case of ‘undelivered water’ – a commonly accepted result of utilities supplying water through piped distribution systems. The leakage from degraded pipes provides ‘unaccounted for’ water that results in both a physical shortage and reduced revenue. In terms of inefficiency of resources and operations, losses are routinely reported as 40 percent and as high as 60 to 70 percent in some major cities. Though it is an endemic problem for most water utilities, its impact on society in terms of wasted water resources is even more substantial.
Further water conservation can be achieved after delivery by improving use practices in households. Reductions in community water use after conservation measures have been applied are reported to be as high as 40 percent. These two situations illustrate to what extent the water that is currently supplied may not actually be needed. By reducing leakage and demand, substantial reductions in the source volumes could be achieved. This should be a clear message in development settings. WDM may obviate the need for some of the proposed large-scale physical or infrastructure investments and thereby provide real efficiency gains to society (GWP, 2005a).
Source & ©:
UNESCO,
The United Nations World Water Development Report 2 (2006)
Section 2: Changing Natural Systems,
Chapter 4 (UNESCO
& WMO, with IAEA),
Part 4. Matching Demands to
Supply, 4d. Demand management, p.149
Water resources assessments (WRAs) are designed to be analyses of available water sources from the perspective of potential water use. Since Rio ‘92, and in particular the Dublin 2000 considerations, water resources have come to be more broadly considered within the dimensions of social equity, economics and ecosystem/ecohydrology. The modern WRA process can be adapted and updated to include these relationships (GWP, 2005b).
Hydrological data and information systems and networks provide the basic and critical input to WRA, whether the assessment is done within an IWRM perspective at the national or basin/sub-basin/aquifer level or otherwise. Factors that affect the accuracy of hydrological input to WRAs include: the number of gauging stations, station distribution within physiographic regions, duration and continuity of observations, quality of measurements, and data processing. The commonly measured parameters include precipitation, evaporation, soil moisture, river level and discharge, groundwater (well) depths, sediment and water quality data on a continuous, hourly, daily or monthly basis.
However, reliability and availability of data have declined sharply since the mid-1980s, particularly in Africa and in Eastern Europe (Rodda, 1998), and that situation has not changed substantively since the turn of the century. Investment in national networks has fallen drastically and is still decreasing. Hydrometric networks, while they are costly to maintain, provide basic WRA input that cannot be collected dependably by any other means (see Chapter 13).
The development of more decentralized and basin-type approaches for WRA is inherent in the internationally agreed upon IWRM principles. It is widely recognized that it will take several decades of institutional adjustment (Blomquist et al., 2005) to reorient water management practices on basins. However, such changes are beginning at the basin level and there are examples of decentralized approaches on most continents in terms of water management processes. An important element of the World Water Assessment Programme’s mission is to assist partner case study countries in developing their own assessment capacity (see Chapter 14). Sovereignity issues and competition will always remain factors in managing the resource. However, the basic WRA scope which broadly defines the extent of available water quantity and quality, including aspects related to environment, pollution and water use, is the basis for effective management. This information can be collected and jointly developed by the nations sharing the resource (see Chapter 11). These will give forward-looking direction not only in water technology areas but also on how improving data, information and assessment practices for water resources will provide critical knowledge that will greatly benefit society, human livelihoods and the environment.
Source & ©:
UNESCO,
The United Nations World Water Development Report 2 (2006)
Section 2: Changing Natural Systems,
Chapter 4 (UNESCO
& WMO, with IAEA),
Part 4. Matching Demands to
Supply, 4f. Water Resources Assessment (WRA), p.151
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