Sustainable Development in an Urban Water Supply Network
Encyclopedia
Water supply
Water supply is the provision of water by public utilities, commercial organisations, community endeavours or by individuals, usually via a system of pumps and pipes...
network concerns all the activities related to provision by third parties of potable water. Sustainable development
Sustainable development
Sustainable development is a pattern of resource use, that aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but also for generations to come...
is a well known resource which involves many issues. Therefore this concept is going to be developed in the water supply in urban areas.
Introduction
WaterWater
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
is an essential natural resource
Natural resource
Natural resources occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. A natural resource is often characterized by amounts of biodiversity and geodiversity existent in various ecosystems....
for human existence. It is needed in almost every process, for instance, it is used for oil refining
Oil refinery
An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas...
, for liquid-liquid extraction
Liquid-liquid extraction
Liquid–liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilities in two different immiscible liquids, usually water and an organic solvent. It is an extraction of a substance from one liquid phase into another liquid...
in hydrometallurgical processes, for cooling, for scrubbing in the iron and the steel industry and for several operations in food processing
Food processing
Food processing is the set of methods and techniques used to transform raw ingredients into food or to transform food into other forms for consumption by humans or animals either in the home or by the food processing industry...
facilities , etc. Due to the pessimistic forecast concerning water shortage in the forthcoming decades and moreover, the increasingly stringent environmental regulations for efficient water utilization and wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
disposal, it becomes necessary to adopt a new approach to design urban water supply networks.
The concept of a sustainable water supply network
Water supply network
A water supply system or water supply network is a system of engineered hydrologic and hydraulic components which provide water supply. A water supply system typically includes:# A drainage basin ;...
is born out of a need for an economical alternative to develop new sources of water and also, for the mitigation of environmental pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
.
Furthermore, in order to have a sustainable water supply network, there are other concepts that must be improved: the safety and the reliability of the network . The latter, with the objective of quickly detecting all the unexpected events that could occur on the networks, such as: damage, leakage
Leakage
Leakage may refer to:*Leakage *Memory leak, in computer science*Leakage *Leakage *Leakage *Leakage...
, maintenance etc. Furthermore, the price of water is increasing so less water must be wasted and actions must be taken to prevent pipeline leakage. It is true that shutting down the supply service to fix the leaks is less and less tolerated by consumer
Consumer
Consumer is a broad label for any individuals or households that use goods generated within the economy. The concept of a consumer occurs in different contexts, so that the usage and significance of the term may vary.-Economics and marketing:...
s. One way to do this is to develop a water network process which aims to minimize the freshwater consumption rate and/or the wastewater generation rate.
Challenges
Most of the urban water supply networks are facing problems every day that need to be solved in an accurate way. In developing countries the networks are involved in several problems related to populationPopulation
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
, water scarcity, environmental pollution management, etc. Moreover, the networks will be affected by unexpected problems. The main problems are below:
Population Growth
Population growth
Population growth
Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement....
is a problem in many cities around the world because the minimum needs of every new citizen have to be met. Several cities are facing problems because of fast urbanization
Urbanization
Urbanization, urbanisation or urban drift is the physical growth of urban areas as a result of global change. The United Nations projected that half of the world's population would live in urban areas at the end of 2008....
caused by the search for a better quality of life. In the year 1900 just 13% of the global population lived in cities. This percentage has been rising and in 2005, 49% of the global population lived in urban areas. In 2030 it is predicted, that this statistic will rise to 60% . As the population increases in a city, it is necessary to expand the water supply network which is a constant burden on government finances as they need to build new infrastructure
Infrastructure
Infrastructure is basic physical and organizational structures needed for the operation of a society or enterprise, or the services and facilities necessary for an economy to function...
, even though in many cases it is not sufficient. The constant apparition of new illegal settlements makes it harder to map and to connect the pipes to the supply network system, that in the end can lead to inadequate management . In 2002, there were 158 million people not served with improved water supply
Water supply
Water supply is the provision of water by public utilities, commercial organisations, community endeavours or by individuals, usually via a system of pumps and pipes...
. Having said that, an increasing number of people located in slum
Slum
A slum, as defined by United Nations agency UN-HABITAT, is a run-down area of a city characterized by substandard housing and squalor and lacking in tenure security. According to the United Nations, the percentage of urban dwellers living in slums decreased from 47 percent to 37 percent in the...
s are not only in inadequate sanitary conditions but at risk of disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
s.
Water Scarcity
Potable water is not well distributed throughout the world and many people do not have access to it or do not have access to standard levels of potable water where the resource is abundant. Geographically speaking, poor people in developing countries can be closer to major rivers or be in rainfall areas but do not have access to potable water at all. In contrast, there are people that live in areas where the lack of water creates millions of deaths every year. Not only that, but many health issues are due to the way the water is supplied. 1.8 million deaths are attributed to unsafe water supplies every year according to the WHO
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
. In Urban areas, where the water supply system network cannot reach the slums, people manage to utilize hand pump
Hand pump
Hand pumps are manually operated pumps; they use human power and mechanical advantage to move fluids or air from one place to another. They are widely used in every country in the world for a variety of industrial, marine, irrigation and leisure activities...
s, reach the dug-wells, river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s, canal
Canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...
s, swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
s and any other source of water which in most cases the sanitary conditions are below the human consumption level. The principal cause of water scarcity is the growth in demand of the resource
Resource
A resource is a source or supply from which benefit is produced, typically of limited availability.Resource may also refer to:* Resource , substances or objects required by a biological organism for normal maintenance, growth, and reproduction...
which is taken from remote areas to satisfy the needs of an urban area. Another reason of this scarcity is climate change, which has generated changes in the water cycle
Water cycle
The water cycle, also known as the hydrologic cycle or H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth. Water can change states among liquid, vapor, and solid at various places in the water cycle...
due to fast industrialization in big cities. Due to this change, there has been a shift in the hydrology
Hydrology
Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
where the water is stored; the rainfalls have changed their frequency; the rivers have decreased their flow rate, lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
s are drying up and the aquifer
Aquifer
An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...
s are being emptied because of the negative rate between the inner flow and the outer flow, the latter being used for consumption
Consumer
Consumer is a broad label for any individuals or households that use goods generated within the economy. The concept of a consumer occurs in different contexts, so that the usage and significance of the term may vary.-Economics and marketing:...
.
Governmental Issues
Another crucial problem is the response of government
Government
Government refers to the legislators, administrators, and arbitrators in the administrative bureaucracy who control a state at a given time, and to the system of government by which they are organized...
to these problems because of new policies which are created everyday in developing countries, where the water demand is exceeding the supply and where a priority in household and industrial water supply exists over other uses, which in the end will lead to water stress
Water stress
Researchers define water stress and water scarcity in different ways. For example, some have presented maps showing the physical existence of water in nature to show nations with lower or higher volumes of water available for use. Others have related water availability to population...
conditions because of the limitation of resources . Neither of the problems that the water supply network systems face can be solved without government help. Many governments in developing countries are corrupted and have stagnant budgets which makes it complex to create sustainable solutions for the current problems. It is important to highlight that potable water has a price in the market; water means power and often it becomes a business
Business
A business is an organization engaged in the trade of goods, services, or both to consumers. Businesses are predominant in capitalist economies, where most of them are privately owned and administered to earn profit to increase the wealth of their owners. Businesses may also be not-for-profit...
for private companies which generate profit
Profit (accounting)
In accounting, profit can be considered to be the difference between the purchase price and the costs of bringing to market whatever it is that is accounted as an enterprise in terms of the component costs of delivered goods and/or services and any operating or other expenses.-Definition:There are...
by putting a higher price on it and imposing a barrier for lower-income people.
In advanced economies the problems are related to the optimization of the current supply network. These economies usually have a constant evolution through the years which allow them to construct the necessary infrastructure to supply water to people. In recent years organizations like the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
have developed a set of rules and policies to overcome the problems that will be presented in the future. Documents like the Millennium Development Goals
Millennium Development Goals
The Millennium Development Goals are eight international development goals that all 193 United Nations member states and at least 23 international organizations have agreed to achieve by the year 2015...
represent a major breakthrough in constructing a better integrated system.
One of the conclusions that this union have come up with is that there are many international documents with interesting ideas nevertheless these ideas are not very specific and therefore, they are not put into practice . Referring to this, recommendations have been made by associations such as the Dublin Statements on Water and Sustainable Development
Dublin Statement
The Dublin Statement on Water and Sustainable Development, also known as the Dublin Principles, was adopted by the United Nations on the 31st of January 1992 at the International Conference on Water and the Environment , Dublin, Ireland, organised on 26-31 January 1992...
paper by the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...
.
Optimizing the water supply network
Every process system has three parts: and input, the process itself, and the output. This part concerns the improvement of the process performance by maximizing the net benefits of the system. The yield of a system can be measured by either its value or its net benefit. For a water supply network (system), the true value or the net benefit is a reliable water supply service having adequate quantity and good quality of the product. For the industries that supply water to the community, it is desirable to have a plan to supply enough water to the community at any given time but to achieve the sustainabilitySustainability
Sustainability is the capacity to endure. For humans, sustainability is the long-term maintenance of well being, which has environmental, economic, and social dimensions, and encompasses the concept of union, an interdependent relationship and mutual responsible position with all living and non...
the water industries have to guarantee the water supply in a reasonable future-planning horizon without compromising the future needs. However, it is known that during this planning period the water demand can be estimated with some uncertainty. For example if the existing water supply network of a certain city needs to be extended to supply a new municipality
Municipality
A municipality is essentially an urban administrative division having corporate status and usually powers of self-government. It can also be used to mean the governing body of a municipality. A municipality is a general-purpose administrative subdivision, as opposed to a special-purpose district...
, it is necessary to analyze the impacts of the new branch of the system in the existing supply network in order to supply the needs of the new system as well as holding the supply capacity of the old system.
The design of the system is governed by multiple criteria or objectives. One of them is the cost criterion, because if the benefit is fixed the least cost design results in a maximum benefit. However the least cost approach normally results in a minimum capacity for a water supply network. A minimum cost design model is usually formulated to search for the least cost solution (pipe sizes) while satisfying the hydraulic constraints such as: required output pressures, maximum pipe flow
Pipe flow
Pipe flow, a branch of Hydraulics and Fluid Mechanics, is a type of liquid flow within a closed conduit . The other type of flow within a conduit being open channel flow....
rate and pipe flow velocities. The cost is function of the pipe diameters therefore the optimization
Process optimization
Process optimization is the discipline of adjusting a process so as to optimize some specified set of parameters without violating some constraint. The most common goals are minimizing cost, maximizing throughput, and/or efficiency...
problem consist to find the minimum cost solution and optimizing the function of the minimum pipe sizes which will carry out the minimum capacity.
However, according to the authors of the paper entitled, “Method for optimizing design and rehabilitation of water distribution systems”, “the least capacity is not a desirable solution to a sustainable water supply network in a long term, due to the uncertainty of the future demand” . It is also necessary to achieve an extra pipe capacity to cope with the demand growth and with the water outages. The previous exists as a consequence of the problem of maximizing the flow capacity, and the problem changes from a single objective optimization problem (minimizing cost), to a multi-objective optimization problem (minimizing cost and maximizing flow capacity).
To solve a multi-objective optimization problem is necessary to convert the problem in a single objective optimization problem by using adjustments including weighted sum of objective
Objective
Objective may refer to:* Objective , to achieve a final set of actions within a given military operation* Objective pronoun, a pronoun as the target of a verb* Objective , an element in a camera or microscope...
s and an ε-constraint methods. The weighted sum approach gives a certain weight to the different objectives functions and then it covers all of these weights and it gets a single objective function that can be solved by the method of single optimization problem. But this solution is not entirely satisfactory because the weights cannot be correctly chosen and this approach is not proper in finding the optimal tradeoff solutions of all the original objectives.
The second approach (the constraint method), chooses one of the objective function as the single objective, and the other objective functions are treat as a constraint with a limited value. However, the optimal solution depends on the pre-defined constraint limits.
The multiple objective optimization problems involve computing the tradeoff between the costs and benefits resulting in a set of solutions that can be use for sensitivity analysis and put in different scenarios. But there is no single optimal solution that may satisfy the global optimality of both objectives. As the both objectives are juxtaposed it cannot be possible to improve one objective without sacrificing the other. It is necessary in some cases use a different approach,(e.g. Parteto Analysis), and chose the best combination.
Returning to the cost objective function, it can not violate any of the operational constraints. Most of the times, this cost is equal to the energy cost incurring in pumping. “The operational constraints include the standards of customer service
Customer service
Customer service is the provision of service to customers before, during and after a purchase.According to Turban et al. , “Customer service is a series of activities designed to enhance the level of customer satisfaction – that is, the feeling that a product or service has met the customer...
, such us: the minimum delivered pressure, in addition to the physical constraints such us the maximum and the minimum water levels in storage tanks to prevent overtopping and emptying respectively.”
In order to optimize the operational performance of the water supply network at the same time as minimizing the energy costs, it is necessary to have some means of predicting the consequences of different pump and valve settings on the behavior of the network.
Apart from the Linear a non-Linear Programming, there are other methods and approach to design, manage and operate a water supply network in order to achieve the sustainability. For instance, the adoption of appropriate technology
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
that needs to be coupled with effective strategies for operation and maintenance to ensure a sustainable water supply network. These strategies must include effective management models, technical support to the householders and industries, sustainable financing mechanisms, and development of sustainable supply chain
Supply chain
A supply chain is a system of organizations, people, technology, activities, information and resources involved in moving a product or service from supplier to customer. Supply chain activities transform natural resources, raw materials and components into a finished product that is delivered to...
s. All these measures must ensure the following: system working lifespan; frequency of rehabilitation; continuity of functioning; down time for repairs; water yield and water quality.
Sustainable development
The concept of sustainability water supply networks also involves aspects technologically and economically feasible, especially when the system already exists and needs to expand the coverage to the new or other urban areas, adapt to the new needs of people served and to change the requirements concerning public healthPublic health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...
and environmental policies. For instance, it happens that in an unsustainable system an insufficient maintenance to the water networks, especially in the major pipe lines in the urban areas, the system can gets seriously deteriorated and will have to require rehabilitation or renewal.
Also, the householders and the wastewater treatment
Wastewater Treatment
Wastewater treatment may refer to:* Sewage treatment* Industrial wastewater treatment...
plants can come up with actions in order to make the water supply network more efficient and sustainable. For example, major improvements in eco-efficiency
Eco-efficiency
The term eco-efficiency was coined by the World Business Council for Sustainable Development in its 1992 publication "Changing Course". It is based on the concept of creating more goods and services while using fewer resources and creating less waste and pollution.The 1992 Earth Summit endorsed...
are gained through a more systematic separation of rainfall and wastewater and also through the use of innovative technologies such as membrane technology for wastewater treatment for recycling water.
Moreover, the municipality in charge of the urban area can develop a “Municipal Water Reuse System” which is a current approach to manage the rainwater. It applies a water reuse scheme for treated wastewater on a municipal scale to provide non-potable water for industry, household and municipal uses. This technology consists in implementing the urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
fraction of sanitary wastewater and separate and collect it for recycling the nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
s. The feces
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
and graywater fraction is collected together with organic wastes from the households using the gravity sewer system
Sanitary sewer
A sanitary sewer is a separate underground carriage system specifically for transporting sewage from houses and commercial buildings to treatment or disposal. Sanitary sewers serving industrial areas also carry industrial wastewater...
continuously flushed with non-potable water. The water is treated anaerobically and the bio-gas is used for energy production.
As part of the sustainable development, sustainable water supply system is an integrated system including water intake, water utilization, wastewater discharge and treatment and water environmental protection
Environmental protection
Environmental protection is a practice of protecting the environment, on individual, organizational or governmental level, for the benefit of the natural environment and humans. Due to the pressures of population and our technology the biophysical environment is being degraded, sometimes permanently...
. It requires reducing freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
and groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
in all sectors of consumption. Nowadays, developing sustainable water supply systems is a tendency because it serves people’s long-term benefits. . There are several ways to re-use and recycle the water, in order to achieve the sustainability for a long-term period, such us:
- Gray water re-use and treatment: Gray water is wastewater coming from bathBathingBathing is the washing or cleansing of the body in a fluid, usually water or an aqueous solution. It may be practised for personal hygiene, religious ritual or therapeutic purposes or as a recreational activity....
s, showerShowerA shower is an area in which one bathes underneath a spray of water.- History :...
s, sinks and washbasins: If this water is treated it could be used as a source of water for other uses besides drinking. Depending on the type of gray water and its level of treatment, it could be re-used for landscapes, irrigationIrrigationIrrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
and toilet flushing. According to an investigation about the impacts of domestic grey water reuse on public health which was carried out by the New South Wales Health Centre in AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
in the year 2000, grey water contains less nitrogenNitrogenNitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
and fecal pathogenic organisms than sewageSewageSewage is water-carried waste, in solution or suspension, that is intended to be removed from a community. Also known as wastewater, it is more than 99% water and is characterized by volume or rate of flow, physical condition, chemical constituents and the bacteriological organisms that it contains...
, and the organic content of grey water decomposes more rapidly.
- Ecological treatment system: This is a system that has low energy consumption. There are many applications for ecological treatment systems in gray water re-use, such us reed bedReed bedReed beds are natural habitats found in floodplains, waterlogged depressions andestuaries. Reed beds are part of a succession from young reed colonising open water or wet ground through a gradation of increasingly dry ground...
s, soil treatment systems and plant filters. This process is ideal for gray water re-use, because of easier maintenance and higher removal rates of organic matter, ammoniaAmmoniaAmmonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, nitrogen and phosphorusPhosphorusPhosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
.
Other possible approaches to scoping model’s for water supply network that are applicable to any urban area could incorporate the following:
- Sustainable Urban Drainage SystemSustainable urban drainage systemsSustainable Drainage Systems , sometimes known as Sustainable Urban Drainage Systems , are designed to reduce the potential impact of new and existing developments with respect to surface water drainage discharges.-Background:...
. - BoreholeBoreholeA borehole is the generalized term for any narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water or other liquid or gases , as part of a geotechnical investigation, environmental site...
extraction. - Intercluster groundwater flow.
- Canal/river extraction.
- Aquifer storage
- A more user-friendly indoor water use.
In terms of what advanced economies have suggested, the “Dublin Statement on Water and Sustainable Development”, mentioned above, is a good example of the new trend to overcome these new problems. This statement has come up with some principles that are of great significance in the urban water supply networks. These are the followings:
1. Fresh water is a finite and vulnerable resource, essential to sustain life, development and the environment.
2. Water development and management should be based on a participatory approach, involving users, planners and policy-makers at all levels.
3. Women play a central part in the provision, management and safeguarding of water. Institutional arrangements should reflect the role of women in water provision and protection
4. Water has an economic value in all its competing uses and should be recognized as an economic good. .
From these statements, developed in 1992, several policies have been created to give importance to water and to put the urban water system management towards the sustainable development. The Water Framework Directive
Water framework directive
The Water Framework Directive is a European Union directive which commits European Union member states to achieve good qualitative and quantitative status of all water bodies The Water Framework Directive (more formally the Directive 2000/60/EC of the European Parliament and of the Council of 23...
by the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
is a good example of what it has been created from former policies.
Future approach
As explained above, nowadays there is high demand for a more sustainable water supply system but in fact, to achieve sustainability several factors must be tackled at the same time: climate change, rising energy, cost and rising population. All of these factors insite changes and put pressure on management of the available water reserves..One of the obstacles against the transformation of today's conventional water supply network to a more sustainable one, is the amount of time that is needed to achieve this transformation. More specifically, the transition phase has to pass through the municipal legislation
Legislation
Legislation is law which has been promulgated by a legislature or other governing body, or the process of making it...
bodies which are always in need of short-term solutions. Another obstacle to achieve the sustainability in the water supply systems is the insufficient practical experience with technologies required for these new concepts and the missing know-how about the organization and the transition process.
The only way to improve this situation is to learn and implement these kind of systems in pilot projects taking into account the costs involved and the benefits that are carried out.