A water supply network or water supply system is a system of engineered hydrologic and hydraulic components that provide water supply. A water supply system typically includes the following:
Water storage facilities such as reservoirs, water tanks, or water towers. Smaller water systems may store the water in cisterns or pressure vessels. Tall buildings may also need to store water locally in pressure vessels in order for the water to reach the upper floors.
Additional water pressurizing components such as pumping stations may need to be situated at the outlet of underground or aboveground reservoirs or cisterns (if gravity flow is impractical).
A pipe network for distribution of water to consumers (which may be private houses or industrial, commercial, or institution establishments) and other usage points (such as fire hydrants)
Connections to the sewers (underground pipes, or aboveground ditches in some developing countries) are generally found downstream of the water consumers, but the sewer system is considered to be a separate system, rather than part of the water supply system.
Virtually all large systems must treat the water; a fact that is tightly regulated by global, state and federal agencies, such as the World Health Organization (WHO) or the United States Environmental Protection Agency (EPA). Water treatment must occur before the product reaches the consumer and afterwards (when it is discharged again). Water purification usually occurs close to the final delivery points to reduce pumping costs and the chances of the water becoming contaminated after treatment.
Traditional surface water treatment plants generally consists of three steps: clarification, filtration and disinfection. Clarification refers to the separation of particles (dirt, organic matter, etc.) from the water stream. Chemical addition (i.e. alum, ferric chloride) destabilizes the particle charges and prepares them for clarification either by settling or floating out of the water stream. Sand, anthracite or activated carbon filters refine the water stream, removing smaller particulate matter. While other methods of disinfection exist, the preferred method is via chlorine addition. Chlorine effectively kills bacteria and most viruses and maintains a residual to protect the water supply through the supply network.
Typical urban water cycle in the United StatesThe Central Arizona Project Aqueduct transfers untreated waterMost (treated) water distribution happens through underground pipes known as water mainsPressurizing the water is required between the small water reserve and the end-user
The product, delivered to the point of consumption, is called potable water if it meets the water quality standards required for human consumption.
The water in the supply network is maintained at positive pressure to ensure that water reaches all parts of the network, that a sufficient flow is available at every take-off point and to ensure that untreated water in the ground cannot enter the network. The water is typically pressurised by pumping the water into storage tanks constructed at the highest local point in the network. One network may have several such service reservoirs.
In small domestic systems, the water may be pressurised by a pressure vessel or even by an underground cistern (the latter however does need additional pressurizing). This eliminates the need of a water tower or any other heightened water reserve to supply the water pressure.
These systems are usually owned and maintained by local governments such as cities or other public entities, but are occasionally operated by a commercial enterprise (see water privatization). Water supply networks are part of the master planning of communities, counties, and municipalities. Their planning and design requires the expertise of city planners and civil engineers, who must consider many factors, such as location, current demand, future growth, leakage, pressure, pipe size, pressure loss, fire fighting flows, etc.—using pipe network analysis and other tools.
As water passes through the distribution system, the water quality can degrade by chemical reactions and biological processes. Corrosion of metal pipe materials in the distribution system can cause the release of metals into the water with undesirable aesthetic and health effects. Release of iron from unlined iron pipes can result in customer reports of "red water" at the tap. Release of copper from copper pipes can result in customer reports of "blue water" and/or a metallic taste. Release of lead can occur from the solder used to join copper pipe together or from brassfixtures. Copper and lead levels at the consumer's tap are regulated to protect consumer health.
Utilities will often adjust the chemistry of the water before distribution to minimize its corrosiveness. The simplest adjustment involves control of pH and alkalinity to produce a water that tends to passivate corrosion by depositing a layer of calcium carbonate. Corrosion inhibitors are often added to reduce release of metals into the water. Common corrosion inhibitors added to the water are phosphates and silicates.
Maintenance of a biologically safe drinking water is another goal in water distribution. Typically, a chlorine based disinfectant, such as sodium hypochlorite or monochloramine is added to the water as it leaves the treatment plant. Booster stations can be placed within the distribution system to ensure that all areas of the distribution system have adequate sustained levels of disinfection.
Topologies
Like electric power lines, roads, and microwave radio networks, water systems may have a loop or branch network topology, or a combination of both. The piping networks are circular or rectangular. If any one section of water distribution main fails or needs repair, that section can be isolated without disrupting all users on the network.
Most systems are divided into zones.[1] Factors determining the extent or size of a zone can include hydraulics, telemetry systems, history, and population density. Sometimes systems are designed for a specific area then are modified to accommodate development. Terrain affects hydraulics and some forms of telemetry. While each zone may operate as a stand-alone system, there is usually some arrangement to interconnect zones in order to manage equipment failures or system failures.
Water network maintenance
Water supply networks usually represent the majority of assets of a water utility. Systematic documentation of maintenance works using a computerized maintenance management system (CMMS) is a key to a successful operation of a water utility.[why?]
Sustainable urban water supply
Clean drinking water is essential to human life.
A sustainable urban water supply network covers all the activities related to provision of potable water. Sustainable development is of increasing importance for the water supply to urban areas. Incorporating innovative water technologies into water supply systems improves water supply from sustainable perspectives. The development of innovative water technologies provides flexibility to the water supply system, generating a fundamental and effective means of sustainability based on an integrated real options approach.[2]
Water is an essential natural resource for human existence. It is needed in every industrial and natural process, for example, it is used for oil refining, for liquid-liquid extraction in hydro-metallurgical processes, for cooling, for scrubbing in the iron and the steel industry, and for several operations in food processing facilities.
It is necessary to adopt a new approach to design urban water supply networks; water shortages are expected in the forthcoming decades and environmental regulations for water utilization and waste-water disposal are increasingly stringent.
To achieve a sustainable water supply network, new sources of water are needed to be developed, and to reduce environmental pollution.
The price of water is increasing, so less water must be wasted and actions must be taken to prevent pipeline leakage. Shutting down the supply service to fix leaks is less and less tolerated by consumers. A sustainable water supply network must monitor the freshwater consumption rate and the waste-water generation rate.
In 1900 just 13% of the global population lived in cities. By 2005, 49% of the global population lived in urban areas. In 2030 it is predicted that this statistic will rise to 60%.[3] Attempts to expand water supply by governments are costly and often not sufficient. The building of new illegal settlements makes it hard to map, and make connections to, the water supply, and leads to inadequate water management.[4] In 2002, there were 158 million people with inadequate water supply.[5] An increasing number of people live in slums, in inadequate sanitary conditions, and are therefore at risk of disease.
Water scarcity
Potable water is not well distributed in the world. 1.8 million deaths are attributed to unsafe water supplies every year, according to the WHO.[6] Many people do not have any access, or do not have access to quality and quantity of potable water, though water itself is abundant. Poor people in developing countries can be close to major rivers, or be in high rainfall areas, yet not have access to potable water at all. There are also people living where lack of water creates millions of deaths every year.
Where the water supply system cannot reach the slums, people manage to use hand pumps, to reach the pit wells, rivers, canals, swamps and any other source of water. In most cases the water quality is unfit for human consumption. The principal cause of water scarcity is the growth in demand. Water is taken from remote areas to satisfy the needs of urban areas. Another reason for water scarcity is climate change: precipitation patterns have changed; rivers have decreased their flow; lakes are drying up; and aquifers are being emptied.
Governmental issues
In developing countries many governments are corrupt and poor and they respond to these problems with frequently changing policies and non clear agreements.[7] Water demand exceeds supply, and household and industrial water supplies are prioritised over other uses, which leads to water stress.[8] Potable water has a price in the market; water often becomes a business for private companies, which earn a profit by putting a higher price on water, which imposes a barrier for lower-income people. The Millennium Development Goals propose the changes required.
Goal 6 of the United Nations' Sustainable Development Goals is to "Ensure availability and sustainable management of water and sanitation for all".[9] This is in recognition of the human right to water and sanitation, which was formally acknowledged at the United Nations General Assembly in 2010, that "clean drinking water and sanitation are essential to the recognition of all human rights".[10] Sustainable water supply includes ensuring availability, accessibility, affordability and quality of water for all individuals.
In advanced economies, the problems are about optimising existing supply networks. These economies have usually had continuing evolution, which allowed them to construct infrastructure to supply water to people. The European Union has developed a set of rules and policies to overcome expected future problems.
The yield of a system can be measured by either its value or its net benefit. For a water supply system, the true value or the net benefit is a reliable water supply service having adequate quantity and good quality of the product. For example, if the existing water supply of a city needs to be extended to supply a new municipality, the impact of the new branch of the system must be designed to supply the new needs, while maintaining supply to the old system.
Single-objective optimization
The design of a system is governed by multiple criteria, one being cost. If the benefit is fixed, the least cost design results in maximum benefit. However, the least cost approach normally results in a minimum capacity for a water supply network. A minimum cost model usually searches for the least cost solution (in pipe sizes), while satisfying the hydraulic constraints such as: required output pressures, maximum pipe flow rate and pipe flow velocities. The cost is a function of pipe diameters; therefore the optimization problem consists of finding a minimum cost solution by optimising pipe sizes to provide the minimum acceptable capacity.
Multi-objective optimization
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”.[12] It is preferable to provide extra pipe capacity to cope with unexpected demand growth and with water outages. The problem changes from a single objective optimization problem (minimizing cost), to a multi-objective optimization problem (minimizing cost and maximizing flow capacity).
Weighted sum method
To solve a multi-objective optimization problem, it is necessary to convert the problem into a single objective optimization problem, by using adjustments, such as a weighted sum of objectives, or an ε-constraint method. The weighted sum approach gives a certain weight to the different objectives, and then factors in all these weights to form a single objective function that can be solved by single factor optimization. This method is not entirely satisfactory, because the weights cannot be correctly chosen, so this approach cannot find the optimal solution for all the original objectives.
The constraint method
The second approach (the constraint method), chooses one of the objective functions as the single objective, and the other objective functions are treated as constraints with a limited value. However, the optimal solution depends on the pre-defined constraint limits.
Sensitivity analysis
The multiple objective optimization problems involve computing the tradeoff between the costs and benefits resulting in a set of solutions that can be used for sensitivity analysis and tested in different scenarios. But there is no single optimal solution that will satisfy the global optimality of both objectives. As both objectives are to some extent contradictory, it is not possible to improve one objective without sacrificing the other. It is necessary in some cases use a different approach. (e.g. Pareto Analysis), and choose the best combination.
Operational constraints
Returning to the cost objective function, it cannot violate any of the operational constraints. Generally this cost is dominated by the energy cost for pumping. “The operational constraints include the standards of customer service, such as: the minimum delivered pressure, in addition to the physical constraints such as the maximum and the minimum water levels in storage tanks to prevent overtopping and emptying respectively.”[13]
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 predict the consequences of different pump and valve settings on the behavior of the network.
Apart from Linear and Non-linear Programming, there are other methods and approaches to design, to manage and operate a water supply network to achieve sustainability—for instance, the adoption of appropriate technology coupled with effective strategies for operation and maintenance. These strategies must include effective management models, technical support to the householders and industries, sustainable financing mechanisms, and development of reliable supply chains. All these measures must ensure the following: system working lifespan; maintenance cycle; continuity of functioning; down time for repairs; water yield and water quality.
Sustainable development
In an unsustainable system there is insufficient maintenance of the water networks, especially in the major pipe lines in urban areas. The system deteriorates and then needs rehabilitation or renewal.
Sustainable development in an urban water network
Householders and sewage treatment plants can both make the water supply networks more efficient and sustainable. Major improvements in eco-efficiency are gained through systematic separation of rainfall and wastewater. Membrane technology can be used for recycling wastewater.
The municipal government 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 separating the urine fraction of sanitary wastewater, and collecting it for recycling its nutrients.[14] The feces and graywater fraction is collected, together with organic wastes from the households, using a gravitysewer system, continuously flushed with non-potable water. The water is treated anaerobically and the biogas is used for energy production.
One effective way to achieve sustainable water management is to shift emphasis towards decentralized water projects, such as drip irrigation diffusion in India.[15] This project covers large spatial areas while relying on individual technological adoption decisions, offering scalable solutions that can mitigate water scarcity and enhance agricultural productivity.
Another method that can be utilized is through the promoting of community engagement and resistance against unsustainable water infrastructure projects. Grassroots movements, as observed in anti-dam protests in various countries, play a crucial role in challenging dominant development narratives and advocating for more socially and ecologically just water management practices.[15]
Municipalities and other forms of local governments should also invest in innovative technologies, such as membrane technology for wastewater recycling, and develop policy frameworks that incentivize eco-efficient practices. Municipal water reuse systems, as demonstrated in implementation, offer promising avenues for integrating wastewater treatment and resource recovery into urban water networks.[15]
The sustainable water supply system is an integrated system including water intake, water utilization, wastewater discharge and treatment and water environmental protection. It requires reducing freshwater and groundwater usage in all sectors of consumption. Developing sustainable water supply systems is a growing trend, because it serves people's long-term interests.[16] There are several ways to reuse and recycle the water, in order to achieve long-term sustainability, such as:
Gray water re-use and treatment: gray water is wastewater coming from baths, showers, sinks and washbasins. If this water is treated it can be used as a source of water for uses other than drinking. Depending on the type of gray water and its level of treatment, it can be re-used for irrigation and toilet flushing. According to an investigation about the impacts of domestic grey water reuse on public health, carried out by the New South Wales Health Centre in Australia in the year 2000[citation needed], grey water contains less nitrogen and fecal pathogenic organisms than sewage, and the organic content of grey water decomposes more rapidly.
Ecological treatment systems use little energy: there are many applications in gray water re-use, such as reed beds, 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, ammonia, nitrogen and phosphorus.
Other possible approaches to scoping models for water supply, applicable to any urban area, include the following:
The Dublin Statement on Water and Sustainable Development is a good example of the new trend to overcome water supply problems. This statement, suggested by advanced economies, has come up with some principles that are of great significance to urban water supply. These are:
Fresh water is a finite and vulnerable resource, essential to sustain life, development and the environment.
Water development and management should be based on a participatory approach, involving users, planners and policy-makers at all levels.
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.
Water has an economic value in all its competing uses and should be recognized as an economic good.[17]
From these statements, developed in 1992, several policies have been created to give importance to water and to move urban water system management towards sustainable development. The Water Framework Directive by the European Commission is a good example of what has been created there out of former policies.
Future approaches
There is great need for a more sustainable water supply systems. To achieve sustainability several factors must be tackled at the same time: climate change, rising energy cost, and rising populations. All of these factors provoke change and put pressure on management of available water resources.[18]
An obstacle to transforming conventional water supply systems, is the amount of time needed to achieve the transformation. More specifically, transformation must be implemented by municipal legislation bodies, which always need short-term solutions too.[citation needed] Another obstacle to achieving sustainability in water supply systems is the insufficient practical experience with the technologies required, and the missing know-how about the organization and the transition process.
Urban water infrastructure faces several challenges that undermine its sustainability and resilience. One critical issue highlighted in recent research is the vulnerability of water networks to climate variability and extreme weather events. Poor seasonal rains, as observed in the case of the Panama Canal's lock and dam infrastructure, exemplify how inadequate water supply can strain water-intensive infrastructure, raising questions about engineering legitimacy and the reliability of water systems.[19]
Another key challenge is the unequal development associated with large-scale water infrastructure projects such as dams and canals . Such projects, while aimed at promoting economic growth, often actually reproduce social and economic inequalities by displacing rural communities and marginalizing indigenous populations.[19] This phenomenon of "accumulation by dispossession" further emphasizes the need for more equitable and inclusive approaches to water infrastructure development.[19]
Possible ways to improve this situation is simulating of the network, implementing pilot projects, learning from the costs involved and the benefits achieved.
Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water delivery are among the most common uses for plumbing, but it is not limited to these applications. The word derives from the Latin for lead, plumbum, as the first effective pipes used in the Roman era were lead pipes.
A sanitary sewer is an underground pipe or tunnel system for transporting sewage from houses and commercial buildings to a sewage treatment plant or disposal.
Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. These systems are what supply drinking water to populations around the globe. Aspects of service quality include continuity of supply, water quality and water pressure. The institutional responsibility for water supply is arranged differently in different countries and regions. It usually includes issues surrounding policy and regulation, service provision and standardization.
Water reclamation is the process of converting municipal wastewater or sewage and industrial wastewater into water that can be reused for a variety of purposes. It is also called wastewater reuse, water reuse or water recycling. There are many types of reuse. It is possible to reuse water in this way in cities or for irrigation in agriculture. Other types of reuse are environmental reuse, industrial reuse, and reuse for drinking water, whether planned or not. Reuse may include irrigation of gardens and agricultural fields or replenishing surface water and groundwater. This latter is also known as groundwater recharge. Reused water also serve various needs in residences such as toilet flushing, businesses, and industry. It is possible to treat wastewater to reach drinking water standards. Injecting reclaimed water into the water supply distribution system is known as direct potable reuse. Drinking reclaimed water is not typical. Reusing treated municipal wastewater for irrigation is a long-established practice. This is especially so in arid countries. Reusing wastewater as part of sustainable water management allows water to remain an alternative water source for human activities. This can reduce scarcity. It also eases pressures on groundwater and other natural water bodies.
Sanitary engineering, also known as public health engineering or wastewater engineering, is the application of engineering methods to improve sanitation of human communities, primarily by providing the removal and disposal of human waste, and in addition to the supply of safe potable water. Traditionally a branch of civil engineering and now a subset of environmental engineering, in the mid-19th century, the discipline concentrated on the reduction of disease, then thought to be caused by miasma. This was accomplished mainly by the collection and segregation of sewerage flow in London specifically, and Great Britain generally. These and later regulatory improvements were reported in the United States as early as 1865.
Water supply and sanitation (WSS) in the European Union (EU) is the responsibility of each member state, but in the 21st century union-wide policies have come into effect. Water resources are limited and supply and sanitation systems are under pressure from urbanisation and climate change. Indeed, the stakes are high as the European Environmental Agency found that one European out of ten already suffers a situation of water scarcity and the IEA measured the energy consumption of the water sector to be equivalent to 3,5% of the electricity consumption of the EU.
Simplified sewerage, also called small-bore sewerage, is a sewer system that collects all household wastewater in small-diameter pipes laid at fairly flat gradients. Simplified sewers are laid in the front yard or under the pavement (sidewalk) or - if feasible - inside the back yard, rather than in the centre of the road as with conventional sewerage. It is suitable for existing unplanned low-income areas, as well as new housing estates with a regular layout. It allows for a more flexible design. With simplified sewerage it is crucial to have management arrangements in place to remove blockages, which are more frequent than with conventional sewers. It has been estimated that simplified sewerage reduces investment costs by up to 50% compared to conventional sewerage.
Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on Earth is salt water and only three percent is fresh water; slightly over two-thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air. Natural sources of fresh water include surface water, under river flow, groundwater and frozen water. Non-natural or human-made sources of fresh water can include wastewater that has been treated for reuse options, and desalinated seawater. People use water resources for agricultural, industrial and household activities.
Water supply and sanitation in Jordan is characterized by severe water scarcity, which has been exacerbated by forced immigration as a result of the 1948 Arab–Israeli War, the Six-Day War in 1967, the Gulf War of 1990, the Iraq War of 2003 and the Syrian Civil War since 2011. Jordan is considered one of the ten most water scarce countries in the world. High population growth, the depletion of groundwater reserves and the impacts of climate change are likely to aggravate the situation in the future.
Drinking water supply and sanitation in Egypt directly impact the country's public health, industrial developments, and agriculture. Egypt's water and sanitation industry is characterized by both achievements and challenges. Among the achievements are an increase of piped water supply between 1998 and 2006 from 89% to 100% in urban areas and from 39% to 93% in rural areas despite rapid population growth; the elimination of open defecation in rural areas during the same period; and in general a relatively high level of investment in infrastructure. Access to an at least basic water source in Egypt is now practically universal with a rate of 98%. On the institutional side, the regulation and service provision have been separated to some extensions through the creation of a national Holding Company for Water and Wastewater in 2004, and of an economic regulator, the Egyptian Water Regulatory Agency (EWRA), in 2006. Despite these successes, many challenges remain. Only about one half of the population is connected to sanitary sewers. Because of this low sanitation coverage, about 50,000 children die each year because of diarrhea. Another challenge is low cost recovery due to water tariffs that are among the lowest in the world. This in turn requires government subsidies even for operating costs, a situation that has been aggravated by salary increases without tariff increases after the Arab Spring. Furthermore, poor operation of facilities, such as water and wastewater treatment plants, as well as limited government accountability and transparency, are also issues.
Greater Mexico City, a metropolitan area with more than 19 million inhabitants including Mexico's capital with about 9 million inhabitants, faces tremendous water challenges. These include groundwater overexploitation, land subsidence, the risk of major flooding, the impacts of increasing urbanization, poor water quality, inefficient water use, a low share of wastewater treatment, health concerns about the reuse of wastewater in agriculture, and limited cost recovery. Overcoming these challenges is complicated by fragmented responsibilities for water management in Greater Mexico City:
Hydrological optimization applies mathematical optimization techniques to water-related problems. These problems may be for surface water, groundwater, or the combination. The work is interdisciplinary, and may be done by hydrologists, civil engineers, environmental engineers, and operations researchers.
Integrated urban water management in Medellín, Colombia is considered to be an overall success and a good example of how a large metropolitan area with moderate income disparity can adequately operate and maintain quality water supply to its many citizens. This is quite remarkable given the large urbanized population in the metropolitan area of the Aburrá Valley of 3.3 million, many of whom live on the slopes of the Aburrá Valley where Medellín is situated and highly prone to landslides and stormwater erosion. Sound urban water management within the metropolitan area of the Aburrá Valley is carried out by a set of technically strong institutions with financial independence—and lack of political interference such as Empresas Publicas de Medellin (EPM).
Stormwater harvesting or stormwater reuse is the collection, accumulation, treatment or purification, and storage of stormwater for its eventual reuse. While rainwater harvesting collects precipitation primarily from rooftops, stormwater harvesting deals with collection of runoff from creeks, gullies, ephemeral streams and underground conveyance. It can also include catchment areas from developed surfaces, such as roads or parking lots, or other urban environments such as parks, gardens and playing fields.
Water supply and sanitation in Japan is characterized by numerous achievements and some challenges. The country has achieved universal access to water supply and sanitation, has one of the lowest levels of water distribution losses in the world, regularly exceeds its own strict standards for the quality of drinking water and treated waste water, uses an effective national system of performance benchmarking for water and sanitation utilities, makes extensive use of both advanced and appropriate technologies such as the jōkasō on-site sanitation system, and has pioneered the payment for ecosystem services before the term was even coined internationally. Some of the challenges are a decreasing population, declining investment, fiscal constraints, ageing facilities, an ageing workforce, a fragmentation of service provision among thousands of municipal utilities, and the vulnerability of parts of the country to droughts that are expected to become more frequent due to climate change.
Sustainable implant is an urban typology that acts as a decentralized infrastructure provision hub on the neighborhood or district scale. Sustainable implants provide integrated infrastructure services that maintain cycles of energy, water and material, as well as provides social and economic returns. The concept originates from Arjan van Timmeren's research, Autonomy & Heteronomy (2006), as an answer to the problem of scale versus innovation in infrastructure; wherein infrastructure benefits from increasing returns to scale but suffer from extremely slow rate of change and turnover. To answer this problem, the sustainable implant is an instrument for mid-scale facilitation of alternative system innovation. The sustainable implant is a synthesis of techniques for sustainable processing of urban flows within an ecological processing device. The objective of a sustainable implant is to generate qualitative and quantitative improvements for utility service provision.
Water-sensitive urban design (WSUD) is a land planning and engineering design approach which integrates the urban water cycle, including stormwater, groundwater, and wastewater management and water supply, into urban design to minimise environmental degradation and improve aesthetic and recreational appeal. WSUD is a term used in the Middle East and Australia and is similar to low-impact development (LID), a term used in the United States; and Sustainable Drainage System (SuDS), a term used in the United Kingdom.
Water supply and sanitation in Vietnam is characterized by challenges and achievements. Among the achievements is a substantial increase in access to water supply and sanitation between 1990 and 2010, nearly universal metering, and increased investment in wastewater treatment since 2007. Among the challenges are continued widespread water pollution, poor service quality, low access to improved sanitation in rural areas, poor sustainability of rural water systems, insufficient cost recovery for urban sanitation, and the declining availability of foreign grant and soft loan funding as the Vietnamese economy grows and donors shift to loan financing. The government also promotes increased cost recovery through tariff revenues and has created autonomous water utilities at the provincial level, but the policy has had mixed success as tariff levels remain low and some utilities have engaged in activities outside their mandate.
Decentralized wastewater systems convey, treat and dispose or reuse wastewater from small and low-density communities, buildings and dwellings in remote areas, individual public or private properties. Wastewater flow is generated when appropriate water supply is available within the buildings or close to them.
A water distribution system is a part of water supply network with components that carry potable water from a centralized treatment plant or wells to consumers to satisfy residential, commercial, industrial and fire fighting requirements.
↑ Water: a shared responsibility. UNESCO World Water Assessment Programme (United Nations). Paris: United Nations Educational, Scientific and Cultural Organization (UNESCO). 2006. ISBN9231040065. OCLC69021428.{{cite book}}: CS1 maint: others (link)
↑ Vairavamoorthy, Kala; Gorantiwar, Sunil D.; Pathirana, Assela (2008). "Managing urban water supplies in developing countries – Climate change and water scarcity scenarios". Physics and Chemistry of the Earth, Parts A/B/C. 33 (5): 330–339. Bibcode:2008PCE....33..330V. doi:10.1016/j.pce.2008.02.008.
↑ Solon, Pablo (28 July 2010). "The Human Right to Water and Sanitation". United Nations General Assembly.
↑ van der Steen, Peter. (2006). “Integrated Urban Water Management: towards sustainability”. Environmental Resources Department. UNESCO-IHE Institute for Water Education. SWITCH.
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