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58-553: The Thames Water Ring Main (TWRM, formerly the London Water Ring Main ) is a system of approximately 80 km (50 mi) of concrete tunnels which transfer drinking water from water treatment works in the Thames and River Lea catchments for distribution within central London . A major part of London's water supply infrastructure , the initial ring was constructed by Thames Water between 1988 and 1993 at

116-500: A tap or spigot. In the United States, the typical water consumption per capita, at home, is 69.3 US gallons (262 L; 57.7 imp gal) of water per day. Of this, only 1% of the water provided by public water suppliers is for drinking and cooking. Uses include (in decreasing order) toilets, washing machines, showers, baths, faucets, and leaks. As of 2015, American households use an average of 300 gallons of water

174-456: A breakdown or design fault in the sanitation system, or by chemical contaminants. Further examples of contamination include: Examples of chemical contamination include: Most water requires some treatment before use; even water from deep wells or springs. The extent of treatment depends on the source of the water. Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs. Only

232-452: A chronic health risk through buildup of heavy metals although some components like nitrates/nitrites and arsenic can have a more immediate impact. Physical parameters affect the aesthetics and taste of the drinking water and may complicate the removal of microbial pathogens. Pesticides are also potential drinking water contaminants of the category chemical contaminants . Pesticides may be present in drinking water in low concentrations, but

290-566: A component of effective policy for health protection." In 1990, only 76 percent of the global population had access to drinking water. By 2015 that number had increased to 91 percent. In 1990, most countries in Latin America, East and South Asia, and Sub-Saharan Africa were well below 90%. In Sub-Saharan Africa, where the rates are lowest, household access ranges from 40 to 80 percent. Countries that experience violent conflict can have reductions in drinking water access: One study found that

348-523: A conflict with about 2,500 battle deaths deprives 1.8% of the population of potable water. Typically in developed countries , tap water meets drinking water quality standards , even though only a small proportion is actually consumed or used in food preparation. Other typical uses for tap water include washing, toilets, and irrigation . Greywater may also be used for toilets or irrigation. Its use for irrigation however may be associated with risks. Globally, by 2015, 89% of people had access to water from

406-586: A cost of £248 million (equivalent to £638 million in 2023), and when completed, it was the longest tunnel in the UK. Two extensions were constructed between 2007 and 2010. The ring main comprises a major loop linking the Hampton , Walton , Ashford and Kempton water treatment works clustered in west London, to central London by a southern branch via Brixton and northern branch via Kew . Spurs run to Coppermills Water Treatment Works near Walthamstow, and to

464-469: A day may be required. About 1 to 2 billion people lack safe drinking water. Water can carry vectors of disease . More people die from unsafe water than from war, then- U.N. secretary-general Ban Ki-moon said in 2010. Developing countries are most affected by unsafe drinking water. Potable water is available in almost all populated areas of the world, although it may be expensive, and the supply may not always be sustainable. Sources where drinking water

522-443: A day. The qualitative and quantitative aspects of drinking water requirements on domesticated animals are studied and described within the context of animal husbandry . For example, a farmer might plan for 35 U.S. gallons (130 L) per day for a dairy cow , a third of that for a horse , and a tenth of that for a hog . However, relatively few studies have been focused on the drinking behavior of wild animals. According to

580-421: A few large urban areas such as Christchurch , New Zealand have access to sufficiently pure water of sufficient volume that no treatment of the raw water is required. In emergency situations when conventional treatment systems have been compromised, waterborne pathogens may be killed or inactivated by boiling but this requires abundant sources of fuel, and can be very onerous on consumers, especially where it

638-754: A hardship. The WHO/ UNICEF Joint Monitoring Program (JMP) for Water Supply and Sanitation is the official United Nations mechanism tasked with monitoring progress towards the Millennium Development Goal (MDG) relating to drinking-water and sanitation (MDG 7, Target 7c), which is to: "Halve, by 2015, the proportion of people without sustainable access to safe drinking-water and basic sanitation". Tooting Commons The Tooting Commons consist of two adjacent areas of common land lying between Balham , Streatham and Tooting , in south west London : Tooting Bec Common and Tooting Graveney Common . Since 1996, they have been wholly within

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696-777: A negative effect on child development (both physical and cognitive). Sixty million people are estimated to have been poisoned by well water contaminated by excessive fluoride , which dissolved from granite rocks. The effects are particularly evident in the bone deformations of children. Similar or larger problems are anticipated in other countries including China, Uzbekistan, and Ethiopia. Although helpful for dental health in low dosage, fluoride in large amounts interferes with bone formation. Long-term consumption of water with high fluoride concentration (> 1.5 ppm F) can have serious undesirable consequences such as dental fluorosis , enamel mottle and skeletal fluorosis , bone deformities in children. Fluorosis severity depends on how much fluoride

754-481: A reservoir, from which supply is drawn as required. An indication of this dynamic variation in demand is that the minimum hydraulic level moves between the Battersea and Park Lane pump-out shafts. The loop is closed to provide the redundancy that allows any segment on the ring to be isolated and drained for maintenance without interrupting the supply to any shaft, not for hydraulic reasons. The 21 shafts connecting

812-578: A source that is suitable for drinking – called improved water source  – and 71% of the world could access safely managed drinking water that is clean and available on-demand. Estimates suggest that at least 25% of improved sources contain fecal contamination. 1.8 billion people still use an unsafe drinking water source which may be contaminated by feces . This can result in infectious diseases , such as gastroenteritis , cholera , and typhoid , among others. Reduction of waterborne diseases and development of safe water resources

870-481: A source that is suitable for drinking – called improved water sources . In sub-Saharan Africa , access to potable water ranged from 40% to 80% of the population. Nearly 4.2 billion people worldwide had access to tap water, while another 2.4 billion had access to wells or public taps. By 2015, 5.2 billion people representing 71% of the global population used safely managed drinking water services. As of 2017, 90% of people having access to water from

928-516: A water table continuous with the underlying Chalk and measured at pressures up to 4 bar (400 kPa). An unexpected entry into the Thanet Sand while excavating near Tooting Bec Common led to the flooding of the tunnel and the temporary abandonment of a tunnel boring machine. A further problem with Thanet Sand was the presence of glauconite , which oxidises on contact with air. The resulting de-oxygenated air resulted in two fatalities during

986-517: Is WASH - standing for water, sanitation and hygiene . The WHO has investigated which proportion of death and disease worldwide can be attributed to insufficient WASH services. In their analysis they focus on the following four health outcomes: diarrhea , acute respiratory infections , malnutrition , and soil-transmitted Helminthiasis (STHs). These health outcomes are also included as an indicator for achieving Sustainable Development Goal 3 ("Good Health and Well-being"): Indicator 3.9.2 reports on

1044-436: Is a major public health goal in developing countries. In 2017, almost 22 million Americans drank from water systems that were in violation of public health standards, which could contribute to citizens developing water-borne illnesses . Safe drinking water is an environmental health concern. Bottled water is sold for public consumption in most parts of the world. Improved sources are also monitored based on whether water

1102-658: Is available when needed (5.8 billion people), located on premises (5.4 billion), free from contamination (5.4 billion), and within a 30-minute round trip. While improved water sources such as protected piped water are more likely to provide safe and adequate water as they may prevent contact with human excreta, for example, this is not always the case. According to a 2014 study, approximately 25% of improved sources contained fecal contamination. The population in Australia, New Zealand, North America and Europe have achieved nearly universal basic drinking water services. Because of

1160-429: Is called Doctor Johnson Avenue . This was originally a country path leading from Streatham Place , and Doctor Johnson is reputed to have regularly walked here when visiting Hester Thrale . Until March 1970 it was called simply The Avenue . Tooting Bec Common includes a number of formal avenues of trees – the first such avenue to be recorded was a line of oaks to commemorate a visit by Elizabeth I in 1600. With

1218-647: Is called desalination and is used mainly in dry areas with access to large bodies of saltwater. Publicly available treated water has historically been associated with major increases in life expectancy and improved public health . Water disinfection can greatly reduce the risks of waterborne diseases such as typhoid and cholera . Chlorination is currently the most widely used water disinfection method, although chlorine compounds can react with substances in water and produce disinfection by-products (DBP) that pose problems to human health. Local geological conditions affecting groundwater are determining factors for

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1276-538: Is commonly obtained include springs , hyporheic zones and aquifers ( groundwater ), from rainwater harvesting , surface water (from rivers, streams, glaciers ), or desalinated seawater . For these water sources to be consumed safely, they must receive adequate water treatment and meet drinking water quality standards . An experimental source is atmospheric water generators . Springs are often used as sources for bottled waters . The most efficient and convenient way to transport and deliver potable water

1334-427: Is difficult to store boiled water in sterile conditions. Other techniques, such as filtration, chemical disinfection, and exposure to ultraviolet radiation (including solar UV) have been demonstrated in an array of randomized control trials to significantly reduce levels of water-borne disease among users in low-income countries, but these suffer from the same problems as boiling methods. Another type of water treatment

1392-513: Is present in the water, as well as people's diet and physical activity. Defluoridation methods include membrane-based methods, precipitation, absorption, and electrocoagulation. Natural arsenic contamination of groundwater is a global threat with 140 million people affected in 70 countries globally. Some well-known examples of water quality problems with drinking water supplies include: Water supply can get contaminated by pathogens which may originate from human excreta , for example due to

1450-486: Is through pipes. Plumbing can require significant capital investment. Some systems suffer high operating costs. The cost to replace the deteriorating water and sanitation infrastructure of industrialized countries may be as high as $ 200 billion a year. Leakage of untreated and treated water from pipes reduces access to water. Leakage rates of 50% are not uncommon in urban systems. Tap water , delivered by domestic water systems refers to water piped to homes and delivered to

1508-458: Is to reach large numbers of low-income households on a sustainable basis. Few POU measures have reached significant scale thus far, but efforts to promote and commercially distribute these products to the world's poor have only been under way for a few years. Solar water disinfection is a low-cost method of purifying water that can often be implemented with locally available materials. Unlike methods that rely on firewood , it has low impact on

1566-671: The European Drinking Water Directive and in the United States, the United States Environmental Protection Agency (EPA) establishes standards as required by the Safe Drinking Water Act . China adopted its own drinking water standard GB3838-2002 (Type II) enacted by Ministry of Environmental Protection in 2002. For countries without a legislative or administrative framework for such standards,

1624-591: The London Borough of Wandsworth , which has administered both commons since 1971. Between 1965 and 1995, the eastern part of Tooting Bec Common was within the adjacent London Borough of Lambeth . Wandsworth's Parks Department erroneously described the two historically separate spaces as Tooting Common for many years, but recent signage uses the plural title. Tooting Bec Common includes Tooting Bec Lido and Tooting Graveney Common includes Tooting Bec Stadium . Tooting Bec Common and Tooting Graveney Common are

1682-512: The West End of London and Crystal Palace Railway line in 1855, and the London, Brighton and South Coast Railway line running north – south which opened in 1861 and was further widened in 1901 after this had become the main line to Brighton . The common today continues to be divided into multiple parcels by these busy transport links. Tooting Bec Common, comprising nearly 152 acres (62 ha),

1740-528: The World Health Organization publishes guidelines on the standards that should be achieved. The World Health Organization considers access to safe drinking-water a basic human right. Contaminated water is estimated to result in more than half a million deaths per year. Contaminated water together with the lack of sanitation was estimated to cause about one percent of disability adjusted life years worldwide in 2010. According to

1798-692: The toxicity of the chemical and the extent of human exposure are factors that are used to determine the specific health risk. Perfluorinated alkylated substances (PFAS) are a group of synthetic compounds used in a large variety of consumer products, such as food packaging , waterproof fabrics, carpeting and cookware. PFAS are known to persist in the environment and are commonly described as persistent organic pollutants . PFAS chemicals have been detected in blood, both humans and animals, worldwide, as well as in food products, water, air and soil. Animal testing studies with PFAS have shown effects on growth and development, and possibly effects on reproduction, thyroid,

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1856-567: The "mortality rate attributed to unsafe water, sanitation, and lack of hygiene". Diarrhea is primarily transmitted through fecal–oral routes . In 2011, infectious diarrhea resulted in about 0.7 million deaths in children under five years old and 250 million lost school days. This equates to about 2000 child deaths per day. Children suffering from diarrhea are more vulnerable to become underweight (due to stunted growth ). This makes them more vulnerable to other diseases such as acute respiratory infections and malaria . Chronic diarrhea can have

1914-550: The London Clay lengths is by design, as being easily excavated, largely impermeable and somewhat self-supporting for short periods it is a near-ideal tunnelling material. Where the design required entry into the Lambeth Group and Thanet Sand, tunnelling was considerably more difficult. In particular, the Thanet Sand requires a high boring torque, is highly abrasive and, most challengingly, sufficiently permeable to contain

1972-510: The WHO, the most common diseases linked with poor water quality are cholera , diarrhea , dysentery , hepatitis A , typhoid , and polio . One of the main causes for contaminated drinking water in developing countries is lack of sanitation and poor hygiene. For this reason, the quantification of the burden of disease from consuming contaminated drinking water usually looks at water, sanitation and hygiene aspects together. The acronym for this

2030-784: The World Health Organization's 2017 report, safe drinking water is water that "does not represent any significant risk to health over a lifetime of consumption, including different sensitivities that may occur between life stages". According to a report by UNICEF and UNESCO , Finland has the best drinking water quality in the world. Parameters for drinking water quality typically fall within three categories: microbiological, chemical, physical. Microbiological parameters include coliform bacteria , E. coli , and specific pathogenic species of bacteria (such as cholera -causing Vibrio cholerae ), viruses , and protozoan parasites . Originally, fecal contamination

2088-475: The common. A few metres of grass behind the railings of the former Tooting Bec Hospital (redeveloped as the Heritage Park residential development) are now part of the common in exchange for the lost land. In 2016, there was a proposal to close Doctor Johnson Avenue and cover the tarmac with grass to make it part of the common. The proposal was overturned after nearly 70% of responses voiced opposition to

2146-401: The demand placed on them, and, by providing an increased level of redundancy, enabled them to be more easily isolated and maintained. The main was constructed in two phases: the southern leg in 1988 to 1991, and the northern leg in 1991 to 1993. A tunnel was also built between Coppermills Water Treatment Works and Stoke Newington at the same time, although this was not connected to the rest of

2204-541: The east of that name. The common is not immediately adjacent to the area now generally known as Tooting Bec . Tooting Graveney Common – the southern and western part of the commons – was in Tooting parish and a thin line of other common land ran further south down Church Lane towards the River Graveney . During the 19th century, the commons at Tooting were divided by building of roads and railways – starting with

2262-404: The environment. In many areas, low concentration of fluoride (< 1.0 ppm F) is intentionally added to tap water to improve dental health , although in some communities water fluoridation remains a controversial issue. (See water fluoridation controversy ). According to the World Health Organization (WHO), "access to safe drinking-water is essential to health, a basic human right and

2320-439: The excavation of a pump-out shaft. Between 2007 and 2010, two extensions to the ring main were constructed. A 4.5 km (2.8 mi) tunnel was built between New River Head and Stoke Newington, connecting the ring main to the tunnel to Coppermills water treatment works, which was built in the initial construction phase. A 5 km (3.1 mi) tunnel was also constructed between Brixton and Honor Oak. These extensions increased

2378-535: The high initial investments, many less wealthy nations cannot afford to develop or sustain appropriate infrastructure, and as a consequence people in these areas may spend a correspondingly higher fraction of their income on water. 2003 statistics from El Salvador, for example, indicate that the poorest 20% of households spend more than 10% of their total income on water. In the United Kingdom, authorities define spending of more than 3% of one's income on water as

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2436-476: The idea. The two commons are recognised as being of Site of Metropolitan importance for Greater London because they include a number of rare wildlife habitats. Although the woodland areas are the most obvious, the unimproved areas of acid grassland are actually far rarer. The two commons were the location for an award-winning British Independent Film, Common People (2013), written/directed by and starring Kerry Skinner and Stewart Alexander. The plot concerns

2494-402: The immune system and liver. As of 2022 the health impacts of many PFAS compounds are not understood. Scientists are conducting research to determine the extent and severity of impacts from PFAS on human health. PFAS have been widely detected in drinking water worldwide and regulations have been developed, or are under development, in many countries. Drinking water quality standards describes

2552-424: The loss of elms along Tooting Bec Road to Dutch Elm Disease , many visitors are now immediately aware of late Victorian era plantings of horse chestnuts on the boundaries, but there are some much older trees – including the oaks parallel to Garrad's Road which are the successors to an avenue first recorded in the 17th century. In the 1990s the junction of Tooting Bec Road and Church Lane was widened, encroaching on

2610-420: The main to the surface are divided into: 51°24.75′N 0°27′W  /  51.41250°N 0.450°W  / 51.41250; -0.450 Drinking water The amount of drinking water required to maintain good health varies, and depends on physical activity level, age, health-related issues, and environmental conditions. For those who work in a hot climate, up to 16 litres (4.2 US gal)

2668-420: The matter is resolved. The ability of point of use (POU) options to reduce disease is a function of both their ability to remove microbial pathogens if properly applied and such social factors as ease of use and cultural appropriateness. Technologies may generate more (or less) health benefit than their lab-based microbial removal performance would suggest. The current priority of the proponents of POU treatment

2726-487: The presence of various metal ions , often rendering the water " soft " or " hard ". In the event of contamination of drinking water, government officials typically issue an advisory regarding water consumption. In the case of biological contamination , residents are usually advised to boil their water before consumption or to use bottled water as an alternative. In the case of chemical contamination , residents may be advised to refrain from consuming tap water entirely until

2784-453: The project consisted of brand new tunnels. Eleven new pumping stations were constructed as part of the project, to extract water from the tunnel and send it to the water distribution network. These were positioned to deliver water to the areas of London with the greatest demand, which often meant they had to be constructed in locations where space was at a premium. In three locations — Barrow Hill, Holland Park Avenue, and Park Lane —

2842-492: The pumping stations were constructed entirely underground. Once the ring main was completed, it was envisaged that four existing water treatment works at Barn Elms, Stoke Newington, Surbiton, and Hornsey would be decommissioned, although Hornsey ultimately remained open. The main lies mostly within London Clay with sections within the overlying alluvium and underlying Lambeth Group and Thanet Sand . The predominance of

2900-443: The quality parameters set for drinking water. Water may contain many harmful constituents , yet there are no universally recognized and accepted international standards for drinking water. Even where standards do exist, the permitted concentration of individual constituents may vary by as much as ten times from one set of standards to another. Many countries specify standards to be applied in their own country. In Europe, this includes

2958-460: The remains of common land that once stretched as far as Mitcham. Tooting Bec Common – the northern and eastern part of the commons – was within the historic parish of Streatham, and takes its name from the area's links to Bec Abbey at Le Bec-Hellouin in Normandy . At various points in history this common has been called Streatham Common, which causes some confusion with the open space a mile to

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3016-428: The reservoir and pumping station at Honor Oak . The total transfer capacity of the system is 1.8  gigalitres (1.8 × 10 litres) per day. The ring main is located well below most water mains, at a depth of 10 to 65 m (33 to 213 ft) below ground level and approximately 10 to 30 m (33 to 98 ft) below sea level. The tunnel is mostly of 2.54 m (100 in) internal diameter, except for

3074-407: The ring main's transfer capacity by 500 million litres per day. Flow through the main is by gravity under the driving head of the service reservoirs. By virtue of its depth, the pipeline is under some pressure. The hydraulic grade line rarely exceeds ground level. To enter, supply water is pumped up into the distribution zones at the pump-out shafts. In some respects, the main can be considered as

3132-486: The ring until the later extension phase. The project was geographically split into stages, separately contracted and constructed largely simultaneously. Different contractors' work resulted in minor variations in tunnel details. The tunnels were constructed using tunnel boring machines , with interlocking wedgelock linings. The southern leg of the project refurbished and reused the existing Southern Tunnel Main, completed in 1974 between Ashford Common and Merton, but otherwise

3190-462: The section between Ashford Common and Kew, where it is 2.91 m (115 in). It is connected to the surface by 21 vertical shafts that extend to ground level. Before the ring main was built, water was transferred within London through a number of trunk mains, mostly located just below the surface. Some of the oldest operational pressure mains in the world — the oldest dating from 1838 —

3248-424: The trunks were weakened by corrosion. Additionally, there was an increased pressure requirement due to increasing water demand, as well as an increase in external stresses due to vehicle traffic. These problems were exacerbated by a lack of system redundancies which limited preventive maintenance, resulting in an increasing number of leaks. The ring main extended the operational life of the high-level trunks by reducing

3306-658: Was determined with the presence of coliform bacteria , a convenient marker for a class of harmful fecal pathogens . The presence of fecal coliforms (like E. Coli ) serves as an indication of contamination by sewage . Additional contaminants include protozoan oocysts such as Cryptosporidium sp. , Giardia lamblia , Legionella , and viruses (enteric). Microbial pathogenic parameters are typically of greatest concern because of their immediate health risk. Physical and chemical parameters include heavy metals , trace organic compounds , total suspended solids , and turbidity . Chemical parameters tend to pose more of

3364-599: Was one of the first commons which the Metropolitan Board of Works took action to preserve following the Metropolitan Commons Act of 1866 when in 1873 it acquired the manorial rights for £13,798. In 1875, the MBW acquired Tooting Graveney Common of 66 acres (27 ha) for £3,000. The road marking the boundary between the two commons (and the historic parish boundary between Streatham and Tooting)

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