Reservoir

A reservoir (from French réservoir – a "tank") is, most commonly, an enlarged natural or artificial lake, pond or impoundment created using a dam or lock to store water.

Reservoirs can be created in a number of ways, including controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an embayment within it, through excavation, or building any number of retaining walls or levees.

Defined as a storage space for fluids, reservoirs may hold water or gasses, including hydrocarbons. Tank reservoirs store these in ground-level, elevated, or buried tanks. Tank reservoirs for water are also called cisterns. Most underground reservoirs are used to store liquids, principally either water or petroleum, below ground.

Types

Dammed valleys

Lakevyrnwysummer
Lake Vyrnwy Reservoir. The dam spans the Vyrnwy Valley and was the first large stone dam built in the United Kingdom.
East Branch Reservoir
The East Branch Reservoir, part of the New York City water supply system, is formed by impounding the eastern tributary of the Croton River.

A dam constructed in a valley relies on the natural topography to provide most of the basin of the reservoir. Dams are typically located at a narrow part of a valley downstream of a natural basin. The valley sides act as natural walls, with the dam located at the narrowest practical point to provide strength and the lowest cost of construction. In many reservoir construction projects, people have to be moved and re-housed, historical artifacts moved or rare environments relocated. Examples include the temples of Abu Simbel[1] (which were moved before the construction of the Aswan Dam to create Lake Nasser from the Nile in Egypt), the relocation of the village of Capel Celyn during the construction of Llyn Celyn,[2] and the relocation of Borgo San Pietro of Petrella Salto during the construction of Lake Salto.

Construction of a reservoir in a valley will usually need the river to be diverted during part of the build, often through a temporary tunnel or by-pass channel.[3]

In hilly regions, reservoirs are often constructed by enlarging existing lakes. Sometimes in such reservoirs, the new top water level exceeds the watershed height on one or more of the feeder streams such as at Llyn Clywedog in Mid Wales.[4] In such cases additional side dams are required to contain the reservoir.

Where the topography is poorly suited to a single large reservoir, a number of smaller reservoirs may be constructed in a chain, as in the River Taff valley where the Llwyn-on, Cantref and Beacons Reservoirs form a chain up the valley.[5]

Coastal

Coastal reservoirs are fresh water storage reservoirs located on the sea coast near the river mouth to store the flood water of a river.[6] As the land based reservoir construction is fraught with substantial land submergence, coastal reservoir is preferred economically and technically since it does not use scarce land area.[7] Many coastal reservoirs were constructed in Asia and Europe. Saemanguem in South Korea, Marina Barrage in Singapore, Qingcaosha in China, and Plover Cove in Hong Kong, etc are few existing coastal reservoirs.[8]

Plover Cove Reservoir form a plane
Aerial view of Plover Cove coastal reservoir.

Bank-side

Where water is pumped or siphoned from a river of variable quality or size, bank-side reservoirs may be built to store the water. Such reservoirs are usually formed partly by excavation and partly by building a complete encircling bund or embankment, which may exceed 6 km (4 miles) in circumference.[9] Both the floor of the reservoir and the bund must have an impermeable lining or core: initially these were often made of puddled clay, but this has generally been superseded by the modern use of rolled clay. The water stored in such reservoirs may stay there for several months, during which time normal biological processes may substantially reduce many contaminants and almost eliminate any turbidity. The use of bank-side reservoirs also allows water abstraction to be stopped for some time, when the river is unacceptably polluted or when flow conditions are very low due to drought. The London water supply system is one example of the use of bank-side storage: the water is taken from the River Thames and River Lee; several large Thames-side reservoirs such as Queen Mary Reservoir can be seen along the approach to London Heathrow Airport.[9]

Service

Service reservoirs[10] store fully treated potable water close to the point of distribution. Many service reservoirs are constructed as water towers, often as elevated structures on concrete pillars where the landscape is relatively flat. Other service reservoirs can be almost entirely underground, especially in more hilly or mountainous country. In the United Kingdom, Thames Water has many underground reservoirs, sometimes also called cisterns, built in the 1800s, most of which are lined with brick. A good example is the Honor Oak Reservoir in London, constructed between 1901 and 1909. When it was completed it was said to be the largest brick built underground reservoir in the world[11] and it is still one of the largest in Europe.[12] This reservoir now forms part of the southern extension of the Thames Water Ring Main. The top of the reservoir has been grassed over and is now used by the Aquarius Golf Club.[13]

Service reservoirs perform several functions, including ensuring sufficient head of water in the water distribution system and providing water capacity to even out peak demand from consumers, enabling the treatment plant to run at optimum efficiency. Large service reservoirs can also be managed to reduce the cost of pumping, by refilling the reservoir at times of day when energy costs are low.

History

Circa 3000 BC, the craters of extinct volcanoes in Arabia were used as reservoirs by farmers for their irrigation water.[14]

Dry climate and water scarcity in India led to early development of stepwells and water resource management techniques, including the building of a reservoir at Girnar in 3000 BC.[15] Artificial lakes dating to the 5th century BC have been found in ancient Greece.[16] The artificial Bhojsagar lake in present-day Madhya Pradesh state of India, constructed in the 11th century, covered 650 square kilometres (250 sq mi).[15]

In Sri Lanka large reservoirs were created by ancient Sinhalese kings in order to save the water for irrigation. The famous Sri Lankan king Parākramabāhu I of Sri Lanka said "Do not let a drop of water seep into the ocean without benefiting mankind". He created the reservoir named Parakrama Samudra (sea of King Parakrama).[17] Vast artificial reservoirs were also built by various ancient kingdoms in Bengal, Assam and Cambodia.

Uses

Direct water supply

Many dammed river reservoirs and most bank-side reservoirs are used to provide the raw water feed to a water treatment plant which delivers drinking water through water mains. The reservoir does not merely hold water until it is needed: it can also be the first part of the water treatment process. The time the water is held before it is released is known as the retention time. This is a design feature that allows particles and silts to settle out, as well as time for natural biological treatment using algae, bacteria and zooplankton that naturally live in the water. However natural limnological processes in temperate climate lakes produce temperature stratification in the water, which tends to partition some elements such as manganese and phosphorus into deep, cold anoxic water during the summer months. In the autumn and winter the lake becomes fully mixed again. During drought conditions, it is sometimes necessary to draw down the cold bottom water, and the elevated levels of manganese in particular can cause problems in water treatment plants.

Hydroelectricity

Hydroelectric dam
Hydroelectric dam in cross section.

In 2005 about 25% of the world's 33,105 large dams (over 15  metres in height) were used for hydroelectricity.[18] However of 80,000 dams of all sizes in the U.S., only 3% produce electricity.[19] A reservoir generating hydroelectricity includes turbines connected to the retained water body by large-diameter pipes. These generating sets may be at the base of the dam or some distance away. In a flat river valley a reservoir needs to be deep enough to create a head of water at the turbines; and if there are periods of drought the reservoir needs to hold enough water to average out the river's flow throughout the year(s). Run-of-the-river hydro in a steep valley with constant flow needs no reservoir.

Some reservoirs generating hydroelectricity use pumped recharge: a high-level reservoir is filled with water using high-performance electric pumps at times when electricity demand is low, and then uses this stored water to generate electricity by releasing the stored water into a low-level reservoir when electricity demand is high. Such systems are called pump-storage schemes.[20]

Controlling watersources

KupferbachStauseeAachen
Recreational-only Kupferbach reservoir near Aachen/Germany.

Reservoirs can be used in a number of ways to control how water flows through downstream waterways:

Downstream water supply – water may be released from an upland reservoir so that it can be abstracted for drinking water lower down the system, sometimes hundred of miles further downstream.
Irrigation – water in an irrigation reservoir may be released into networks of canals for use in farmlands or secondary water systems. Irrigation may also be supported by reservoirs which maintain river flows, allowing water to be abstracted for irrigation lower down the river.[21]
Flood control – also known as an "attenuation" or "balancing" reservoirs, flood control reservoirs collect water at times of very high rainfall, then release it slowly during the following weeks or months. Some of these reservoirs are constructed across the river line, with the onward flow controlled by an orifice plate. When river flow exceeds the capacity of the orifice plate, water builds up behind the dam; but as soon as the flow rate reduces, the water behind the dam is slowly released until the reservoir is empty again. In some cases, such reservoirs only function a few times in a decade, and the land behind the reservoir may be developed as community or recreational land. A new generation of balancing dams are being developed to combat the possible consequences of climate change. They are called "Flood Detention Reservoirs". Because these reservoirs will remain dry for long periods, there may be a risk of the clay core drying out, reducing its structural stability. Recent developments include the use of composite core fill made from recycled materials as an alternative to clay.
Canals – Where a natural watercourse's water is not available to be diverted into a canal, a reservoir may be built to guarantee the water level in the canal: for example, where a canal climbs through locks to cross a range of hills.[22]
Recreation – water may be released from a reservoir to create or supplement white water conditions for kayaking and other white-water sports.[23] On salmonid rivers special releases (in Britain called freshets) are made to encourage natural migration behaviours in fish and to provide a variety of fishing conditions for anglers.

Flow balancing

Reservoirs can be used to balance the flow in highly managed systems, taking in water during high flows and releasing it again during low flows. In order for this to work without pumping requires careful control of water levels using spillways. When a major storm approaches, the dam operators calculate the volume of water that the storm will add to the reservoir. If forecast storm water will overfill the reservoir, water is slowly let out of the reservoir prior to, and during, the storm. If done with sufficient lead time, the major storm will not fill the reservoir and areas downstream will not experience damaging flows. Accurate weather forecasts are essential so that dam operators can correctly plan drawdowns prior to a high rainfall event. Dam operators blamed a faulty weather forecast on the 2010–2011 Queensland floods. Examples of highly managed reservoirs are Burrendong Dam in Australia and Bala Lake (Llyn Tegid) in North Wales. Bala Lake is a natural lake whose level was raised by a low dam and into which the River Dee flows or discharges depending upon flow conditions, as part of the River Dee regulation system. This mode of operation is a form of hydraulic capacitance in the river system.

Recreation

Many reservoirs often allow some recreational uses, such as fishing and boating. Special rules may apply for the safety of the public and to protect the quality of the water and the ecology of the surrounding area. Many reservoirs now support and encourage less formal and less structured recreation such as natural history, bird watching, landscape painting, walking and hiking, and often provide information boards and interpretation material to encourage responsible use.

Operation

Water falling as rain upstream of the reservoir, together with any groundwater emerging as springs, is stored in the reservoir. Any excess water can be spilled via a specifically designed spillway. Stored water may be piped by gravity for use as drinking water, to generate hydro-electricity or to maintain river flows to support downstream uses. Occasionally reservoirs can be managed to retain water during high rainfall events to prevent or reduce downstream flooding. Some reservoirs support several uses, and the operating rules may be complex.

Llyn Brianne spillway
Spillway of Llyn Brianne dam in Wales.

Most modern reservoirs have a specially designed draw-off tower that can discharge water from the reservoir at different levels, both to access water as the water level falls, and to allow water of a specific quality to be discharged into the downstream river as "compensation water": the operators of many upland or in-river reservoirs have obligations to release water into the downstream river to maintain river quality, support fisheries, to maintain downstream industrial and recreational uses or for a range of other purposes. Such releases are known as compensation water.

Terminology

Garaio - Embalse de Ullíbarri-Gamboa - Nivel 01
Water level marker in a reservoir

The units used for measuring reservoir areas and volumes vary from country to country. In most of the world, reservoir areas are expressed in square kilometres; in the United States, acres are commonly used. For volume, either cubic metres or cubic kilometres are widely used, with acre-feet used in the US.

The capacity, volume, or storage of a reservoir is usually divided into distinguishable areas. Dead or inactive storage refers to water in a reservoir that cannot be drained by gravity through a dam's outlet works, spillway, or power plant intake and can only be pumped out. Dead storage allows sediments to settle, which improves water quality and also creates an area for fish during low levels. Active or live storage is the portion of the reservoir that can be used for flood control, power production, navigation, and downstream releases. In addition, a reservoir's "flood control capacity" is the amount of water it can regulate during flooding. The "surcharge capacity" is the capacity of the reservoir above the spillway crest that cannot be regulated.[24]

In the United States, the water below the normal maximum level of a reservoir is called the "conservation pool".[25]

In the United Kingdom, "top water level" describes the reservoir full state, while "fully drawn down" describes the minimum retained volume.

Modelling reservoir management

There is a wide variety of software for modelling reservoirs, from the specialist Dam Safety Program Management Tools (DSPMT) to the relatively simple WAFLEX, to integrated models like the Water Evaluation And Planning system (WEAP) that place reservoir operations in the context of system-wide demands and supplies.

Safety

In many countries large reservoirs are closely regulated to try to prevent or minimise failures of containment.[26][27]

While much of the effort is directed at the dam and its associated structures as the weakest part of the overall structure, the aim of such controls is to prevent an uncontrolled release of water from the reservoir. Reservoir failures can generate huge increases in flow down a river valley, with the potential to wash away towns and villages and cause considerable loss of life, such as the devastation following the failure of containment at Llyn Eigiau which killed 17 people.[28](see also List of dam failures)

A notable case of reservoirs being used as an instrument of war involved the British Royal Air Force Dambusters raid on Germany in World War II (codenamed "Operation Chastise"[29]), in which three German reservoir dams were selected to be breached in order to damage German infrastructure and manufacturing and power capabilities deriving from the Ruhr and Eder rivers. The economic and social impact was derived from the enormous volumes of previously stored water that swept down the valleys, wreaking destruction. This raid later became the basis for several films.

Environmental impact

Brushes Clough Reservoir - geograph.org.uk - 715413
Brushes Clough Reservoir, located above Shaw and Crompton, England.

Whole life environmental impact

All reservoirs will have a monetary cost/benefit assessment made before construction to see if the project is worth proceeding with.[30] However, such analysis can often omit the environmental impacts of dams and the reservoirs that they contain. Some impacts, such as the greenhouse gas production associated with concrete manufacture, are relatively easy to estimate. Other impact on the natural environment and social and cultural effects can be more difficult to assess and to weigh in the balance but identification and quantification of these issues are now commonly required in major construction projects in the developed world[31]

Climate change

Reservoir greenhouse gas emissions

Naturally occurring lakes receive organic sediments which decay in an anaerobic environment releasing methane and carbon dioxide. The methane released is approximately 8 times more potent as a greenhouse gas than carbon dioxide.[32]

As a man-made reservoir fills, existing plants are submerged and during the years it takes for this matter to decay, will give off considerably more greenhouse gases than lakes do. A reservoir in a narrow valley or canyon may cover relatively little vegetation, while one situated on a plain may flood a great deal of vegetation. The site may be cleared of vegetation first or simply flooded. Tropical flooding can produce far more greenhouse gases than in temperate regions.

The following table indicates reservoir emissions in milligrams per square meter per day for different bodies of water.[33]

Location Carbon Dioxide Methane
Lakes 700 9
Temperate reservoirs 1500 20
Tropical reservoirs 3000 100

Hydroelectricity and climate change

Depending upon the area flooded versus power produced, a reservoir built for hydro-electricity generation can either reduce or increase the net production of greenhouse gases when compared to other sources of power.

A study for the National Institute for Research in the Amazon found that hydroelectric reservoirs release a large pulse of carbon dioxide from decay of trees left standing in the reservoirs, especially during the first decade after flooding.[34] This elevates the global warming impact of the dams to levels much higher than would occur by generating the same power from fossil fuels.[34] According to the World Commission on Dams report (Dams And Development), when the reservoir is relatively large and no prior clearing of forest in the flooded area was undertaken, greenhouse gas emissions from the reservoir could be higher than those of a conventional oil-fired thermal generation plant.[35] For instance, In 1990, the impoundment behind the Balbina Dam in Brazil (inaugurated in 1987) had over 20 times the impact on global warming than would generating the same power from fossil fuels, due to the large area flooded per unit of electricity generated.[34]

The Tucuruí Dam in Brazil (completed in 1984) had only 0.4 times the impact on global warming than would generating the same power from fossil fuels.[34]

A two-year study of carbon dioxide and methane releases in Canada concluded that while the hydroelectric reservoirs there do emit greenhouse gases, it is on a much smaller scale than thermal power plants of similar capacity.[36] Hydropower typically emits 35 to 70 times less greenhouse gases per TWh of electricity than thermal power plants.[37]

A decrease in air pollution occurs when a dam is used in place of thermal power generation, since electricity produced from hydroelectric generation does not give rise to any flue gas emissions from fossil fuel combustion (including sulfur dioxide, nitric oxide and carbon monoxide from coal).

Biology

Dams can produce a block for migrating fish, trapping them in one area, producing food and a habitat for various water-birds. They can also flood various ecosystems on land and may cause extinctions.

Human impact

Dams can severely reduce the amount of water reaching countries downstream of them, causing water stress between the countries, e.g. the Sudan and Egypt, which damages farming businesses in the downstream countries, and reduces drinking water.

Farms and villages, e.g. Ashopton can be flooded by the creation of reservoirs, ruining many livelihoods. For this very reason, worldwide 80 million people (figure is as of 2009, from the Edexcel GCSE Geography textbook) have had to be forcibly relocated due to dam construction.

Limnology

The limnology of reservoirs has many similarities to that of lakes of equivalent size. There are however significant differences.[38] Many reservoirs experience considerable variations in level producing significant areas that are intermittently underwater or dried out. This greatly limits the productivity or the water margins and also limits the number of species able to survive in these conditions.

Upland reservoirs tend to have a much shorter residence time than natural lakes and this can lead to more rapid cycling of nutrients through the water body so that they are more quickly lost to the system. This may be seen as a mismatch between water chemistry and water biology with a tendency for the biological component to be more oligotrophic than the chemistry would suggest.

Conversely, lowland reservoirs drawing water from nutrient rich rivers, may show exaggerated eutrophic characteristics because the residence time in the reservoir is much greater than in the river and the biological systems have a much greater opportunity to utilise the available nutrients.

Deep reservoirs with multiple level draw off towers can discharge deep cold water into the downstream river greatly reducing the size of any hypolimnion. This in turn can reduce the concentrations of phosphorus released during any annual mixing event and may therefore reduce productivity.

The dams in front of reservoirs act as knickpoints-the energy of the water falling from them reduces and deposition is a result below the dams.

Seismicity

The filling (impounding) of reservoirs has often been attributed to reservoir-triggered seismicity (RTS) as seismic events have occurred near large dams or within their reservoirs in the past. These events may have been triggered by the filling or operation of the reservoir and are on a small scale when compared to the amount of reservoirs worldwide. Of over 100 recorded events, some early examples include the 60 m (197 ft) tall Marathon Dam in Greece (1929), the 221 m (725 ft) tall Hoover Dam in the U.S. (1935). Most events involve large dams and small amounts of seismicity. The only four recorded events above a 6.0-magnitude (Mw) are the 103 m (338 ft) tall Koyna Dam in India and the 120 m (394 ft) Kremasta Dam in Greece which both registered 6.3-Mw, the 122 m (400 ft) high Kariba Dam in Zambia at 6.25-Mw and the 105 m (344 ft) Xinfengjiang Dam in China at 6.1-Mw. Disputes have occurred regarding when RTS has occurred due to a lack of hydrogeological knowledge at the time of the event. It is accepted, though, that the infiltration of water into pores and the weight of the reservoir do contribute to RTS patterns. For RTS to occur, there must be a seismic structure near the dam or its reservoir and the seismic structure must be close to failure. Additionally, water must be able to infiltrate the deep rock stratum as the weight of a 100 m (328 ft) deep reservoir will have little impact when compared the deadweight of rock on a crustal stress field, which may be located at a depth of 10 km (6 mi) or more.[39]

Liptovska Mara
Liptovská Mara in Slovakia (built in 1975) – an example of an artificial lake which significantly changed the local microclimate.

Microclimate

Reservoirs may change the local micro-climate increasing humidity and reducing extremes of temperature, especially in dry areas. Such effects are claimed also by some South Australian wineries as increasing the quality of the wine production.

List of reservoirs

In 2005 there were 33,105 large dams (≥15 m height) listed by the International Commission on Large Dams (ICOLD).[18]

List of reservoirs by area

Volta lake
Lake Volta from space (April 1993).

List of reservoirs by volume

Lake Kariba
Lake Kariba from space.
The world's ten largest reservoirs by volume
Rank Name Country Volume Notes
km3 cu mi
1 Lake Kariba Zimbabwe, Zambia 180 43
2 Bratsk Reservoir Russia 169 41
3 Lake Nasser Egypt, Sudan 157 38
4 Lake Volta Ghana 148 36
5 Manicouagan Reservoir Canada 142 34 [47]
6 Lake Guri Venezuela 135 32
7 Williston Lake Canada 74 18 [48]
8 Krasnoyarsk Reservoir Russia 73 18
9 Zeya Reservoir Russia 68 16

See also

References

  1. ^ UNESCO World Heritage Centre. "Nubian Monuments from Abu Simbel to Philae". Retrieved 20 September 2015.
  2. ^ Capel Celyn, Ten Years of Destruction: 1955–1965, Thomas E., Cyhoeddiadau Barddas & Gwynedd Council, 2007, ISBN 978-1-900437-92-9
  3. ^ Construction of Hoover Dam: a historic account prepared in cooperation with the Department of the Interior. KC Publications. 1976. ISBN 0-916122-51-4.
  4. ^ "Llanidloes Mid Wales – Llyn Clywedog". Retrieved 20 September 2015.
  5. ^ Reservoirs of Fforest Fawr Geopark
  6. ^ "International Association for Coastal Reservoir Research". Retrieved 9 July 2018.
  7. ^ "Assessment of social and environmental impacts of coastal reservoirs (page 19)". Retrieved 9 July 2018.
  8. ^ "Coastal reservoirs strategy for water resource development-a review of future trend". Retrieved 9 March 2018.
  9. ^ a b Bryn Philpott-Yinka Oyeyemi-John Sawyer (2009). "ICE Virtual Library: Queen Mary and King George V emergency draw down schemes". Dams and Reservoirs. 19 (2): 79–84. doi:10.1680/dare.2009.19.2.79.
  10. ^ "Open Learning – OpenLearn – Open University". Retrieved 20 September 2015.
  11. ^ "Honor Oak Reservoir" (PDF). London Borough of Lewisham. Archived from the original (PDF) on 18 March 2012. Retrieved 1 September 2011.
  12. ^ "Honor Oak Reservoir". Mott MacDonald. Archived from the original on 9 December 2011. Retrieved 1 September 2011.
  13. ^ "Aquarius Golf Club". Retrieved 20 September 2015.
  14. ^ Smith, S. et al. (2006) Water: the vital resource, 2nd edition, Milton Keynes, The Open University
  15. ^ a b Rodda, John; Ubertini, Lucio, eds. (2004). The Basis of Civilization – Water Science?. International Association of Hydrological Science. p. 161. ISBN 978-1-901502-57-2. OCLC 224463869.
  16. ^ Wilson & Wilson (2005). Encyclopedia of Ancient Greece. Routledge. ISBN 0-415-97334-1. pp. 8
  17. ^ – International Lake Environment Committee – Parakrama Samudra Archived 5 June 2011 at the Wayback Machine
  18. ^ a b Soumis, Nicolas; Lucotte, Marc; Canuel, René; Weissenberger, Sebastian; Houel, Stéphane; Larose, Catherine; Duchemin, Éric (2005). Hydroelectric Reservoirs as Anthropogenic Sources of Greenhouse Gases. Water Encyclopedia. doi:10.1002/047147844X.sw791. ISBN 978-0471478447.
  19. ^ "Small Hydro: Power of the Dammed: How Small Hydro Could Rescue America's Dumb Dams". Retrieved 20 September 2015.
  20. ^ "First Hydro Company Pumped Storage". Archived from the original on 29 July 2010.
  21. ^ "Irrigation UK" (PDF). Retrieved 20 September 2015.
  22. ^ "Huddersfield Narrow Canal Reservoirs". Archived from the original on 23 December 2001. Retrieved 20 September 2015.
  23. ^ "Canoe Wales – National White Water Rafting Centre". Retrieved 20 September 2015.
  24. ^ Votruba, Ladislav; Broža, Vojtěch (1989). Water Management in Reservoirs. Developments in Water Science. 33. Elsevier Publishing Company. p. 187. ISBN 978-0-444-98933-8.
  25. ^ "Water glossary". Retrieved 20 September 2015.
  26. ^ North Carolina Dam safety law Archived 16 April 2010 at the Wayback Machine
  27. ^ "Reservoirs Act 1975". www.opsi.gov.uk.
  28. ^ "Llyn Eigiau". Retrieved 20 September 2015.
  29. ^ "Commonwealth War Graves Commission – Operation Chastise" (PDF).
  30. ^ CIWEM – Reservoirs:Global Issues Archived 12 May 2008 at the Wayback Machine
  31. ^ Proposed reservoir – Environmental Impact Assessment (EIA) Scoping Report Archived 8 March 2009 at the Wayback Machine
  32. ^ Houghton, John (4 May 2005). "Global warming". Reports on Progress in Physics. 68 (6): 1362. doi:10.1088/0034-4885/68/6/R02.
  33. ^ "Reservoir Surfaces as Sources of Greenhouse Gases to the Atmosphere: A Global Estimate" (PDF). era.library.ualberta.ca.
  34. ^ a b c d Fearnside, P.M. (1995). "Hydroelectric dams in the Brazilian Amazon as sources of 'greenhouse' gases". Environmental Conservation. 22 (1): 7–19. doi:10.1017/s0376892900034020.
  35. ^ Graham-Rowe, Duncan. "Hydroelectric power's dirty secret revealed".
  36. ^ Éric Duchemin (1 December 1995). "Production of the greenhouse gases CH4 and CO2 by hydroelectric reservoirs of boreal region". ResearchGate. Retrieved 20 September 2015.
  37. ^ "The Issue of Greenhouse Gases from Hydroelectric Reservoirs from Boreal to Tropical Regions". researchgate.net.
  38. ^ "Ecology of Reservoirs and Lakes". Retrieved 20 September 2015.
  39. ^ "The relationship between large reservoirs and seismicity 08 February 2010". International Water Power & Dam Construction. 20 February 2010. Archived from the original on 18 June 2012. Retrieved 12 March 2011.
  40. ^ International Lake Environment Committee – Volta Lake Archived 6 May 2009 at the Wayback Machine
  41. ^ Maccallum, Ian. "Smallwood Reservoir".
  42. ^ International Lake Environment Committee – Reservoir Kuybyshev Archived 3 September 2009 at the Wayback Machine
  43. ^ International Lake Environment Committee – Lake Kariba Archived 26 April 2006 at the Wayback Machine
  44. ^ International Lake Environment Committee – Bratskoye Reservoir Archived 21 September 2010 at the Wayback Machine
  45. ^ International Lake Environment Committee – Aswam high dam reservoir Archived 20 April 2012 at the Wayback Machine
  46. ^ International Lake Environment Committee – Caniapiscau Reservoir Archived 19 July 2009 at the Wayback Machine
  47. ^ International Lake Environment Committee – Manicouagan Reservoir Archived 14 May 2011 at the Wayback Machine
  48. ^ International Lake Environment Committee – Williston Lake Archived 21 July 2009 at the Wayback Machine

External links

Ashokan Reservoir

The Ashokan Reservoir (; Iroquois for "place of fish") is a reservoir in Ulster County, New York. The reservoir is in the eastern end of the Catskill Park, and is one of several in the region created to provide the City of New York with water. It is the city's deepest reservoir, 190 feet (58 m) deep near the dam at the former site of Bishop Falls.

Battle of Chosin Reservoir

The Battle of Chosin Reservoir, also known as the Chosin Reservoir Campaign or the Battle of Jangjin Lake (Korean: 장진호 전투; Hanja: 長津湖戰鬪; RR: Jangjinho jeontu; MR: Changjinho chŏnt'u) was an important battle in the Korean War. The name "Chosin" is derived from the Japanese pronunciation "Chōshin", instead of the Korean pronunciation.Official Chinese sources refer to this battle as the eastern part of the Second Phase Campaign (or Offensive) (Chinese: 第二次战役东线; pinyin: Dì'èrcì Zhànyì Dōngxiàn). The western half of the Second Phase Campaign resulted in a Chinese victory in the Battle of the Ch'ongch'on River.

The battle took place about a month after the People's Republic of China entered the conflict and sent the People's Volunteer Army (PVA) 9th Army to infiltrate the northeastern part of North Korea. On 27 November 1950, the Chinese force surprised the US X Corps commanded by Major General Edward Almond at the Chosin Reservoir area. A brutal 17-day battle in freezing weather soon followed. Between 27 November and 13 December, 30,000 United Nations Command troops (later nicknamed "The Chosin Few") under the field command of Major General Oliver P. Smith were encircled and attacked by about 120,000 Chinese troops under the command of Song Shilun, who had been ordered by Mao Zedong to destroy the UN forces. The UN forces were nevertheless able to break out of the encirclement and to make a fighting withdrawal to the port of Hungnam, inflicting heavy casualties on the Chinese. US Marine units were supported in their withdrawal by the US Army's Task Force Faith to their east, which suffered heavy casualties and the full brunt of the Chinese offensive. The retreat of the US Eighth Army from northwest Korea in the aftermath of the Battle of the Ch'ongch'on River and the evacuation of the X Corps from the port of Hungnam in northeast Korea marked the complete withdrawal of UN troops from North Korea.

Hydroelectricity

Hydroelectricity is electricity produced from hydropower. In 2015, hydropower generated 16.6% of the world's total electricity and 70% of all renewable electricity, and was expected to increase by about 3.1% each year for the next 25 years.

Hydropower is produced in 150 countries, with the Asia-Pacific region generating 33 percent of global hydropower in 2013. China is the largest hydroelectricity producer, with 920 TWh of production in 2013, representing 16.9% of domestic electricity use.

The cost of hydroelectricity is relatively low, making it a competitive source of renewable electricity. The hydro station consumes no water, unlike coal or gas plants. The typical cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt hour. With a dam and reservoir it is also a flexible source of electricity, since the amount produced by the station can be varied up or down very rapidly (as little as a few seconds) to adapt to changing energy demands. Once a hydroelectric complex is constructed, the project produces no direct waste, and in many cases it has a considerably lower output level of greenhouse gases than fossil fuel powered energy plants.

Lake Berryessa

Lake Berryessa is the largest lake in Napa County, California. This reservoir in the Vaca Mountains was formed following the construction of the Monticello Dam on Putah Creek in the 1950s. Since the early 1960s, this reservoir has provided water and hydroelectricity to the North Bay region of the San Francisco Bay Area.

The reservoir was named for the first European settlers in the Berryessa Valley, José Jesús and Sexto "Sisto" Berrelleza (a Basque surname, Anglicized to "Berreyesa", then later respelled "Berryessa"), who were granted Rancho Las Putas in 1843.

List of dams and reservoirs in India

This page shows the state-wise list of dams and reservoirs in India. It also includes . Nearly 3200 major / medium dams and barrages had been constructed in India by the year 2012.

List of lakes in California

There are more than 3,000 named lakes, reservoirs, and dry lakes in the U.S. state of California.

List of places in Greater Manchester

Map of places in Greater Manchester compiled from this list

This is a partial list of places in Greater Manchester, in North West England.

Manicouagan Reservoir

Manicouagan Reservoir (also Lake Manicouagan) is an annular lake in central Quebec, Canada, covering an area of 1,942 km2 (750 sq mi). The lake island in its centre is known as René-Levasseur Island, and its highest point is Mount Babel. The structure was created 214 (±1) million years ago by the impact of a meteorite of five km (three mi) diameter. The lake and island are clearly seen from space and are sometimes called the "eye of Quebec". The lake has a volume of 137.9 km3 (33.1 cu mi).

National Register of Historic Places listings in Framingham, Massachusetts

Framingham, Massachusetts, has 18 locations listed on the National Register of Historic Places.

This National Park Service list is complete through NPS recent listings posted June 21, 2019.

Petroleum reservoir

A petroleum reservoir or oil and gas reservoir is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. Petroleum reservoirs are broadly classified as conventional and unconventional reservoirs. In case of conventional reservoirs, the naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability. While in unconventional reservoirs the rocks have high porosity and low permeability which keeps the hydrocarbons trapped in place, therefore not requiring a cap rock. Reservoirs are found using hydrocarbon exploration methods.

Puzhal aeri

Puzhal aeri, or Puzhal lake, also known as the Red Hills Lake, is located in Red Hills, Chennai, India. It lies in Thiruvallur district of Tamil Nadu state. It is one of the two rain-fed reservoirs from where water is drawn for supply to Chennai City, the other one being the Chembarambakkam Lake and Porur Lake.

The full capacity of the lake is 3,300 million ft³ (93 million m³).

Quabbin Reservoir

The Quabbin Reservoir is the largest inland body of water in Massachusetts, and was built between 1930 and 1939. Today, along with the Wachusett Reservoir, it is the primary water supply for Boston, some 65 miles (105 km) to the east as well as 40 other communities in Greater Boston. It also supplies water to three towns west of the reservoir and acts as backup supply for three others. It has an aggregate capacity of 412 billion US gallons (1,560 GL) and an area of 38.6 square miles (99.9 km2).

Radiocarbon dating

Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.

The method was developed in the late 1940s by Willard Libby, who received the Nobel Prize in Chemistry for his work in 1960. It is based on the fact that radiocarbon (14C) is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting 14C combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire 14C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and from that point onwards the amount of 14C it contains begins to decrease as the 14C undergoes radioactive decay. Measuring the amount of 14C in a sample from a dead plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died. The older a sample is, the less 14C there is to be detected, and because the half-life of 14C (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods occasionally permit accurate analysis of older samples.

Research has been ongoing since the 1960s to determine what the proportion of 14C in the atmosphere has been over the past fifty thousand years. The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age. Other corrections must be made to account for the proportion of 14C in different types of organisms (fractionation), and the varying levels of 14C throughout the biosphere (reservoir effects). Additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s. Because the time it takes to convert biological materials to fossil fuels is substantially longer than the time it takes for its 14C to decay below detectable levels, fossil fuels contain almost no 14C, and as a result there was a noticeable drop in the proportion of 14C in the atmosphere beginning in the late 19th century. Conversely, nuclear testing increased the amount of 14C in the atmosphere, which attained a maximum in about 1965 of almost twice what it had been before the testing began.

Measurement of radiocarbon was originally done by beta-counting devices, which counted the amount of beta radiation emitted by decaying 14C atoms in a sample. More recently, accelerator mass spectrometry has become the method of choice; it counts all the 14C atoms in the sample and not just the few that happen to decay during the measurements; it can therefore be used with much smaller samples (as small as individual plant seeds), and gives results much more quickly. The development of radiocarbon dating has had a profound impact on archaeology. In addition to permitting more accurate dating within archaeological sites than previous methods, it allows comparison of dates of events across great distances. Histories of archaeology often refer to its impact as the "radiocarbon revolution". Radiocarbon dating has allowed key transitions in prehistory to be dated, such as the end of the last ice age, and the beginning of the Neolithic and Bronze Age in different regions.

Reclaimed water

Reclaimed or recycled water (also called wastewater reuse or water reclamation) is the process of converting wastewater into water that can be reused for other purposes. Reuse may include irrigation of gardens and agricultural fields or replenishing surface water and groundwater (i.e., groundwater recharge). Reused water may also be directed toward fulfilling certain needs in residences (e.g. toilet flushing), businesses, and industry, and could even be treated to reach drinking water standards. This last option is called either "direct potable reuse" or "indirect potable" reuse, depending on the approach used. Colloquially, the term "toilet to tap" also refers to potable reuse.Reclaiming water for reuse applications instead of using freshwater supplies can be a water-saving measure. When used water is eventually discharged back into natural water sources, it can still have benefits to ecosystems, improving streamflow, nourishing plant life and recharging aquifers, as part of the natural water cycle.Wastewater reuse is a long-established practice used for irrigation, especially in arid countries. Reusing wastewater as part of sustainable water management allows water to remain as an alternative water source for human activities. This can reduce scarcity and alleviate pressures on groundwater and other natural water bodies.

Reservoir Dogs

Reservoir Dogs is a 1992 American heist film written and directed by Quentin Tarantino in his feature-length debut. It stars Harvey Keitel, Tim Roth, Chris Penn, Steve Buscemi, Lawrence Tierney, Michael Madsen, Tarantino, and Edward Bunker, as diamond thieves whose planned heist of a jewelry store goes terribly wrong. The film depicts the events before and after the heist. Kirk Baltz, Randy Brooks and Steven Wright also play supporting roles. It incorporates many motifs that have become Tarantino's hallmarks: violent crime, pop culture references, profanity, and nonlinear storytelling.

The film is regarded as a classic of independent film and a cult film, and was named "Greatest Independent Film of all Time" by Empire. Although controversial for its depictions of violence and use of profanity, Reservoir Dogs was generally well received, with the cast being praised by many critics. Despite not being heavily promoted during its theatrical run, the film became a modest success in the United States after grossing $2.8 million against its $1.2 million budget, and was more successful in the United Kingdom, grossing nearly £6.5 million. It achieved higher popularity after the success of Tarantino's next film, Pulp Fiction (1994). A soundtrack was released featuring songs used in the film, which are mostly from the 1970s.

San Luis Reservoir

The San Luis Reservoir is an artificial lake on San Luis Creek in the eastern slopes of the Diablo Range of Merced County, California, approximately 12 mi (19 km) west of Los Banos on State Route 152, which crosses Pacheco Pass and runs along its north shore. It is the fifth largest reservoir in California. The reservoir stores water taken from the San Joaquin-Sacramento River Delta. Water is pumped uphill into the reservoir from the O'Neill Forebay which is fed by the California Aqueduct and is released back into the forebay to continue downstream along the aqueduct as needed for farm irrigation and other uses. Depending on water levels, the reservoir is approximately nine miles long from north to south at its longest point, and five miles (8 km) wide. At the eastern end of the reservoir is the San Luis Dam, or the B.F. Sisk Dam, the fourth largest embankment dam in the United States, which allows for a total capacity of 2,041,000 acre feet (2,518,000 dam3).

Completed in 1967 on land formerly part of Rancho San Luis Gonzaga, the 12,700 acres (5,100 ha) reservoir is a joint use facility, being a part of both the California State Water Project and Central Valley Project, which together form a network of reservoirs, dams, pumping stations, and 550 miles (885 km) of canals and major conduits to move water across California. The San Luis Reservoir is located in Merced County, and has a visitor center located at the Romero Outlook where visitors can learn more about the dam and reservoir. The surface of the reservoir lies at an elevation of approximately 544 ft (166 m), with the O'Neill Forebay below the dam at 225 ft (69 m) above sea level. This elevation difference allows for a hydroelectric plant to be constructed - the Gianelli Hydroelectric Plant. Power from this plant is sent to a Path 15 substation, Los Banos via a short power line. Those 500 kV wires, carrying both the power generated here and elsewhere, leave the area and cross the O'Neill Forebay on several man-made islands.

San Luis Reservoir also supplies water to 63,500 acres (25,700 ha) of land in the Santa Clara Valley west of the Coast Ranges. San Justo Dam stores water diverted from San Luis Reservoir through the Pacheco Tunnel and Hollister Conduit, which travel through the Diablo Range. A separate canal, the Santa Clara Tunnel and Conduit, carries water to the Coyote Pumping Station in the Santa Clara Valley.

Spillway

A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure that the water does not overflow and damage or destroy the dam.

Floodgates and fuse plugs may be designed into spillways to regulate water flow and reservoir level. Such a spillway can be used to regulate downstream flows – by releasing water in small amounts before the reservoir is full, operators can prevent sudden large releases that would happen if the dam were overtopped.

Other uses of the term "spillway" include bypasses of dams or outlets of channels used during high water, and outlet channels carved through natural dams such as moraines.

Water normally flows over a spillway only during flood periods – when the reservoir cannot hold the excess of water entering the reservoir over the amount used. In contrast, an intake tower is a structure used to release water on a regular basis for water supply, hydroelectricity generation, etc.

Wachusett Reservoir

The Wachusett Reservoir is the second largest body of water in the state of Massachusetts. It is located in central Massachusetts, northeast of Worcester. It is part of the water supply system for metropolitan Boston maintained by the Massachusetts Water Resources Authority (MWRA). It has an aggregate capacity of 65 billion US gallons (250,000,000 m3) and an area of almost 7 square miles (18.2 km²). Water from the Wachusett flows to the covered Norumbega Storage Facility via the Cosgrove Tunnel and the MetroWest Water Supply Tunnel. The reservoir has a maximum depth of 120 feet (36.5 m) and a mean depth of 48 feet (14.6 m).

The reservoir serves as both an intermediate storage reservoir for water from the Quabbin Reservoir, and a water source itself, fed by its own watershed. The reservoir is fed by the Quinapoxet, and Stillwater rivers, along with the Quabbin Aqueduct, which carries water from the Quabbin Reservoir. It is part of the Nashua River Watershed and is the headwaters of the Nashua River. Because it is an intermediate storage reservoir, its water levels are kept relatively constant while the Quabbin Reservoir fluctuates based on precipitation and demand. At times when the Wachusett Reservoir becomes high due to its own watershed producing a large amount of runoff such as during snow melting, the flow from the Quabbin is shut off and water from the Ware River flows backwards down the Quabbin Aqueduct into the Quabbin Reservoir for storage.

The world's ten largest reservoirs by surface area
Rank Name Country Surface area Notes
km2 sq mi
1 Lake Volta Ghana 8,482 3,275 [40]
2 Smallwood Reservoir Canada 6,527 2,520 [41]
3 Kuybyshev Reservoir Russia 6,450 2,490 [42]
4 Lake Kariba Zimbabwe, Zambia 5,580 2,150 [43]
5 Bukhtarma Reservoir Kazakhstan 5,490 2,120
6 Bratsk Reservoir Russia 5,426 2,095 [44]
7 Lake Nasser Egypt, Sudan 5,248 2,026 [45]
8 Rybinsk Reservoir Russia 4,580 1,770
9 Caniapiscau Reservoir Canada 4,318 1,667 [46]
10 Lake Guri Venezuela 4,250 1,640

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