114-715: Laggan Dam is a mass concrete gravity dam located on the River Spean south west of Loch Laggan in the Scottish Highlands . It forms the second reservoir for the Lochaber hydroelectric scheme . The structure was built as part of the Lochaber hydroelectric scheme by Balfour Beatty for the British Aluminium Company and construction was finished in 1934. The supervising engineers were
228-401: A balancing compression stress in the downstream face, providing additional economy. For this type of dam, it is essential to have an impervious foundation with high bearing strength. Permeable foundations have a greater likelihood of generating uplift pressures under the dam. Uplift pressures are hydrostatic pressures caused by the water pressure of the reservoir pushing up against the bottom of
342-416: A capacity of 40,000,000 cubic metres (1.4 billion cubic feet), between a top water level of 820 feet (250 m) OD and maximum drawdown level of 804 feet (245 m) OD, giving an operational range of 16 feet (4.9 m). The whole crest of the dam, except for a section in the middle that houses equipment, is a spillway broken into 29 bays by piers that support a roadway across the dam. As well as
456-544: A dam as "jurisdictional" or "non-jurisdictional" varies by location. In the United States, each state defines what constitutes a non-jurisdictional dam. In the state of Colorado a non-jurisdictional dam is defined as a dam creating a reservoir with a capacity of 100 acre-feet or less and a surface area of 20 acres or less and with a height measured as defined in Rules 4.2.5.1. and 4.2.19 of 10 feet or less. In contrast,
570-499: A dam that directed waterflow. It was finished in 251 BC. A large earthen dam, made by Sunshu Ao , the prime minister of Chu (state) , flooded a valley in modern-day northern Anhui Province that created an enormous irrigation reservoir (100 km (62 mi) in circumference), a reservoir that is still present today. Roman dam construction was characterized by "the Romans' ability to plan and organize engineering construction on
684-738: A demonstrative ( þis , þat ), after a possessive pronoun (e.g., hir , our ), or with a name or in a form of address. This derives from the Old English "weak" declension of adjectives. This inflexion continued to be used in writing even after final -e had ceased to be pronounced. In earlier texts, multisyllable adjectives also receive a final -e in these situations, but this occurs less regularly in later Middle English texts. Otherwise, adjectives have no ending and adjectives already ending in -e etymologically receive no ending as well. Earlier texts sometimes inflect adjectives for case as well. Layamon's Brut inflects adjectives for
798-493: A distinct vertical curvature to it as well lending it the vague appearance of a concave lens as viewed from downstream. The multiple-arch dam consists of a number of single-arch dams with concrete buttresses as the supporting abutments, as for example the Daniel-Johnson Dam , Québec, Canada. The multiple-arch dam does not require as many buttresses as the hollow gravity type but requires a good rock foundation because
912-478: A grand scale." Roman planners introduced the then-novel concept of large reservoir dams which could secure a permanent water supply for urban settlements over the dry season. Their pioneering use of water-proof hydraulic mortar and particularly Roman concrete allowed for much larger dam structures than previously built, such as the Lake Homs Dam , possibly the largest water barrier to that date, and
1026-502: A largely Anglo-Saxon vocabulary (with many Norse borrowings in the northern parts of the country) but a greatly simplified inflectional system. The grammatical relations that were expressed in Old English by the dative and instrumental cases were replaced in Early Middle English with prepositional constructions. The Old English genitive - es survives in the -'s of the modern English possessive , but most of
1140-494: A lengthened – and later also modified – pronunciation of a preceding vowel. For example, in name , originally pronounced as two syllables, the /a/ in the first syllable (originally an open syllable) lengthened, the final weak vowel was later dropped, and the remaining long vowel was modified in the Great Vowel Shift (for these sound changes, see Phonology , above). The final ⟨e⟩ , now silent, thus became
1254-495: A lesser extent), and, therefore, it cannot be attributed simply to the influence of French-speaking sections of the population: English did, after all, remain the vernacular . It is also argued that Norse immigrants to England had a great impact on the loss of inflectional endings in Middle English. One argument is that, although Norse and English speakers were somewhat comprehensible to each other due to similar morphology,
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#17327909755531368-511: A minor tributary of the Nieuwe Maas . The central square of Amsterdam, covering the original site of the 800-year-old dam, still carries the name Dam Square . The Romans were the first to build arch dams , where the reaction forces from the abutment stabilizes the structure from the external hydrostatic pressure , but it was only in the 19th century that the engineering skills and construction materials available were capable of building
1482-509: A notable increase in interest in SHPs. Couto and Olden (2018) conducted a global study and found 82,891 small hydropower plants (SHPs) operating or under construction. Technical definitions of SHPs, such as their maximum generation capacity, dam height, reservoir area, etc., vary by country. A dam is non-jurisdictional when its size (usually "small") excludes it from being subject to certain legal regulations. The technical criteria for categorising
1596-593: A process called apophony ), as in Modern English. With the discontinuation of the Late West Saxon standard used for the writing of Old English in the period prior to the Norman Conquest, Middle English came to be written in a wide variety of scribal forms, reflecting different regional dialects and orthographic conventions. Later in the Middle English period, however, and particularly with
1710-649: A profession based on a rigorously applied scientific theoretical framework. This new emphasis was centered around the engineering faculties of universities in France and in the United Kingdom. William John Macquorn Rankine at the University of Glasgow pioneered the theoretical understanding of dam structures in his 1857 paper On the Stability of Loose Earth . Rankine theory provided a good understanding of
1824-566: A settling pond, and a 1,000 m (3,300 ft) canal to a distribution tank. These works were not finished until 325 AD when the dam permitted the irrigation of 25,000 acres (100 km ). Eflatun Pınar is a Hittite dam and spring temple near Konya , Turkey. It is thought to date from the Hittite empire between the 15th and 13th centuries BC. The Kallanai is constructed of unhewn stone, over 300 m (980 ft) long, 4.5 m (15 ft) high and 20 m (66 ft) wide, across
1938-473: A tunnel to Loch Laggan. This was constructed by the 1st Tunnelling Company of the Canadian Army. Dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation , human consumption , industrial use , aquaculture , and navigability . Hydropower
2052-524: A variant of the Northumbrian dialect (prevalent in northern England and spoken in southeast Scotland ). During the Middle English period, many Old English grammatical features either became simplified or disappeared altogether. Noun, adjective, and verb inflections were simplified by the reduction (and eventual elimination) of most grammatical case distinctions. Middle English also saw considerable adoption of Anglo-Norman vocabulary, especially in
2166-408: A whole dam itself, that dam also would be held in place by gravity, i.e., there is no tension in the upstream face of the dam holding the top of the dam down. The designer does this because it is usually more practical to make a dam of material essentially just piled up than to make the material stick together against vertical tension. The shape that prevents tension in the upstream face also eliminates
2280-543: Is curved upstream like an arch dam with a radius of curvature of 2,000 ft (610 m), but works purely on the principle of a gravity dam . The dam impounds Laggan Reservoir and Loch Laggan, which are connected via a short section of the River Spean. This was dredged and straightened over a length of approximately 1.3 miles (2 km) to the confluence of the Amhainn Ghuilbinn. The reservoir has
2394-424: Is dependent on the strength of the side wall abutments, hence not only should the arch be well seated on the side walls but also the character of the rock should be carefully inspected. Two types of single-arch dams are in use, namely the constant-angle and the constant-radius dam. The constant-radius type employs the same face radius at all elevations of the dam, which means that as the channel grows narrower towards
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#17327909755532508-433: Is now rare and used only in oxen and as part of a double plural , in children and brethren . Some dialects still have forms such as eyen (for eyes ), shoon (for shoes ), hosen (for hose(s) ), kine (for cows ), and been (for bees ). Grammatical gender survived to a limited extent in early Middle English before being replaced by natural gender in the course of the Middle English period. Grammatical gender
2622-480: Is often used in conjunction with dams to generate electricity. A dam can also be used to collect or store water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes ) are used to manage or prevent water flow into specific land regions. The word dam can be traced back to Middle English , and before that, from Middle Dutch , as seen in
2736-471: Is sloped the distribution is more complicated. The normal component of the weight of the arch ring may be taken by the arch action, while the normal hydrostatic pressure will be distributed as described above. For this type of dam, firm reliable supports at the abutments (either buttress or canyon side wall) are more important. The most desirable place for an arch dam is a narrow canyon with steep side walls composed of sound rock. The safety of an arch dam
2850-399: Is the more widely used of the two, though the hollow dam is frequently more economical to construct. Grand Coulee Dam is a solid gravity dam and Braddock Locks & Dam is a hollow gravity dam. A gravity dam can be combined with an arch dam into an arch-gravity dam for areas with massive amounts of water flow but less material available for a pure gravity dam. The inward compression of
2964-590: Is the thinnest arch dam in the world and one of the oldest arch dams in Asia. It was constructed some 700 years ago in Tabas county , South Khorasan Province , Iran . It stands 60 meters tall, and in crest is a one meter width. Some historians believe the dam was built by Shāh Abbās I, whereas others believe that he repaired it. In the Netherlands , a low-lying country, dams were often built to block rivers to regulate
3078-766: The A86 road from Fort William, however there is no public access over it. The catchment area of the dam was increased by an aqueduct which diverts flow from the River Mashie into the River Pattack. This can be seen at the side of the A86 road in Strath Mashie . Between 1941 and 1943, the catchment was further expanded by constructing another dam across the headwaters of the River Spey , and diverting flow through
3192-524: The Augustinian canon Orrm wrote the Ormulum , one of the oldest surviving texts in Middle English. The influence of Old Norse aided the development of English from a synthetic language with relatively free word order to a more analytic language with a stricter word order. Both Old English and Old Norse were synthetic languages with complicated inflections. Communication between Vikings in
3306-597: The Danelaw and their Anglo-Saxon neighbours resulted in the erosion of inflection in both languages. Old Norse may have had a more profound impact on Middle and Modern English development than any other language. The effect of Old Norse on Old English was substantive, pervasive, and of a democratic character. Like close cousins, Old Norse and Old English resembled each other, and with some words and grammatical structures in common, speakers of each language roughly understood each other, but according to historian Simeon Potler
3420-616: The Early Modern English and Modern English eras. Middle English generally did not have silent letters . For example, knight was pronounced [ˈkniçt] (with both the ⟨k⟩ and the ⟨gh⟩ pronounced, the latter sounding as the ⟨ch⟩ in German Knecht ). The major exception was the silent ⟨e⟩ – originally pronounced but lost in normal speech by Chaucer's time. This letter, however, came to indicate
3534-657: The Fayum Depression to the Nile in Middle Egypt. Two dams called Ha-Uar running east–west were built to retain water during the annual flood and then release it to surrounding lands. The lake called Mer-wer or Lake Moeris covered 1,700 km (660 sq mi) and is known today as Birket Qarun. By the mid-late third millennium BC, an intricate water-management system in Dholavira in modern-day India
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3648-579: The Harbaqa Dam , both in Roman Syria . The highest Roman dam was the Subiaco Dam near Rome ; its record height of 50 m (160 ft) remained unsurpassed until its accidental destruction in 1305. Roman engineers made routine use of ancient standard designs like embankment dams and masonry gravity dams. Apart from that, they displayed a high degree of inventiveness, introducing most of
3762-670: The National Inventory of Dams (NID). Middle English Middle English (abbreviated to ME ) is a form of the English language that was spoken after the Norman Conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English period. Scholarly opinion varies, but the University of Valencia states the period when Middle English
3876-585: The Norman Conquest , had normally been written in French. Like Chaucer's work, this new standard was based on the East Midlands-influenced speech of London. Clerks using this standard were usually familiar with French and Latin , influencing the forms they chose. The Chancery Standard, which was adopted slowly, was used in England by bureaucrats for most official purposes, excluding those of
3990-645: The University of Oxford published a study of the cost of large dams – based on the largest existing dataset – documenting significant cost overruns for a majority of dams and questioning whether benefits typically offset costs for such dams. Dams can be formed by human agency, natural causes, or even by the intervention of wildlife such as beavers . Man-made dams are typically classified according to their size (height), intended purpose or structure. Based on structure and material used, dams are classified as easily created without materials, arch-gravity dams , embankment dams or masonry dams , with several subtypes. In
4104-645: The 12th century, incorporating a unique phonetic spelling system; and the Ancrene Wisse and the Katherine Group , religious texts written for anchoresses , apparently in the West Midlands in the early 13th century. The language found in the last two works is sometimes called the AB language . Additional literary sources of the 12th and 13th centuries include Layamon's Brut and The Owl and
4218-422: The 13th century and was replaced by thorn. Thorn mostly fell out of use during the 14th century and was replaced by ⟨th⟩ . Anachronistic usage of the scribal abbreviation [REDACTED] ( þe , "the") has led to the modern mispronunciation of thorn as ⟨ y ⟩ in this context; see ye olde . Wynn, which represented the phoneme /w/ , was replaced by ⟨ w ⟩ during
4332-409: The 13th century. Due to its similarity to the letter ⟨p⟩ , it is mostly represented by ⟨w⟩ in modern editions of Old and Middle English texts even when the manuscript has wynn. Under Norman influence, the continental Carolingian minuscule replaced the insular script that had been used for Old English. However, because of the significant difference in appearance between
4446-473: The 14th century, even after the loss of the majority of the continental possessions of the English monarchy . In the aftermath of the Black Death of the 14th century, there was significant migration into London , of people to the counties of the southeast of England and from the east and central Midlands of England, and a new prestige London dialect began to develop as a result of this clash of
4560-604: The 1540s after the printing and wide distribution of the English Bible and Prayer Book , which made the new standard of English publicly recognizable and lasted until about 1650. The main changes between the Old English sound system and that of Middle English include: The combination of the last three processes listed above led to the spelling conventions associated with silent ⟨e⟩ and doubled consonants (see under Orthography , below). Middle English retains only two distinct noun-ending patterns from
4674-544: The British began construction in 1898. The project was designed by Sir William Willcocks and involved several eminent engineers of the time, including Sir Benjamin Baker and Sir John Aird , whose firm, John Aird & Co. , was the main contractor. Capital and financing were furnished by Ernest Cassel . When initially constructed between 1899 and 1902, nothing of its scale had ever before been attempted; on completion, it
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4788-572: The Church and legalities, which used Latin and Law French respectively. The Chancery Standard's influence on later forms of written English is disputed, but it did undoubtedly provide the core around which Early Modern English formed. Early Modern English emerged with the help of William Caxton 's printing press, developed during the 1470s. The press stabilized English through a push towards standardization, led by Chancery Standard enthusiast and writer Richard Pynson . Early Modern English began in
4902-520: The Colorado River is a constant-angle arch dam. A similar type is the double-curvature or thin-shell dam. Wildhorse Dam near Mountain City, Nevada , in the United States is an example of the type. This method of construction minimizes the amount of concrete necessary for construction but transmits large loads to the foundation and abutments. The appearance is similar to a single-arch dam but with
5016-680: The Colorado River. By 1997, there were an estimated 800,000 dams worldwide, with some 40,000 of them over 15 meters high. Early dam building took place in Mesopotamia and the Middle East . Dams were used to control water levels, for Mesopotamia's weather affected the Tigris and Euphrates Rivers. The earliest known dam is the Jawa Dam in Jordan , 100 kilometres (62 mi) northeast of
5130-714: The Middle Ages, dams were built in the Netherlands to regulate water levels and prevent sea intrusion. In the 19th century, large-scale arch dams were constructed around the British Empire, marking advances in dam engineering techniques. The era of large dams began with the construction of the Aswan Low Dam in Egypt in 1902. The Hoover Dam, a massive concrete arch-gravity dam, was built between 1931 and 1936 on
5244-557: The Nightingale . Some scholars have defined "Early Middle English" as encompassing English texts up to 1350. This longer time frame would extend the corpus to include many Middle English Romances (especially those of the Auchinleck manuscript c. 1330 ). Gradually, the wealthy and the government Anglicised again, although Norman (and subsequently French ) remained the dominant language of literature and law until
5358-591: The Norse speakers' inability to reproduce the ending sounds of English words influenced Middle English's loss of inflectional endings. Important texts for the reconstruction of the evolution of Middle English out of Old English are the Peterborough Chronicle , which continued to be compiled up to 1154; the Ormulum , a biblical commentary probably composed in Lincolnshire in the second half of
5472-544: The Old English -eþ , Midland dialects showing -en from about 1200, and Northern forms using -es in the third person singular as well as the plural. The past tense of weak verbs was formed by adding an -ed(e) , -d(e) , or -t(e) ending. The past-tense forms, without their personal endings, also served as past participles with past-participle prefixes derived from Old English: i- , y- , and sometimes bi- . Strong verbs , by contrast, formed their past tense by changing their stem vowel (e.g., binden became bound ,
5586-713: The Old Norse influence was strongest in the dialects under Danish control that composed the southern part of the Northern England (corresponding to the Scandinavian Kingdom of Jórvík ), the East Midlands and the East of England , words in the spoken language emerged in the 10th and 11th centuries near the transition from Old to Middle English. Influence on the written languages only appeared from
5700-495: The United States alone, there are approximately 2,000,000 or more "small" dams that are not included in the Army Corps of Engineers National Inventory of dams . Records of small dams are kept by state regulatory agencies and therefore information about small dams is dispersed and uneven in geographic coverage. Countries worldwide consider small hydropower plants (SHPs) important for their energy strategies, and there has been
5814-524: The World Commission on Dams also includes in the "large" category, dams which are between 5 and 15 m (16 and 49 ft) high with a reservoir capacity of more than 3 million cubic metres (2,400 acre⋅ft ). Hydropower dams can be classified as either "high-head" (greater than 30 m in height) or "low-head" (less than 30 m in height). As of 2021 , ICOLD's World Register of Dams contains 58,700 large dam records. The tallest dam in
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#17327909755535928-710: The abundance of Modern English words for the mechanisms of government that are derived from Anglo-Norman, such as court , judge , jury , appeal , and parliament . There are also many Norman-derived terms relating to the chivalric cultures that arose in the 12th century, an era of feudalism , seigneurialism , and crusading . Words were often taken from Latin, usually through French transmission. This gave rise to various synonyms, including kingly (inherited from Old English), royal (from French, inherited from Vulgar Latin), and regal (from French, which borrowed it from Classical Latin). Later French appropriations were derived from standard, rather than Norman, French. Examples of
6042-403: The arch dam, stability is obtained by a combination of arch and gravity action. If the upstream face is vertical the entire weight of the dam must be carried to the foundation by gravity, while the distribution of the normal hydrostatic pressure between vertical cantilever and arch action will depend upon the stiffness of the dam in a vertical and horizontal direction. When the upstream face
6156-494: The areas of politics, law, the arts, and religion, as well as poetic and emotive diction. Conventional English vocabulary remained primarily Germanic in its sources, with Old Norse influences becoming more apparent. Significant changes in pronunciation took place, particularly involving long vowels and diphthongs, which in the later Middle English period began to undergo the Great Vowel Shift . Little survives of early Middle English literature , due in part to Norman domination and
6270-666: The back of the dam through a large pipe to drive a water wheel and watermill . In the 10th century, Al-Muqaddasi described several dams in Persia. He reported that one in Ahwaz was more than 910 m (3,000 ft) long, and that it had many water-wheels raising the water into aqueducts through which it flowed into reservoirs of the city. Another one, the Band-i-Amir Dam, provided irrigation for 300 villages. Shāh Abbās Arch (Persian: طاق شاه عباس), also known as Kurit Dam ,
6384-638: The beginning of the 13th century, this delay in Scandinavian lexical influence in English has been attributed to the lack of written evidence from the areas of Danish control, as the majority of written sources from Old English were produced in the West Saxon dialect spoken in Wessex , the heart of Anglo-Saxon political power at the time. The Norman Conquest of England in 1066 saw the replacement of
6498-491: The bottom of the dam the central angle subtended by the face of the dam becomes smaller. Jones Falls Dam , in Canada, is a constant radius dam. In a constant-angle dam, also known as a variable radius dam, this subtended angle is kept constant and the variation in distance between the abutments at various levels is taken care of by varying the radii. Constant-radius dams are much less common than constant-angle dams. Parker Dam on
6612-402: The buttress loads are heavy. In a gravity dam, the force that holds the dam in place against the push from the water is Earth's gravity pulling down on the mass of the dam. The water presses laterally (downstream) on the dam, tending to overturn the dam by rotating about its toe (a point at the bottom downstream side of the dam). The dam's weight counteracts that force, tending to rotate the dam
6726-501: The capital Amman . This gravity dam featured an originally 9-metre-high (30 ft) and 1 m-wide (3.3 ft) stone wall, supported by a 50 m-wide (160 ft) earthen rampart. The structure is dated to 3000 BC. However, the oldest continuously operational dam is Lake Homs Dam , built in Syria between 1319-1304 BC. The Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, about 25 km (16 mi) south of Cairo ,
6840-646: The city. The masonry arch dam wall was designed by Lieutenant Percy Simpson who was influenced by the advances in dam engineering techniques made by the Royal Engineers in India . The dam cost £17,000 and was completed in 1856 as the first engineered dam built in Australia, and the second arch dam in the world built to mathematical specifications. The first such dam was opened two years earlier in France . It
6954-414: The clergy for written communication and record-keeping. A significant number of Norman words were borrowed into English and used alongside native Germanic words with similar meanings. Examples of Norman/Germanic pairs in Modern English include pig and pork , calf and veal , wood and forest , and freedom and liberty . The role of Anglo-Norman as the language of government and law can be seen in
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#17327909755537068-507: The comparative and superlative (e.g., greet , great; gretter , greater). Adjectives ending in -ly or -lich formed comparatives either with -lier , -liest or -loker , -lokest . A few adjectives also displayed Germanic umlaut in their comparatives and superlatives, such as long , lenger . Other irregular forms were mostly the same as in modern English. Middle English personal pronouns were mostly developed from those of Old English , with
7182-433: The construction of the Rideau Canal in Canada near modern-day Ottawa and built a series of curved masonry dams as part of the waterway system. In particular, the Jones Falls Dam , built by John Redpath , was completed in 1832 as the largest dam in North America and an engineering marvel. In order to keep the water in control during construction, two sluices , artificial channels for conducting water, were kept open in
7296-469: The dam by the water reduces the lateral (horizontal) force acting on the dam. Thus, the gravitational force required by the dam is lessened, i.e., the dam does not need to be so massive. This enables thinner dams and saves resources. A barrage dam is a special kind of dam that consists of a line of large gates that can be opened or closed to control the amount of water passing the dam. The gates are set between flanking piers which are responsible for supporting
7410-441: The dam was built in seven sections, with copper strip and hot poured asphalt water stops in the joints. Water from the dam is conveyed to Loch Treig through three miles (5 kilometres) of tunnel. From there, the waters travel through a further 15 miles (24 kilometres) of tunnel, 15 feet (4.6 metres) in diameter, before descending the hillside to a power house at Fort William through five steel pipes. The dam can be found next to
7524-533: The dam was submitted by a consortium called Six Companies, Inc. Such a large concrete structure had never been built before, and some of the techniques were unproven. The torrid summer weather and the lack of facilities near the site also presented difficulties. Nevertheless, Six Companies turned over the dam to the federal government on 1 March 1936, more than two years ahead of schedule. By 1997, there were an estimated 800,000 dams worldwide, some 40,000 of them over 15 m (49 ft) high. In 2014, scholars from
7638-605: The dam. If large enough uplift pressures are generated there is a risk of destabilizing the concrete gravity dam. On a suitable site, a gravity dam can prove to be a better alternative to other types of dams. When built on a solid foundation, the gravity dam probably represents the best-developed example of dam building. Since the fear of flood is a strong motivator in many regions, gravity dams are built in some instances where an arch dam would have been more economical. Gravity dams are classified as "solid" or "hollow" and are generally made of either concrete or masonry. The solid form
7752-407: The dam. The first was near the base of the dam on its east side. A second sluice was put in on the west side of the dam, about 20 ft (6.1 m) above the base. To make the switch from the lower to upper sluice, the outlet of Sand Lake was blocked off. Hunts Creek near the city of Parramatta , Australia , was dammed in the 1850s, to cater to the demand for water from the growing population of
7866-450: The dams' potential range and magnitude of environmental disturbances. The International Commission on Large Dams (ICOLD) defines a "large dam" as "A dam with a height of 15 m (49 ft) or greater from lowest foundation to crest or a dam between 5 m (16 ft) metres and 15 metres impounding more than 3 million cubic metres (2,400 acre⋅ft )". "Major dams" are over 150 m (490 ft) in height. The Report of
7980-419: The development of the Chancery Standard in the 15th century, orthography became relatively standardised in a form based on the East Midlands-influenced speech of London. Spelling at the time was mostly quite regular . (There was a fairly consistent correspondence between letters and sounds.) The irregularity of present-day English orthography is largely due to pronunciation changes that have taken place over
8094-432: The different dialects, that was based chiefly on the speech of the East Midlands but also influenced by that of other regions. The writing of this period, however, continues to reflect a variety of regional forms of English. The Ayenbite of Inwyt , a translation of a French confessional prose work, completed in 1340, is written in a Kentish dialect . The best known writer of Middle English, Geoffrey Chaucer , wrote in
8208-531: The double consonant represented a sound that was (or had previously been) geminated (i.e., had genuinely been "doubled" and would thus have regularly blocked the lengthening of the preceding vowel). In other cases, by analogy, the consonant was written double merely to indicate the lack of lengthening. The basic Old English Latin alphabet consisted of 20 standard letters plus four additional letters: ash ⟨æ⟩ , eth ⟨ð⟩ , thorn ⟨þ⟩ , and wynn ⟨ƿ⟩ . There
8322-468: The end of the Middle English period only the strong -'s ending (variously spelled) was in use. Some formerly feminine nouns, as well as some weak nouns, continued to make their genitive forms with -e or no ending (e.g., fole hoves , horses' hooves), and nouns of relationship ending in -er frequently have no genitive ending (e.g., fader bone , "father's bane"). The strong -(e)s plural form has survived into Modern English. The weak -(e)n form
8436-418: The exception of the third person plural, a borrowing from Old Norse (the original Old English form clashed with the third person singular and was eventually dropped). Also, the nominative form of the feminine third person singular was replaced by a form of the demonstrative that developed into sche (modern she ), but the alternative heyr remained in some areas for a long time. As with nouns, there
8550-472: The firm of C S Meik and William Halcrow, now known as the Halcrow Group . The dam was designated a Category B listed building in 1985. It was upgraded to Category A listing in 2011, following a review as part of Hydroelectric Power Thematic Survey 2010. The dam is about 700 feet (210 metres) long, and 48 m (157 ft) high between the level of the foundations and the crest of the spillway. It
8664-561: The first large-scale arch dams. Three pioneering arch dams were built around the British Empire in the early 19th century. Henry Russel of the Royal Engineers oversaw the construction of the Mir Alam dam in 1804 to supply water to the city of Hyderabad (it is still in use today). It had a height of 12 m (39 ft) and consisted of 21 arches of variable span. In the 1820s and 30s, Lieutenant-Colonel John By supervised
8778-742: The first was the Roman-built dam bridge in Dezful , which could raise water 50 cubits (c. 23 m) to supply the town. Also diversion dams were known. Milling dams were introduced which the Muslim engineers called the Pul-i-Bulaiti . The first was built at Shustar on the River Karun , Iran, and many of these were later built in other parts of the Islamic world . Water was conducted from
8892-534: The force of water. A fixed-crest dam is a concrete barrier across a river. Fixed-crest dams are designed to maintain depth in the channel for navigation. They pose risks to boaters who may travel over them, as they are hard to spot from the water and create induced currents that are difficult to escape. There is variability, both worldwide and within individual countries, such as in the United States, in how dams of different sizes are categorized. Dam size influences construction, repair, and removal costs and affects
9006-412: The indicator of the longer and changed pronunciation of ⟨a⟩ . In fact, vowels could have this lengthened and modified pronunciation in various positions, particularly before a single consonant letter and another vowel or before certain pairs of consonants. A related convention involved the doubling of consonant letters to show that the preceding vowel was not to be lengthened. In some cases,
9120-561: The main difference lied on their inflectional endings, which led to much confusion within the mixed population that existed in the Danelaw, this endings tended gradually to become obscured and finally lost, "simplifying English grammar" in the process. In time, the inflections melted away and the analytic pattern emerged. Viking influence on Old English is most apparent in pronouns , modals, comparatives, pronominal adverbs (like hence and together ), conjunctions, and prepositions show
9234-645: The main stream of the Kaveri River in Tamil Nadu , South India . The basic structure dates to the 2nd century AD and is considered one of the oldest water diversion or water regulating structures still in use. The purpose of the dam was to divert the waters of the Kaveri across the fertile delta region for irrigation via canals. Du Jiang Yan is the oldest surviving irrigation system in China that included
9348-417: The masculine accusative, genitive, and dative, the feminine dative, and the plural genitive. The Owl and the Nightingale adds a final -e to all adjectives not in the nominative, here only inflecting adjectives in the weak declension (as described above). Comparatives and superlatives were usually formed by adding -er and -est . Adjectives with long vowels sometimes shortened these vowels in
9462-427: The more complex system of inflection in Old English : Nouns of the weak declension are primarily inherited from Old English n -stem nouns but also from ō -stem, wō -stem, and u -stem nouns, which did not inflect in the same way as n -stem nouns in Old English, but joined the weak declension in Middle English. Nouns of the strong declension are inherited from the other Old English noun stem classes. Some nouns of
9576-490: The most marked Danish influence. The best evidence of Scandinavian influence appears in extensive word borrowings; however, texts from the period in Scandinavia and Northern England do not provide certain evidence of an influence on syntax. However, at least one scholarly study of this influence shows that Old English may have been replaced entirely by Norse, by virtue of the change from Old English to Norse syntax. While
9690-551: The most part, being improvised. By the end of the period (about 1470), and aided by the invention of the printing press by Johannes Gutenberg in 1439, a standard based on the London dialects (Chancery Standard) had become established. This largely formed the basis for Modern English spelling, although pronunciation has changed considerably since that time. Middle English was succeeded in England by Early Modern English , which lasted until about 1650. Scots developed concurrently from
9804-633: The names of many old cities, such as Amsterdam and Rotterdam . Ancient dams were built in Mesopotamia and the Middle East for water control. The earliest known dam is the Jawa Dam in Jordan , dating to 3,000 BC. Egyptians also built dams, such as Sadd-el-Kafara Dam for flood control. In modern-day India, Dholavira had an intricate water-management system with 16 reservoirs and dams. The Great Dam of Marib in Yemen, built between 1750 and 1700 BC,
9918-693: The old insular g and the Carolingian g (modern g ), the former continued in use as a separate letter, known as yogh , written ⟨ȝ⟩ . This was adopted for use to represent a variety of sounds: [ɣ], [j], [dʒ], [x], [ç] , while the Carolingian g was normally used for [g]. Instances of yogh were eventually replaced by ⟨j⟩ or ⟨y⟩ and by ⟨gh⟩ in words like night and laugh . In Middle Scots , yogh became indistinguishable from cursive z , and printers tended to use ⟨z⟩ when yogh
10032-683: The other basic dam designs which had been unknown until then. These include arch-gravity dams , arch dams , buttress dams and multiple arch buttress dams , all of which were known and employed by the 2nd century AD (see List of Roman dams ). Roman workforces also were the first to build dam bridges, such as the Bridge of Valerian in Iran. In Iran , bridge dams such as the Band-e Kaisar were used to provide hydropower through water wheels , which often powered water-raising mechanisms. One of
10146-423: The other case endings disappeared in the Early Middle English period, including most of the roughly one dozen forms of the definite article ("the"). The dual personal pronouns (denoting exactly two) also disappeared from English during this period. The loss of case endings was part of a general trend from inflections to fixed word order that also occurred in other Germanic languages (though more slowly and to
10260-429: The other way about its toe. The designer ensures that the dam is heavy enough that the dam's weight wins that contest. In engineering terms, that is true whenever the resultant of the forces of gravity acting on the dam and water pressure on the dam acts in a line that passes upstream of the toe of the dam. The designer tries to shape the dam so if one were to consider the part of the dam above any particular height to be
10374-403: The prestige that came with writing in French rather than English. During the 14th century, a new style of literature emerged with the works of writers including John Wycliffe and Geoffrey Chaucer , whose Canterbury Tales remains the most studied and read work of the period. The transition from Late Old English to Early Middle English had taken place by the 1150s to 1180s, the period when
10488-607: The principles behind dam design. In France, J. Augustin Tortene de Sazilly explained the mechanics of vertically faced masonry gravity dams, and Zola's dam was the first to be built on the basis of these principles. The era of large dams was initiated with the construction of the Aswan Low Dam in Egypt in 1902, a gravity masonry buttress dam on the Nile River . Following their 1882 invasion and occupation of Egypt ,
10602-569: The resulting doublet pairs include warden (from Norman) and guardian (from later French; both share a common ancestor loaned from Germanic). The end of Anglo-Saxon rule did not result in immediate changes to the language. The general population would have spoken the same dialects as they had before the Conquest. Once the writing of Old English came to an end, Middle English had no standard language, only dialects that evolved individually from Old English. Early Middle English (1150–1350) has
10716-807: The second half of the 14th century in the emerging London dialect, although he also portrays some of his characters as speaking in northern dialects, as in " The Reeve's Tale ". In the English-speaking areas of lowland Scotland , an independent standard was developing, based on the Northumbrian dialect . This would develop into what came to be known as the Scots language . A large number of terms for abstract concepts were adopted directly from scholastic philosophical Latin (rather than via French). Examples are "absolute", "act", "demonstration", and "probable". The Chancery Standard of written English emerged c. 1430 in official documents that, since
10830-458: The second person singular in -(e)st (e.g., þou spekest , "thou speakest"), and the third person singular in -eþ (e.g., he comeþ , "he cometh/he comes"). ( þ (the letter "thorn") is pronounced like the unvoiced th in "think", but under certain circumstances, it may be like the voiced th in "that"). The following table illustrates a typical conjugation pattern: Plural forms vary strongly by dialect, with Southern dialects preserving
10944-493: The spillway, there are six self-priming siphons embedded into the centre of the dam, controlled automatically by system of air valves. The siphons are set to operate in pairs, priming at 820.5, 821.0, and 821.25 feet OD (250.1, 250.2, 250.3 m OD), and discharge through 4′2″ (1.3 m) diameter Glenfield-Kennedy jet disperser pipes. Laggan Dam was the first large siphon spillway used in the UK. The foundations are built on granite , and
11058-487: The state of New Mexico defines a jurisdictional dam as 25 feet or greater in height and storing more than 15 acre-feet or a dam that stores 50 acre-feet or greater and is six feet or more in height (section 72-5-32 NMSA), suggesting that dams that do not meet these requirements are non-jurisdictional. Most US dams, 2.41 million of a total of 2.5 million dams, are not under the jurisdiction of any public agency (i.e., they are non-jurisdictional), nor are they listed on
11172-409: The strong type have an -e in the nominative/accusative singular, like the weak declension, but otherwise strong endings. Often, these are the same nouns that had an -e in the nominative/accusative singular of Old English (they, in turn, were inherited from Proto-Germanic ja -stem and i -stem nouns). The distinct dative case was lost in early Middle English, and although the genitive survived, by
11286-440: The top levels of the English-speaking political and ecclesiastical hierarchies by Norman rulers who spoke a dialect of Old French , now known as Old Norman , which developed in England into Anglo-Norman . The use of Norman as the preferred language of literature and polite discourse fundamentally altered the role of Old English in education and administration, even though many Normans of this period were illiterate and depended on
11400-406: The water level and to prevent the sea from entering the marshlands. Such dams often marked the beginning of a town or city because it was easy to cross the river at such a place, and often influenced Dutch place names. The present Dutch capital, Amsterdam (old name Amstelredam ), started with a dam on the river Amstel in the late 12th century, and Rotterdam began with a dam on the river Rotte ,
11514-642: The water load, and are often used to control and stabilize water flow for irrigation systems. An example of this type of dam is the now-decommissioned Red Bluff Diversion Dam on the Sacramento River near Red Bluff, California . Barrages that are built at the mouths of rivers or lagoons to prevent tidal incursions or use the tidal flow for tidal power are known as tidal barrages . Embankment dams are made of compacted earth, and are of two main types: rock-fill and earth-fill. Like concrete gravity dams, embankment dams rely on their weight to hold back
11628-581: The world is the 305 m-high (1,001 ft) Jinping-I Dam in China . As with large dams, small dams have multiple uses, such as, but not limited to, hydropower production, flood protection, and water storage. Small dams can be particularly useful on farms to capture runoff for later use, for example, during the dry season. Small scale dams have the potential to generate benefits without displacing people as well, and small, decentralised hydroelectric dams can aid rural development in developing countries. In
11742-548: Was 102 m (335 ft) long at its base and 87 m (285 ft) wide. The structure was built around 2800 or 2600 BC as a diversion dam for flood control, but was destroyed by heavy rain during construction or shortly afterwards. During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III , and Amenemhat IV dug a canal 16 km (9.9 mi) long linking
11856-715: Was an engineering wonder, and Eflatun Pinar, a Hittite dam and spring temple in Turkey, dates to the 15th and 13th centuries BC. The Kallanai Dam in South India, built in the 2nd century AD, is one of the oldest water regulating structures still in use. Roman engineers built dams with advanced techniques and materials, such as hydraulic mortar and Roman concrete, which allowed for larger structures. They introduced reservoir dams, arch-gravity dams, arch dams, buttress dams, and multiple arch buttress dams. In Iran, bridge dams were used for hydropower and water-raising mechanisms. During
11970-560: Was built. The system included 16 reservoirs, dams and various channels for collecting water and storing it. One of the engineering wonders of the ancient world was the Great Dam of Marib in Yemen . Initiated sometime between 1750 and 1700 BC, it was made of packed earth – triangular in cross-section, 580 m (1,900 ft) in length and originally 4 m (13 ft) high – running between two groups of rocks on either side, to which it
12084-425: Was indicated by agreement of articles and pronouns (e.g., þo ule "the feminine owl") or using the pronoun he to refer to masculine nouns such as helm ("helmet"), or phrases such as scaft stærcne (strong shaft), with the masculine accusative adjective ending -ne . Single-syllable adjectives added -e when modifying a noun in the plural and when used after the definite article ( þe ), after
12198-488: Was linked by substantial stonework. Repairs were carried out during various periods, most importantly around 750 BC, and 250 years later the dam height was increased to 7 m (23 ft). After the end of the Kingdom of Saba , the dam fell under the control of the Ḥimyarites (c. 115 BC) who undertook further improvements, creating a structure 14 m (46 ft) high, with five spillways, two masonry-reinforced sluices,
12312-520: Was not yet a distinct j , v , or w , and Old English scribes did not generally use k , q , or z . Ash was no longer required in Middle English, as the Old English vowel /æ/ that it represented had merged into /a/ . The symbol nonetheless came to be used as a ligature for the digraph ⟨ae⟩ in many words of Greek or Latin origin, as did ⟨œ⟩ for ⟨oe⟩ . Eth and thorn both represented /θ/ or its allophone / ð / in Old English. Eth fell out of use during
12426-417: Was ousted by it in most dialects by the 15th. The following table shows some of the various Middle English pronouns. Many other variations are noted in Middle English sources because of differences in spellings and pronunciations at different times and in different dialects. As a general rule, the indicative first person singular of verbs in the present tense ended in -e (e.g., ich here , "I hear"),
12540-404: Was possibly the world's first concrete arch dam. Designed by Henry Charles Stanley in 1880 with an overflow spillway and a special water outlet, it was eventually heightened to 10 m (33 ft). In the latter half of the nineteenth century, significant advances in the scientific theory of masonry dam design were made. This transformed dam design from an art based on empirical methodology to
12654-475: Was some inflectional simplification (the distinct Old English dual forms were lost), but pronouns, unlike nouns, retained distinct nominative and accusative forms. Third person pronouns also retained a distinction between accusative and dative forms, but that was gradually lost: The masculine hine was replaced by him south of the River Thames by the early 14th century, and the neuter dative him
12768-593: Was spoken as being from 1150 to 1500. This stage of the development of the English language roughly coincided with the High and Late Middle Ages . Middle English saw significant changes to its vocabulary, grammar, pronunciation, and orthography . Writing conventions during the Middle English period varied widely. Examples of writing from this period that have survived show extensive regional variation. The more standardized Old English literary variety broke down and writing in English became fragmented and localized and was, for
12882-461: Was the first French arch dam of the industrial era , and it was built by François Zola in the municipality of Aix-en-Provence to improve the supply of water after the 1832 cholera outbreak devastated the area. After royal approval was granted in 1844, the dam was constructed over the following decade. Its construction was carried out on the basis of the mathematical results of scientific stress analysis. The 75-miles dam near Warwick , Australia,
12996-682: Was the largest masonry dam in the world. The Hoover Dam is a massive concrete arch-gravity dam , constructed in the Black Canyon of the Colorado River , on the border between the US states of Arizona and Nevada between 1931 and 1936 during the Great Depression . In 1928, Congress authorized the project to build a dam that would control floods, provide irrigation water and produce hydroelectric power . The winning bid to build
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