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72-417: The monumental fountain was designed by Frà Bevignate da Cingoli and built between 1275 and 1277 to celebrate the arrival of water in the acropolis of the city, by means of the new aqueduct . Bevignate cooperated with other talented professionals, as Boninsegna Veneziano , a hydraulic engineer, who accomplished an incredible audacious endeavour, being able to carry the water coming from monte Pacciano, located

144-424: A lake , bay or ocean but joins another river (a parent river). Sometimes also called a branch or fork. A distributary , or a distributary channel , is a stream that branches off and flows away from a main stream channel, and the phenomenon is known as river bifurcation . Distributaries are common features of river deltas , and are often found where a valleyed stream enters wide flatlands or approaches

216-403: A bed armor layer, and other depositional features, plus well defined banks due to bank erosion, are good identifiers when assessing for perennial streams. Particle size will help identify a perennial stream. Perennial streams cut through the soil profile, which removes fine and small particles. By assessing areas for relatively coarse material left behind in the stream bed and finer sediments along

288-564: A bridge carrying an artificial watercourse . Aqueducts were used in ancient Greece , the ancient Near East , ancient Rome , ancient Aztec , and ancient Inca . The simplest aqueducts are small ditches cut into the earth. Much larger channels may be used in modern aqueducts. Aqueducts sometimes run for some or all of their path through tunnels constructed underground. Modern aqueducts may also use pipelines. Historically, agricultural societies have constructed aqueducts to irrigate crops and supply large cities with drinking water. The word aqueduct

360-625: A construction material widely used by the Nazca culture. The time period in which they were constructed is still debated, but some evidence supports circa A.D. 540–552, in response to drought periods in the region. The Guayabo National Monument of Costa Rica, a park covering the largest archaeological site in the country, contains a system of aqueducts. The complex network of uncovered and covered aqueducts still functions well. The aqueducts are constructed from rounded river stones, which are mostly made of volcanic rock . The civilization that constructed

432-658: A continuous aquatic habitat until they reach maturity. Crayfish and other crustaceans , snails , bivalves (clams), and aquatic worms also indicate the stream is perennial. These require a persistent aquatic environment for survival. Fish and amphibians are secondary indicators in assessment of a perennial stream because some fish and amphibians can inhabit areas without persistent water regime. When assessing for fish, all available habitat should be assessed: pools, riffles, root clumps and other obstructions. Fish will seek cover if alerted to human presence, but should be easily observed in perennial streams. Amphibians also indicate

504-470: A continuous or intermittent stream. The same non-perennial channel might change characteristics from intermittent to ephemeral over its course. Washes can fill up quickly during rains, and there may be a sudden torrent of water after a thunderstorm begins upstream, such as during monsoonal conditions. In the United States, an intermittent or seasonal stream is one that only flows for part of

576-422: A drainage network. Although each tributary has its own source, international practice is to take the source farthest from the river mouth as the source of the entire river system, from which the most extended length of the river measured as the starting point is taken as the length of the whole river system, and that furthest starting point is conventionally taken as the source of the whole river system. For example,

648-464: A few kilometres, without the help of pumps. By means of a forced pressure duct, he managed to give to the water the opposite movement, i.e., the water flowed uphill instead of downhill. Another co-worker was the melter Rosso Padellaio , who created the bronze upper part of the fountain. The marble reliefs were placed from 1278, carved by the most important sculptors of the period: Nicola Pisano , in partnership with Giovanni , his son. The fountain

720-545: A fragment remains in Mexico City today. Extensive usage of elaborate aqueducts have been found to have been used in ancient Sri Lanka . The best example is the Yoda Ela or Jaya Ganga, an 87 kilometres (54 mi) long water canal carrying excess water between two artificial reservoirs with a gradient of 10 to 20 cm per kilometer during the fifth century AD. However, the ancient engineering methods in calculating

792-527: A new aqueduct is built alongside the old one because it cannot be shut down during construction. Watercourse A stream is a continuous body of surface water flowing within the bed and banks of a channel . Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long, large streams are usually called rivers , while smaller, less voluminous and more intermittent streams are known as streamlets , brooks or creeks . The flow of

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864-404: A path into mines or other underground chambers. According to official U.S. definitions, the channels of intermittent streams are well-defined, as opposed to ephemeral streams, which may or may not have a defined channel, and rely mainly on storm runoff, as their aquatic bed is above the water table . An ephemeral stream does not have the biological, hydrological, and physical characteristics of

936-412: A perennial stream and include tadpoles , frogs , salamanders , and newts . These amphibians can be found in stream channels, along stream banks, and even under rocks. Frogs and tadpoles usually inhabit shallow and slow moving waters near the sides of stream banks. Frogs will typically jump into water when alerted to human presence. Well defined river beds composed of riffles, pools, runs, gravel bars,

1008-483: A perennial stream, fine sediment may cling to riparian plant stems and tree trunks. Organic debris drift lines or piles may be found within the active overbank area after recent high flow. Streams, headwaters, and streams flowing only part of the year provide many benefits upstream and downstream. They defend against floods, remove contaminants, recycle nutrients that are potentially dangerous as well as provide food and habitat for many forms of fish. Such streams also play

1080-437: A series of well-like vertical shafts, connected by gently sloping horizontal tunnels. There are three types of falaj: These enabled large scale agriculture to flourish in a dry land environment. In Persia , starting around 3000 years ago a system of underground aqueducts called qanāts were constructed, a series of well-like vertical shafts, connected by gently sloping tunnels. This technique: Throughout Petra , Jordan,

1152-406: A slow-moving wetted channel or stagnant area. This is evidence that iron-oxidizing bacteria are present, indicating persistent expression of oxygen-depleted ground water. In a forested area, leaf and needle litter in the stream channel is an additional indicator. Accumulation of leaf litter does not occur in perennial streams since such material is continuously flushed. In the adjacent overbank of

1224-515: A source such as a river, spring, reservoir, qanat , or aqueduct for domestic consumption or agricultural irrigation of crop land uses. Rills were traditionally used in Middle Eastern and Mediterranean climate cultures of ancient and historical eras; and other climates and continents worldwide. They are distinguished from a 'water ditch ' by being lined to reduce absorption losses and to increase durability. The Falaj irrigation system at

1296-486: A stream as intermittent, "showing interruptions in time or space". Generally, streams that flow only during and immediately after precipitation are termed ephemeral . There is no clear demarcation between surface runoff and an ephemeral stream, and some ephemeral streams can be classed as intermittent—flow all but disappearing in the normal course of seasons but ample flow (backups) restoring stream presence — such circumstances are documented when stream beds have opened up

1368-424: A stream is a critical factor in determining its character and is entirely determined by its base level of erosion. The base level of erosion is the point at which the stream either enters the ocean, a lake or pond, or enters a stretch in which it has a much lower gradient, and may be specifically applied to any particular stretch of a stream. In geological terms, the stream will erode down through its bed to achieve

1440-574: A stream is controlled by three inputs – surface runoff (from precipitation or meltwater ), daylighted subterranean water , and surfaced groundwater ( spring water ). The surface and subterranean water are highly variable between periods of rainfall. Groundwater, on the other hand, has a relatively constant input and is controlled more by long-term patterns of precipitation. The stream encompasses surface, subsurface and groundwater fluxes that respond to geological, geomorphological, hydrological and biotic controls. Streams are important as conduits in

1512-524: A thin layer called sheet wash, combined with a network of tiny rills, which together form the sheet runoff; when this water is focused in a channel, a stream is born. Some rivers and streams may begin from lakes or ponds. Freshwater's primary sources are precipitation and mountain snowmelt. However, rivers typically originate in the highlands, and are slowly created by the erosion of mountain snowmelt into lakes or rivers. Rivers usually flow from their source topographically, and erode as they pass until they reach

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1584-642: A third is from the Colorado River. In modern civil engineering projects, detailed study and analysis of open-channel flow is commonly required to support flood control, irrigation systems, and large water supply systems when an aqueduct rather than a pipeline is the preferred solution. In the past, aqueducts often had channels made of earth or other porous materials but significant amounts of water are lost through such unlined aqueducts. As water gets increasingly scarce, these canals are being lined with concrete, polymers , or impermeable soil. In some cases,

1656-627: A vital role in preserving our drinking water quality and supply, ensuring a steady flow of water to surface waters and helping to restore deep aquifers. The extent of land basin drained by a stream is termed its drainage basin (also known in North America as the watershed and, in British English, as a catchment). A basin may also be composed of smaller basins. For instance, the Continental Divide in North America divides

1728-482: A wind rose, where at each cardinal point there are relevant characters; i.e., the representation of Augusta Perusia with the cornucopia on her lap, which draw nourishment from the ears of wheat brought by the lady of Chiusi (once the granary of Perugia) and from the fish offered by Domina Iacus, the nymph of the Lake Trasimeno. Then follows all the characters related to the city. In the opposite cardinal point, to

1800-414: Is a large natural stream that is much wider and deeper than a creek and not easily fordable, and may be a navigable waterway . The linear channel between the parallel ridges or bars on a shoreline beach or river floodplain, or between a bar and the shore. Also called a swale . A tributary is a contributory stream to a larger stream, or a stream which does not reach a static body of water such as

1872-532: Is believed to have some of the earliest aqueducts. Evidence can be found at the sites of present-day Hampi, Karnataka . The massive aqueducts near Tungabhadra River supplying irrigation water were once 15 miles (24 km) long. The waterways supplied water to royal bath tubs. In Oman from the Iron Age , in Salut, Bat, and other sites, a system of underground aqueducts called falaj or qanāts were constructed,

1944-656: Is called a qanat. One historic example found in Syria, the Qanat Firaun, extends over 100 kilometers. Modern aqueducts may also make extensive use of pipelines. Pipelines are useful for transporting water over long distances when it needs to move over hills, or where open channels are poor choices due to considerations of evaporation , freezing, pollution, or environmental impact. They can also be used to carry treated water . Historically, agricultural societies have constructed aqueducts to irrigate crops. Archimedes invented

2016-723: Is derived from the Latin words aqua ( water ) and ductus ( led or guided ). Although particularly associated with the Romans, aqueducts were devised much earlier in Greece, the Near East , Nile Valley , and Indian subcontinent , where peoples such as the Egyptians and Harappans built sophisticated irrigation systems. The Aztecs and Incans also built such systems independently later. Roman-style aqueducts were used as early as

2088-590: Is dwarfed by aqueducts in the far west of the country, most notably the 242-mile (389-km) Colorado River Aqueduct , which supplies the Los Angeles area with water from the Colorado River nearly 250 miles to the east and the 701.5-mile (1,129.0 km) California Aqueduct , which runs from the Sacramento-San Joaquin River Delta to Lake Perris . The Central Arizona Project is the largest and most expensive aqueduct constructed in

2160-441: Is known as surface hydrology and is a core element of environmental geography . A brook is a stream smaller than a creek, especially one that is fed by a spring or seep . It is usually small and easily forded . A brook is characterised by its shallowness. A creek ( / k r iː k / ) or crick ( / k r ɪ k / ): In hydrography, gut is a small creek; this is seen in proper names in eastern North America from

2232-425: Is sometimes termed a "young" or "immature" stream, and the later state a "mature" or "old" stream. Meanders are looping changes of direction of a stream caused by the erosion and deposition of bank materials. These are typically serpentine in form. Typically, over time the meanders gradually migrate downstream. If some resistant material slows or stops the downstream movement of a meander, a stream may erode through

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2304-456: Is usually called a creek and marked on topographic maps with a solid blue line. There are five generic classifications: "Macroinvertebrate" refers to easily seen invertebrates , larger than 0.5 mm, found in stream and river bottoms. Macroinvertebrates are larval stages of most aquatic insects and their presence is a good indicator that the stream is perennial. Larvae of caddisflies , mayflies , stoneflies , and damselflies require

2376-675: The Al Ain Oasis , in present-day Abu Dhabi Emirate , uses rills as part of its qanat water system. Sometimes in the Spanish language they are called Acequias . Rills are also used for aesthetic purposes in landscape design. Rills are used as narrow channels of water inset into the pavement of a garden , as linear water features , and often tiled and part of a fountain design. The historical origins are from paradise garden religious images that first translated into ancient Persian Gardens . Rills were later exceptionally developed in

2448-506: The Bible and the history of Rome ; in this specific order: In the upper basin, 24 statues at the corners, representing saints and mythological and biblical characters from the New and Old Testament. As in the lower basin, there is no contrast between the new Judeo-Cristian civilization and the ancient Greek-Roman civilization, they are harmonized and placed in continuity. The basin can be seen as

2520-954: The Moorish (Spanish) Gardens of Al-andalus , such as at the Alhambra in Granada ; and also in other Islamic gardens, cultures, and countries. Early 20th century examples are in the María Luisa Park gardens in Seville, Spain; and at the Casa del Herrero gardens in Montecito, California . Aqueducts sometimes run for some or all of their path through tunnels constructed underground. A version of this common in North Africa and Central Asia that has vertical wells at regular intervals

2592-590: The Nabataean engineers took advantage of every natural spring and every winter downpour to channel water where it was needed. They constructed aqueducts and piping systems that allowed water to flow across mountains, through gorges and into the temples, homes, and gardens of Petra's citizens. Walking through the Siq , one can easily spot the remains of channels that directed water to the city center, as well as durable retention dams that kept powerful flood waters at bay. On

2664-599: The Poste Italiane (Italian Posts) dedicated to Fontana Maggiore a 40 Lire stamp (ex-Italian currency), for the collection "Fontane d’Italia"(Italian fountains). ⧼Sisterprojects⧽ Aqueduct (water supply) An aqueduct is a watercourse constructed to carry water from a source to a distribution point far away. In modern engineering, the term aqueduct is used for any system of pipes, ditches, canals, tunnels, and other structures used for this purpose. The term aqueduct also often refers specifically to

2736-681: The South–North Water Transfer Project aims to connect the Yangtze River basin to Beijing through three separate systems. The project will reuse part of the Grand Canal of China . The simplest aqueducts are small ditches cut into the earth. Much larger channels may be used in modern aqueducts, for instance the Central Arizona Project uses 7.3 m (24 ft) wide channels. A major factor in

2808-691: The Tombigbee River basin. Continuing in this vein, a component of the Mississippi River basin is the Ohio River basin, which in turn includes the Kentucky River basin, and so forth. Stream crossings are where streams are crossed by roads , pipelines , railways , or any other thing which might restrict the flow of the stream in ordinary or flood conditions. Any structure over or in a stream which results in limitations on

2880-713: The coastal plains around a lake or an ocean . They can also occur inland, on alluvial fans , or where a tributary stream bifurcates as it nears its confluence with a larger stream. Common terms for individual river distributaries in English-speaking countries are arm and channel . There are a number of regional names for a stream. A stream's source depends on the surrounding landscape and its function within larger river networks. While perennial and intermittent streams are typically supplied by smaller upstream waters and groundwater, headwater and ephemeral streams often derive most of their water from precipitation in

2952-428: The velocity of the stream. A perennial stream is one which flows continuously all year. Some perennial streams may only have continuous flow in segments of its stream bed year round during years of normal rainfall. Blue-line streams are perennial streams and are marked on topographic maps with a solid blue line. The word "perennial" from the 1640s, meaning "evergreen," is established in Latin perennis, keeping

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3024-416: The water cycle , instruments in groundwater recharge , and corridors for fish and wildlife migration. The biological habitat in the immediate vicinity of a stream is called a riparian zone . Given the status of the ongoing Holocene extinction , streams play an important corridor role in connecting fragmented habitats and thus in conserving biodiversity . The study of streams and waterways in general

3096-528: The water screw to raise water for use in irrigation of croplands. Another use for aqueducts is to supply large cities with drinking water. They also help drought-prone areas with water supply . Some of the Roman aqueducts still supply water to Rome today. In California , United States, three large aqueducts supply water over hundreds of miles to the Los Angeles area. Two are from the Owens River area, and

3168-420: The 12 months of the year, each of which is related to a zodiac symbol. Each month is connected to scenes of daily life and the characteristic farming work. As in other contemporary sculptures from Europe, in which the months are represented, here the manual work obtains dignity. In this basin manual labour is in fact represented together with the arti liberali (liberal arts), with philosophy, with characters from

3240-622: The 7th century BC, when the Assyrians built an 80 km long limestone aqueduct, which included a 10 m high section to cross a 300 m wide valley, to carry water to their capital city, Nineveh . Although particularly associated with the Romans , aqueducts were likely first used by the Minoans around 2000 BCE. The Minoans had developed what was then an extremely advanced irrigation system , including several aqueducts. The Indian subcontinent

3312-840: The Mid-Atlantic states (for instance, The Gut in Pennsylvania, Ash Gut in Delaware, and other streams) down into the Caribbean (for instance, Guinea Gut , Fish Bay Gut , Cob Gut , Battery Gut and other rivers and streams in the United States Virgin Islands , in Jamaica (Sandy Gut, Bens Gut River, White Gut River), and in many streams and creeks of the Dutch Caribbean ). A river

3384-633: The North, Euliste, the legendary founder of Perugia. To the West, Rome, related to the representation of the Roman Church and of Divinitas Excelsa and of Saints Pietro and Paolo. Another important character to the East is S. Giovanni Battista, for the role of the water as an essential and sacred element; it is associated with Salomè and other biblical characters. The representation of the 24 statues are: In

3456-787: The United States. It stretches 336 miles from its source near Parker, Arizona to the metropolitan areas of Phoenix and Tucson . An aqueduct in New Zealand, "the Oamaru Borough Race", was constructed in the late 19th century to deliver water (and water-power) about 50 km from the Waitaki River at Kurow to the coastal town of Oamaru . In Spain, the Tagus-Segura Water Transfer system of aqueducts opened in 1979 and transports water 286 kilometres (178 mi) from north to south. In China,

3528-604: The aqueduct system remains a mystery to archaeologists; it is suspected that Guayabo's aqueducts sat at a point of ancient cultural confluence between Aztecs, Mayans, and Incas. When Europeans saw the Aztec capital Tenochtitlan , early in the 16th century, the city was watered by two aqueducts. One of these, Chapultepec aqueduct , built c.  1420 , was rebuilt by the Spanish almost three hundred years later. Originally tracing part of its path over now-gone Lake Texcoco , only

3600-533: The atmosphere either by evaporation from soil and water bodies, or by plant evapotranspiration. By infiltration some of the water sinks into the earth and becomes groundwater, much of which eventually enters streams. Most precipitated water is partially bottled up by evaporation or freezing in snow fields and glaciers. The majority of the water flows as a runoff from the ground; the proportion of this varies depending on several factors, such as climate, temperature, vegetation, types of rock, and relief. This runoff begins as

3672-525: The base level of erosion throughout its course. If this base level is low, then the stream will rapidly cut through underlying strata and have a steep gradient, and if the base level is relatively high, then the stream will form a flood plain and meander. Typically, streams are said to have a particular elevation profile , beginning with steep gradients, no flood plain, and little shifting of channels, eventually evolving into streams with low gradients, wide flood plains, and extensive meanders. The initial stage

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3744-597: The base stage of erosion. The scientists have offered a way based on data to define the origin of the lake. A classified sample was the one measured by the Chinese researchers from the University of Chinese Academy of Sciences. As an essential symbol of the river formation environment, the river source needs an objective and straightforward and effective method of judging . A calculation model of river source catchment area based on critical support flow (CSD) proposed, and

3816-493: The design of all open channels is its gradient. A higher gradient allows a smaller channel to carry the same amount of water as a larger channel with a lower gradient, but increases the potential of the water to damage the aqueduct's structure. A typical Roman aqueduct had a gradient of about 1:4800. A constructed functional rill is a small canal or aqueduct of stone, brick, concrete, or other lining material, usually rectilinear in cross section , for water transportation from

3888-524: The empire, and set a standard of engineering that was not surpassed for more than a thousand years. Bridges, built in stone with multiple arches, were a distinctive feature of Roman aqueducts and hence the term aqueduct is often applied specifically to a bridge for carrying water . Near the Peruvian town of Nazca, an ancient pre-Columbian system of aqueducts called puquios were built and are still in use today. They were made of intricately placed stones,

3960-430: The exact elevation between the two reservoirs and the exact gradient of the canal to such fine precision had been lost with the fall of the civilization in 13th Century. Modern aqueducts are a central part of many countries' water distribution infrastructure. The United States' aqueducts are some of the world's largest. The Catskill Aqueduct carries water to New York City over a distance of 120 miles (190 km), but

4032-707: The flow is reduced to a trickle or less. Typically torrents have Apennine rather than Alpine sources, and in the summer they are fed by little precipitation and no melting snow. In this case the maximum discharge will be during the spring and autumn. An intermittent stream can also be called a winterbourne in Britain, a wadi in the Arabic -speaking world or torrente or rambla (this last one from arabic origin) in Spain and Latin America. In Australia, an intermittent stream

4104-447: The form of rain and snow. Most of this precipitated water re-enters the atmosphere by evaporation from soil and water bodies, or by the evapotranspiration of plants. Some of the water proceeds to sink into the earth by infiltration and becomes groundwater, much of which eventually enters streams. Some precipitated water is temporarily locked up in snow fields and glaciers , to be released later by evaporation or melting. The rest of

4176-610: The island of Samos , the Tunnel of Eupalinos was built during the reign of Polycrates (538–522 BC). It is considered an underground aqueduct and brought fresh water to Pythagoreion for roughly a thousand years. Roman aqueducts were built in all parts of the Roman Empire , from Germany to Africa, and especially in the city of Rome, where they totalled over 415 kilometres (258 mi). The aqueducts supplied fresh water to public baths and for drinking water, in large cities across

4248-532: The lake has significant feeder rivers. The Kagera River, which flows into Lake Victoria near Bukoba's Tanzanian town , is the longest feeder, though sources do not agree on which is the Kagera's longest tributary and therefore the Nile's most remote source itself. To qualify as a stream, a body of water must be either recurring or perennial. Recurring (intermittent) streams have water in the channel for at least part of

4320-437: The lower frame of the second basins, Latin verses are carved; epigraphic abbreviation provides information on the authors and the date of the sculpture, and they are an invitation to examine and interpret the fountain: "Guarda tu che passi questa fontana dal lieto mormorio, se osservi bene puoi vedere cose mirabili…." (Look, you who pass by this fountain with its babbling, if you look closer you can see wonderful things.) In 1974,

4392-683: The mainly easterly-draining Atlantic Ocean and Arctic Ocean basins from the largely westerly-flowing Pacific Ocean basin. The Atlantic Ocean basin, however, may be further subdivided into the Atlantic Ocean and Gulf of Mexico drainages. (This delineation is termed the Eastern Continental Divide .) Similarly, the Gulf of Mexico basin may be divided into the Mississippi River basin and several smaller basins, such as

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4464-412: The meaning as "everlasting all year round," per "over" plus annus "year." This has been proved since the 1670s by the "living years" in the sense of botany. The metaphorical sense of "enduring, eternal" originates from 1750. They are related to "perennial." See biennial for shifts in vowels. Perennial streams have one or more of these characteristics: Absence of such characteristics supports classifying

4536-453: The neck between two legs of a meander to become temporarily straighter, leaving behind an arc-shaped body of water termed an oxbow lake or bayou . A flood may also cause a meander to be cut through in this way. The stream load is defined as the solid matter carried by a stream. Streams can carry sediment, or alluvium. The amount of load it can carry (capacity) as well as the largest object it can carry (competence) are both dependent on

4608-596: The origin of the Nile River is the confluence of the White Nile and the Blue Nile, but the source of the whole river system is in its upper reaches. If there is no specific designation, "length of the Nile" refers to the "river length of the Nile system", rather than to the length of the Nile river from the point where it is formed by a confluence of tributaries. The Nile's source is often cited as Lake Victoria, but

4680-469: The relationship between CSA and CSD with a minimum catchment area established. Using the model for comparison in two basins in Tibet (Helongqu and Niyang River White Water), the results show that the critical support flow (Qc) of the housing dragon song is 0.0028 m /s. At the same time, the white water curvature is 0.0085 m /s. Besides, the critical support flow can vary with hydrologic climate conditions, and

4752-425: The side of the stream or within the floodplain will be a good indicator of persistent water regime. A perennial stream can be identified 48 hours after a storm. Direct storm runoff usually has ceased at this point. If a stream is still flowing and contributing inflow is not observed above the channel, the observed water is likely baseflow. Another perennial stream indication is an abundance of red rust material in

4824-655: The vital support flow Qc in wet areas (white water) is larger than in semi-arid regions (heap slot). The proposed critical support flow (CSD) concept and model method can be used to determine the hydrographic indicators of river sources in complex geographical areas, and it can also reflect the impact of hydrologic climate change on river recharge in different regions. The source of a river or stream (its point of origin) can consist of lakes, swamps, springs, or glaciers. A typical river has several tributaries; each of these may be made up of several other smaller tributaries, so that together this stream and all its tributaries are called

4896-512: The water flows off the land as runoff, the proportion of which varies according to many factors, such as wind, humidity, vegetation, rock types, and relief. This runoff starts as a thin film called sheet wash, combined with a network of tiny rills, together constituting sheet runoff; when this water is concentrated in a channel, a stream has its birth. Some creeks may start from ponds or lakes. The streams typically derive most of their water from rain and snow precipitation. Most of this water re-enters

4968-521: The year and is marked on topographic maps with a line of blue dashes and dots. A wash , desert wash, or arroyo is normally a dry streambed in the deserts of the American Southwest , which flows after sufficient rainfall. In Italy, an intermittent stream is termed a torrent ( Italian : torrente ). In full flood the stream may or may not be "torrential" in the dramatic sense of the word, but there will be one or more seasons in which

5040-402: The year. A stream of the first order is a stream which does not have any other recurring or perennial stream feeding into it. When two first-order streams come together, they form a second-order stream. When two second-order streams come together, they form a third-order stream. Streams of lower order joining a higher order stream do not change the order of the higher stream. The gradient of

5112-464: Was damaged by the earthquake of 1348, with the subsequent random reconstruction of the tile order; it was refurbished the first time in 1948/49 and then again in 1995/99. The fountain inspired Jacopo di Grondalo for the construction of the fountain Sturinalto of Fabriano in 1285. In the early 20th century, the fountain was refurbished by the architect Giuseppe Sacconi .   The fountain

5184-440: Was prepared in a workshop and then assembled in the centre of the square; it was made of stone from Assisi . The fountain consists of two concentric polygonal marble basins, on top a bronze cup (by the artisan Rosso Padellaio from Perugia) decorated with a coloured bronze group of feminine figures (perhaps nymphs) out of which comes the water.   The lower basin is made up of 25 mirrors, each divided into 2 tiles that describe

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