1.
Water
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Water is a transparent and nearly colorless chemical substance that is the main constituent of Earths streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen, Water strictly refers to the liquid state of that substance, that prevails at standard ambient temperature and pressure, but it often refers also to its solid state or its gaseous state. It also occurs in nature as snow, glaciers, ice packs and icebergs, clouds, fog, dew, aquifers, Water covers 71% of the Earths surface. It is vital for all forms of life. Only 2. 5% of this water is freshwater, and 98. 8% of that water is in ice and groundwater. Less than 0. 3% of all freshwater is in rivers, lakes, and the atmosphere, a greater quantity of water is found in the earths interior. Water on Earth moves continually through the cycle of evaporation and transpiration, condensation, precipitation. Evaporation and transpiration contribute to the precipitation over land, large amounts of water are also chemically combined or adsorbed in hydrated minerals. Safe drinking water is essential to humans and other even though it provides no calories or organic nutrients. There is a correlation between access to safe water and gross domestic product per capita. However, some observers have estimated that by 2025 more than half of the population will be facing water-based vulnerability. A report, issued in November 2009, suggests that by 2030, in developing regions of the world. Water plays an important role in the world economy, approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a source of food for many parts of the world. Much of long-distance trade of commodities and manufactured products is transported by boats through seas, rivers, lakes, large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a variety of chemical substances, as such it is widely used in industrial processes. Water is also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, Water is a liquid at the temperatures and pressures that are most adequate for life. Specifically, at atmospheric pressure of 1 bar, water is a liquid between the temperatures of 273.15 K and 373.15 K
2.
Sediment transport
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Sediment transport is the movement of solid particles, typically due to a combination of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained. Sediment transport due to fluid motion occurs in rivers, oceans, lakes, seas, Transport is also caused by glaciers as they flow, and on terrestrial surfaces under the influence of wind. Sediment transport due only to gravity can occur on sloping surfaces in general, including hillslopes, scarps, cliffs, sediment transport is important in the fields of sedimentary geology, geomorphology, civil engineering and environmental engineering. Aeolian or eolian is the term for sediment transport by wind and this process results in the formation of ripples and sand dunes. Typically, the size of the sediment is fine sand and smaller, because air is a fluid with low density and viscosity. Bedforms are generated by aeolian sediment transport in the terrestrial near-surface environment, ripples and dunes form as a natural self-organizing response to sediment transport. Aeolian sediment transport is common on beaches and in the regions of the world, because it is in these environments that vegetation does not prevent the presence. Wind-blown very fine-grained dust is capable of entering the upper atmosphere, dust from the Sahara deposits on the Canary Islands and islands in the Caribbean, and dust from the Gobi desert has deposited on the western United States. This sediment is important to the budget and ecology of several islands. Deposits of fine-grained wind-blown glacial sediment are called loess, in geology, physical geography, and sediment transport, fluvial processes relate to flowing water in natural systems. This encompasses rivers, streams, periglacial flows, flash floods, sediment moved by water can be larger than sediment moved by air because water has both a higher density and viscosity. In typical rivers the largest carried sediment is of sand and gravel size, coastal sediment transport takes place in near-shore environments due to the motions of waves and currents. At the mouths of rivers, coastal sediment and fluvial sediment transport processes mesh to create river deltas, coastal sediment transport results in the formation of characteristic coastal landforms such as beaches, barrier islands, and capes. As glaciers move over their beds, they entrain and move material of all sizes, glaciers can carry the largest sediment, and areas of glacial deposition often contain a large number of glacial erratics, many of which are several metres in diameter. Glaciers also pulverize rock into glacial flour, which is so fine that it is carried away by winds to create loess deposits thousands of kilometres afield. Sediment entrained in glaciers often moves approximately along the glacial flowlines, in hillslope sediment transport, a variety of processes move regolith downslope. For this reason, the tops of hills generally have a parabolic concave-up profile, as hillslopes steepen, however, they become more prone to episodic landslides and other mass wasting events. Large masses of material are moved in debris flows, hyperconcentrated mixtures of mud, clasts that range up to boulder-size, debris flows move as granular flows down steep mountain valleys and washes
3.
Sediment
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For sediment in beverages, see dregs. For example, sand and silt can be carried in suspension in water and on reaching the sea be deposited by sedimentation. Sediments are most often transported by water, but also wind, beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of transport and deposition. Glacial moraine deposits and till are ice-transported sediments, sediment can be classified based on its grain size and/or its composition. Sediment size is measured on a log base 2 scale, called the Phi scale, composition of sediment can be measured in terms of, parent rock lithology mineral composition chemical make-up. This leads to an ambiguity in which clay can be used as both a size-range and a composition, sediment is transported based on the strength of the flow that carries it and its own size, volume, density, and shape. Stronger flows will increase the lift and drag on the particle, causing it to rise, rivers and streams carry sediment in their flows. This sediment can be in a variety of locations within the flow and these relationships are shown in the following table for the Rouse number, which is a ratio of sediment fall velocity to upwards velocity. If the upwards velocity is less than the settling velocity, but still high enough for the sediment to move, it will move along the bed as bed load by rolling, sliding. If the upwards velocity is higher than the velocity, the sediment will be transported high in the flow as wash load. As there are generally a range of different particle sizes in the flow, sediment motion can create self-organized structures such as ripples, dunes, antidunes on the river or stream bed. These bedforms are often preserved in rocks and can be used to estimate the direction. Overland flow can erode soil particles and transport them downslope, the erosion associated with overland flow may occur through different methods depending on meteorological and flow conditions. If the initial impact of rain droplets dislodges soil, the phenomenon is called rainsplash erosion, if overland flow is directly responsible for sediment entrainment but does not form gullies, it is called sheet erosion. If the flow and the substrate permit channelization, gullies may form, glaciers carry a wide range of sediment sizes, and deposit it in moraines. The overall balance between sediment in transport and sediment being deposited on the bed is given by the Exner equation and this expression states that the rate of increase in bed elevation due to deposition is proportional to the amount of sediment that falls out of the flow. This can be localized, and simply due to obstacles, examples are scour holes behind boulders, where flow accelerates
4.
Stream gauge
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A stream gauge, streamgage or gauging station is a location used by hydrologists or environmental scientists to monitor and test terrestrial bodies of water. Hydrometric measurements of water surface elevation and/or volumetric discharge are generally taken and observations of biota. The location of gauging stations are found on topographical maps. Some gauging stations are automated and may include telemetry capability transmitted to a central data logging facility. Automated direct measurement of streamflow discharge is difficult at present, in place of the direct measurement of streamflow discharge, one or more surrogate measurements can be used to produce discharge values. In the majority of cases, a measurement is used as the surrogate. Low gradient streams are influenced by variable downstream channel conditions. For these streams, a stream gauge would be installed. This value would be used along with the measurement to more accurately determine the streamflow discharge. These sensors are mounted in the stream and measure velocity at a particular location in the stream. In those instances where only a stage measurement is used as the surrogate, a rating curve is the functional relation between stage and discharge. Once the rating curve is established, it can be used in conjunction with measurements to determine the volumetric streamflow discharge. This record then serves as an assessment of the volume of water passes by the stream gauge and is useful for many tasks associated with hydrology. In those instances where a velocity measurement is used as a surrogate. This analysis uses a velocity sensor, often either magnetic or acoustic, once again, discrete measurements of streamflow discharge are made by the technician or hydrologist at a variety of stages. For each discrete determination of streamflow discharge, the velocity of the cross section is determined by dividing streamflow discharge by the cross-sectional area. A rating curve, similar to that used for stage-discharge determinations, is constructed using the mean velocity, an additional rating curve is constructed that relates stage of the stream to cross-sectional area. The streamflow discharge is computed as the estimate of the cross section area, electromagnetic gauges Discharge measurements of a stream or canal without an established stream gage can be made using a current meter or Acoustic Doppler current profiler
5.
United States Department of Agriculture
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Approximately 80% of USDAs $140 billion budget goes to the Food and Nutrition Service program. The largest component of the FNS budget is the Supplemental Nutrition Assistance Program, after the resignation of Thomas Vilsack on January 13,2017 and the departure of President Barack Obama from office on January 20,2017, the acting Secretary of Agriculture is Michael Young. Activities in this include the Supplemental Nutrition Assistance Program, which provides healthy food to over 40 million low-income. The USDA also is concerned with assisting farmers and food producers with the sale of crops and it plays a role in overseas aid programs by providing surplus foods to developing countries. This aid can go through USAID, foreign governments, international bodies such as World Food Program, the Agricultural Act of 1949, section 416 and Agricultural Trade Development and Assistance Act of 1954, also known as Food for Peace, provides the legal basis of such actions. The USDA is a partner of the World Cocoa Foundation, early in its history, the economy of the United States was largely agrarian. Officials in the government had long sought new and improved varieties of seeds, plants. In 1837 Henry Leavitt Ellsworth, a Yale-educated attorney interested in improving agriculture, became Commissioner of Patents and he began collecting and distributing new varieties of seeds and plants through members of the Congress and agricultural societies. In 1839, Congress established the Agricultural Division within the Patent Office and allotted $1,000 for the collection of agricultural statistics, Ellsworth was called the Father of the Department of Agriculture. In 1849, the Patent Office was transferred to the newly created Department of the Interior, in the ensuing years, agitation for a separate bureau of agriculture within the department or a separate department devoted to agriculture kept recurring. Lincoln called it the peoples department, in the 1880s, varied advocacy groups were lobbying for Cabinet representation. Business interests sought a Department of Commerce and Industry, and farmers tried to raise the Department of Agriculture to Cabinet rank, finally, on February 9,1889, President Grover Cleveland signed a bill into law elevating the Department of Agriculture to Cabinet level. In 1887, the Hatch Act provided for the funding of agricultural experiment stations in each state. The Smith-Lever Act of 1914 then funded cooperative extension services in each state to teach agriculture, home economics, with these and similar provisions, the USDA reached out to every county of every state. During the Great Depression, farming remained a way of life for millions of Americans. The Department of Agricultures Bureau of Home Economics, established in 1923, published shopping advice and recipes to stretch family budgets and make food go farther. USDA helped ensure that continued to be produced and distributed to those who needed it, assisted with loans for small landowners. The Department of Agriculture was authorized a budget for Fiscal Year 2015 of $139.7 billion, the Washington Post reports that he said There are days when I have literally nothing to do, he recalled thinking as he weighed his decision to quit
6.
Hydropower
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Hydropower or water power is power derived from the energy of falling water or fast running water, which may be harnessed for useful purposes. A trompe, which compressed air from falling water, is sometimes used to power other machinery at a distance. In the late 19th century, hydropower became a source for generating electricity, cragside in Northumberland was the first house powered by hydroelectricity in 1878 and the first commercial hydroelectric power plant was built at Niagara Falls in 1879. In 1881, street lamps in the city of Niagara Falls were powered by hydropower, since the early 20th century, the term has been used almost exclusively in conjunction with the modern development of hydroelectric power. In China and the rest of the Far East, hydraulically operated pot wheel pumps raised water into crop or irrigation canals, the power of a wave of water released from a tank was used for extraction of metal ores in a method known as hushing. The method was first used at the Dolaucothi Gold Mines in Wales from 75 AD onwards, hushing was also widely used in Britain in the Medieval and later periods to extract lead and tin ores. It later evolved into hydraulic mining when used during the California Gold Rush and these include an endless belt with jugs attached, a cow-powered shadoof, and a reciprocating device with hinged valves. In 1753, French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical-, the growing demand for the Industrial Revolution would drive development as well. At the beginning of the Industrial Revolution in Britain, water was the source of power for new inventions such as Richard Arkwrights water frame. In the 1830s, at the peak in US canal-building, hydropower provided the energy to transport barge traffic up. Technological advances had moved the water wheel into an enclosed turbine or water motor. Francis, while working as engineer of Lowells Locks and Canals company. He applied scientific principles and testing methods to the problem of turbine design and his mathematical and graphical calculation methods allowed confident design of high efficiency turbines to exactly match a sites specific flow conditions. The Francis reaction turbine is still in use today. Hydraulic power networks used pipes to carrying pressurized water and transmit power from the source to end users. The power source was normally a head of water, which could also be assisted by a pump and these were extensive in Victorian cities in the United Kingdom. A hydraulic power network was developed in Geneva, Switzerland. The world-famous Jet dEau was originally designed as the relief valve for the network
7.
Hydroelectricity
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Hydroelectricity is electricity produced from hydropower. In 2015 hydropower generated 16. 6% of the total electricity and 70% of all renewable electricity. 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 percent of domestic electricity use. The cost of hydroelectricity is relatively low, making it a source of renewable electricity. The hydro station consumes no water, unlike coal or gas plants, the average 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 source of electricity since the amount produced by the station can be changed up or down very quickly to adapt to changing energy demands. Once a hydroelectric complex is constructed, the project produces no direct waste, Hydropower has been used since ancient times to grind flour and perform other tasks. In the mid-1770s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical-, by the late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand for the Industrial Revolution would drive development as well, in 1878 the worlds first hydroelectric power scheme was developed at Cragside in Northumberland, England by William George Armstrong. It was used to power an arc lamp in his art gallery. The old Schoelkopf Power Station No.1 near Niagara Falls in the U. S. side began to produce electricity in 1881. The first Edison hydroelectric power station, the Vulcan Street Plant, began operating September 30,1882, in Appleton, Wisconsin, by 1886 there were 45 hydroelectric power stations in the U. S. and Canada. By 1889 there were 200 in the U. S. alone, at the beginning of the 20th century, many small hydroelectric power stations were being constructed by commercial companies in mountains near metropolitan areas. Grenoble, France held the International Exhibition of Hydropower and Tourism with over one million visitors, by 1920 as 40% of the power produced in the United States was hydroelectric, the Federal Power Act was enacted into law. The Act created the Federal Power Commission to regulate hydroelectric power stations on federal land, as the power stations became larger, their associated dams developed additional purposes to include flood control, irrigation and navigation. Federal funding became necessary for development and federally owned corporations, such as the Tennessee Valley Authority. Hydroelectric power stations continued to become larger throughout the 20th century, Hydropower was referred to as white coal for its power and plenty. Hoover Dams initial 1,345 MW power station was the worlds largest hydroelectric station in 1936
8.
Dam
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A dam is a barrier that impounds water or underground streams. Reservoirs created by not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture. Hydropower is often used in conjunction with dams to generate electricity, a dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the purpose of retaining water, while other structures such as floodgates or levees 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, the first known appearance of dam occurs in 1165. However, there is one village, Obdam, that is mentioned in 1120. The word seems to be related to the Greek word taphos, so the word should be understood as dike from dug out earth. The names of more than 40 places from the Middle Dutch era such as Amsterdam and Rotterdam, early dam building took place in Mesopotamia and the Middle East. Dams were used to control the level, for Mesopotamias weather affected the Tigris. The earliest known dam is the Jawa Dam in Jordan,100 kilometres northeast of the capital Amman and this gravity dam featured an originally 9-metre-high and 1 m-wide stone wall, supported by a 50 m-wide earth rampart. The structure is dated to 3000 BC, the Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km south of Cairo, was 102 m long at its base and 87 m wide. The structure was built around 2800 or 2600 BC as a dam for flood control. During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III, 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 km2 and is today as Berkat Qaroun. One of the wonders of the ancient world was the Great Dam of Marib in Yemen. Repairs were carried out during various periods, most important around 750 BC and these extensive works were not actually finalized until 325 AD and allowed the irrigation of 25,000 acres. By the mid-late 3rd century BC, an intricate water-management system within Dholavira in modern-day India was built, the system included 16 reservoirs, dams and various channels for collecting water and storing it. Eflatun Pınar is a Hittite dam and spring temple near Konya and it is thought to be from the time of the Hittite empire between the 15th and 13th century BC
9.
Francis turbine
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The Francis turbine is a type of water turbine that was developed by James B. Francis in Lowell, Massachusetts. It is a reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today and they operate in a water head from 40 to 600 m and are primarily used for electrical power production. The electric generators that most often use this type of turbine have an output that generally ranges just a few kilowatts up to 800 MW. Penstock diameters are between 3 and 33 ft, the speed range of the turbine is from 75 to 1000 rpm. A wicket gate around the outside of the turbines rotating runner controls the rate of flow through the turbine for different power production rates. Francis turbines are almost always mounted with the vertical to isolate water from the generator. This also facilitates installation and maintenance, water wheels of different types have been used historically for more than 1,000 years to power mills of all types, but they were relatively inefficient. Nineteenth-century efficiency improvements of water turbines allowed them to nearly all water wheel applications. After electric generators were developed in the late 1800s turbines were a source of generator power where potential hydro-power sources existed. In 1826 Benoit Fourneyron developed a high efficiency outward-flow water turbine, water was directed tangentially through the turbine runner, causing it to spin. Jean-Victor Poncelet designed a turbine in about 1820 that used the same principles. Howd obtained a US patent in 1838 for a similar design and he applied scientific principles and testing methods to produce a very efficient turbine design. More importantly, his mathematical and graphical calculation methods improved turbine design and his analytical methods allowed confident design of high efficiency turbines to precisely match a sites water flow and pressure. A Francis turbine consists of the main parts, Spiral casing. Throughout its length, it has openings at regular intervals to allow the working fluid to impinge on the blades of the runner. These openings convert the energy of the fluid into momentum energy just before the fluid impinges on the blades. Guide or stay vanes, The primary function of the guide or stay vanes is to convert the energy of the fluid into the momentum energy
10.
Kaplan turbine
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The Kaplan turbine is a propeller-type water turbine which has adjustable blades. The Kaplan turbine was an evolution of the Francis turbine and its invention allowed efficient power production in low-head applications that was not possible with Francis turbines. The head ranges from 10–70 metres and the output from 5 to 200 MW, runner diameters are between 2 and 11 metres. Turbines rotate at a constant rate, which varies from facility to facility and that rate ranges from as low as 69.2 rpm to 429 rpm. Kaplan turbines are now used throughout world in high-flow, low-head power production. Viktor Kaplan living in Brno, Czech Republic, obtained his first patent for an adjustable blade propeller turbine in 1912, but the development of a commercially successful machine would take another decade. Kaplan struggled with problems, and in 1922 abandoned his research for health reasons. In 1919 Kaplan installed a demonstration unit at Poděbrady, Czechoslovakia, in 1922 Voith introduced an 1100 HP Kaplan turbine for use mainly on rivers. In 1924 an 8 MW unit went on line at Lilla Edet and this marked the commercial success and widespread acceptance of Kaplan turbines. The Kaplan turbine is an outward flow turbine, which means that the working fluid changes pressure as it moves through the turbine. Power is recovered from both the head and from the kinetic energy of the flowing water. The design combines features of radial and axial turbines, the inlet is a scroll-shaped tube that wraps around the turbines wicket gate. Water is directed tangentially through the gate and spirals on to a propeller shaped runner. The outlet is a specially shaped tube that helps decelerate the water and recover kinetic energy. The turbine does not need to be at the lowest point of water flow as long as the tube remains full of water. A higher turbine location, however, increases the suction that is imparted on the blades by the draft tube. The resulting pressure drop may lead to cavitation, variable geometry of the wicket gate and turbine blades allow efficient operation for a range of flow conditions. Kaplan turbine efficiencies are typically over 90%, but may be lower in very low head applications, current areas of research include CFD driven efficiency improvements and new designs that raise survival rates of fish passing through
11.
Water wheel
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A water wheel is a machine for converting the energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface. Most commonly, the wheel is mounted vertically on a horizontal axle, vertical wheels can transmit power either through the axle or via a ring gear and typically drive belts or gears, horizontal wheels usually directly drive their load. Water wheels were still in use well into the 20th century. Uses included milling flour in gristmills, grinding wood into pulp for papermaking, hammering wrought iron, machining, some water wheels are fed by water from a mill pond, which is formed when a flowing stream is dammed. A channel for the water flowing to or from a wheel is called a mill race. The race bringing water from the pond to the water wheel is a headrace. In the mid to late 18th century John Smeatons scientific investigation of the water led to significant increases in efficiency supplying much needed power for the Industrial Revolution. Water wheels began being displaced by the smaller, less expensive and more efficient turbine, developed by Benoît Fourneyron, turbines are capable of handling high heads, or elevations, that exceed the capability of practical-sized waterwheels. The main difficulty of water wheels is their dependence on flowing water, modern hydroelectric dams can be viewed as the descendants of the water wheel, as they too take advantage of the movement of water downhill. The two main functions of water wheels were historically water-lifting for irrigation purposes and as a power source, when used for water-lifting power can be supplied by either human or animal force or by the water current itself. Water wheels come in two designs, either a vertical or a horizontal axle. The latter type can be subdivided, depending on where the hits the wheel. Engineers of the Hellenistic era Mediterranean region are credited with the development of the water wheel, Mediterranean engineers of the Hellenistic and Roman periods were also the first to use it for both irrigation and as a power source. The technological breakthrough occurred in the advanced and scientifically minded Hellenistic period between the 3rd and 1st centuries BCE. This is seen as an evolution of the paddle-driven water-lifting wheels that had appeared in ancient Egypt by the 4th century BCE. According to John Peter Oleson, both the wheel and the hydraulic Noria appeared in Egypt by the 4th century BCE. This is supported by finds at Faiyum, where the oldest archeological evidence of a water-wheel has been found
12.
Rhine
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The largest city on the river Rhine is Cologne, Germany, with a population of more than 1,050,000 people. It is the second-longest river in Central and Western Europe, at about 1,230 km, with an average discharge of about 2,900 m3/s. The Rhine and the Danube formed most of the inland frontier of the Roman Empire and, since those days. The many castles and fortifications along the Rhine testify to its importance as a waterway in the Holy Roman Empire, in the modern era, it has become a symbol of German nationalism. The variant of the name of the Rhine in modern languages are all derived from the Gaulish name Rēnos, spanish is with French in adopting the Germanic vocalism Rin-, while Italian, Occitan and Portuguese retain the Latin Ren-. The Gaulish name Rēnos belongs to a class of river names built from the PIE root *rei- to move, flow, run, the grammatical gender of the Celtic name is masculine, and the name remains masculine in German, Dutch and French. The Old English river name was variously inflected as masculine or feminine, the length of the Rhine is conventionally measured in Rhine-kilometers, a scale introduced in 1939 which runs from the Old Rhine Bridge at Constance to Hoek van Holland. The river length is shortened from the rivers natural course due to a number of canalisation projects completed in the 19th and 20th century. The total length of the Rhine, to the inclusion of Lake Constance and its course is conventionally divided as follows, The Rhine carries its name without distinctive accessories only from the confluence of the Vorderrhein and Hinterrhein near Tamins-Reichenau. Above this point is the catchment of the headwaters of the Rhine. It belongs almost exclusively to the Swiss Canton of Graubünden, ranging from Gotthard Massif in the west via one valley lying in Ticino, traditionally, Lake Toma near the Oberalp Pass in the Gotthard region is seen as the source of the Vorderrhein and the Rhine as a whole. The Hinterrhein rises in the Rheinwald valley below Mount Rheinwaldhorn, the Vorderrhein, or Anterior Rhine, springs from Lai da Tuma, near the Oberalp Pass and passes the impressive Ruinaulta formed by the largest visible rock slide in the alps, the Flims Rockslide. A multiday trekking route is signposted along the young Rhine called Senda Sursilvana, the Hinterrhein/Rein Posteriur, or Posterior Rhine, starts from the Paradies Glacier, near the Rheinwaldhorn. One of its tributaries, the Reno di Lei, drains the Valle di Lei on politically Italian territory, after three main valleys separated by the two gorges, Roflaschlucht and Viamala, it reaches Reichenau. The Vorderrhein arises from numerous source streams in the upper Surselva, one source is Lai da Tuma with the Rein da Tuma, which is usually indicated as source of the Rhine, flowing through it. Into it flow tributaries from the south, some longer, some equal in length, such as the Reno di Medel, the Rein da Maighels, and the Rein da Curnera. The Cadlimo Valley in the Canton of Ticino is drained by the Reno di Medel, all streams in the source area are partially, sometimes completely, captured and sent to storage reservoirs for the local hydro-electric power plants. In its lower course the Vorderrhein flows through a gorge named Ruinaulta through the Flims Rockslide, the whole stretch of the Vorderrhein to the Rhine confluence near Reichenau-Tamins is accompanied by a long-distance hiking trail called Senda Sursilvana
