Surface runoff is the flow of water that occurs when excess stormwater, meltwater, or other sources flows over the Earth's surface. This might occur because soil is saturated to full capacity, because rain arrives more than soil can absorb it, or because impervious areas send their runoff to surrounding soil that cannot absorb all of it. Surface runoff is a major component of the water cycle, it is the primary agent in soil erosion by water. Runoff that occurs on the ground surface before reaching a channel is called a nonpoint source. If a nonpoint source contains man-made contaminants, or natural forms of pollution the runoff is called nonpoint source pollution. A land area which produces runoff that drains to a common point is called a drainage basin; when runoff flows along the ground, it can pick up soil contaminants including petroleum, pesticides, or fertilizers that become discharge or nonpoint source pollution. In addition to causing water erosion and pollution, surface runoff in urban areas is a primary cause of urban flooding which can result in property damage and mold in basements, street flooding.
Surface runoff glaciers. Snow and glacier melt occur only in areas cold enough for these to form permanently. Snowmelt will peak in the spring and glacier melt in the summer, leading to pronounced flow maxima in rivers affected by them; the determining factor of the rate of melting of snow or glaciers is both air temperature and the duration of sunlight. In high mountain regions, streams rise on sunny days and fall on cloudy ones for this reason. In areas where there is no snow, runoff will come from rainfall. However, not all rainfall will produce runoff. On the ancient soils of Australia and Southern Africa, proteoid roots with their dense networks of root hairs can absorb so much rainwater as to prevent runoff when substantial amounts of rain fall. In these regions on less infertile cracking clay soils, high amounts of rainfall and potential evaporation are needed to generate any surface runoff, leading to specialised adaptations to variable streams; this occurs when the rate of rainfall on a surface exceeds the rate at which water can infiltrate the ground, any depression storage has been filled.
This is called flooding Hortonian overland flow, or unsaturated overland flow. This more occurs in arid and semi-arid regions, where rainfall intensities are high and the soil infiltration capacity is reduced because of surface sealing, or in paved areas; this occurs in city areas where pavements prevent water from flooding. When the soil is saturated and the depression storage filled, rain continues to fall, the rainfall will produce surface runoff; the level of antecedent soil moisture is one factor affecting the time. This runoff is called saturated overland flow or Dunne runoff. Soil retains a degree of moisture after a rainfall; this residual water moisture affects the soil's infiltration capacity. During the next rainfall event, the infiltration capacity will cause the soil to be saturated at a different rate; the higher the level of antecedent soil moisture, the more the soil becomes saturated. Once the soil is saturated, runoff occurs. After water infiltrates the soil on an up-slope portion of a hill, the water may flow laterally through the soil, exfiltrate closer to a channel.
This is called throughflow. As it flows, the amount of runoff may be reduced in a number of possible ways: a small portion of it may evapotranspire. Any remaining surface water flows into a receiving water body such as a river, estuary or ocean. Urbanization increases surface runoff by creating more impervious surfaces such as pavement and buildings that do not allow percolation of the water down through the soil to the aquifer, it is instead forced directly into streams or storm water runoff drains, where erosion and siltation can be major problems when flooding is not. Increased runoff reduces groundwater recharge, thus lowering the water table and making droughts worse for agricultural farmers and others who depend on the water wells; when anthropogenic contaminants are dissolved or suspended in runoff, the human impact is expanded to create water pollution. This pollutant load can reach various receiving waters such as streams, lakes and oceans with resultant water chemistry changes to these water systems and their related ecosystems.
A 2008 report by the United States National Research Council identified urban stormwater as a leading source of water quality problems in the U. S; as humans continue to alter the climate through the addition of greenhouse gases to the atmosphere, precipitation patterns are expected to change as the atmospheric capacity for water vapor increases. This will have direct consequences on runoff amounts. Surface runoff can cause erosion of the Earth's surface. There are four main types of soil erosion by water: splash erosion, sheet erosion, rill erosion and gully erosion. Splash erosion is the result of mechanical collision of raindrops with the soil surface: soil particles which are dislodged by the impact move with the surface runoff. Sheet erosion is the overland transport of sediment by runoff without a well d
The Meskwaki are a Native American people known by Western society as the Fox tribe. They have been linked to the Sauk people of the same language family. In the Meskwaki language, the Meskwaki call themselves Meshkwahkihaki, which means "the Red-Earths", related to their creation story, their homelands were in the Great Lakes region. The tribe coalesced in the St. Lawrence River Valley in Canada. Under French colonial pressures, it migrated to the southern side of the Great Lakes to territory that much was organized by European Americans as the states of Michigan, Wisconsin and Iowa; the Meskwaki suffered damaging wars with French and their Native American allies in the early 18th century, with one in 1730 decimating the tribe. In the 19th century, Euro-American colonization and settlement proceeded by the United States, they forced the Meskwaki/Fox west into the tall grass prairie in the American Midwest. In 1851 the Iowa state legislature passed an unusual act to allow the Fox to buy land and stay in the state.
Other Sac and Fox were removed to Indian territory in what became Kansas and Nebraska. In the 21st century, two federally recognized tribes of "Sac and Fox" have reservations, one has a settlement; the name is derived from the Meskwaki creation myth, in which their culture hero, created the first humans out of red clay. They called themselves Meshkwahkihaki in Meskwaki, meaning "the Red-Earths"; the name Fox was derived from a French mistake during the colonial era: hearing a group of Indians identify as "Fox", the French applied what was a clan name to the entire tribe who spoke the same language, calling them "les Renards." The English and Anglo-Americans adopted the French name, using its translation in English as "Fox." This name was used by the United States government from the 19th century. The Meskwaki used Triodanis perfoliata as an emetic in tribal ceremonies to make one "sick all day long." They traditionally smoked it at purification and other spiritual rituals. They smudge Symphyotrichum novae-angliae and use it to revive unconscious people, They used Agastache scrophulariifolia, an infusion of the root being used as a diuretic, used a compound of the plant heads medicinally.
They eat the fruits of Viburnum prunifolium raw, cook them into a jam. They make the flowers of Solidago rigida into a lotion and use them on bee stings and for swollen faces. Meskwaki are of Algonquian origin from the prehistoric Woodland period culture area; the Meskwaki language is a dialect of the language spoken by the Sauk and Kickapoo, within the Algonquian languages family. This broad group includes many tribes around the Great Lakes; the Meskwaki and Sauk peoples are two distinct tribal groups. Linguistic and cultural connections between the two tribes have made them associated in history. Under US government recognition treaties, officials treat the Sac and Meskwaki as a single political unit, despite their distinct identities; the Meskwaki lived along the Saint Lawrence River in present-day Ontario, northeast of Lake Ontario. The tribe may have numbered as many as 10,000, but years of war with the Huron, whom French colonial agents supplied with arms, exposure to new European infectious diseases reduced their numbers.
In response to these pressures, the Meskwaki migrated west, first to present-day eastern Michigan in the area between Saginaw Bay and Detroit west of Lake Huron. They moved further west into what is now Wisconsin; the Meskwaki gained control of the Fox River system in central Wisconsin. This river became vital for the colonial New France fur trade through the interior of North America between northern French Canada, via the Mississippi River, the French ports on the Gulf of Mexico; as part of the Fox–Wisconsin Waterway, the Fox River allowed travel from Lake Michigan and the other Great Lakes via Green Bay to the Mississippi River system. At first European contact in 1698, the French estimated the number of Meskwaki as about 6,500. By 1712, the number of Meskwaki had declined to 3,500; the Meskwaki fought against the French, in what are called the Fox Wars, for more than three decades to preserve their homelands. The Meskwaki resistance to French encroachment was effective; the King of France signed a decree commanding the complete extermination of the Meskwaki, the only edict of its kind in French history.
The First Fox War with the French lasted from 1712-1714. This first Fox War was purely economic in nature, as the French wanted rights to use the river system to gain access to the Mississippi. After the Second Fox War of 1728, the Meskwaki were reduced to some 1500 people, they found shelter with the Sac. In the Second Fox War, the French increased their pressure on the tribe to gain access to the Fox and Wolf rivers. Nine hundred Fox: 300 warriors and the remainder women and children, tried to break out in Illinois to reach the English and Iroquois to the east, but a combined French and hundreds of allied Native American force outnumbered them. On September 9, 1730, most of the Fox warriors were killed; the Sauk and Meskwaki allied in 1735 in defense against their allied Indian tribes. Descendants spread through southern Wisconsin, along the present-day Illinois-Iowa border. In 1829 the US government estimated. Both tribes relocated southward from Wisconsin into Iowa and Missouri. There are accounts of Meskwaki as far sou
The Ho-Chunk known as Hoocąągra or Winnebago, are a Siouan-speaking Native American people whose historic territory includes parts of Wisconsin, Minnesota and Illinois. Today, Ho-Chunk people are enrolled in two federally recognized tribes, the Ho-Chunk Nation of Wisconsin and the Winnebago Tribe of Nebraska; the Winnebago Tribe of Nebraska have an Indian reservation in Nebraska. While related, the two tribes are distinct federally recognized sovereign nations and peoples, each having its own constitutionally formed government, separate governing and business interests. Since the late 20th century, both tribal councils have authorized the development of casinos to generate revenue to support economic development, health care and education; the Ho-Chunk Nation has developed a Hoocąąk-language iOS app. Since 1988, it has pursued a claim to the Badger Army Ammunition Plant as traditional territory; the department supported the Ho-Chunk claim in 1998, but in 2011 refused to accept the property on their behalf.
In 1994, to build on its revenues from casinos, the Winnebago Tribe of Nebraska created an economic development corporation. With a number of subsidiaries, it employs more than 1400 people, it has contributed to housing construction on the reservation. Like more than 60% of federally recognized tribes, the Winnebago Tribe has legalized alcohol sales on the reservation to secure revenues that went to the state in retail taxes; the Ho-Chunk was the dominant tribe in its territory in the 16th century, with a population estimated at several thousand. Their traditions hold. Ethnologists have speculated that, like some other Siouan peoples, the Ho-Chunk originated along the East Coast and migrated west in ancient times. Nicolas Perrot wrote that the names given to them by neighboring Algonquian peoples may have referred to their origin near a salt water sea; the Ho-Chunk suffered severe population losses in the 17th century, to a low of as few as 500 individuals. This has been attributed to the loss of hundreds of warriors in a lake storm, epidemics of infectious disease, competition for resources from migrating Algonquian tribes.
By the early 1800s, their population had increased to 2,900, but they suffered further losses in the smallpox epidemic of 1836. In 1990 they numbered 7,000; the Ho-Chunk are a matrilineal indigenous tribe who speak a Siouan language, which they believe to be given to them by their creator, Waxopini Xete. The Hoocąągra were called various names by other tribes inspired by their fierceness in battle. At one point, they were called "Stinkards" due to living by water sources with large algae blooms, including Green Bay and Lake Winnebago; the term "Winnebago" is a term used by the Potawatomi, pronounced as "Winnipego." Their native name is Ho-Chąąnk, meaning "sacred voice". They refer to themselves as Hoocąąk-waazija-haa-chi meaning "sacred voice people of the Pines"; the Jesuit Relations of 1659-1660 said: He started, in the month of June of the year one thousand six hundred and fifty-eight, from the lake of the Ouinipegouek, only a large bay in lake Huron. It is called by others, the lake of the stinkards, not because it is salt like the water of the Sea -- which the Savages call Ouinipeg, or stinking water -- but because it is surrounded by sulphurous soil, whence issue several springs which convey into this lake the impurities absorbed by their waters in the places of their origin.
Nicolas Perrot was a 17th century French trader who believed that the Algonquian terms referred to salt-water seas, as these have a distinctive aroma compared with fresh-water lakes. An early Jesuit record says that the name refers to the origin of Le Puans near the salt water seas to the north. Algonquins called the Winnebago, "the people of the sea." When the explorers Jean Nicolet and Samuel de Champlain learned of the "sea" connection to the tribe's name, they were optimistic that it meant Les puans were from or had lived near the Pacific Ocean. They hoped. In recent studies, ethnologists have concluded that the Hoocąągra, like the other Siouan-speaking peoples, originated on the east coast of North America and migrated west. Several Hoocąąk elders have claimed that they originated in the Midwest and that they predated the last ice age; the early 20th-century researcher H. R. Holand claimed they originated in Mexico, where they had contact with the Spanish and gained a knowledge of horses.
David Lee contends. His evidence derived from a culture based on corn growing, civilization type, mound building; this followed the receding ice shield. However, Holand cites the records of Jonathan Carver, who lived with the Hoocąągra in 1766–1768. But, contact with the Spanish could have occurred along the Gulf of Mexico or the south Atlantic coast, where other Hoocąąk type tribes originated and lived for centuries. Others suggested that the Hoocąągra originated near saltwater, to explain how mid-western tribes had a knowledge of the Pacific Ocean, which they described as being located where the earth ends and the sun sets into the sea; the Hoocąągra claim that their people have always lived in what is now the north central United States. Linguistic and e
A gristmill grinds cereal grain into flour and middlings. The term can refer to the building that holds it; the Greek geographer Strabo reports in his Geography a water-powered grain-mill to have existed near the palace of king Mithradates VI Eupator at Cabira, Asia Minor, before 71 BC. The early mills had horizontal paddle wheels, an arrangement which became known as the "Norse wheel", as many were found in Scandinavia; the paddle wheel was attached to a shaft which was, in turn, attached to the centre of the millstone called the "runner stone". The turning force produced by the water on the paddles was transferred directly to the runner stone, causing it to grind against a stationary "bed", a stone of a similar size and shape; this simple arrangement required no gears, but had the disadvantage that the speed of rotation of the stone was dependent on the volume and flow of water available and was, only suitable for use in mountainous regions with fast-flowing streams. This dependence on the volume and speed of flow of the water meant that the speed of rotation of the stone was variable and the optimum grinding speed could not always be maintained.
Vertical wheels were in use in the Roman Empire by the end of the first century BC, these were described by Vitruvius. The peak of Roman technology is the Barbegal aqueduct and mill where water with a 19-metre fall drove sixteen water wheels, giving a grinding capacity estimated at 2.4 to 3.2 tonnes per hour. Water mills seem to have remained in use during the post-Roman period, by 1000 AD, mills in Europe were more than a few miles apart. In England, the Domesday survey of 1086 gives a precise count of England's water-powered flour mills: there were 5,624, or about one for every 300 inhabitants, this was typical throughout western and southern Europe. From this time onward, water wheels began to be used for purposes other than grist milling. In England, the number of mills in operation followed population growth, peaked at around 17,000 by 1300. Limited extant examples of gristmills can be found in Europe from the High Middle Ages. An extant well-preserved waterwheel and gristmill on the Ebro River in Spain is associated with the Real Monasterio de Nuestra Senora de Rueda, built by the Cistercian monks in 1202.
The Cistercians were known for their use of this technology in Western Europe in the period 1100 to 1350. Geared gristmills were built in the medieval Near East and North Africa, which were used for grinding grain and other seeds to produce meals. Gristmills in the Islamic world were powered by both wind; the first wind-powered gristmills were built in the 9th and 10th centuries in what are now Afghanistan and Iran. Although the terms "gristmill" or "corn mill" can refer to any mill that grinds grain, the terms were used for a local mill where farmers brought their own grain and received back ground meal or flour, minus a percentage called the "miller's toll." Early mills were always built and supported by farming communities and the miller received the "miller's toll" in lieu of wages. Most towns and villages had their own mill so that local farmers could transport their grain there to be milled; these communities were dependent on their local mill. Classical mill designs are water-powered, though some are powered by the wind or by livestock.
In a watermill a sluice gate is opened to allow water to flow onto, or under, a water wheel to make it turn. In most watermills the water wheel was mounted vertically, i.e. edge-on, in the water, but in some cases horizontally. Designs incorporated horizontal steel or cast iron turbines and these were sometimes refitted into the old wheel mills. In most wheel-driven mills, a large gear-wheel called the pit wheel is mounted on the same axle as the water wheel and this drives a smaller gear-wheel, the wallower, on a main driveshaft running vertically from the bottom to the top of the building; this system of gearing ensures that the main shaft turns faster than the water wheel, which rotates at around 10 rpm. The millstones themselves turn at around 120 rpm, they are laid one on top of the other. The bottom stone, called the bed, is fixed to the floor, while the top stone, the runner, is mounted on a separate spindle, driven by the main shaft. A wheel called the stone nut connects the runner's spindle to the main shaft, this can be moved out of the way to disconnect the stone and stop it turning, leaving the main shaft turning to drive other machinery.
This might include driving a mechanical sieve to refine the flour, or turning a wooden drum to wind up a chain used to hoist sacks of grain to the top of the mill house. The distance between the stones can be varied to produce the grade of flour required; the grain is lifted in sacks onto the sack floor at the top of the mill on the hoist. The sacks are emptied into bins, where the grain falls down through a hopper to the millstones on the stone floor below; the flow of grain is regulated by shaking it in a sloping trough from which it falls into a hole in the center of the runner stone. The milled grain is collected as it emerges through the grooves in the runner stone from the outer rim of the stones and is fed down a chute to be collected in sacks on the ground or meal floor. A similar process is used for grains such as wheat to make flour, for maize to make corn meal. In order to prevent the vibrations of the mill machinery from shaking the building apart, a gristmill will have at least two separate foundations.
The Driftless Area is a region in southeastern Minnesota, southwestern Wisconsin, northeastern Iowa, the extreme northwestern corner of Illinois, of the American Midwest. The region escaped glaciation during the last ice age and is characterized by steep, forested ridges, deeply-carved river valleys, karst geology characterized by spring-fed waterfalls and cold-water trout streams. Ecologically, the flora and fauna of the Driftless Area are more related to those of the Great Lakes region and New England rather than those of the broader Midwest and central Plains regions. Colloquially, the term includes the incised Paleozoic Plateau of southeastern Minnesota and northeastern Iowa; the region includes elevations ranging from 603 to 1,719 feet at Blue Mound State Park and covers an area of 24,000 square miles. The rugged terrain is due both to the lack of glacial deposits, or drift, to the incision of the upper Mississippi River and its tributaries into bedrock. An alternative, less restrictive definition of the Driftless Area includes the sand Plains region located northeast of Wisconsin's portion of the incised Paleozoic Plateau in the southwestern part of the state.
This portion of the Driftless Area in the southwestern section of Wisconsin's Central Plain lacks evidence of glaciation, contains many isolated Hills, Mesas and Pinnacles that are outlying eroded Cambrian bedrock remnants of the plateau to the southwest. Retreating glaciers leave behind silt, sand and boulders called drift. Glacial drift includes unsorted material called till and layers deposited by meltwater streams called outwash. While drift from early glaciations has been found in some parts of the region, much of the incised Paleozoic Plateau of Wisconsin and northwestern Illinois holds no evidence for glaciation; the region has been subject to large floods from the melting Laurentide ice sheet and subsequent catastrophic discharges from its proglacial lakes, such as Glacial Lake Wisconsin, Glacial Lake Agassiz, Glacial Lake Grantsburg, Glacial Lake Duluth. The last phases of the Wisconsin Glaciation involved several major lobes of the Laurentide ice sheet: the Des Moines lobe, which flowed down toward Des Moines on the west.
The northern and eastern lobes were in part diverted around the area by the Watersmeet Dome, an ancient uplifted area of Cambrian rock underlain by basalt in northern Wisconsin and western upper Michigan. The southward movement of the continental glacier was hindered by the great depths of the Lake Superior basin and the adjacent highlands of the Bayfield Peninsula, Gogebic Range, Porcupine Mountains, Keweenaw Peninsula, the Huron Mountains along the north rim of the Superior Upland bordering Lake Superior; the Green Bay and Lake Michigan lobes were partially blocked by the bedrock of the Door Peninsula, which presently separates Green Bay from Lake Michigan. In earlier phases of the Wisconsinan, the Driftless Area was surrounded by ice, with eastern and western lobes joining together to the south of it; the latest concept explaining the origin of the Driftless Area is the pre-Illinoian continental glacial ice flowing over the Driftless Area and depositing on it pre-Illinoian till, more than 790,000 years old.
When the ice retreated and uncovered the area, intensive periglacial erosion removed it. Anticyclonic snow-bearing winds episodically dropped large amounts of snow, which gradually removed superficial sediment from slopes by solifluction and snowmelt overland flow, washing the deposits down to stream valleys that flowed into the Mississippi River. In the adjacent glaciated regions, the glacial retreat left behind drift, which buried all former topographical features. Surface water was forced to carve out new stream beds. Overall, the region is characterized by an eroded plateau with bedrock overlain by varying thicknesses of loess. Most characteristically, the river valleys are dissected; the bluffs lining this reach of the Mississippi River climb to nearly 600 feet. In Minnesota, Pre-Illinoian-age till was removed by natural means prior to the deposition of loess; the sedimentary rocks of the valley walls date to the Paleozoic Era and are covered with colluvium or loess. Bedrock, where not directly exposed, is near the surface and is composed of "primarily Ordovician dolomite and sandstone in Minnesota, with Cambrian sandstone and dolomite exposed along the valley walls of the Mississippi River."
In the east, the Baraboo Range, an ancient, profoundly eroded monadnock in south central Wisconsin, consists of Precambrian quartzite and rhyolite. The area has not undergone much tectonic action, as all the visible layers of sedimentary rock are horizontal. Karst topography is found throughout the Driftless area; this is characterized by caves and cave systems, disappearing streams, blind valleys, underground streams, sinkholes and cold streams. Disappearing streams occur where surface waters sinks down into the earth through fractured bedrock or a sinkhole, either joining an aquifer, or becoming an underground stream. Blind valleys are formed by disappearing lack an outlet to any other stream. Sinkholes are the result of the collapse of the roof of a cave, surface water can flow directly into them. Disappearing streams can re-emerge as large cold springs. Cold streams with cold springs; the Mississippi River passes through the Driftless Area between and including P
The Mississippi River is the second-longest river and chief river of the second-largest drainage system on the North American continent, second only to the Hudson Bay drainage system. Its source is Lake Itasca in northern Minnesota and it flows south for 2,320 miles to the Mississippi River Delta in the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains all or parts of 32 U. S. two Canadian provinces between the Rocky and Appalachian mountains. The main stem is within the United States; the Mississippi ranks as the fifteenth-largest river by discharge in the world. The river either borders or passes through the states of Minnesota, Iowa, Missouri, Tennessee, Arkansas and Louisiana. Native Americans have lived along its tributaries for thousands of years. Most were hunter-gatherers, but some, such as the Mound Builders, formed prolific agricultural societies; the arrival of Europeans in the 16th century changed the native way of life as first explorers settlers, ventured into the basin in increasing numbers.
The river served first as a barrier, forming borders for New Spain, New France, the early United States, as a vital transportation artery and communications link. In the 19th century, during the height of the ideology of manifest destiny, the Mississippi and several western tributaries, most notably the Missouri, formed pathways for the western expansion of the United States. Formed from thick layers of the river's silt deposits, the Mississippi embayment is one of the most fertile regions of the United States. During the American Civil War, the Mississippi's capture by Union forces marked a turning point towards victory, due to the river's strategic importance to the Confederate war effort; because of substantial growth of cities and the larger ships and barges that replaced steamboats, the first decades of the 20th century saw the construction of massive engineering works such as levees and dams built in combination. A major focus of this work has been to prevent the lower Mississippi from shifting into the channel of the Atchafalaya River and bypassing New Orleans.
Since the 20th century, the Mississippi River has experienced major pollution and environmental problems – most notably elevated nutrient and chemical levels from agricultural runoff, the primary contributor to the Gulf of Mexico dead zone. The word Mississippi itself comes from Misi zipi, the French rendering of the Anishinaabe name for the river, Misi-ziibi. In the 18th century, the river was the primary western boundary of the young United States, since the country's expansion westward, the Mississippi River has been considered a convenient if approximate dividing line between the Eastern and Midwestern United States, the Western United States; this is exemplified by the Gateway Arch in St. Louis and the phrase "Trans-Mississippi" as used in the name of the Trans-Mississippi Exposition, it is common to qualify a regionally superlative landmark in relation to it, such as "the highest peak east of the Mississippi" or "the oldest city west of the Mississippi". The FCC uses it as the dividing line for broadcast call-signs, which begin with W to the east and K to the west, mixing together in media markets along the river.
The Mississippi River can be divided into three sections: the Upper Mississippi, the river from its headwaters to the confluence with the Missouri River. The Upper Mississippi runs from its headwaters to its confluence with the Missouri River at St. Louis, Missouri, it is divided into two sections: The headwaters, 493 miles from the source to Saint Anthony Falls in Minneapolis, Minnesota. The source of the Upper Mississippi branch is traditionally accepted as Lake Itasca, 1,475 feet above sea level in Itasca State Park in Clearwater County, Minnesota; the name "Itasca" was chosen to designate the "true head" of the Mississippi River as a combination of the last four letters of the Latin word for truth and the first two letters of the Latin word for head. However, the lake is in turn fed by a number of smaller streams. From its origin at Lake Itasca to St. Louis, the waterway's flow is moderated by 43 dams. Fourteen of these dams are located above Minneapolis in the headwaters region and serve multiple purposes, including power generation and recreation.
The remaining 29 dams, beginning in downtown Minneapolis, all contain locks and were constructed to improve commercial navigation of the upper river. Taken as a whole, these 43 dams shape the geography and influence the ecology of the upper river. Beginning just below Saint Paul and continuing throughout the upper and lower river, the Mississippi is further controlled by thousands of wing dikes that moderate the river's flow in order to maintain an open navigation channel and prevent the river from eroding its banks; the head of navigation on the Mississippi is the Coon Rapids Dam in Minnesota. Before it was built in 1913, steamboats could go upstream as far as Saint Cloud, depending on river conditions; the uppermost lock and dam on the Upper Mississippi River is the Upper St. Anthony Falls Lock an
Fishing is the activity of trying to catch fish. Fish are caught in the wild. Techniques for catching fish include hand gathering, netting and trapping. “Fishing” may include catching aquatic animals other than fish, such as molluscs, cephalopods and echinoderms. The term is not applied to catching farmed fish, or to aquatic mammals, such as whales where the term whaling is more appropriate. In addition to being caught to be eaten, fish are caught as recreational pastimes. Fishing tournaments are held, caught fish are sometimes kept as preserved or living trophies; when bioblitzes occur, fish are caught and released. According to the United Nations FAO statistics, the total number of commercial fishermen and fish farmers is estimated to be 38 million. Fisheries and aquaculture provide direct and indirect employment to over 500 million people in developing countries. In 2005, the worldwide per capita consumption of fish captured from wild fisheries was 14.4 kilograms, with an additional 7.4 kilograms harvested from fish farms.
Fishing is an ancient practice that dates back to at least the beginning of the Upper Paleolithic period about 40,000 years ago. Isotopic analysis of the skeletal remains of Tianyuan man, a 40,000-year-old modern human from eastern Asia, has shown that he consumed freshwater fish. Archaeology features such as shell middens, discarded fish bones, cave paintings show that sea foods were important for survival and consumed in significant quantities. Fishing in Africa is evident early on in human history. Neanderthals were fishing by about 200,000 BC to have a source of food for their families and to trade or sell. People could have developed basketry for fish traps, spinning and early forms of knitting in order to make fishing nets to be able to catch more fish in larger quantities. During this period, most people lived a hunter-gatherer lifestyle and were, of necessity on the move. However, where there are early examples of permanent settlements such as those at Lepenski Vir, they are always associated with fishing as a major source of food.
The British dogger was an early type of sailing trawler from the 17th century, but the modern fishing trawler was developed in the 19th century, at the English fishing port of Brixham. By the early 19th century, the fishermen at Brixham needed to expand their fishing area further than before due to the ongoing depletion of stocks, occurring in the overfished waters of South Devon; the Brixham trawler that evolved there was of a sleek build and had a tall gaff rig, which gave the vessel sufficient speed to make long distance trips out to the fishing grounds in the ocean. They were sufficiently robust to be able to tow large trawls in deep water; the great trawling fleet that built up at Brixham, earned the village the title of'Mother of Deep-Sea Fisheries'. This revolutionary design made large scale trawling in the ocean possible for the first time, resulting in a massive migration of fishermen from the ports in the South of England, to villages further north, such as Scarborough, Grimsby and Yarmouth, that were points of access to the large fishing grounds in the Atlantic Ocean.
The small village of Grimsby grew to become the largest fishing port in the world by the mid 19th century. An Act of Parliament was first obtained in 1796, which authorised the construction of new quays and dredging of the Haven to make it deeper, it was only in the 1846, with the tremendous expansion in the fishing industry, that the Grimsby Dock Company was formed. The foundation stone for the Royal Dock was laid by Albert the Prince consort in 1849; the dock covered 25 acres and was formally opened by Queen Victoria in 1854 as the first modern fishing port. The elegant Brixham trawler spread across the world. By the end of the 19th century, there were over 3,000 fishing trawlers in commission in Britain, with 1,000 at Grimsby; these trawlers were sold to fishermen including from the Netherlands and Scandinavia. Twelve trawlers went on to form the nucleus of the German fishing fleet; the earliest steam powered fishing boats first appeared in the 1870s and used the trawl system of fishing as well as lines and drift nets.
These were large boats 80–90 feet in length with a beam of around 20 feet. They travelled at 9 -- 11 knots; the earliest purpose built fishing vessels were designed and made by David Allan in Leith, Scotland in March 1875, when he converted a drifter to steam power. In 1877, he built. Steam trawlers were introduced at Hull in the 1880s. In 1890 it was estimated; the steam drifter was not used in the herring fishery until 1897. The last sailing fishing trawler was built in 1925 in Grimsby. Trawler designs adapted as the way they were powered changed from sail to coal-fired steam by World War I to diesel and turbines by the end of World War II. In 1931, the first powered drum was created by Laurie Jarelainen; the drum was a circular device, set to the side of the boat and would draw in the nets. Since World War II, radio navigation aids and fish finders have been used; the first trawlers fished over the side, rather than over the stern. The first purpose built stern trawler was Fairtry built in 1953 at Scotland.
The ship was much larger than any other trawlers in operation and inaugurated the era of the'super trawler'. As the ship pulled its nets over the stern, it could lift out a much greater haul of up to 60 tons; the ship served as a basis for the expansion of'su