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30-541: Wharram Percy is a deserted medieval village and former civil parish near Wharram-le-Street , now in the parish of Wharram , on the western edge of the chalk Wolds of North Yorkshire , England. It is about 1 mile (1.6 km) south of Wharram-le-Street and is signposted from the Beverley to Malton road ( B1248 ). Wharram Percy was part of the East Riding of Yorkshire until the 1974 boundary changes . In 1931

60-436: A long period, from as early as Anglo-Saxon times to as late as the 1960s, due to numerous different causes. Over the centuries, settlements have been deserted as a result of natural events, such as rivers changing course or silting up , flooding (especially during the wet 13th and 14th centuries) as well as coastal and estuarine erosion or being overwhelmed by windblown sand. Many were thought to have been abandoned due to

90-462: A regression developed from water samples that are filtered, dried, and weighed), multiplying the concentration with the discharge as above, and integrating over the entire plume. To distinguish the spill contribution, the background turbidity is subtracted from the spill plume turbidity. Since the spill plume in open water varies in space and time, an integration over the entire plume is required, and repeated many times to get acceptably low uncertainty in

120-405: A sizeable collection of human skeletal remains, excavated from the churchyard of the deserted village, reveals details of disease, diet and death in the rural medieval community. This used the latest scientific techniques to make observations about childhood growth, duration of breastfeeding, and osteoporosis and tuberculosis . The Yorkshire Wolds Way National Trail passes through the site, and

150-414: Is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay . It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary or permanent) of fine sediments on bottoms where they are undesirable. Siltation is most often caused by soil erosion or sediment spill. It is sometimes referred to by

180-720: Is at Wharram Percy in North Yorkshire , because of the extensive archaeological excavations conducted there between its discovery in 1948 and 1990. Its ruined church and its former fishpond are still visible. In Northamptonshire , around 100 villages can be classified as deserted: there are articles relating to many of them, such as Onley , Althorp , Canons Ashby , Church Charwelton and Coton along with Faxton , Glendon , Snorscombe , Wolfhampcote and Wythmail . Other examples are at Gainsthorpe and Burreth in Lincolnshire . Silting up Siltation

210-537: The Centenary Way long-distance footpath passes to the east of the village. St Martin's Church has evolved, through six phases, between the early 12th and early 17th centuries. The tower collapsed in 1959 and thereafter the interior was excavated, revealing a smaller, mid-11th-century stone church and an earlier, mid- to late 10th-century, timber building. Deserted medieval village Not all sites are medieval: villages reduced in size or disappeared over

240-460: The University of Leeds . The site is now in the care of Historic England (formerly English Heritage ). Although the site seems to have been settled since prehistory , the village appears to have been most active from the 10th to the 12th centuries. The Domesday Book of 1086 records it as 'Warran' or 'Warron'. The suffix 'Percy' stems from the prominent, aristocratic family that owned

270-475: The offshore dumping of material dredged from harbours and navigation channels. The deposition may also be to build up the coastline, for artificial islands , or for beach replenishment . Climate change also affects siltation rates. Another important cause of siltation is the septage and other sewage sludges that are discharged from households or business establishments with no septic tanks or wastewater treatment facilities to bodies of water. While

300-455: The sediment in transport is in suspension , it acts as a pollutant for those who require clean water, such as for cooling or in industrial processes, and it includes aquatic life that are sensitive to suspended material in the water. While nekton have been found to avoid spill plumes in the water (e.g. the environmental monitoring project during the building of the Øresund Bridge ), filtering benthic organisms have no way of escape. Among

330-468: The 15th century, pastoral farming (particularly sheep) was more profitable for landowners than cereal farming. Over the century following, the Hylton family devoted more and more land to sheep, as their employment of agricultural labour decreased. During the early 16th century, the last residents of Wharram Percy were evicted and their homes were demolished to make room for more sheep pasture. On 1 April 1935

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360-426: The ambiguous term " sediment pollution ", which can also refer to a chemical contamination of sediments accumulated on the bottom, or to pollutants bound to sediment particles. Although "siltation" is not perfectly stringent, since it also includes particle sizes other than silt, it is preferred for its lack of ambiguity. The origin of the increased sediment transport into an area may be erosion on land or activities in

390-586: The area during the Middle Ages. The Black Death of 1348–49 does not seem to have played a significant part in the desertion of Wharram Percy, although the large fall in population in the country as a whole at that time must have encouraged relocation to larger settlements. In 1402 or 1403, the Percy family exchanged their holdings in the area with the Hylton family . Following changes in prices and wages during

420-753: The deaths of their inhabitants from the Black Death in the mid-14th century. While the plague must often have greatly hastened the population decline, which had already set in by the early 14th century in England because of soil exhaustion and disease, most DMVs actually seem to have become deserted during the 15th century. At this time, Inclosure Acts and other policies allowed land traditionally cultivated for cereals and vegetables to be transformed into pastures for sheep. The medieval ridge and furrow cultivation pattern remains evident in fields, even until today. This change of land use by landowners, which

450-429: The first line of defense is to maintain land cover and prevent soil erosion in the first place. The second line of defense is to trap the material before it reaches the stream network (known as sediment control ). In urban areas, the defenses are to keep land uncovered for as short a time as possible during construction and to use silt screens to prevent the sediment from getting released in water bodies. During dredging,

480-410: The food gathering of filtering organisms, and the sediment accumulation on the bottom may bury organisms to the point that they starve or even die. It is only if the concentration is extreme that it decreases the light level sufficiently for impacting primary productivity. An accumulation of as little as 1 mm (0.039 in) may kill coral polyps. While the effect of the siltation on the biota (once

510-455: The harm is already done) can be studied by repeated inspection of selected test plots, the magnitude of the siltation process in the impact area may be measured directly by monitoring in real time. Parameters to measure are sediment accumulation, turbidity at the level of the filtering biota, and optionally incident light. Siltation of the magnitude that it affects shipping can also be monitored by repeated bathymetric surveys. In rural areas,

540-476: The most difficult conflicts of interest to resolve, as regards siltation mitigation, is perhaps beach nourishment . When sediments are placed on or near beaches in order to replenish an eroding beach, any fines in the material will continue to be washed out for as long as the sand is being reworked. Since all replenished beaches are eroding or they would not need replenishment, they will contribute to nearshore siltation almost for as long as it takes to erode away what

570-436: The most sensitive organisms are coral polyps. Generally speaking, hard bottom communities and mussel banks (including oysters) are more sensitive to siltation than sand and mud bottoms. Unlike in the sea, in a stream, the plume will cover the entire channel, except possibly for backwaters, and so fish will also be directly affected in most cases. Siltation can also affect navigation channels or irrigation channels. It refers to

600-403: The original land-covering vegetation and temporarily creating something akin to an urban desert from which fines are easily washed out during rainstorms. In water, the main pollution source is sediment spill from dredging , the transportation of dredged material on barges, and the deposition of dredged material in or near water. Such deposition may be made to get rid of unwanted material, such as

630-429: The parish had a population of 40. The earthworks of the village have been known for many years, and outlines of house platforms were drawn onto the first Ordnance Survey six-inch maps of Yorkshire published in 1854. The site was researched each summer by combined teams of archaeologists, historians and even botanists, from about 1950 to 1990 after it was singled out for study in 1948 by Professor Maurice Beresford of

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660-531: The parish was abolished and merged with Raisthorpe and Burdale and Wharram le Street to form Wharram. The site is now in the care of Historic England . Although only the ruined church is easily visible above ground, much more of the village layout can be seen in the surrounding fields. The site has been subject to archaeological investigations since the 1950s. In 2002 English Heritage (now called Historic England) undertook an archaeological investigation and analytical field survey of Wharram Percy. A 2004 study of

690-474: The proportion of fines in sediments typically increases in the offshore direction, the deposited sand will inevitably contain a significant percentage of siltation-contributing fines. It is desirable to minimize the siltation of irrigation channels by hydrologic design, the objective being not to create zones with falling sediment transport capacity, as that is conducive to sedimentation. Once sedimentation has occurred, in irrigation or navigation channels, dredging

720-474: The results. The measurements are made close to the source, in the order of a few hundred meters. Anything beyond a work area buffer zone for sediment spill is considered the potential impact area. In the open sea, the impact of concern is almost exclusively with the sessile bottom communities since empirical data show that fish effectively avoid the impacted area. The siltation affects the bottom community in two main ways. The suspended sediment may interfere with

750-409: The spill can be minimized but not eliminated completely by the way the dredger is designed and operated. If the material is deposited on land, efficient sedimentation basins can be constructed. If it is dumped into relatively deep water, there will be a significant spill during dumping but not thereafter, and the spill that arises has minimal impact if there are only fine-sediment bottoms nearby. One of

780-445: The stream, by measuring the sediment concentration and multiplying that with the discharge ; for example, 50 mg/L (1.8 × 10  lb/cu in) times 30 m /s (1,100 cu ft/s) gives 1.5 kg/s (200 lb/min). Also, sediment spill is better measured in transport than at the source. The sediment transport in open water is estimated by measuring the turbidity , correlating turbidity to sediment concentration (using

810-409: The undesired accumulation of sediments in channels intended for vessels or for distributing water. One may distinguish between measurements at the source, during transport, and within the affected area. Source measurements of erosion may be very difficult since the lost material may be a fraction of a millimeter per year. Therefore, the approach taken is typically to measure the sediment in transport in

840-400: The water. In rural areas, the erosion source is typically soil degradation by intensive or inadequate agricultural practices, leading to soil erosion , especially in fine-grained soils such as loess . The result will be an increased amount of silt and clay in the water bodies that drain the area. In urban areas, the erosion source is typically construction activities, which involve clearing

870-422: Was added, albeit with somewhat decreasing intensity over time. Since the leakage is detrimental to coral reefs, the practice leads to a direct conflict between the public interest of saving beaches, and preserving any nearshore coral reefs. To minimize the conflict, beach replenishment should not be done with sand containing any silt or clay fractions. In practice the sand is often taken from offshore areas, and since

900-410: Was to take advantage of the profitable wool trade, led to hundreds of villages being deserted. Later, the aristocratic fashion for grand country mansions , parks and landscaped gardens led to whole villages being moved or destroyed to enable lords of the manor to participate in this trend: a process often called emparkment or enclosure . Perhaps the best-known deserted medieval village in England

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