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92-535: Ouse Washes is a linear 2,513.6-hectare (6,211-acre) biological Site of Special Scientific Interest stretching from near St Ives in Cambridgeshire to Downham Market in Norfolk. It is also a Ramsar internationally important wetland site, a Special Protection Area for birds, a Special Area of Conservation and a Nature Conservation Review site, Grade I. An area of 186 hectares (460 acres) between March and Ely

184-493: A Ramsar internationally important wetland site, a Special Protection Area for birds, a Special Area of Conservation , and a Nature Conservation Review site, Grade I. 52°28′N 0°11′E  /  52.46°N 0.19°E  / 52.46; 0.19 Site of Special Scientific Interest A site of special scientific interest ( SSSI ) in Great Britain , or an area of special scientific interest ( ASSI ) in

276-425: A falcated duck , Britain's first, in 1986, and a canvasback in 1997. More recent visitors have included a northern harrier in 2013, a Baikal teal in 2014, an isabelline wheatear in 2016 and a gull-billed tern in 2017. Scarce waders such as pectoral sandpiper , Temminck's stint and red-necked phalarope are almost annual. Of the large mammals, Roe deer , water deer , badgers and otters are common on

368-507: A naturalist and founder of what is now the Wildfowl & Wetlands Trust (WWT) became a regular visitor to the washes, and in 1967 he purchased 40 hectares (100 acres) for £4000 to form the core of what is now WWT Welney Wetland Centre. The Royal Society for the Protection of Birds (RSPB) also actively purchased large areas of land, and the Cambridgeshire and Isle of Ely Naturalists' Trust (now

460-407: A channel. Sediments from the crevasse spread out as delta -shaped deposits with numerous distributary channels. Crevasse formation is most common in sections of rivers where the river bed is accumulating sediments ( aggrading ). Repeated flooding eventually builds up an alluvial ridge, whose natural levees and abandoned meander loops may stand well above most of the floodplain. The alluvial ridge

552-580: A continuation of the historical management of the land. Where an owner or occupier is unwilling or unable to carry out management, ultimately the conservation body can require it to be done. Public bodies which own or occupy an SSSI have a duty to manage it properly. Site management statements for SSSI in Scotland are available to download from the NatureScot website using the "Sitelink" facility. The law protecting SSSIs now covers everyone, not just public bodies and

644-582: A drainage charter to the 4th Earl of Bedford and his Adventurers , who constructed the Old Bedford River between Earith , Cambridgeshire and Downham Market , Norfolk, to facilitate drainage of the large area that became known as the Bedford Level. The Dutch engineer Cornelius Vermuyden was engaged to complete the project and constructed the New Bedford River parallel to the old. The start of

736-543: A flood-prone property to qualify for government-subsidized insurance, a local community must adopt an ordinance that protects the floodway and requires that new residential structures built in Special Flood Hazard Areas be elevated to at least the level of the 100-year flood. Commercial structures can be elevated or floodproofed to or above this level. In some areas without detailed study information, structures may be required to be elevated to at least two feet above

828-445: A floodplain. The quantity of sediments in a floodplain greatly exceeds the river load of sediments. Thus, floodplains are an important storage site for sediments during their transport from where they are generated to their ultimate depositional environment. When the rate at which the river is cutting downwards becomes great enough that overbank flows become infrequent, the river is said to have abandoned its floodplain. Portions of

920-474: A long way upstream of a wetland SSSI might require consultation. Some developments might be neutral or beneficial, even if they are within the SSSI itself – the critical point is whether they harm the interest features. The owners and occupiers of SSSIs are required (Scotland, England, Wales) to obtain consent from the relevant nature conservation body if they want to carry out, cause or permit to be carried out within

1012-407: A proposed activity would not affect the interest or is beneficial to it, then the conservation body will issue a "consent" allowing it to be carried out without further consultation. If it would be harmful, the conservation body may issue consent subject to conditions or refuse the application. If consent in writing is not given the operation must not proceed. Conditions may cover any relevant aspect of

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1104-413: A regime that minimises the amount of disturbance to the breeding waders and controls water levels within the washes. There are also "scrapes", areas of bare mud situated so as to be readily visible to birdwatchers. The new areas outside the washes are kept wet through a closely spaced network of ditches filled from ground aquifers by submersible pumps, and protected by fox- and badger-proof fences. It

1196-428: A site may contain strata containing vertebrate fossils, insect fossils and plant fossils and it may also be of importance for stratigraphy . Geological sites fall into two types, having different conservation priorities: exposure sites, and deposit sites. Exposure sites are where quarries , disused railway cuttings, cliffs or outcrops give access to extensive geological features, such as particular rock layers. If

1288-425: A standard list for that country. The ORCs/OLDs are not "banned" activities – the list includes activities which would damage the interest, but also many which might be beneficial. For example, " grazing " (a standard item on the list) would require consent, even on a chalk grassland or heathland where grazing is an essential part of management. In England and Wales the list of OLDs is almost the same for each SSSI – and

1380-546: Is a problem in freshwater systems. Much of the phosphorus in freshwater systems comes from municipal wastewater treatment plants and agricultural runoff. Stream connectivity controls whether phosphorus cycling is mediated by floodplain sediments or by external processes. Under conditions of stream connectivity, phosphorus is better able to be cycled, and sediments and nutrients are more readily retained. Water in freshwater streams ends up in either short-term storage in plants or algae or long-term in sediments. Wet/dry cycling within

1472-406: Is advantageous for the rapid colonization of large areas of the floodplain. This allows them to take advantage of shifting floodplain geometry. For example, floodplain trees are fast-growing and tolerant of root disturbance. Opportunists (such as birds) are attracted to the rich food supply provided by the flood pulse. Floodplain ecosystems have distinct biozones. In Europe, as one moves away from

1564-510: Is anticipated that a combination of lower flows in the Great Ouse and higher sea water levels will make it harder to manage drainage, although more areas of shallow water might benefit potential colonising breeders including the glossy ibis , black-winged stilt and various heron and egret species. Because of its importance to wildlife, the Ouse Washes is a Site of Special Scientific Interest

1656-498: Is any area subject to inundation by a 100-year flood. A problem is that any alteration of the watershed upstream of the point in question can potentially affect the ability of the watershed to handle water, and thus potentially affects the levels of the periodic floods. A large shopping center and parking lot, for example, may raise the levels of 5-year, 100-year, and other floods, but the maps are rarely adjusted and are frequently rendered obsolete by subsequent development. In order for

1748-516: Is governed by published SSSI Selection Guidelines. Within each area, a representative series of the best examples of each significant natural habitat may be notified, and for rarer habitats all examples may be included. Sites of particular significance for various taxonomic groups may be selected (for example birds, dragonflies , butterflies , reptiles, amphibians , etc.)—each of these groups has its own set of selection guidelines. Conservation of biological SSSI/ASSIs usually involves continuation of

1840-565: Is largely a result of flood control, hydroelectric development (such as reservoirs), and conversion of floodplains to agriculture use. Transportation and waste disposal also have detrimental effects. The result is the fragmentation of these ecosystems, resulting in loss of populations and diversity and endangering the remaining fragments of the ecosystem. Flood control creates a sharper boundary between water and land than in undisturbed floodplains, reducing physical diversity. Floodplain forests protect waterways from erosion and pollution and reduce

1932-546: Is managed by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire and another area near Chatteris is managed by the Royal Society for the Protection of Birds . The Wildfowl & Wetlands Trust manages another area near Welney . The site lies between the Old Bedford River in the north-west and the New Bedford River in the south-east. The Washes are a flood storage area and are often under water in

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2024-469: Is mostly within 1 kilometre (0.62 mi) of the SSSI but outside the barrier walls. A survey of the ditches showed that they were important for amphibians water voles , dragonflies and damselflies . More than 100 water beetle species included five for which the Fens are their national stronghold, and the 175 drain plants included eight of conservation concern. RSPB Ouse Washes is a nature reserve, managed by

2116-420: Is not necessarily absolute—generally it requires the SSSI interest to be considered properly against other factors. Local planning authorities are required to have policies in their development plans which protect SSSIs. They are then required to consult the appropriate conservation body over planning applications which might affect the interest of an SSSI (such a development might not be within or even close to

2208-441: Is often pronounced "triple-S I". Sites notified for their biological interest are known as Biological SSSIs (or ASSIs), and those notified for geological or physiographic interest are Geological SSSIs (or ASSIs). Sites may be divided into management units, with some areas including units that are noted for both biological and geological interest. Biological SSSI/ASSIs may be selected for various reasons, which for Great Britain

2300-708: Is topped by a channel belt formed by successive generations of channel migration and meander cutoff. At much longer intervals, the river may abandon the channel belt and build a new one at another position on the floodplain. This process is called avulsion and occurs at intervals of 10–1000 years. Historical avulsions leading to catastrophic flooding include the 1855 Yellow River flood and the 2008 Kosi River flood . Floodplains can form around rivers of any kind or size. Even relatively straight stretches of river are capable of producing floodplains. Mid-channel bars in braided rivers migrate downstream through processes resembling those in point bars of meandering rivers and can build up

2392-640: The Isle of Man and Northern Ireland , is a conservation designation denoting a protected area in the United Kingdom and Isle of Man . SSSI/ASSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in the United Kingdom are based upon them, including national nature reserves , Ramsar sites , Special Protection Areas , and Special Areas of Conservation . The acronym "SSSI"

2484-449: The Marine and Coastal Access Act 2010 ). Access to SSSIs is the same as for the rest of the countryside of the relevant country. Most SSSIs/ASSIs are in private ownership and form parts of working farms, forests and estates. In Scotland, people may use their rights of responsible access to visit SSSIs. When designating an SSSI/ASSI, the relevant nature conservation body must formally notify

2576-501: The Meuse and Rhine Rivers in 1993 found average sedimentation rates in the floodplain of between 0.57 and 1.0 kg/m . Higher rates were found on the levees (4 kg/m or more) and on low-lying areas (1.6 kg/m ). Sedimentation from the overbank flow is concentrated on natural levees, crevasse splays , and in wetlands and shallow lakes of flood basins. Natural levees are ridges along river banks that form from rapid deposition from

2668-927: The National Parks and Access to the Countryside Act 1949 , but the current legal framework for SSSIs is provided in England and Wales by the Wildlife and Countryside Act 1981 , amended in 1985 and further substantially amended in 2000 (by the Countryside and Rights of Way Act 2000 ), in Scotland by the Nature Conservation (Scotland) Act 2004 and in Northern Ireland by the Nature Conservation and Amenity Lands (Northern Ireland) Order 1985 . SSSIs are also covered under

2760-497: The Royal Society for the Protection of Birds at Welches Dam. It is signposted from Manea village which is 9.7 kilometres (6 mi) east of Chatteris on the A142 / A141 between Ely and March. The RSPB facilities also cover the area owned by WTBCN. The reserve is on the western side of the washes, south of the A1101 road . Its unstaffed visitor centre is open from 9 am to 5 pm,

2852-561: The Water Resources Act 1991 and related legislation. An SSSI may be made on any area of land which is considered to be of special interest by virtue of its fauna , flora , geological or physiographical / geomorphological features. SSSI notification can cover any "land" within the area of the relevant nature conservation body, including dry land, land covered by fresh water . The extent to which an SSSI/ASSI may extend seawards differs between countries. In Scotland an SSSI may include

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2944-602: The Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire (WTBCN)) bought 186 hectares (460 acres) . By 2010, the three conservation bodies owned 1,540 hectares (3,800 acres) of the site. 200 hectares (490 acres) is held by other organisations, including the Fenland Wildfowlers Association (53 hectares (132 acres), the Spalding & District Wildfowlers Association (25 hectares (62 acres) and private individuals. The wildfowling clubs work closely with

3036-547: The Yellow River in China – see list of deadliest floods . The worst of these, and the worst natural disaster (excluding famine and epidemics), was the 1931 China floods , estimated to have killed millions. This had been preceded by the 1887 Yellow River flood , which killed around one million people and is the second-worst natural disaster in history. The extent of floodplain inundation depends partly on flood magnitude, defined by

3128-703: The return period . In the United States, the Federal Emergency Management Agency (FEMA) manages the National Flood Insurance Program (NFIP). The NFIP offers insurance to properties located within a flood-prone area, as defined by the Flood Insurance Rate Map (FIRM), which depicts various flood risks for a community. The FIRM typically focuses on the delineation of the 100-year flood inundation area, also known within

3220-710: The variable damselfly , scarce chaser , wall brown and clouded yellow . Apart from the grassland, there are small patches of trees and osier , but the main interest lies in rare aquatic plants such as greater water-parsnip and fringed water lily , although the diversity and numbers of such species has reduced due to nutrient deposition by floodwater. The areas neighbouring the washland, used for intensive arable farming for 50 years, have now been reseeded with grasses and associated plants such as meadow buttercup , tufted vetch , ribwort plantain . and flowering rush . The washes are managed for traditional grazing and hay-making using professional livestock managers to determine

3312-446: The "new" meadows is 350 hectares (860 acres). The Ouse Washes are the most important site in England and Wales for breeding snipe , and also hold good populations of lapwings and redshanks and oystercatchers . Black-tailed godwits were found breeding in 1952, and reached a peak of 65 pairs by 1972, but flooding severely reduced breeding success until the extension projects enabled up to 19 pairs to breed. Corn crakes released on

3404-545: The NFIP as the Special Flood Hazard Area. Where a detailed study of a waterway has been done, the 100-year floodplain will also include the floodway, the critical portion of the floodplain which includes the stream channel and any adjacent areas that must be kept free of encroachments that might block flood flows or restrict storage of flood waters. Another commonly encountered term is the Special Flood Hazard Area, which

3496-628: The Nene Washes from 2005 as part of a reintroduction scheme found the Ouse Washes more to their liking with up to seven calling males each year, and several spotted crakes also call in the spring. Breeding ducks include 15% of the UK's garganey . Recent colonisers include the little egret (77 pairs in 2020, great white egret and bittern , while some former breeders including ruff and Savi's warbler have been lost. Little gulls , black terns and black-winged stilts have occasionally bred. Waders breed on

3588-479: The New Bedford River to the tidal Great Ouse and hence to the sea. At capacity, the site can accommodate 90,000,000 cubic metres (3.2 × 10 cu ft), although it only completely filled in 1947. The washland area between the rivers is 32 kilometres (20 mi) long and about 1 kilometre (0.62 mi) wide and acts as a floodplain during the winter and, increasingly, also in the summer. The area between

3680-560: The ORC lists for each SSSI and removed those activities that were unlikely to happen and if they were to would be unlikely to damage the protected natural features, and other activities adequately regulated by other statutory regimes. The intention of this was to remove the need for owners and occupiers to obtain SSSI consent as well as licences/ permits from other authorities (who must consult NatureScot prior to determining such applications). Purely geological SSSIs often have much shorter OLD lists. If

3772-581: The SSSI Register, hosted by The Registers of Scotland . Further information about SSSIs in Scotland is available on the NatureScot website. The decision to notify an SSSI is made by the relevant nature conservation body (the appropriate conservation body ) for that part of the United Kingdom: Northern Ireland Environment Agency , Natural England , NatureScot or Natural Resources Wales . SSSIs were originally set up by

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3864-414: The SSSI any of the activities listed in the notification. Formerly these activities were called 'potentially damaging operations' or PDOs. Under the current legal arrangements they are called 'operations requiring consent' or ORCs (Scotland), or 'operations likely to damage the SSSI interest' or OLDs (England & Wales). The list of ORCs/OLDs for each SSSI is unique to that site – though all are derived from

3956-402: The SSSI itself). The effect of this is to prevent development which harms the interest – except where the value of that interest is over-ridden by some more important factor, for example a requirement for a major road or port or oil pipe. The requirement for consultation covers any development which might affect the interest, not just developments within the SSSI itself – for example, a development

4048-400: The abandoned floodplain may be preserved as fluvial terraces . Floodplains support diverse and productive ecosystems . They are characterized by considerable variability in space and time, which in turn produces some of the most species-rich of ecosystems. From the ecological perspective, the most distinctive aspect of floodplains is the flood pulse associated with annual floods, and so

4140-511: The advantages provided by the richness of the alluvial soil of the floodplain are severely offset by frequent floods brought on by cyclones and annual monsoon rains. These extreme weather events cause severe economic disruption and loss of human life in the densely-populated region. Floodplain soil composition is unique and varies widely based on microtopography. Floodplain forests have high topographic heterogeneity which creates variation in localized hydrologic conditions. Soil moisture within

4232-491: The area is open water, but most of the habitat is grassland with reed canary-grass in the wettest locations, transitioning through reed sweet-grass to the creeping bent that dominates in the drier areas. The Ouse Washes are important as one of only two remaining large regularly flooded washlands in Britain, the other being the nearby Nene Washes in Cambridgeshire. When at Cambridge University , Peter Scott , who would become

4324-669: The automatic sluice at Earith, thereby releasing water to the Old Bedford River, which eventually overflows onto the washland between the Bedford rivers, with the Welmore automatic sluice controlling outflow. When levels drop, the washes drain back into the Old Bedford River. The Environment Agency sets the trigger level for the sluices, allowing higher levels in the Great Ouse in summer than in winter.The enclosed area of washland runs from Earith northeast to Downham Market where it links via

4416-529: The bank can be very muddy. The 1,000 hectares (2,500 acres) of the Welney Wetland Centre is one of ten wildfowl and wetland reserves managed by the Wildfowl & Wetlands Trust (WWT). It lies north of the A1101 road where it crosses the washes. It has a visitor centre and café, and viewing facilities include an observatory with two wing hides. There is a further bird hide south of the observatory and four to

4508-409: The car park, toilets and the reserve itself are always open, but there is no shop. There are two birds hides south of the visitor centre, the nearer, 300 metres (980 ft) from the centre, is wheelchair accessible, the further is 850 metres (2,790 ft). there are six hides north of the visitor centre, the furthest being 2,800 metres (9,200 ft) from the centre. In wet conditions, the path along

4600-487: The conservation bodies to protect breeding birds. The Ouse Washes Landscape Partnership scheme (OWLP) was a £1 million, 3-year project supported by the Heritage Lottery Fund which ran from 2014 to 2017. The scheme focused on the promotion of the area surrounding the Ouse Washes, the heart of the Cambridgeshire and Norfolk Fens, and on encouraging community engagement with the area's diverse heritage. The area

4692-404: The day, returning to the washes in the evening, where visitors can watch them being fed under floodlight near the visitor centre. More than 12,500 whooper swans wintered in 2021, about 5% of the world population. The number of Bewick's swans reaching the UK has fallen dramatically in the current century, as milder winters encourage them to remain in continental Europe, but several hundred still visit

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4784-837: The designating authority is NatureScot ; the role in Wales is performed by Natural Resources Wales (formerly the Countryside Council for Wales ). In the Isle of Man the role is performed by the Department of Environment, Food and Agriculture . Geological SSSI/ASSIs are selected by a different mechanism to biological ones, with a minimalistic system selecting one site for each geological feature in Great Britain. Academic geological specialists have reviewed geological literature, selecting sites within Great Britain of at least national importance for each of

4876-461: The exposure becomes obscured, the feature could in principle be re-exposed elsewhere. Conservation of these sites usually concentrates on maintenance of access for future study. Deposit sites are features which are limited in extent or physically delicate—for example, they include small lenses of sediment , mine tailings , caves and other landforms . If such features become damaged they cannot be recreated, and conservation usually involves protecting

4968-405: The extension areas at a density of about four pairs per hectare (two pairs per acre), 18 times the level on the main site. Hobbies , marsh harriers and barn owls all breed around the washes, as do yellow wagtails , corn buntings and tree sparrows , and kingfishers nest in artificial banks. The Ouse Washes hosts Bewick's and whooper swans in winter, which feed on nearby farmland during

5060-459: The feature from erosion or other damage. Following devolution, legal arrangements for SSSIs (Scotland, England, Wales) and ASSIs (Northern Ireland) differ between the countries of the UK. The Isle of Man ASSI system is a separate entity. NatureScot publishes a summary of the SSSI arrangements for SSSI owners and occupiers (other than public bodies) which can be downloaded from its website. Legal documents for all SSSIs in Scotland are available on

5152-448: The floodplain ecosystem is defined as the part of the river valley that is regularly flooded and dried. Floods bring in detrital material rich in nutrients and release nutrients from dry soil as it is flooded. The decomposition of terrestrial plants submerged by the floodwaters adds to the nutrient supply. The flooded littoral zone of the river (the zone closest to the river bank) provides an ideal environment for many aquatic species, so

5244-462: The floodplain has a big impact on phosphorus availability because it alters water level, redox state, pH, and physical properties of minerals. Dry soils that were previously inundated have reduced availability of phosphorus and increased affinity for obtaining phosphorus. Human floodplain alterations also impact the phosphorus cycle. Particulate phosphorus and soluble reactive phosphorus (SRP) can contribute to algal blooms and toxicity in waterways when

5336-579: The floodplain. Other smaller-scale mitigation efforts include acquiring and demolishing flood-prone buildings or flood-proofing them. In some floodplains, such as the Inner Niger Delta of Mali , annual flooding events are a natural part of the local ecology and rural economy , allowing for the raising of crops through recessional agriculture . However, in Bangladesh , which occupies the Ganges Delta ,

5428-645: The ice retreated during the Mesolithic, the sea level rose, filling what is now the North Sea , and bringing the Norfolk coastline much closer to its present line. Coastal woodland was drowned by the returning sea and slowly degraded to peat overlying deposits of marine clays and creating the Fens . Prior to the seventeenth century the Fens of eastern England were tidal marshland . frequently flooded and suitable for little more than summer grazing. In 1630, King Charles I granted

5520-465: The impact of floodwaters. The disturbance by humans of temperate floodplain ecosystems frustrates attempts to understand their natural behavior. Tropical rivers are less impacted by humans and provide models for temperate floodplain ecosystems, which are thought to share many of their ecological attributes. Excluding famines and epidemics , some of the worst natural disasters in history (measured by fatalities) have been river floods, particularly in

5612-405: The interest), but not illegal trail biking. This loophole was closed by the Countryside and Rights of Way Act 2000 and section 19 of the Nature Conservation (Scotland) Act 2004. Funding for the monitoring of SSSIs in England has been cut from £1.58 million in 2010 to £700,000 in 2018, causing concern that many have not been inspected over the last six years, as required by guidelines. Since

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5704-473: The interested parties and allow a period for them to make representations before confirming the notification. When creating a new SSSI/ASSI the designation has legal effect from the date of notification. The interested parties include central government, local planning authorities , national park authorities, all the owners and occupiers of the land, relevant public bodies such as the utility providers e.g., water companies . In Scotland, NatureScot must also notify

5796-464: The intertidal land down to mean low water spring or to the extent of the local planning authority area, thus only limited areas of estuaries and coastal waters beyond MLWS may be included. In England, Natural England may notify an SSSI over estuarial waters and further adjacent waters in certain circumstances (section 28(1A & 1B) of the Wildlife and Countryside Act 1981 as amended by Part 2 of Annex 13 of

5888-402: The list for an SSSI will only omit activities impossible on the particular SSSI (such as fishing where there is no water), and things requiring planning permission (which are covered by the local planning authority consultation process). In Scotland, and following the implementation of the Nature Conservation (Scotland) Act 2004, Scottish Natural Heritage (the former name for NatureScot) reviewed

5980-617: The makeup towards ash (49%) with maple increasing to 14% and oak decreasing to 25%. Semiarid floodplains have a much lower species diversity. Species are adapted to alternating drought and flood. Extreme drying can destroy the ability of the floodplain ecosystem to shift to a healthy wet phase when flooded. Floodplain forests constituted 1% of the landscape of Europe in the 1800s. Much of this has been cleared by human activity, though floodplain forests have been impacted less than other kinds of forests. This makes them important refugia for biodiversity. Human destruction of floodplain ecosystems

6072-492: The meander cuts into higher ground. The overall effect is that, as the river meanders, it creates a level flood plain composed mostly of point bar deposits. The rate at which the channel shifts varies greatly, with reported rates ranging from too slow to measure to as much as 2,400 feet (730 m) per year for the Kosi River of India. Overbank flow takes place when the river is flooded with more water than can be accommodated by

6164-448: The meander. This is described as lateral accretion since the deposition builds the point bar laterally into the river channel. Erosion on the outside of the meander usually closely balances deposition on the inside so that the channel shifts in the direction of the meander without changing significantly in width. The point bar is built up to a level very close to that of the river banks. Significant net erosion of sediments occurs only when

6256-519: The most important features within each geological topic (or block ). Each of these sites is described, with most published in the Geological Conservation Review series, and so becomes a GCR site . Almost all GCR sites (but no other sites) are subsequently notified as geological SSSIs, except some that coincide with designated biological SSSI management units. A GCR site may contain features from several different topic blocks, for example

6348-400: The natural and artificial processes which resulted in their development and survival, for example the continued traditional grazing of heathland or chalk grassland . In England, the designating body for SSSIs, Natural England , selects biological SSSIs from within natural areas which are areas with particular landscape and ecological characteristics, or on a county basis. In Scotland,

6440-979: The new Act, often with boundary changes. This complex process took some ten years to complete for the several thousand SSSIs. For the purposes of selecting the original tranche of SSSIs, Natural England's predecessors (the Nature Conservancy, the Nature Conservancy Council and English Nature ) used a system termed "areas of search" (AOSs). In England these were largely based on the 1974–1996 administrative counties (with larger counties divided into two or more areas), whereas in Scotland and Wales they are based around districts. The individual AOSs are between 400 km (150 sq mi) and 4,000 km (1,500 sq mi) in size. There were 59 AOSs in England, 12 in Wales, and 44 in Scotland. Watsonian vice-counties were formerly used for selection over

6532-404: The night on the washes after foraging for maize stubble on the arable farmland. A paid of cranes bred successfully on Lady Fen in 2018. Large numbers of migrants may seek temporary refuge on the marshes, including 2 million sand martins (1968) 5,000 common snipe (1979), 500 ruffs (1989) and 130 red-breasted mergansers (1956). Major rarities recorded include a pied-billed grebe in 1968,

6624-754: The nitrogen-to-phosphorus ratios are altered farther upstream. In areas where the phosphorus load is primarily particulate phosphorus, like the Mississippi River, the most effective ways of removing phosphorus upstream are sedimentation, soil accretion, and burial. In basins where SRP is the primary form of phosphorus, biological uptake in floodplain forests is the best way of removing nutrients. Phosphorus can transform between SRP and particulate phosphorus depending on ambient conditions or processes like decomposition, biological uptake, redoximorphic release, and sedimentation and accretion. In either phosphorus form, floodplain forests are beneficial as phosphorus sinks, and

6716-505: The north. All the main hides are accessible except the third to the north. There are also some two-person hides accessed by steps. Road access to the reserve car park is via Hundred Foot Bank, Welney , Norfolk. There is an entry charge for non-members of the WWT. The visitor centre is open from 10 am to 4 pm, although the café closes at 3.30 pm. The centre received 29,372 visitors in 2018. Increased summer flooding led to declines in

6808-399: The notification is then confirmed or withdrawn (in whole or part). At the time of the passing of the Wildlife and Countryside Act 1981 , many SSSIs were already in existence, having been notified over the previous decades under the National Parks and Access to the Countryside Act 1949 . Each of these was considered in turn, and either denotified, or renotified —brought under the provisions of

6900-579: The numbers of breeding waders from the 1970s onwards, and to counteract this areas of former farmland adjacent to the washes were acquired and converted to wet grassland. The WWT's Lady Fen is adjacent to the Welney Wetland Centre and was converted from farmland between 2007 and 2013. The RSPB, WWT and WTBCN have also modified land adjacent to the RSPB reserve. The eventual aim is to expand this to 1,000 hectares (2,500 acres), although as of 2022 only 135 hectares (330 acres) had been acquired. The total additional area of

6992-448: The outer barrier banks of the two artificial rivers covers about 1,900 hectares (4,700 acres). As the peat underlying the Fens has dried out through drainage, it has shrunk and lowered the level of the washlands, making flooding more frequent. The Washes and its banks have a total area of 2,400 hectares (5,900 acres), and newly created wet grasslands adjacent to the washes increase the total area to 2,750 hectares (6,800 acres). About 10% of

7084-442: The overbank flow. Most of the suspended sand is deposited on the levees, leaving the silt and clay sediments to be deposited as floodplain mud further from the river. Levees are typically built up enough to be relatively well-drained compared with nearby wetlands, and levees in non-arid climates are often heavily vegetated. Crevasses are formed by breakout events from the main river channel. The river bank fails, and floodwaters scour

7176-447: The owners and occupiers of SSSIs. Previously, activities by "third parties" were not illegal under the SSSI legislation. This meant that damaging activities such as fly-tipping , intensive bait-digging or trail biking on an SSSI were only prevented if done (or permitted) by the owner or occupier – not if done by trespassers or under public rights. The effect was, for example, to allow control of legal trail biking on SSSIs (where damaging to

7268-517: The proposed operation and may, for example, limit its timing, location or intensity. The process is slightly different where the owner or occupier is a public body, but the effect is broadly similar. The relevant nature conservation body sends all SSSI owners and occupiers a site-specific 'site management statement' describing the ideal management (there may be grants available to help fund management). Owners and occupiers are encouraged to carry out this management, which in many (but not all) cases will be

7360-557: The referendum to leave the EU in 2016, more than 450 staff have been transferred to the Department for Environment, Food and Rural Affairs (Defra). Neglected areas include Exmoor , the Lake District , the Pennines , and The Wash . The process of designating a site as of Special Scientific Interest is called notification; this is followed by consultation with the site's owners and occupiers, and

7452-560: The relevant community councils and community group having registered an interest in the land. The notification includes a description of the land and the natural features for which it is notified ("the citation"), a boundary map, and a list of the acts or omissions (activities) that the nature conservation body regulates through the issue of consents. The various laws protect the interest features of SSSIs from development, from other damage, and (since 2000 in England) also from neglect. Protection

7544-405: The rich soil and freshwater. However, the risk of inundation has led to increasing efforts to control flooding . Most floodplains are formed by deposition on the inside of river meanders and by overbank flow. Wherever the river meanders, the flowing water erodes the river bank on the outside of the meander. At the same time, sediments are simultaneously deposited in a bar on the inside of

7636-400: The river channel. Flow over the banks of the river deposits a thin veneer of sediments that is coarsest and thickest close to the channel. This is described as vertical accretion , since the deposits build upwards. In undisturbed river systems, overbank flow is frequent, typically occurring every one to two years, regardless of climate or topography. Sedimentation rates for a three-day flood of

7728-511: The river, the successive plant communities are bank vegetation (usually annuals); sedge and reeds; willow shrubs; willow-poplar forest; oak-ash forest; and broadleaf forest. Human disturbance creates wet meadows that replace much of the original ecosystem. The biozones reflect a soil moisture and oxygen gradient that in turn corresponds to a flooding frequency gradient. The primeval floodplain forests of Europe were dominated by oak (60%) elm (20%) and hornbeam (13%), but human disturbance has shifted

7820-408: The spawning season for fish often coincides with the onset of flooding. Fish must grow quickly during the flood to survive the subsequent drop in water level. As the floodwaters recede, the littoral experiences blooms of microorganisms, while the banks of the river dry out and terrestrial plants germinate to stabilize the bank. The biota of floodplains has high annual growth and mortality rates, which

7912-459: The surrounding grade. Many State and local governments have, in addition, adopted floodplain construction regulations which are more restrictive than those mandated by the NFIP. The US government also sponsors flood hazard mitigation efforts to reduce flood impacts. California 's Hazard Mitigation Program is one funding source for mitigation projects. A number of whole towns such as English, Indiana , have been completely relocated to remove them from

8004-672: The upper 30 cm of the soil profile also varies widely based on microtopography which affects oxygen availability. Floodplain soil stays aerated for long stretches of time in between flooding events, but during flooding, saturated soil can become oxygen-depleted if it stands stagnant for long enough. More soil oxygen is available at higher elevations farther from the river. Floodplain forests generally experience alternating periods of aerobic and anaerobic soil microbe activity which affects fine root development and desiccation. Floodplains have high buffering capacity for phosphorus to prevent nutrient loss to river outputs. Phosphorus nutrient loading

8096-419: The washes, with brown hare on the adjacent grasslands and small numbers of water voles in the wet areas. Regularly recorded bats include soprano pipistrelle , noctule and Daubenton's bat . The large fish population includes European eel and spined loach . There is a rich invertebrate fauna, including tansy beetle , which here feeds on water mint rather than the normal tansy . Scarce insects include

8188-453: The washes. The washes are of international importance for six species of wintering ducks, notably more than 20,000 wigeon . High waters levels prevent wigeon grazing on grass, and the extension areas were designed with this species in mind, so that they could feed when the main site was flooded. Up to 40 tundra bean geese and 130 white-fronted geese visit annually. Gulls roost overnight, as do hen harriers , and common cranes also spend

8280-516: The whole of Great Britain. Floodplain Because of regular flooding, floodplains frequently have high soil-fertility since nutrients are deposited with the flood waters. This can encourage farming ; some important agricultural regions, such as the Nile and Mississippi river basins , heavily exploit floodplains. Agricultural and urban regions have developed near or on floodplains to take advantage of

8372-433: The winter. It is internationally significant for wintering and breeding wildfowl and waders, especially teal , pintail , Eurasian wigeon , shoveler , pochard and Bewick's swans . The site also has rich aquatic fauna and flora, and areas of unimproved grassland. After the last glaciation between 100,000 and 10,000 years ago the sea level in eastern England was about 30 metres (98 ft) lower than at present. As

8464-611: The works was interrupted by the English Civil War , but recommenced under Oliver Cromwell in 1649, and was completed in 1656. The Ouse Washes are part of the system for controlling the flow of the Great Ouse when water levels in the river are high. In normal conditions, the waters of the Great Ouse run through the New Bedford River (or Hundred Foot Drain) to join the tidal stretch of the river at Welmore Lake Sluice, where another automatic system controls outflow. High water levels open

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