The position of The Fens in eastern England.^[1]

The Fens, also known as the Fenland(s), are a naturally marshy region in eastern England. Most of the fens were drained several centuries ago, resulting in a flat, damp, low-lying agricultural region.

A fen is the local name for an individual area of marshland or former marshland and also designates the type of marsh typical of the area, which has neutral or alkaline water chemistry and relatively large quantities of dissolved minerals, but few other plant nutrients.

The Fenland primarily lies around the coast of the Wash; it reaches into two of the nine official regions of England (the East of England and the East Midlands), four ceremonial counties (Lincolnshire, Cambridgeshire, Norfolk and a small area of Suffolk), eleven District Councils and six postcode areas (LN, PE, CB, IP, NR and NG). The whole occupies an area of nearly 1,500 sq mi (3,900 km²).^[2]

Most of the Fenland lies within a few metres of sea-level. As with similar areas in the Netherlands, much of the Fenland originally consisted of fresh- or salt-water wetlands, which have been artificially drained and continue to be protected from floods by drainage banks and pumps. With the support of this drainage system, the Fenland has become a major arable agricultural region in Britain for grains and vegetables. The Fens are particularly fertile, containing around half of the grade 1 agricultural land in England.

The Fens have been referred to as the "Holy Land of the English" because of the churches and cathedrals of Ely, Ramsey, Crowland, Thorney and Peterborough.^[3][4] Other significant towns in the Fens include Cambridge, Boston, Spalding, Wisbech and King's Lynn.

Introduction[link]

A windpump at Wicken Fen

The Fens are very low-lying compared with the chalk and limestone uplands that surround them – in most places no more than 10 m above sea level. Indeed, as a result of drainage and the subsequent shrinkage of the peat fens, many parts of the Fens now lie below mean sea level. Although one writer in the seventeenth century described the Fenland as all lying above sea level (in contrast to the Netherlands),^[5] the area is now home to the lowest land point in the United Kingdom, Holme Fen in Cambridgeshire, at around 2.75 metres below sea level.^[6] Within the Fens there are a few hills, which have historically been called "islands" as they remained dry when the low-lying fens around them were flooded. The largest of the fen-islands is the Isle of Ely, on which the cathedral city of Ely was built; its highest point is 39 m above mean sea-level.^[7]

Without artificial drainage and flood protection, the Fens would be liable to periodic flooding, particularly in winter due to the heavy load of water flowing down from the uplands and overflowing the rivers. Some areas of the Fens were once permanently flooded, creating small lakes or meres, while others were only flooded during periods of high water. In the pre-modern period arable farming was limited to the higher areas of the surrounding uplands, the fen islands and the so-called Townlands, an arch of silt ground around the Wash where the towns had their arable fields. Though these lands were lower than the peat fens before the peat shrinkage began, the more stable silt soils were reclaimed by medieval farmers and embanked against any floods coming down from the peat areas or from the sea. The rest of the Fenland was dedicated to pastoral farming, fishing, fowling and the harvesting of reeds or sedge, for example for thatch. In this way, the medieval and early modern Fens stood in contrast to the rest of southern England, which was primarily an arable agricultural region.

Since the advent of modern drainage in the nineteenth and twentieth centuries, the Fens have been radically transformed, so that today arable farming has almost entirely replaced pastoral and the economy of the Fens is heavily invested in the production of crops such as grains, vegetables and some cash crops such as rapeseed or canola.

Drainage in the Fenland consists of both river drainage and internal drainage of the land between the rivers. The internal drainage was organized by levels or districts, each of which includes the fen parts of one or several parishes. The details of the organization vary with the history of their development, but the areas include:

• The Great Level of the Fens is the largest region of fen in eastern England: including the lower drainage basins of the River Nene and the Great Ouse, it covers approximately 500 sq mi (1,300 km²). It is also known as the Bedford Level, after Francis Russell, 4th Earl of Bedford, who headed the so-called adventurers (investors) in the seventeenth century drainage in this area; his son became the first governor of the Bedford Level Corporation. In the seventeenth century, the Great Level was divided into the North, Middle and South Levels for the purposes of administration and maintenance. In the twentieth century, these levels have gained new boundaries, and include some fens which were never part of the jurisdiction of the Bedford Level Corporation.
  • The South Level lies to the southeast of the Ouse Washes and surrounds Ely, as it did in the seventeenth century.
  • The Middle Level currently lies between the Ouse Washes and the Nene, but historically lay between the Ouse Washes and Morton's Leam, a fifteenth century canal which runs north of the town of Whittlesey.
  • The North Level now includes all of the fens in Cambridgeshire and Lincolnshire between the Nene and the River Welland, but originally included only a small part of these lands, including those of the ancient parishes of Thorney and Crowland, but excluding most of Wisbech Hundred and Lincolnshire, which were under their own local jurisdictions.^[8]
• Deeping Fen, in the southern part of Lincolnshire, lies between the River Welland and the River Glen with its tributary the Bourne Eau.
• The Black Sluice District, much of which was known as the Lindsey Level when it was first drained in 1639, extends from the Glen and Bourne Eau to Swineshead. Its water is carried through to the Haven at Boston.

The above were all re-drained at one time or another after the Civil War(1642-1649).

• The Witham Commission Fens:
  • First District: from Washingborough to Billinghay Dales;
  • Second District: Blacksluice – Holland Fen;
  • Third District: north of the River Witham above Bardney;
  • Fourth District: East, West and Wildmore Fens and the Townland from Boston to Wainfleet;
  • Fifth District: Kyme Eau to Billinghay Skirth;
  • Sixth District: Blacksluice – Helpringham Eau to Kyme Eau.

These were drained in the eighteenth and nineteenth centuries.^[9]

Formation and geography[link]

At the end of the most recent glacial period, known in Britain as the Devensian, ten thousand years ago, Britain and continental Europe were joined by the ridge between Friesland and Norfolk. The topography of the bed of the North Sea indicates that the rivers of the southern part of eastern England flowed into the Rhine, hence through the English Channel. From the Fens northward along the modern coast, the drainage flowed into the northern North Sea basin. As the ice melted, the rising sea level drowned the lower lands, leading ultimately to the present coastline.^[10]

These rising sea levels flooded the previously inland woodland of the Fenland basin, and over the next few thousand years led to extensive development of both salt-water and fresh-water wetlands. Silt and clay soils were deposited by marine floods in the salt-water areas and along the beds of tidal rivers, while organic soils, or peats, developed in the fresh-water marshes. Fenland water levels peaked in the Iron Age; earlier Bronze and Neolithic settlements were covered by peat deposits, and have only recently been found.^[10] During the Roman period, water levels fell once again, and settlements were possible on the new silt soils deposited near the coast. Though water levels rose once again in the early medieval period, by this time artificial banks protected the coastal settlements and the interior from further deposits of marine silts, though peats continued to develop in the freshwater wetlands of the interior fens.^[10]

The wetlands of the fens have historically included:

• Washes: these are places such as tidal mud flats and braided rivers, which are sometimes exposed and at other times covered with water.
• Salt marsh: this is the higher part of a tidal wash, on which salt-adapted plants grew.
• Fen: this is a broad expanse of nutrient-rich shallow water in which dead plants do not fully decay, resulting in a flora of emergent plants growing in saturated peat.
• Moor: this developed where the peat grew above the reach of the land water which carried the nutrients to the fen. Its development was enabled where the fen was watered directly by rainfall. The slightly acidic rain washed the hydroxide ions out of the peat, making it more suitable for acid-loving plants, notably Sphagnum species. This is exactly the same as bog, but the word moor was applied to this acid peatland occurring on hills. These moors disappeared in the nineteenth century, and it had been thought that the Fenland did not have this kind of peat, until archeological and documentary evidence demonstrated that it did until the early nineteenth century.
• Waters: these have included:
  • tidal creeks, which reached from the sea into the marsh, the Townlands and in some places, the fen, and seem to have been named only if big enough to be regarded as havens;
  • meres, or shallow lakes which were more or less static but aerated by wind action;
  • many rivers, both natural and (from Roman times on) artificial.

Major areas for settlement were:

• the Townlands, a broad bank of silt (the remains of the huge creek levees that developed naturally during the Bronze and Iron Ages), on which the settlers built their homes and grew their vegetables;
• the fen islands: areas of higher land which were never covered by the growing peat;
• the fen edges: uplands surrounding the fens.

In general, of the three principal soil types found in the Fenland today, the mineral-based silt resulted from the energetic marine environment of the creeks, the clay was deposited in tidal mud-flats and salt-marsh, while the peat grew in the fen and bog. The peat produces black soils, which are directly comparable to the American muck soils. A roddon, the dried raised bed of a watercourse, is more suitable for building than the less stable peat.

Since the 19th century, all of the acid peat in the Fens has disappeared; drying and wastage of peats has greatly reduced the depth of the alkaline peat soils and reduced the overall elevation of large areas of the peat fens.

History[link]

Pre-Roman settlement[link]

There is evidence of human settlement near the Fens from the Mesolithic on. The evidence suggests that Mesolithic settlement in Cambridgeshire was particularly along the fen edges and on the low islands within the fens, to take advantage of the hunting and fishing opportunities of the wetlands.^[11]

Roman farming and engineering[link]

The Romans constructed the Fen Causeway, a road across the Fens to link what later became East Anglia with what later became central England; it runs between Denver and Peterborough. They also linked Cambridge and Ely, but generally their road system avoided the Fens except for minor roads designed for exporting the products of the region, especially salt, beef and leather. Sheep were probably raised on the higher ground of the Townlands and fen islands, then as in the early nineteenth century. The Roman period also possibly saw some drainage efforts, including the Car Dyke along the western edge of the Fenland between Peterborough and Lincolnshire, but most canals were constructed for transportation.^[12]