Characteristics
Where land similar to that of Martin Mere, gently undulating glacial till, becomes flooded and develops fen and bog, the remnants of the original mere remain until the whole is filled with peat. This can be delayed where the mere is fed by lime-rich water from chalk or limestone upland and a significant proportion of the outflow from the mere takes the form of evaporation. In these circumstances, the lime (typically calcium carbonate) is deposited on the peaty bed and inhibits plant growth, therefore, peat formation. A typical feature of these meres is that they are alongside a river rather than having the river flowing through them. In this way, the mere is replenished by seepage from the bed of the lime-rich river, through the river's natural levée, or by winter floods. The water of the mere is then static through the summer, when the concentration of the calcium carbonate rises until it is precipitated on the bed of the mere.
Even quite shallow lake water can develop a thermocline in the short term but where there is a moderately windy climate, the circulation caused by wind drift is sufficient to break this up. (The surface is blown down-wind in a seiche and a return current passes either near the bottom or just above the thermocline if that is present at a sufficient depth.) This means that the bed of the shallow mere is aerated and bottom-feeding fish and wildfowl can survive, providing a livelihood for people around. Expressed more technically, the mere consists entirely of the epilimnion. This is quite unlike Windermere where in summer, there is a sharp thermocline at a depth of 9 to 15 metres, well above the maximum depth of 60 metres or so. (M&W p36)
At first sight, the defining feature of a mere is its breadth in relation to its shallow depth. This means that it has a large surface in proportion to the volume of water it contains. However, there is a limiting depth beyond which a lake does not behave as a mere since the sun does not warm the deeper water and the wind does not mix it. Here, a thermocline develops but where the limiting dimensions lie is influenced by the sunniness and windiness of the site and the murkiness of the water. This last usually depends on how eutrophic (rich in plant nutrients) the water is. Nonetheless, in general, with the enlargement of the extent of a mere, the depth has to become proportionately less if it is to behave as a mere.
English meres
- Aqualate Mere, Staffordshire
- Cop Mere, Staffordshire
- Bomere Pool, Shropshire
- Buttermere, Cumbria (Lake District)
- Diss Mere, Norfolk
- Brooke Mere, Norfolk
- Fowlmere, Cambridgeshire
- Grasmere, Cumbria (Lake District)
- Hornsea Mere, East Riding of Yorkshire
- Horsey Mere, Norfolk
- Martin Mere, Lancashire
- The Meres, south and east of Ellesmere, Shropshire (see below)
- Orton Mere, Cambridgeshire
- Quidenham Mere, Norfolk
- Raby Mere, Merseyside
- Scarborough Mere, North Yorkshire
- Scoulton Mere, Norfolk
- Sea Mere, Norfolk
- Thirlmere, Cumbria (Lake District)
- Thorpeness Meare (Suffolk)
- Windermere, Cumbria (Lake District)
- Marton Mere, Blackpool (Lancashire)
There are many examples in Cheshire, including:
Many examples also occur in north Shropshire, especially around the town of Ellesmere, which is sometimes known as 'the Shropshire lake district', such as:
- Blakemere
- Colemere
- Crosemere
- Ellesmere (The Mere)
- Kettlemere
- Newtonmere
- Sweatmere
- Whitemere
Fenland
The Fens of eastern England, as well as fen, lowland moor (bog) and other habitats, included a number of meres. As at Martin Mere in Lancashire, when the fens were being drained to convert the land to pasture and arable agriculture, the meres went too but some are easily traced owing to the characteristic soil. For the reasons given above, it is rich in both calcium carbonate and humus. On the ground, its paleness stands out against the surrounding black, humic soils and on the soil map, the former meres show as patches of the Willingham soil association, code number 372 (Soil Map).
Apart from those drained in the medieval period, they are shown in Saxton's map of the counties (as they were in his time) of Cambridgeshire and Huntingdonshire. The following is a list of known meres of the eastern English Fenland with their grid references.
Saxton's meres are named as:
- Trundle Mere TL2091
- Whittlesey Mere TL2291
- Stretham Mere TL5272
- Soham Mere. TL5773
- Ug Mere TL2487
- Ramsey Mere TL3189
In Jonas Moor's "map of the Great Levell of the Fenns" of 1720, though Trundle Mere is not named, the above are all named but one, included with the addition of:
In the interval, Stretham Mere had gone and the main features of the modern drainage pattern had appeared.
Ugg, Ramsey and Benwick meres do not show in the soil map. Others which do but which appear to have been drained before Saxton's mapping in 1576 are at:
- TL630875
- TL6884
- TL5375
- TL5898
The last appears to be the "mare 'Wide' vocatum" of Robert of Swaffham's version of the Hereward story (Chapter XXVI). If it is, it will have been in existence in the 1070s, when the events of the story took place.
Loch is a word meaning "lake" or "sea inlet" in Scottish and Irish Gaelic, subsequently borrowed into English. In Irish contexts, it often appears in the anglicized form "lough".
The Wash is a shallow natural rectangular bay and multiple estuary on the east coast of England, United Kingdom. The bay is an inlet of the North Sea. It is the largest estuary system in the United Kingdom, the largest natural bay in England and one of the most important places of conservation in Europe, with several nature reserves.
National nature reserves in England are designated by Natural England as key places for wildlife and natural features in England. They were established to protect the most significant areas of habitat and of geological formations. NNRs are managed on behalf of the nation, many by Natural England itself, but also by non-governmental organisations, including the members of The Wildlife Trusts partnership, the National Trust, and the Royal Society for the Protection of Birds.
The Fens or Fenlands in eastern England are a naturally marshy region supporting a rich ecology and numerous species. Most of the fens were drained centuries ago, resulting in a flat, dry, low-lying agricultural region supported by a system of drainage channels and man-made rivers and automated pumping stations. There have been unintended consequences to this reclamation, as the land level has continued to sink and the dykes have been built higher to protect it from flooding.
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 between March and Ely 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.
Windermere is a ribbon lake in Cumbria, England, and part of the Lake District. It is the largest lake in England by length, area, and volume, but considerably smaller than the largest Scottish lochs and Northern Irish loughs.
Soham is a town and civil parish in the district of East Cambridgeshire, in Cambridgeshire, England, just off the A142 between Ely and Newmarket. Its population was 12,336 at the 2021 census.
Ellesmere is a town in the civil parish of Ellesmere Urban, in Shropshire, England; it is located near to the Welsh border, the towns of Oswestry and Whitchurch, and the Welsh city of Wrexham. It is notable for its proximity to a number of prominent meres.
A thermocline is a distinct layer based on temperature within a large body of fluid with a high gradient of distinct temperature differences associated with depth. In the ocean, the thermocline divides the upper mixed layer from the calm deep water below.
The River Perry is a river in Shropshire, England. It rises near Oswestry and flows south to meet the River Severn above Shrewsbury. Along its 24 miles (39 km) length, its level drops by some 320 feet (95 m). The channel has been heavily engineered, both to enable water mills to be powered by it, and to improve the drainage of the surrounding land. There were at least seven corn mills in the 1880s, and the last one remained operational until 1966. The middle section of the river crosses Baggy Moor, where major improvements were made in 1777 to drain the moor. The scheme was one of the largest to enclose and improve land in North Shropshire, and the quality of the reclaimed land justified the high cost. A section of the river bed was lowered in the 1980s, to continue the process.
England comprises most of the central and southern two-thirds of the island of Great Britain, in addition to a number of small islands of which the largest is the Isle of Wight. England is bordered to the north by Scotland and to the west by Wales. It is closer to continental Europe than any other part of mainland Britain, divided from France only by a 33 km (21 mi) sea gap, the English Channel. The 50 km (31 mi) Channel Tunnel, near Folkestone, directly links England to mainland Europe. The English/French border is halfway along the tunnel.
The Dümmer or officially Dümmer See is a large lake in southern Lower Saxony (Germany). It has a surface of 13.5 km2 and an average depth of one metre. Its elevation is 37 metres.
Martin Mere is a mere near Burscough, in Lancashire, England, on the West Lancashire Coastal Plain. The mere is a vast marsh, around grid reference SD 41 15 that was, until it was drained, the largest body of fresh water in England.
Whittlesea Mere was an area of open water in the Fenland area of the county of Huntingdonshire, England. The mere occupied the land southeast of Yaxley Fen, south of Farcet Fen and north of Holme Fen. The town of Whittlesey lay to the northeast.
Little Thetford is a small village in the civil parish of Thetford, 3 miles (5 km) south of Ely in Cambridgeshire, England, about 76 miles (122 km) by road from London. The village is built on a boulder clay island surrounded by flat fenland countryside, typical of settlements in this part of the East of England.
A roddon, also written as rodham, roddam or rodden, is the dried raised bed of a watercourse such as a river or tidal-creek, especially in The Fens in eastern England. Such raised silt and clay-filled beds are ideal for settlement in the less firm peat of The Fens. Many writers have followed the archaeologist Major Gordon Fowler's preference for the word roddon to define such structures though modern researchers suggest the word rodham is the more correct local word.
The Natural Areas of England are regions, officially designated by Natural England, each with a characteristic association of wildlife and natural features. More formally, they are defined as "biogeographic zones which reflect the geological foundation, the natural systems and processes and the wildlife in different parts of England...".
