LCA 8: Otmoor Lowlands

Location and key characteristics

The Otmoor Lowlands form the south-eastern part of the district and county, adjoining Bicester to the north, Buckinghamshire to the east, South Oxfordshire to the south and Oxford to the south-west. Although principally a flat and open landscape the southern part of the character area includes some of the higher area of Coral Rag hills that runs east-west through Oxfordshire.

Flat, low-lying wet meadows and pastures associated with the River Ray and Cherwell floodplains, rising to include higher ground on the south-eastern boundary of the area such as Muswell Hill, and also to the east of Horton-cum-Studley.
Land uses are mixed but dominated by traditional small to medium-sized pasture fields divided by overgrown hawthorn hedges, water-filled drainage ditches and willow-lined watercourses.
Tree cover is concentrated on the steeper slopes and higher ground in the southern part of the character area such as around Arncott, sincluding several woodland blocks and also some well-treed field boundaries in areas of arable farmland. Elsewhere, such as at Graven Hill, tree cover is used as a way of screening infrastructure.
Settlements are small in scale and linear in form, typically located just above the level of the floodplain, close to watercourses and often on outcrops of Cornbrash limestone.
Overgrown hawthorn hedges and lines of willows in the pastoral landscape limit views from within the flat floodplain. This contrasts with longer views across the floodplain, where roads are built above the level of the fields and, or from higher ground in the southern part of the Character Area.

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Floodplain landscape in the south

Settlement located close to watercourse

Pasture fields bordered by hedgerows and trees

Steep limestone slopes of Muswell Hill

Description

Natural (landform, water, semi-natural land cover)

The underlying geology mostly comprises extensive deposits of Oxford Clay, a Jurassic mudstone, and lies between 59-75 metres AOD. Cornbrash Formation limestone underlies the River Ray, which winds its way east-west across the lowlands, and the area southwest of Islip where the rivers Ray and Cherwell meet. Along the northern edge of the character area a band of Cornbrash limestone rises gently away from the vale.
Within the mudstone lowlands there are two prominent small hills at Upper Arncott and Graven Hill, which rise above 100 metres, some 40 metres higher than the surrounding low-lying flat floodplain. There are significantly higher sandstone and limestone beds at Muswell Hill (197 metres above sea level).
Faulting within the Oxford Clay causes the Cornbrash to outcrop on a southwest-northeast axis which is apparent in a slight rise in ground to the north of the River Ray.
Otmoor is a unique area to the south of the River Ray, which for the most part lies below 60m. Alluvium overlies the bedrock geology here and along the riverbeds in the Character Area. Otmoor is ecologically significant with a series of grassland types within a Site of Special Scientific Interest.
There are few trees across most of the lower parts of the Character Area but woodland covers the tops of Graven Hill and the hill at Upper Arncott, and there are some woodlands on the slopes in the south of the character area, such as Noke Wood and Studley Wood. Hedgerow trees are also more prominent along the southern border of the district.

Cultural/social (land use, settlement, infrastructure, historic character)

Owing to its poor drainage, traditional land cover has consisted of grazed wet meadows, some of which remain in and around Otmoor with willow pollards lining streams. Extensive drainage of the heavy wet soils has enabled over half of the land to be brought into arable production, but areas of the clay vale are still often waterlogged for periods during the winter months. Horse-grazed pasture features close to settlements.
Arable fields tend to be large with weak boundaries, often the result of 20^th century field amalgamation. The remaining pastures are typically smaller, divided through 19^th century and earlier enclosure into fields with hedge and ditch boundaries. Overgrown hawthorn hedges and willow trees lining the watercourses create some enclosure within the floodplain.
Where the land rises up at the southern edge of the area a pattern of smaller fields of download pasture have developed on the steeper slopes, while open grazing persists on the higher open ground. Some remnant upland heath characteristics occur, with sheep grazing and bracken and gorse on the highest slopes.
The majority of villages are small in scale and linear in form as a result of their position along a through route and/or a topographical restriction. Where the land drains poorly, settlements are situated just above the level of the floodplain, often on dry outcrops of Cornbrash, for example Oddington, Merton and Ambrosden. Settlements in the far south and east are located either at the base or sides of hills.
The A34, A41 and M40 pass through the Otmoor Lowlands, the A-roads meet at Bicester, linking into the busy ring road which circumnavigates the town and also comprises the A4421 and A4095.
Villages have an agricultural origin but there is also significant military-related development in the area, notably around Graven Hill and Upper Arncott. In 1920 the Royal Air Force acquired Otmoor for use as a bombing range, and a large part of the Otmoor SSSI remains in military use as a rifle range. The former airfield at RAF Bicester is also a designated Scheduled Monument and Conservation Area, with numerous listed buildings and structures associated with its development in the 1930’s and World War 2.

Perceptual (views, tranquillity, associations)

Views are limited where riverside vegetation intervenes but a small rise in height can provide extensive views over the plain. The roads which cross this landscape are usually built up above the level of the surrounding fields which means that hedges appear to be sunken and have little visual impact, giving rise to an open, exposed landscape with long, uninterrupted views.
Those villages which are raised above the floodplain level are visually prominent, with church towers providing focal points. Trees both within and surrounding the villages anchor the settlements into the landscape.
An area almost 3km across at the heart of Otmoor remains free from all development, aside from the military use of part of the area.
Tranquillity is relatively high across the character area, owing to its rural, pastoral character, but is reduced around Bicester where the spread of residential development, convergence of busy A-roads, and areas of industrial land use detract aurally and visually from the farmland landscape.
The idea of the chess board in Alice in Wonderland is said to have come to Lewis Carroll at the top of Noke Hill looking down at the fields of Otmoor that were divided into a grid pattern by hedges and ditches.

County landscape typology

The Oxfordshire Wildlife and Landscape Study (see the map at the top of the page) identifies a series of bands running roughly southwest to northeast. The lowest areas, around the River Ray and Otmoor, are classified as Alluvial Lowlands, with the immediate surrounds of the River Cherwell and the lower reaches of the River Ray defined as River Meadowlands.
Rising up north-westwards is a band of Clay Vale and beyond that the Character Area includes the fringes of the Wooded Estatelands LCT (north-east and south-west of Bicester). Southeast of the Alluvial Lowlands the landform rises to Wooded Farmland and, beyond that, includes the edges of another area of Wooded Estatelands.
The band of Cornbrash limestone running through the Alluvial Lowlands, along which a number of villages are located above the surrounding floodplain, is classed as Lowland Village Farmlands. The distinctive, isolated hills south of Bicester are Wooded Hills in the OWLS typology, whilst the hill between Islip and Woodeaton is the only example in Cherwell of the Farmland Hills LCT.

Valued qualities

The low-lying area forming the core of Otmoor is wet grassland with high ecological value (in particular for birds) but also a distinctive landscape character. Unimproved neutral grasslands are found at Wendlebury Meads, Murcott Meadows and Arncott Bridge Meadows. They all show some evidence of ploughing during the medieval period, but essentially have a long uninterrupted history as grassland under traditional management.
The flat, open, wetlands of Otmoor RSPB Nature Reserve have a strong sense of tranquillity. The reserve also provides good recreation for visitors looking to explore unique wildlife species.
Woodland sites such as Whitecross Green Wood and Oriel Wood provide tree cover within a relatively open landscape. This woodland tract was part of the Royal Forest of Shotover, and its boundary has remained unchanged since 1590. Hazel, maple, and ash coppice is punctuated by oak standards, and a relatively recent pine plantation is being removed in stages to allow for natural regeneration.
Although the scale of this landscape varies considerably, with 20^th century field amalgamation in many locations, some historic small linear fields have survived from earlier periods around the 16^th-17^th A good example of an early post-Medieval field pattern can be found at Mansmoor Closes, near Charlton-on-Otmoor.
The area is of historic and archaeological interest due to its Roman sites. Woodeaton temple is a Romano-British temple of two phases, dating from the 1st century AD, with traces of Iron Age occupation. The archaeological site of Islip Roman villa is also a Scheduled Monument, as well as the Alchester Fort site and the Roman town of Alchester, located at the junction of two Roman roads.
The Oxfordshire Way long distance route passes across the character area, linking several of the historic villages: Weston-on-the-Green, Islip and Noke.
The setting of, and views to, churches in this area are very important to villages. Villages such as Noke, Charlton-on-Otmoor, and Chesterton all have Grade II* listed churches and grounds that form a prominent part of the village.

Forces for change

Bicester has grown significantly in recent years, resulting in an expansion of urbanising influence on the countryside, and further areas are allocated for development, including Wretchwick and parts of Graven Hill. Large scale development is also approved on land west of Chesterton, with a leisure resort (on land currently forming part of the Bicester Hotel golf course) and formal sporting facilities (to the south of the golf course). To the west of Little Chesterton, a combined research, development and production facility has been approved. There is also a large strategic development site on the edge of Oxford.
The landscape is susceptible to the impacts of climate change, including higher average temperatures and drier summers, wetter winters, more frequent winter storms and flooding leading to:
- Changes to seasonal flooding and flash floods, and potential for increasing demand for flood defence activity. This could create more physical habitat degradation and introduce potentially detracting features.
- Loss of woodland /trees due to wind-throw and of dieback in drought prone locations.
- Spread of non-native and invasive species such as giant hogweed.
- Changes in cropping and land use as a response to climate change impacting the character of the farmland.
- Drought conditions leading to crop failures, and reduced productivity changing the character of the farmed landscape.
Net zero targets are likely to result in pressure for solar development and potentially for wind turbines on the relatively flat alluvial lowlands.

Landscape strategy and guidelines

Retain the role of the River Ray and Otmoor as distinctive landscape features contributing to a sense of place and as ecologically important site.

Prevent damage to ecologically important habitats and to maintain their capacity to take floodwater new development will not normally be acceptable within the floodplain.
Maintain the open character of farmland, contributing to long views across the lowland landscape.
Maintain tree cover that contributes to linear character of river and avoid planting that would detract from this linear character.
Consider opportunities for meandering and naturalised sections of the River Ray to slow water flows and reduce flood impacts, in accordance with the Cherwell and Ray Catchment Partnership and Thames River Basin Management Plan.
Ensure that new development does not detract from the sense of place associated with the river and Otmoor.
Further vehicular crossings of the River Ray should be restricted.

Preserve the tranquillity and strong rural character of locations remote from transport infrastructure and urban edges.

Avoid development that would intrude on locations currently remote from urbanising influences, either through its size, scale or character, or its impact on levels of activity (such as traffic generation).
Buildings or other forms of new development will not normally be acceptable within Otmoor itself.
Ensure open, rural character of flat lowlands and of the Cherwell Valley is maintained, including maintaining distinction between the latter and allocated development to the north-east of Oxford.
The Oxfordshire Treescape Project considers that sites with multiple benefits for woodland opportunities are located along the course of the rivers Ray and Cherwell, northwest of Otmoor, and in the north-eastern portion of the character area.

Retain the traditional character of the area’s villages.

Where trees play a significant role in defining a village edge avoid development that extends the form of the village beyond that boundary.
Use new planting to soften the edges of new development, integrating it where possible with existing vegetation. Consider the biodiversity value of new planting as well as the landscape value.
Loss of hedgerows should be avoided, as this will damage landscape character by creating monotonous exposed plains.
Retain the physical distinction between historic villages and the expanding town of Bicester, in particular considering impact on Conservation Areas (such as at Chesterton). Where open land makes a significant contribution to the historic setting of a village, avoid development that would weaken this link. New development should respect the views to, and setting of, important landmark buildings such as churches.