Sections of eight National Character Areas fall within Oxfordshire’s county boundaries reflecting its great range of landscape types. Each is defined by a unique combination of landscape, biodiversity, geodiversity and cultural and economic activity. Their boundaries follow natural lines in the landscape rather than administrative boundaries, making them a good decision making framework for the natural environment.

‍Oxfordshire’s NCAs, in descending order of sum of area in Oxfordshire (Hectares):

‍NCA 108 : Upper Thames Clay Vales 107,329 Ha
The Upper Thames Clay Vales are a low-lying and undulating clay vale landscape, contrasting with elevated landforms in bordering NCAs and with Midvale Ridge NCA in its midst. The NCA is the central section of a huge belt of low-lying land running through south central England from Somerset to Lincolnshire.

‍NCA 107 : Cotswolds 73,991 Ha
The Cotswolds form the best-known section of the predominantly oolitic Jurassic Limestone belt that stretches from the Dorset coast to Lincolnshire. The dominant pattern of the Cotswold landscape is of a steep scarp crowned by a high, open wold; the beginning of a long and rolling dip slope cut by a series of increasingly wooded valleys.

‍NCA 110 : Chilterns 26,059Ha
Chilterns is one of several NCAs that make up an outcrop of the Chalk stretching from East Anglia to Dorset and to the South Downs. To the north-east, the Chiltern escarpment lowers into the East Anglian Chalk. In the south-west, the neighbouring escarpments of the Chilterns and the Berkshire and Marlborough Downs face each other across the Thames at the Goring Gap. From the northwest-facing escarpment, the Chilterns dip slope descends to the south-east into the London Basin, where the Chalk is overlain by younger bedrock.

‍NCA 109 : Midvale Ridge 23,248 Ha
The Midvale Ridge NCA is a band of low-lying limestone hills stretching east–west from the Vale of Aylesbury in Buckinghamshire to Swindon. It is surrounded by the flat lands of the Oxfordshire clay vales, giving extensive views across the surrounding countryside. It is a predominantly agricultural area with a mixed arable/ pastoral farming landscape, cereals being the most important arable crop.

‍NCA 116 : Berkshire and Marlborough Downs 15,589 Ha
Vast arable fields stretch across the sparsely settled, rolling Chalk hills of the Berkshire and Marlborough Downs NCA. There are extensive views from the escarpment in particular, punctuated by landmarks including chalk-cut horse figures, beech clumps and ancient monuments. Historic routeways, including the Ridgeway National Trail, provide public access across this landscape.

‍NCA 95 : Northamptonshire Uplands 11,232 Ha
The Northamptonshire Uplands NCA is s mainly underlain by middle Jurassic limestones and clays of the Lias, capped locally by the iron-stone bearing Marlstone and Northampton Sands. The Oxford Canal and River Cherwell run through part of this NCA which is in the most northerly part of Cherwell District.

‍NCA 88 : Bedfordshire and Cambridgeshire Claylands  2,972 Ha
The Bedfordshire and Cambridgeshire Claylands NCA comprises a broad sweep of lowland plateau, dissected by a number of shallow valleys, including the rivers Great Ouse and Ivel. It is typically an empty gently undulating lowland landscape. A small portion of this NCA occupies a north-easterly corner of Cherwell District.

‍NCA 115 : Thames Valley 165 Ha
The Thames Valley is a mainly low-lying, wedge-shaped area, widening from Reading, which includes Slough, Windsor, the Colne Valley and the south- west London fringes. The River Thames provides a unifying feature through a very diverse landscape of urban and suburban settlements, infrastructure networks, fragmented agricultural land, historic parks, commons, woodland, reservoirs and extensive minerals workings.

River Catchments in Oxfordshire

Oxfordshire has a number of major rivers; the Leach, Windrush, Evenlode, Glyme, Cherwell, Ray, Ock, and Thame and many smaller tributaries that flow through the county and into the Thames. Wild Rivers and streams in semi-natural landscapes are typically associated with complexes of wetland habitats including floodplain wetlands, fens, wet grassland, oxbow lakes, permanent and temporary ponds and wet woodland.

Through pilots the Environment Agency found that improvements to water quality are most effectively delivered by local partnerships, and that a river catchment was a good ecological unit to use. Each catchment has a host organisation whose role is to deliver wildlife and water benefits through bringing together partners, identifying work and finding funding.

The River Evenlode rises out of the limestone that underlies the Cotswolds, flowing south-east towards the clay vales of the River Thames. The catchment contains 16 river water bodies including the Evenlode, and major tributaries the Glyme and Dorn. The landscape in this catchment is some of the finest in the county, forming part of the Cotswolds AONB, the remains of the ancient Royal Hunting forest of Wychwood and the World Heritage Site of Blenheim Palace. There are many historic market towns such as Chipping Norton, Moreton-in-Marsh and Woodstock.

Habitats include oak-ash  woodland, limestone grasslands, lowland meadows and fen, which support a wide range of wildlife. Priority species present in the catchment include remnant populations of our nationally endangered native crayfish, water voles and rare plant species including fen violet and downy woundwort.

The river habitat and fish populations in the Evenlode catchment are degraded through a combination of historical channel modification and pollution (sediment and phosphate) from waste water and rural areas. In many places rivers been over-deepened, widened and straightened, resulting in uniform channel morphology, a river divorced from its floodplain and extensive in-channel siltation. There are also numerous weirs, (35 on the Glyme), impounding the flow and creating barriers to fish movement. The combined impacts leave the catchment vulnerable to flooding and pollution and contribute to reduced water quality, biodiversity and fisheries interest.

To help tackle these issues, Wild Oxfordshire has worked in the Evenlode Catchment since 2014, securing funds and developing a wide successful partnership of conservation bodies, farmers, commercial companies and statutory agencies.

Take a look at the Evenlode Catchment Partnership to see how we're restoring this catchment.

The South Chilterns catchment is hosted by Thames 21 with the support of the Environment Agency.  The South Chilterns operational catchment includes part of the Chilterns Area of Outstanding Natural Beauty (AONB). It has three distinct geographical areas: in the West is the river Pang, a chalk stream in a rural area flowing through Pangbourne; the navigable river Thames flows through the middle of the catchment between Wallingford and Cookham; and in the east is the river Wye, an urban chalk stream rising near High Wycombe

The Cherwell and Ray catchment is hosted by the Berks, Bucks & Oxon Wildlife Trust (BBOWT), and Thames 21.

The catchment of the Cherwell is divided into two sub-catchments of differing character: the River Cherwell and the River Ray (the Cherwell’s largest tributary).

From its headwaters near the village of Charwelton (Northamptonshire), the River Cherwell flows southwards, passing through Banbury and Kidlington before flowing into the Thames at New Hinksey (Oxford). Other than these key urban areas, the Cherwell catchment is very rural, with a high proportion of arable land as well as some improved pasture. The underlying geology is clay. For much of its length, the Cherwell runs parallel with the Oxford Canal, crossing it at Nellbridge and sharing the same channel between Enslow and Shipton-on-Cherwell.

The catchment of the River Ray is  predominantly rural. From its headwaters near Quainton, the Ray flows slowly south-west to its confluence with the River Cherwell at Islip.

The Ray is of particular significance as, despite heavy modifications to its channel, its floodplain includes areas of nationally rare species-rich meadow (including several SSSIs). BBOWT now manages a number of these sites, including Meadow Farm, a site of historical importance with medieval ridge-and-furrow farming techniques still visible today. BBOWT’s wider vision is to connect its nature reserves and the wider River Ray landscape through its Upper River Ray Floodplain Living Landscape project.

Further downstream, the RSPB manages a large nature reserve at Otmoor, famous for its bird life. Both the Ray and the Cherwell form part of the RSPB’s wide reaching Futurescapes project for the Upper Thames River Valleys, highlighting once again the national importance of this area

The Freshwater Habitats Trust (FHT) was appointed as the catchment host for the Ock in 2013 and is leading the development of the catchment partnership with the support of the Environment Agency.

The Ock rises in Little Coxwell and flows eastward for 38km to join the Thames at Abindgon. The Ock catchment is characterised by clay, but is bordered to the north by limestone and sandstone which form a small escarpment, and to the south by chalk which forms an upland ridge. Spread across the catchment are a range of springs, headwaters, ponds, small lakes, and the larger streams and rivers. The catchment is also well-known for its fens, and wet meadows, all of which are affected by the quality and quantity of the water in the environment.

The 2013 water quality data from the Environment Agency suggests that water quality across the different streams and brooks is generally “Moderate” or “Poor”. Factors influencing the water environment in the Ock catchment are likely to be rural and urban diffuse pollution, waste water discharges, road run-off, loss of habitat and biodiversity and invasive non-native species.

The Windrush catchment is hosted by the Cotswolds Rivers Trust, with the support of the Environment Agency and The Rivers Trust. It is a sub-catchment of the much larger Cotswolds catchment, and includes, as well as the River Windrush, the River Leach and the River Thames from its confluence with the Leach at Lechlade-on-Thames to its confluence with the Evenlode at Cassington.

The Windrush catchment is full of character, with a number of projects currently working towards improving its value for people and wildlife. The catchment is divided between Gloucestershire in the west and Oxfordshire in the east, with the River Windrush flowing through the Cotswolds Area of Outstanding Natural Beauty. The River Thames flows through the southern part of the Windrush catchment, and forms the southern boundary of BBOWT’s largest nature reserve, Chimney Meadows (also a National Nature Reserve). This reserve lies at the centre of BBOWT’s Upper Thames Living Landscape project, which aims to manage, restore, and recreate floodplain habitats.

Poor water quality is a persistent problem in the Catchment and Windrush Against Sewage Pollution (WASP) are a charitable trust working to put an end to this issue. WASP collect and analyse data on water quality, the processes that lead to sewage pollution and the impact it has on the environment. As well as informing the public WASP also engages with companies and government agencies to push for responsible sewage management.