©Crown Copyright. All rights reserved. Hertfordshire County Council, LA 076678, 2001
| Landscape Character Assessment | HertsDirect | Environment | |||
| |||||
©Crown
Copyright. All rights reserved. Hertfordshire County Council, LA 076678, 2001
The Vale is situated south of St Albans and north of Shenley Ridge between the A5 and North Mymms Park
©Crown
Copyright. All rights reserved. Hertfordshire County Council, LA 076678, 2001
A broad and shallow basin of the upper River Colne, with some extensive panoramas over arable fields, both along the Vale and up towards Shenley Ridge to the south. Mixed land uses include arable, extensive areas of active and restored mineral extraction and urban fringe development. Areas of wooded farmland estate characterise the north-eastern part of the area.
Restored wetland, London Colney (J. Billingsley)
| ^ |
Geology and soils. The geology in the core of the Vale comprises Aeolian silty drift and till. These form deep stoneless well-drained silty soils over gravel (Hamble 2 series) with, to the east, stoneless slowly permeable seasonally waterlogged coarse loamy and silty soils (Gresham series, some Grade 2). To the base of the Shenley Ridge, brown earths (Marlow series) overlie plateau and river terrace drift and chalk. To the north around Napsbury sandy brown earths and clay soils (Hornbeam 3) overlie glacial drift.
Topography. Levels along the Vale are almost level. Gently undulating landforms towards St Albans and the lower slopes of the Shenley Ridge.
Degree of slope. Typically 1 in 400 along the valley floor and 1 in 100 across the valley. Side slopes increase to between 1 in 50 and 1 in 25.
Altitude range. 75 to 60m along a length of 6km. Across the centre of the Vale side slopes rise up to 95m at the foot of Shenley Ridge.
Hydrology. The broad valley is a product of the proto-Thames, which flowed north of its present course during the last Ice Age and covered the Central River Valleys region. The small acidic upper Colne flows in the area at Park Corner on the Tyttenhanger estate. Downstream four substantial waterbodies have been created through Tyttenhanger Park following mineral extraction. Between London Colney and the confluence with the Ver there are a number of disturbed habitats along the river including some species-rich chalky habitats associated with calcareous gravel pits. Lakes have also been created at Broad Colney where the site is managed for nature conservation. The Colne is fed by a series of smaller seasonal tributary streams. Isolated ponds are associated with farmhouses, parkland and a moated site at Salisbury Hall.
Land cover and land use. This area is mainly in arable production, the open landscape punctuated by a few small isolated copses. Extensive areas have been excavated for minerals, including both farmland and parkland, most notably at Tyttenhanger Park, where the setting of the Hall is encircled by mounds of overburden and spoil, with attendant conveyor belts and plant. Some sites have been used for landfill and then restored to sheep grazing, whilst others have been returned to wetland habitats along the Colne. The area is also subject to re-development pressure for commercial and industrial units on the former Handley Page site at Colney Street and at London Colney. Both Harperbury and Napsbury Hospital sites, with their mature Victorian parkland and associated exotic tree species, are earmarked for residential redevelopment and conversion.
Vegetation and wildlife. Woodland areas are either associated with the parkland at Tyttenhanger or in more discrete and linear blocks, e.g. at the foot of the Shenley Ridge. Some of the woods at Tyttenhanger, e.g. Coppice Wood, comprise an oak/hornbeam mix, indicating lighter acidic soil conditions. Scots pine and sweet chestnut are also present on these soils, together with oak, ash, sycamore, field maple and some holly. Around some of the restored water bodies there are areas of willow, alder, birch, cherry and oak.
Where present, hedges are hawthorn, field maple, hazel and blackthorn with occasional elder and elm. Oak is the most common standard tree with some ash, alder and willow. Some of the woods are in poor condition, e.g. Garden Wood, which has been cleared for war games. Wet acidic grasslands in the Tyttenhanger estate are important for birds. The large arable area south of Coursers Road attracts flocks of wintering golden plovers and is the home of a colony of tree sparrows. South of Napsbury Hospital there is an important area of rare arable weeds, including the largest colony of cornflower in the county.
The moated Salisbury Hall, once the home of Nell Gwynne, was used by the De Havillands during WWII. The prototype of the Mosquito was built there and it is now a museum to the aircraft
Field pattern. Areas of pre-18th century origin enclosure survive, but the cultural pattern has been widely affected throughout most of the area due to land-use change over the last 100 years. Field boundaries have been removed and there are large prairie fields to the east. Mineral extraction and landfill have changed the local landscape character and landform patterns. Where present, field sizes are typically large and regular. Field boundaries often comprise ditches and tracks, rather than hedgerows.
Transport pattern. . There are few historic roads through the area with the exception of Coursers Road. There are a number of busy modern roads, most notably the M25. The St.Pancras railway line crosses to the west.
Settlements and built form. The settlement pattern owes its origins to the estates in the area. The result is a dispersed pattern with just a few farms and cottages on the agricultural land and larger houses set in parkland.
English Heritage Register of Parks and Gardens.
English Heritage Register of Scheduled Ancient Monuments
| ^ |
There are extensive views both into and within most of the area, particularly where the M25 comes off Shenley Ridge. The area has lost a large part of its historic character and is now an open and disjointed area with road and rail noise being a detracting feature. The parkland areas have a strong sense of neglect.
Rarity and distinctiveness. The area is unusual by virtue of its openness, flatness, the extent of mineral extraction and its relatively poor condition.
Although there are a number of detracting features within the landscape, bunding and roadside planting have ensured they are at least partly concealed from many public views. However, some of the bunds create their own impact, especially around many of the mineral sites. Prominent detracting features include the M25 and industrial and commercial buildings on the perimeter of London Colney and Colney Street, which exert a considerable visual influence on the surrounding area. Local treasures include All Saints Pastoral centre and Napsbury water tower.
There is a moderately good network of rights of way across much of the area. However, many of the routes are uninviting and forbidding, directly affected by active or recent mineral extraction, whilst others are over large open arable areas affected by views of major roads. Noted recreational uses include horse riding and walking. Local centres for recreation include the De Havilland Aircraft Museum at Salisbury Hall, Bowmans Green Open Farm and Broad Colney restored lakes.
There is little evidence that this area is valued for distinctiveness (E). Some features, including the parkland, are valued as distinctive (D).
Watling Chase Community Forest.
SAM: Colney Chapel moated site (London Colney).
English Heritage Register of Historic Parks and gardens: Napsbury Hospital (Grade II).
| CONDITION | |
|---|---|
| Land cover change: | widespread |
| Age structure of tree cover: | mature |
| Extent of semi-natural habitat survival: | mature or young |
| Management of semi-natural habitat: | fragmented |
| Survival of cultural pattern: | variable |
| Impact of built development: | high |
| Impact of land-use change: | high |
| ROBUSTNESS | |
| Impact of landform: | apparent |
| Impact of land cover: | insignificant |
| Impact of historic pattern: | relic |
| Visibility from outside: | widely visible |
| Sense of enclosure: | open |
| Visual unity: | incoherent |
| Distinctiveness/rarity: | unusual |
| ^ |
Open arable fields towards Shenley Ridge (J. Billingsley)
| ^ |