2.1.1 Geology and Soils
Hertfordshire is not old in geological terms. Its base stratum is heavy blue-grey
gault clay, which forms an impermeable layer beneath the chalk, whose outward
expression is best seen in the Chilterns, in the north west of the county. Over
the chalk a thin layer of clays, sands and pebbles - the Reading Beds - was then
deposited. In the south-eastern part of the county (Rickmansworth to Bishop's
Stortford) a layer of thick London clay was later laid down. Still later (about
200,000 years ago during the last Ice Age) glaciers moved southwards over the
chalk, depositing 'drift' - layers of broken rock from the areas further north
over which the glacier had passed, which were then left behind as it melted.
This is the chalky boulder clay found in the north-eastern part of the county.
In the west of the county, where there were no glaciers, a natural weathering
process produced the 'clay-with-flints' - a clay deposit containing
frost-shattered flints and pebbles from the Reading Beds. Glaciation had one
other significant impact on the county's geology - the proto-Thames. During the
last Ice Age what is now the Vale of St Albans was the valley of a much larger
Thames, with lakes at Wheathampstead and St Albans. Eventually the Thames cut
itself a new valley further south and, when the ice melted, the earlier valley
formed the Lea and Colne rivers.
Today the soils within the county are of two kinds: alkaline or neutral
chalky soil (boulder clay) in the north and east of the county; and more or less
acid leached soils over the centre and west of the county. These two soil types,
which divide the county very roughly along a north-west/south-east line between
Stevenage/Hitchin and Ware/Hoddesdon, have had a defining impact on vegetation,
agriculture and development - that is, on fundamental aspects of the landscape
character of the county. The light chalky soils of the north west were easily
cultivated, if not particularly fertile, and were possibly never heavily wooded
in any event. Cultivation of the boulder clay seems to have been intense in the
early medieval period, especially on sloping land where drainage could be more
easily achieved.
On the heavy, poorly-drained London clay, south east of a line drawn roughly
between Rickmansworth and Hertford, via Hatfield, cultivation proved very
difficult, so it was long left to support oak and hornbeam forest and pasture.
There is very little arable farming and, until comparatively recently, little
settlement. North and west of this area lie the Lea and Colne gravel regions.
The river diversion mentioned above left rich gravel deposits in the old Thames
valley, which provided better-drained, more accessible routes through the county
than the forested clays. Settlements grew up in these valleys, and most of the
modern towns in Hertfordshire are on these gravels. The river valleys are
therefore the areas most heavily affected by human interference, settlement
throughout the centuries and, more recently, transport routes and gravel
extraction.
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Figure 04 Soils
©Crown
Copyright. All rights reserved. Hertfordshire County Council, LA 076678, 2001
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RENDZINAS: Associated - Brown Calcareous
earths and argillic or paleo-argillic earths. Parent material: Chalk
and associated drift. Character: Well drained, shallow chalky soils,
with deeper loamy or clayey/flinty soils. |
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STAGNOGLEY SOILS: Associated -
Calcareous pelosols and brown earths and brown earth. Parent
material: Jurassic or cretaceous clay and associated drift.
Character clayey soils and non-calcareous loamy or loamy over clayey
soils |
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BROWN EARTHS: Associated -
Argillic brown earths and alluvial gley soils. Parent material:
River-terrace drift and associated alluvium. Character: Deep or
moderately deep, well-drained loam soils, locally shallow over
gravel, associated with clayey or loamy soils with high ground
water. |
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STAGNOGLEY SOILS: Associated - Argillic
brown earths or brown earths. Parent material: Cretaceous or
Tertiary clay and associated drift. Character: Clayey or loamy over
clayey soils with impeded drainage, associated locally with
better-drained mainly loamy soils. |
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PALEO ARGILLIC BROWN EARTHS: Associated
- Brown calcareous earths and argillic brown earths. Parent
material: Plateau drifts (clay with flints) and associated drift
over chalk. Character: Deep well drained to moderately well drained
loamy (usually silty) over clayey or occasionally clayey soils with
associated less clayey or calcareous soils. |
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CALCAREOUS PELOSOLS: Associated -
Stagnogley soils and argillic brown earths. Parent material: Chalky
glacial drift. Character: Slowly permeable, well structured,
calcareous clayey soils, associated with non calcareous clayey soils
with impeded drainage or less clayey better drained soils, often
stony. |
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PALEO ARGILLIC BROWN EARTHS: Associated
- Argillic brown earths and stagnogley soils. Parent material:
Glacial, glaciofluvial or river-terrace drift and associated brick
earth. Character: Deep well-drained to moderately well-drained loamy
(often silty) or loamy over clayey soils, usually stony and locally
shallow over gravel. Associated with loamy over clayey soils with
impeded drainage. |
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ARGILLIC BROWN EARTHS: Associated: Paleo
argillic brown earths and alluvial gley soils. Parent material:
river-terrace drift, brick earth and associated alluvium. Character:
Deep well-drained loamy (often silty) soils, locally stony or
shallow over gravel, associated with poorly-drained and clayey soils
with high ground water. |
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2.1.2 Topography
Hertfordshire contains three upland areas: the southern upland area of London
clay; the north-east upland area of boulder clay; and the western
chalk/clay-with-flints uplands. They are divided by lowland areas. The valleys
of the Colne, Lea and Stort form a broad belt from Rickmansworth to Ware,
curving round to Bishops Stortford, while the north-eastern and western uplands
are divided by a narrow belt of lower ground stretching from Hitchin through
Stevenage to Ware. The western rivers are generally shallow. Only within the
boulder clay of the north east are the rivers deeply incised, often within very
narrow valleys of no great length. There is therefore no great topographical
variation within the southern part of the county, rather a general undulation
more or less masked by vegetation.
2.2.1 History
Early activity in the county was focused on the river valleys and the lighter
gravel soils, especially around the proto-Thames, although it may have been
limited by swamplands. Significant areas of woodland were cleared from the mid
to late Bronze Age onwards. This process accelerated during the Iron Age and was
nearly complete by the Roman period.
Following an intense period of development during the late Iron Age, the
Roman occupation had a strong impact on the landscape, linked to the development
of existing settlements at Verulamium, (now St Albans), Welwyn, Braughing and
Ware and the roads between these and other strategic locations. This was
combined with 'industrial' activity at Berkhamsted and Verulamium and
large-scale tile and pottery production, using local materials, at Elstree,
Radlett, Bricket Wood and Verulamium. Many villas were built in Hertfordshire
and the villa of Gorhambury, for example, shows evidence of the use of the
landscape for recreational purposes, in that there was probably a covered
walkway and an avenue of trees and shrubs.
The division of the country under Danelaw (the frontier ran approximately
north west to south east across the county) led to a divergence in settlement
patterns and associated landscape management. Evidence can be found in the
pattern of place names and the contrast between villages and greens in the east
and larger areas of commonland in the west.
The Normans built castles at strategic locations: Great Berkhamsted (guarding
the Tring gap), Hertford (at the confluence of several rivers with the Lea) and
Waytemore (the Bishop of London's stronghold at Bishop's Stortford). These were
superimposed on an already well-settled landscape; by the time of the Domesday
Book there were 168 settlements recorded for Hertfordshire, the majority in the
north east. Medieval farming practices developed and the Abbey of St Albans, a
major landowner, continued to have a widespread influence on land management.
Hunting parks, more for food than ornament, became major features in the
landscape in the medieval period and Hertfordshire probably has a higher density
than any other county. Relic features from these are still present today in
several areas
The Plague of 1348 reduced the rural population and a number of the villages
and lands around were abandoned, especially in the north and east of the county.
On the Dissolution of the Monasteries, much of the land confiscated by the
Crown from St Albans Abbey was conveyed to courtiers and businessmen, all keen
for status and a healthy retreat from the capital. This change in ownership
accounts for a growth in country-house building in the mid-16th century, for
example at Cassiobury,
Gorhambury, Knebworth and Theobalds. The parks associated with these houses
were increasingly ornamental as well as functional. Status was an important
motivator here and the gardens at Theobalds, created under James I, became very
influential. Morden, writing in 1704, stated: 'This County has an incredible
number of Pallaces and fair Structures of the gentry and Nobility...The rich
Soil and wholesome Air, and the excellence of the County, have drawn hither the
Wealthiest Citizens of London.' (R. Morden, The New Description and State of
England, 2nd edn. (1704), p.71).
Hertfordshire's links with the London commercial centre grew in importance
and there emerged a stronger radial force within the developing geography.
Development was not consistent or uniform, with buildings constructed, altered,
destroyed and rebuilt, lands emparked and later disemparked, and great houses
built and later abandoned. This process continued throughout the following
centuries and is still evident today. As Lionel Munby remarked, 'the surviving
parks are among the most beautiful places in Hertfordshire', and Hertfordshire
is often the first move out to 'the country' for many Londoners.
Hertfordshire shares much in common with other Home Counties in its pattern
of development from the 17th century onwards, although the construction of the
New River in the Lea Valley to supply London with water was notable. As
elsewhere, lands were enclosed, creating the regular patchwork pattern of much
of the landscape, and communications improved as canals, roads and later
railways were built, most often along the river valleys. Town growth was slow,
but for a time in the 19th century the scale of malting and brewing, and
associated cereal growing in eastern Hertfordshire made it one of the largest
centres of the industry in western Europe.
2.2.2 Buildings and settlement
Since the middle of the 19th century there has been a major change in the
landscape of the county. Until then it had no useable natural resources on which
to base an Industrial Revolution (see transport section below). The development
of modern Portland cement in 1900 made reinforced concrete viable, using the
gravel deposits of the proto-Thames basin, with consequent effect on the local
landscape. The arrival of the railway provided a focus for new settlements
around stations and the development of light industry. Hertfordshire became a
commuter belt; free first-class railway tickets were handed out to purchasers of
the houses in the new garden cities. The development of the New Towns after WWII
increased the demand for local gravels and perpetuates a seemingly natural
division in the county. Most construction within the last century and a half has
been in the southern and south-western parts of the county, while the north
east, which was the most populated during the medieval period, remains sparsely
populated and rural. This is probably the most obvious pattern in the landscape
of the county.
2.3.1 Roads
The prehistoric routes in the county are notable for their continuity. They
result from topography and geology, following the chalk scarp and the river
valleys. The Romans then constructed radial routes from their Thames
crossing-place, which became Londinium. Their main roads went through the Tring
Gap (Akeman Street), through Verulamium (Watling Street) and up the Lea Valley
(Ermine Street). Other roads connected the towns to each other. Puckeridge, for
example, became a nexus of roads, on the route between Colchester and Sandy.
The poor state of roads through the county demanded significant financial
input - the first successful toll-house in the country was at Wadesmill. A
parallel system of drove roads - used for animals rather than vehicles - is
still partly visible in the green lanes and footpaths, often with the name
'green', 'travellers' or 'bull' attached. It is recorded that in 1766, 992,400
head of beef cattle were driven to Smithfield, many of them through
Hertfordshire, so these tracks were an important part of the transport network.
Only in the 19th century was there a significant improvement in the county's
roads - due chiefly to the efforts of John and James McAdam, sometime Hoddesdon
residents.
The late-19th and 20th century growth of settlements in the county entailed a
massive change in the road system, with ever more elaborate routes radiating out
from London, compounded by the exceptionally high rate of car ownership in the
county. One of the first bypasses in the county opened in 1928, round Welwyn. In
1959 the first motorway, the M1, was built through Hertfordshire. Now a long
section of the M25 and an upgraded A1(M) are included, the former the first
non-traditional route since the Roman occupation.
2.3.2 Rivers
The rivers have always been important transport routes, not least because of
the poor state of the roads, which on the London clay became impassable in wet
weather until the use of tarmacadam became widespread in the 19th century. The
rivers provided the only industrial focus, with overlapping uses for the
watermills as technology advanced. Flour production until the 16th century was
contemporary with wool fulling (12th - 17th centuries) and paper milling (15th -
19th centuries), with malting from the 17th to the 19th centuries. At Hertford
there was even a mill for grinding oak bark for tanning in the early 19th
century. The river Lea linked the rich grain-producing lands of the north east
and adjoining counties to the insatiable markets in London, its continuous
programme of improvements regulated by Act of Parliament. The Lea Navigation
canal and lock system is today part of the Regional Park and used for recreation
rather than transport. An aqueduct was constructed in 1609 to carry unpolluted
water from Amwell to Stoke Newington, a distance of some 20 miles. This too is
still a visible landscape feature (the New River) and a unique industrial relic,
while the canal system to the west - the Grand Union Canal - is also used now
for recreational purposes and has become in places a notable landscape feature.
2.3.3 Railways
Like the road system, the railway spread in a radial pattern from the
capital. The London and Birmingham Railway followed the route of the Grand
Junction Canal up the Tring valley. Its builders encountered similar problems
with landowners to those of the canal builders - but railways 'cannot easily
be turned into a landscape improvement'. The most obvious industrial relic
in the county is the Digswell Viaduct - 475m long and over 30m high, constructed
to avoid the parks of the gentry in the Mimram valley.
Hertfordshire is an enclosed county. Sir John Parnell, writing in 1769,
called it 'a most exquisitely Beautifull cultivated Hedgerow'ed country',
while Walker described it in 1785 thus: 'The land is generally inclosed,
though there are many small common fields, or lands, laying intermixed in small
pieces, the property of different persons, which are cultivated nearly in the
same way as inclosed lands; the large common fields lie towards Cambridgeshire.'
(Quoted in Munby, The Hertfordshire Landscape (1977)).
Agriculture was the dominant source of employment. Additional factors were
market gardening on the fertile alluvial land between Hoddesdon and Wormley and
on the eastern side of the Lea valley and forest industries in the north-west
and south. Patten and clog makers, coopers and stavemakers all used wood, and
other woodland products included shovels, spoons, bowls and other 'hollow
wares'. Significant and ecologically valuable areas of woodland remain,
especially on the heavy London clay which is unfit for arable cultivation. Both
woodland and hedges were an important part of the rural economy as well as of
its landscape: 'I know of no part of England more beautiful in its stile than
Hertfordshire: thro'out the oak and Elm hedgerows Appear Rather the work of
Nature than Plantation, generally Extending thirty or forty feet Broad, growing
irregularly in these stripes, and giving the fields the air of being reclaimed
from a general tract of woodland.' (Thomas Fuller, The Worthies of England,
ed. J. Freeman (1952), p.229).
Parliamentary enclosure was the last major transformation of the rural
landscape before the ploughing-out of hedgerows of the mid-20th century. In the
south and west, where piecemeal enclosure had already transformed the arable,
enclosure was largely of the surviving commons. In the early 1960s some 5500
acres were common, almost all of it in the west of the county. In the north and
north east enclosure was of open arable fields, generally after the General Act
of 1845. Thus the present landscape of this part of the county has now, after
the impact of 20th century arable intensification, largely reverted to its
pre-enclosure pattern.
Before 1900 the major impact on the landscape other than agriculture was
parkland. The gentry of Hertfordshire were pioneer gardeners, laying out a new
landscape as a frame for the house and as a status symbol in its own right. Lord
Burghley built himself a palace at Theobalds in 1564. His son, Robert Cecil,
spent £40,000 on building Hatfield House and rearranged the entire landscape to
give himself more privacy. Woodland and arable were switched around on a grand
scale. Today there are still almost no views into the parkland from outside.
Country house building took place in waves: pre-1580 and between 1640s and
1660, with a lot of 'improvements' between 1680 and 1720. Another building boom
took place between 1750 and 1780. The fashionable site for a country house
changed, from proximity to remoteness, from hilltops to near water, with four
grand houses built along the Mimram valley in the 18th century. But parklands
could be destroyed even more quickly than they were made. The opportunities for
profitable farming were such that medieval parkland was ploughed up whenever
there was no permanent resident on the estate. Some parklands were first wooded,
then cleared for farming, returned to open woodland as a deer park and then
cleared and ploughed for farmland once again. In the 20th century the greatest
threats to parkland were from housing development, the transport infrastructure
and mineral extraction, whereas arable farming of former wood pasture at least
retains woodland boundaries and the outline of the park.
