Summary of a report on the research by Dr. Jim Galloway
Background
The later middle ages were a period of climate change.
Unlike the present, however, this was an age of climate
cooling, at least in the North Atlantic region, including
northern and western Europe. A relatively warm climatic
phase was coming to an end in the 13th century, and a
cooling trend had set in which, with some temporary
interruptions, led into the well-known ‘Little Ice Age’ of
the early modern period. This process was associated with an
increase in storminess, particularly marked in the countries
bordering the southern North Sea, where damaging storm
surges became more common. In the Low Countries such storms
caused widespread loss of life and the permanent loss of
extensive areas of land, which had been reclaimed in earlier
centuries. Numerous storms and storm surges also battered
the coasts of eastern and southern England between the 13th
and 15th centuries, among the most damaging being those of
1236, 1286–88, 1334, 1375, 1404 and 1421.
During this research project (January–June 2006), Dr. Jim
Galloway investigated the impact of the increasing
storminess upon the coasts of the Thames Estuary (including
the tidal river downstream of London Bridge and the mouth of
the Medway) between 1250 and 1450. This was one of the most
economically advanced areas of medieval England,
characterised by – for a pre-industrial society –
significant levels of urbanisation and by a
commercially-oriented agrarian sector. It was in no sense a
subsistence economy wholly at the mercy of natural forces.
Nevertheless, the climatic deterioration posed real
challenges, particularly as it coincided with a ‘stalling’
of economic growth about 1300 and a collapse in population
caused by recurrent outbreaks of plague (the ‘Black Death’)
after 1349.
Sources
Violent storms, which caused the deaths of men and
animals, damaged buildings and infrastructure, sank ships
and disrupted trade, naturally attracted the interest of
contemporary writers. The chronicler Matthew Paris described
how a major storm in November 1236 ‘deprived all ports
of ships, tearing away their anchors, drowned a multitude of
men, destroyed flocks of sheep and herds of cattle, plucked
out trees by the roots, overturned dwellings [and] dispersed
beaches’. In the same year, recounts Stow the historian
of London, flooding of the Thames turned the river marshes
to sea, while ‘in the great palace of Westminster men did
row with wherries in the midst of the hall.’
The reports of chroniclers must be treated with caution,
however, and correlated where possible by other sources. The
main body of sources drawn upon in this project were the
less colourful but more reliable and voluminous documentary
records created by the royal and local bureaucracies of
medieval England. Three main types were: The published Calendar of Patent Rolls (HMSO, various dates), which records royal letters and
instructions to local officials on a wide variety of
subjects, including responses to petitions from local
landholders affected by flooding, and the establishment of
commissions to enquire into drainage and coastal defence in
specific localities and manuscript Inquisitions Post
Mortem and miscellaneous inquisitions, comprising
enquiries into landholding and valuations of landed assets.
The ‘extents’ appended to these inquisitions often make
reference to factors influencing local land values, which
may include the effects of flooding or the costs of
maintaining sea and river defences. The manuscript
inquisitions are held in the National Archives at
Kewmanorial account rolls held in the National Archives and
Canterbury Cathedral Archives. These accounts provide
detailed annual accounts of farming practice and finances on
a range of demesnes – lands that were farmed directly on
behalf of manorial lords. Accounts for manors with holdings
in the estuarine marshlands often record expenses of
maintaining sea defences, and may record the direct impact
of flooding upon cropped land and livestock herds.
The Tidal Thames
Along the tidal river downstream of London storms allied
to a high and growing tidal range caused repeated breaches
of the river walls. Recurrent flooding affected the lands of
the Abbess of Barking, and other breaches occurred near
Rotherhithe and in the stretch of the Thames between
Woolwich and Greenwich. In Stepney a sequence of damaging
floods began on New Year’s Eve 1323 with the inundation of
100 acres of land, an event the lord of the manor described
as ‘a mighty flood, proceeding from the tempestuousness of
the sea, which overflowed all the banks.’ As the waters
ebbed they tore a great breach in the river wall, allowing
subsequent tides to flow across the land.
Over the following 100 years, numerous commissions of
walls and ditches (later known as commissions of sewers)
were appointed to oversee defence against the tidal river in
Stepney and adjacent areas, but flooding still recurred. A
further disastrous breach occurred in 1448, possibly the
result of a North Sea surge, and around 1000 acres of land
were submerged. Much of this land remained subject to the
tides for the remainder of the 15th century, resulting in
loss of livelihood to tenants and loss of revenue to the
lord of the manor. Abandoning attempts to defend some
marshlands may, however, have been a sensible response to an
increased flooding threat in a century of depressed
agricultural prices and rising labour costs.
Even flooded land was capable of generating some income
for lords and tenants. For example, there was rich fishing
in Barking during the 1380s on grounds that were inundated
when a breach in the river wall was left unrepaired.
The Outer Estuary
In the outer estuary a variety of activities were
threatened by an increase in the frequency and severity of
marine flooding. Here extensive unenclosed saltmarsh and
mudflats coexisted with highly-valued reclaimed pasture and
arable land behind sea walls. The former environments were
characterised by the grazing of large sheep flocks,
producing wool for export and for the local cloth industries
of Kent and Essex, by salt-making and by fishing using large
‘kiddles’ or fish-traps – medieval examples of which have
been uncovered by archaeologists working in the inter-tidal
zone. The ‘inned’ or reclaimed lands provided richer grazing
and highly productive arable land, the grain from which was
in demand from London and other urban markets at home and
abroad. An increase in storm surges threatened both
environments, drowning sheep in open or lightly-defended
marshes, eroding saltmarshes, damaging salt-making and
fishing structures and threatening reclaimed land with loss
of crops and salt damage to soils.
The extensive marshes around the mouth of the Medway in
northern Kent were particularly vulnerable. Detailed
manuscript accounts surviving for the manor of Barksore in
this area show that it suffered serious damage in the storms
of 1286–87, necessitating ten times the normal expenditure
on walls and ditches in the marsh, and was even harder hit
in the 1330s when large numbers of sheep were drowned. A
major breach in a sea wall occurred in the winter of
1334–35, probably caused by the same surge that struck the
coasts of Flanders, Holland and Zeeland in November 1334.
Several thousand man-days of labour were expended in
repairing and heightening sea walls on the manor over the
following three years, only for the work to be largely
undone by a further inundation in the winter of 1337–38.
A vivid picture of the almost tsunami-like impact of a
major storm surge in this same location several centuries
later was given by Mr. A. Hawkins of Lower Halstow,
adjoining Barksore in 1897:
‘The day was the 18th of November
1897 and the wind had switched suddenly into the opposite
direction from that it had been blowing the day before. The
day was overcast and dull, and the morning tide had ebbed so
far out that no water could be seen in the creek. After
dinner the tide suddenly appeared far down the creek and
rushing up with a ridge of white foam at its front edge.
Very soon it was breaking over the sea walls, overflowing
low-lying roads, houses and buildings. The marshes of great
Barksoar Farm were flooded and many sheep were drowned in
spite of great efforts of Mr. Hanmer and his farm hands…’
(cited by J.H. Evans ‘Archaeological horizons in the
North Kent marshes’, Archaeologia Cantiana 66 (1953), p118). Two farmhands stranded on the sea wall between two breaches
had a narrow escape and were rescued by boat.
Long-term Impacts
While many of the outer estuary marshes continued, by
considerable human effort and expenditure, to be defended
against ‘the violence of the sea’ throughout the later
middle ages, in some locations there was long-term or
permanent reversion to inter-tidal conditions. Slayhills
marsh, part of the Upchurch marshes northwest of Barksore,
was severely flooded, along with large parts of the Isle of
Sheppey and the north Kent coast, by a storm surge in the
autumn of 1404. Four years later it was reported that the
profits of the marsh there had been ‘mostly lost’ since that
time, its lord’s income from it falling from £10 to 26s8d
per year, and the tithe income accruing to Rainham church
from the marsh had also fallen to no more than an eighth of
its previous level. In the eighteenth century the 500 acre
Slayhills marsh was described by the historian Edward Hasted
as ‘gone to sea…nearly the whole of it is become a tract of
salts, which is covered by every spring tide.’
Overall indications are that there was no wholesale
abandonment of marshland around the Thames estuary, but
climatic deterioration, particularly the increasing
frequency and severity of storms, made it increasingly
difficult and uneconomic to defend the more vulnerable
stretches of coast during the period 1250–1450. The
abandonment of some land may, however, have enhanced the
security of other areas by increasing the extent of
inter-tidal and saltmarsh buffer zones capable of absorbing
the power of waves and storing the floodwaters driven
against the coast by all but the most exceptional surges –
strategies which would today be termed ‘managed retreat.’
This report summarises research carried out by Dr
Jim Galloway during a fellowship at the National Maritime
Museum, Greenwich in 2006. The research was subsequently
taken further in a project based at the Institute of
Historical Research, University of London, between 2008 and
2010. Further details and links to publications can be found
on Dr. Galloway's webpages:
https://independent.academia.edu/JimGalloway