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Climate Change and the Vulnerability of the Historic Landscape

Isabel Cook (University of Sheffield) imcook1@sheffield.ac.uk

Abstract

Sea-level rise and coastal erosion have the potential to damage or destroy coastal archaeology and

cultural heritage assets. With a focus on the Dysynni valley, west Wales, this paper proposes a

landscape-scale approach to vulnerability assessment, using Historic Landscape Characterisation in

GIS to capture the time-depth of the cultural landscape. Vulnerability indices will be developed for

assessing the threat posed to the historic character of the landscape. This differs from the site-based

focus of most archaeological vulnerability assessments.

Introduction

Climate change poses a serious yet under-researched threat to archaeological sites and landscapes,

particularly in coastal areas. Research that predicts potential threats to sites is needed to appropriately

manage and mitigate against the risks. Of the forward-looking vulnerability studies that exist, the

majority focus on archaeological sites as separate entities (e.g. Westley et al. 2011; Daire et al. 2012;

Reeder et al. 2012; Daly 2013). This article proposes an alternative approach to assessing the

vulnerability of archaeology to climate change, using a landscape-level perspective based on the

concept of the historic landscape. The increasing threat posed by climate change to archaeology

means that heritage management decisions must prioritise which aspects of cultural heritage to

protect. Approaching the issue with a broader, landscape perspective can help identify the assets most

important to local cultural heritage (Landorf 2009).

Case-study area

The research uses a case study in the Dysynni valley and estuary, situated in Cardigan Bay, in the

county of Gwynedd, North Wales (see Figure 1). The Dysynni Valley is designated as a Landscape of

Special Historic Importance by Cadw, the Welsh Government's historic environment service, as the

region has a long and rich history of human settlement. Most known archaeological sites are in the

upland areas, partly due to the disruption caused by centuries of agricultural activity in the lowlands,

and a lack of archaeological survey in these areas. However, complex cropmarks, field boundary

morphology and the location of find-spots indicate that there remains a wealth of archaeological

information on the valley floor.

The lower and middle reaches of the Dysynni valley are flat and low-lying, with the land below 10m

OD (Ordnance Datum) stretching up to 10km inland. Consequently, the floodplain is vulnerable to

sea-level rise, storm surges, high rainfall events, and other flooding mechanisms. Prior to extensive

drainage and land improvement schemes in the 19th and 20th centuries, large areas of land in the valley

were unproductive marshland. This is indicated by local place-names such as ‘Glan-y-morfa’ (next to

the marsh or salt-marsh), which is now adjacent to drained and improved land, and Penllyn (head of

the lake), south of Tywyn, which is next to a large tidal pool depicted on the early-19th-century tithe

map (Cynefin 2017).

The nature of the Dysynni Valley, as extremely low-lying and overlain by soft alluvial deposits,

means that the coastal effects of climate change such as sea-level rise and storm-surges may impact

archaeological and historical sites located several kilometres inland. Some of these archaeological

sites may be exposed to the effects of climate change before they have been discovered or

investigated. This study area therefore provides a unique opportunity to develop indices of

susceptibility to environmental change for sites that have not, as yet, been researched or protected.

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Coastal impacts of Climate Change

Climate change refers to the observed and projected changes to the Earth’s climate system, mainly

attributed to the effect of anthropogenic emissions (e.g. CO2) on radiative forcing. In the UK, a

temperature rise of 2.5-3°C is predicted by 2100, with accompanying changes to seasonal

precipitation patterns, extreme weather events and sea-level rise (Met Office 2011).

Sea-level rise is predicted to cause an increase in the frequency of flood events due to higher water

levels, an increase in frequency of storm surges, and a change in tidal ranges (Fitzpatrick et al. 2006;

Kelly 2009; Kriebel et al. 2015). The coastline of the Dysynni valley may experience a rise in sea-

level of around 0.905m by 2100 under the A1FI climate scenario (Lowe et al. 2009), mean high tide

of 2.965m above current OD, and extreme high-water levels up to 5.715m above current OD (see

Figure 2; Lowe et al. 2009; National Tidal and Sea Level Facility 2017a; National Tidal and Sea

Level Facility 2017b). Recently flooded areas will develop new drainage patterns, which may create

channels that could cause scour and erode archaeological deposits (Chapman 2002; Edwards et al.

2007; Herle et al. 2009; Kelly 2009). In severe storm events, dunes or sea walls may be breached,

meaning that sites that were previously protected from coastal processes will now be subjected to

saturation and erosion (Murphey et al. 2009).

Figure 1: The Dysynni valley, the case-study area used to demonstrate the proposed landscape-

level methodology of vulnerability assessment. Basemap from ©Wikimedia

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Figure 2: Welsh HLC of the Dysynni Valley (above; Gwynedd Archaeological Trust, n.d.), and English-

style HLC of the Dysynni Valley and surrounding uplands (below).

An increased magnitude of storm events and coastal erosion may also increase the likelihood of

coastal landslides and cliff-collapse, resulting in a permanent loss of archaeological information

(Croft 2013). The threat of erosion is mainly confined to coastlines with soft bedrock and overlying

sediments, including sandstone, boulder clay and alluvial/marine mud (Jones 2002; Trow 2003;

Edwards et al. 2007; Westley et al. 2011; Kelly 2009; Reeder et al. 2012; Croft 2013; Dawson 2015).

Shorelines with more resistant rock, such as granite cliffs, are not significantly threatened by wave

action. However, Trow (2003) states that soft coastlines, for instance estuaries and saltmarshes, are

very important for archaeology as they often maintain favourable preservation conditions, and have

been known to contain middens, submerged Mesolithic sites, shipwrecks, and submerged forests.

Therefore, it may be the coastlines that have the greatest archaeological potential that are at the

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greatest risk of erosion. For instance, on the Scottish Island of North Uist, a storm in 2005 uncovered

Iron Age stone walls at Sloc Sabhaidh (Pitts 2011). The exposed section of the walls was

subsequently washed away, while the area buried beneath a sand-dune remained intact (ibid.). An

increase in the magnitude of storm events will increase the threat of erosion to sites such as this.

Inland impacts of Climate Change

Another impact of climate change is the increased frequency of both drought and high-magnitude

precipitation events. The UKCP09 climate ensemble predictions for mean winter precipitation change

in Wales under the SRES A1B emissions scenario is an increase of 30-40% by the end of the 21st

century, compared to a 1961-1990 baseline (Murphy et al. 2009). High precipitation events, such as

those projected in future climate scenarios, can result in flash flooding and torrents, which can cause

soil erosion in mountainous areas (De Roo 1998). This can also result in erosion and damage to any

archaeological sites located in susceptible areas. In contrast, precipitation during summer months is

predicted to decrease by 10-20% in Wales by the end of the 21st century in the same emissions

scenario (Murphy et al. 2009). This could result in a loss of soil structure, and increase the likelihood

of instability, soil erosion, and landslides, thus endangering the integrity of any archaeological sites

on, or within, the affected area (Colette 2007; Herle et al. 2009; Holický and Sýkora 2010). In hilly

areas, Meylemans et al. (2008) identified that there are more scattered archaeological artefacts on the

surface in areas that have higher erosion rates, which indicates that buried features are being disturbed

and scattered by soil erosion. Earthwork features are particularly threatened as they are eroded with

the surrounding sediment and may leave little trace (ibid.). This threatens not only the archaeological

sites themselves, but also the character of the landscape.

Climate models predict that sub-zero temperatures will become less common during winter months as

a result of climate change, so the main threat of temperature change will be caused by rising summer

temperatures (Murphy et al. 2009; Jones et al. 2010). In a medium emissions scenario, mean daily

maximum summer temperature in Wales is projected to increase by 4-5°C by the 2080s (UKCP09:

Murphy et al. 2009). This may cause desiccation of peat and soils, thus increasing the risk of soil

erosion and the desiccation of any wet-preserved remains.

Current vulnerability assessment methodologies in Archaeology

In order to assess the vulnerability of coastal archaeological sites and features to the threats posed by

climate change, many studies develop Vulnerability Indices (VIs). They can take into account the

exposure of the site to risks and the sensitivity of the cultural heritage resource itself. VIs have been

developed for archaeological and historical sites in many locations worldwide, including

Newfoundland, France, the Santa Barbara Channel, Skellig Michael, Chesapeake Bay, and Northern

Ireland, (Westley et al. 2011; Daire et al. 2012; Reeder et al. 2012; Daly 2013; Chadwick-Moore

2014; Westley and McNeary 2014, respectively).

VIs assessing the vulnerability of coastal archaeology to coastal processes and climate change are

generally developed to examine the vulnerability of individual sites. They can be used to generate

statistical data about the number of sites threatened in different climate change scenarios. For

example, Westley and McNeary (2014) studied which archaeological sites on the Irish coastline were

at risk of erosion. They identified the actively eroding areas of coastline, and determined which sites

were located within 15m and 150m of these areas. In their results, each archaeological site is

characterised as having low, medium or high vulnerability to erosion. This site-focussed approach is

common across almost all VI assessments of archaeology (e.g. Daire et al. 2012; Reeder et al. 2012;

Chadwick-Moore 2014; Van Rensselaer 2014).

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There are several limitations to this approach when assessing the vulnerability of the cultural heritage

of an area. Focussing on sites alone may not provide a full picture of the threat to cultural heritage if

the study area has not been systematically surveyed, and not all archaeological sites have been

discovered. For instance, little archaeological research has been carried out in the lowlands of the

Dysynni valley. A site-based vulnerability assessment based on incomplete knowledge about the

sites that exist in the study area will not provide an accurate picture of the vulnerability of the local

cultural heritage. Furthermore, the meaning and value of archaeological sites is informed by their

relationship with the surrounding sites and landscape. However, most studies do not consider the

impact of any damage to sites on the overall character of the historic environment, for instance

whether the majority of sites at risk are a relic of military activity or are characteristic of local

industrial activity. Therefore, the results of these studies can only inform a comparison between single

sites and do not reveal threats to the wider cultural heritage and historic landscape.

Another limitation is that there is no consensus around what exactly constitutes a site, and how it

might be delineated from the surrounding landscape. Often, the term ‘site’ is used to refer to a place in

which there is a concentration of evidence of human activity, such as monuments, shipwrecks, or

clusters of artefacts, but it is not used for single find-spots (Dunnell 1992). Dunnell (1992) argues,

therefore, that ‘sites’ are “not really things or qualities, but rather concentrations or quantities” (p.29).

Using this argument, the archaeological record could be seen not as a collection of individual sites,

but as a more or less concentrated distribution of artefacts across the Earth’s surface (Dunnell and

Dancey 1983). This raises questions about how ‘sites’, as concentrations of the evidence of activity,

can be removed from the surrounding landscape, in which human activity also took place (Cooney

2003). From the perspective of VIs, assessing the ‘sites’ individually does not take into account the

broader vulnerability of the historic landscape and cultural heritage of the area, which substantially

contributes to the meaning and value of specific places (or sites).

A Landscape-focussed approach

To address the limitations in assessing the vulnerability of archaeology on a site-by-site basis, this

article proposes a methodology for assessing the vulnerability of cultural heritage on a landscape

level. The approach proposed in this paper is based on the concept of the historic landscape. The

underpinning philosophy is that the historic landscape is not a physical object or defined geographical

area, but rather it is “an artefact of past land-use, social structures and political decisions” (Fairclough

et al. 2002, p.70). The historic landscape is considered to be spatially continuous rather than atomised

into individual historic sites. This recognises the historic presence of humans in the landscape around

their settlements and monuments, rather than isolating archaeological sites from their surroundings

(Clark et al. 2004). Moreover, it considers sites to be meaningful as they exist within their spatial

context, rather than their importance and meaning being separate from the landscape. Therefore, this

paper considers the impact of climate change not on the archaeological and historical sites of the

valley in isolation, but rather the impact of climate change on the historic landscape comprising the

sites and features within it.

Historic Landscape Characterisation

The research uses Historic Landscape Characterisation (HLC), a method of landscape analysis and

interpretation, to analyse the historic landscape and classify areas of different historic character (see

Fairclough 2006; Turner 2006; Historic England 2017). The basic premise of HLC is that human

activity during different periods of history shaped the aesthetic character of landscapes, for instance

through the structure of settlements, field boundaries, and the location of industry (Fairclough et al.

2002; Rippon 2013). The visible evidence of past land-use in the present landscape represents the

historic, political or social processes that occurred there (Fairclough 2003; Bradley et al. 2004). HLC

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is well-established in England as an approach to mapping the character and time-depth of a landscape;

Historic England manage an HLC programme, with most of the work undertaken at a local level by

local authorities and commercial companies. However, the approach used in Wales varies

significantly from the English methods. In England, areas of land are characterised into pre-defined,

thematic Landscape Character Areas (LCAs), whereas in Welsh HLC projects each LCA is uniquely

defined, which obscures the trends in historic land-uses across the landscape. For instance, HLC has

already been undertaken for the Dysynni Valley by Gwynedd Archaeological Trust, with LCAs such

as Dysynni lowlands, Tywyn, Llanegryn, Intermediate slopes, Upper slopes, Enclosed northern slopes

(Gwynedd Archaeological Trust, n.d., see Figure 2). In contrast, in English HLC projects attributes

are grouped to form LCA types, such as Settlements, Woodland, Military Land, and different types of

field system, so similar but geographically separate areas are characterised by the same LCA type

(Clarke et al. 2004; see Figure 2). The LCA types in Welsh HLC projects are not useful for

characterising the landscape or defining past land use. There are areas of very similar character in

different areas of the valley, suggesting that similar activities and land-use took place in different

areas. By creating different LCA types for different areas of the landscape, it implies that past

activities and land use in one area were separate and distinct from those in another area. Therefore, the

English method is the most suitable for the purpose of this research.

A range of sources were used to identify and classify the different areas of historic character into LCA

types in the Dysynni valley (see Figure 2). Modern and historic maps dating to the 19th century were

compared to identify areas in which the current landscape structure was a relic of historic land use.

The HLC was also informed by the location of known archaeological sites in the Historic

Environment Record (HER) and National Monuments Record Wales (NMRW). These provide a

comprehensive record of the known archaeological features in the study area, and contain information

such as the age, type, and description of each site. Cropmarks identified in aerial photographs, and

subterranean features revealed in geophysical surveys, also informed the characterisation of areas of

the landscape (See Figure 3).

Figure 3: Location of known cropmarks in the study area, as identified in aerial photographs Basemap

from ©OpenStreetMap

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Methodology

The approach proposed by this paper addresses vulnerability to climate change on a landscape level

using a VI with two equations. The first calculates the vulnerability of a select number of

archaeological features using criteria based on the characteristics of the site and surrounding area,

such as level of preservation, resistance of local substrate, and slope steepness. The second equation

calculates the vulnerability of each LCA based on the results of the first equation, and the exposure of

the LCA to future sea-level rise, coastal erosion and soil erosion.

Vulnerability of archaeological features

Five variables were considered in the vulnerability equation for the archaeological features: current

levels of preservation, resistance of the remains, resistance of the local substrate, the susceptibility of

the feature to projected temperature changes, and the susceptibility of the feature to projected

precipitation changes in the 21st century. These variables are all scored between 1 (low vulnerability)

and 5 (high vulnerability) (See Table 1, Appendix).

The vulnerability score for each archaeological site (VA) is calculated using the following equation:

𝑉𝐴 =𝑎 + 𝑏 + 𝑐 + 𝑑 + 𝑒

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Where a = level of preservation, b = resistance of the remains, c = resistance of the local substrate, d =

susceptibility to projected climate change (precipitation), e = susceptibility to projected climate

change (temperature). The score calculated is an average of the different variable scores, as the VA

will be used in a second equation in which the variables are also scored between 1 and 5.

Variables a, b and e will be measured during site visits, and variable c will be assessed based on local

geology maps. For variable d, a model of flow accumulation was created to identify the areas most

susceptible to projected increases in precipitation, to indicate which sites may be at risk, and to inform

the vulnerability index and influence decision-making. Flow accumulation is an indication of where

water flowing down a slope will accumulate based on the topography, for instance in gullies and

valley bottoms. Areas with greater flow accumulation are areas in which runoff from upslope areas

accumulates, and are therefore areas that are more likely to experience torrents and gully erosion

during high rainfall events (Mitasova et al. 1996; Zlocha and Hofierka 2014). The r.flow algorithm

was used in GIS, which uses a digital elevation model (DEM) to construct flowlines downhill from

each cell in order to identify areas where flowlines accumulate (Heywood et al. 2011).

A limitation of this model is that the amount and pattern of runoff in a catchment is related not only to

the likely direction of water flow, but also factors such as the amount of infiltration into groundwater,

soil water storage, soil moisture, evapotranspiration, and the presence of vegetation (Gurtz et al.

2003). Therefore, the model produced based on the DEM alone is unlikely to be a very accurate

representation of the amount of discharge and runoff in different parts of the catchment. However, a

high level of accuracy is not necessarily required in this study, as the aim is to identify areas at more

or less risk of erosion from runoff rather than to project exact volumes of discharge (see De Roo

1998).

Vulnerability of Landscape Character Areas

A vulnerability score for the historic landscape character areas is calculated using the vulnerability of

the archaeological sites, such as those in the HER and NMRW databases, that characterise the LCA. It

will also include the number of similar sites that exist in the LCA, the proportion of the LCA that is

threatened by sea-level rise and inundation, the proximity of the LCA to an eroding stretch of

shoreline, and the susceptibility of the soil types in the LCA to erosion. As before, each criterion is

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scored between 1 and 5 (see Table 2, appendix).

The equation for calculating the vulnerability of LCAs (VLCA) is:

𝑉𝐿𝐶𝐴 = 𝑉𝐴 + 𝑓 + 𝑔 + ℎ + 𝑖

Where VA = the vulnerability score for the archaeological sites that characterise that LCA, f = number

of archaeological sites of that type in the LCA, g = proximity to eroding shoreline, h = risk of coastal

flooding, and i = susceptibility of soil type to erosion.

Variable VA is based on the results of the first vulnerability equation, and variable f is informed by the

data available in the HER and NMRW databases. Variable g is informed by the amount of coastal

retreat identified between the mean high-water (MHW) marks on the OS 1st Edition County Series

map (1853-1904, last amended in 1888) and the modern OS map. Using GIS, points were created

every 200m along the modern MHW mark including information on the amount of retreat between the

two maps, which can be used to calculate the rate of erosion (see Figure 5). The greatest retreat

measured was 56m, which is an average of 43.75cm per year. This could result in an additional

36.75m of erosion in this area should the rate of erosion stay constant. A limitation of this approach is

that projected sea-level rise, changes to wave conditions and storminess have not been included in the

amount of erosion predicted. Furthermore, this model does not consider the location of coastal

defences.

The risk of coastal flooding (variable h) in the sea-level rise scenarios mentioned above was modelled

in GIS. Masks were created of the areas that would be below the three projected water levels (see

Figure 6). This was based on UKCP09 and IPCC sea-level projections for 2100, and tidal data from

Barmouth, 12.4 kilometers north of the mouth of the Dysynni. Some scholars predict that sea-level

rise may lead to an increase in estuarine tidal range (e.g. Fujii 2012, Robins et al. 2016). However,

due to the uncertainty around the impact of future mean sea-level change on estuarine dynamics and

high-water levels (see Lewis et al. 2011), the tidal range of the Dysynni was kept constant in models

used in this research. The results indicate that significant areas of land would be at or below the water

level under these scenarios, and therefore at risk of inundation and flooding. This model is simplistic,

and therefore does not include consideration of the coastal defences that exist in some areas.

However, due to the very low-lying nature of the valley floor, even a small gap in defences could lead

to large areas of flooding.

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Figure 4: Flow accumulation in the study area. The colour of the point data indicates the flow density

at the location of each archaeological site. The unit of measurement for flow accumulation is the

cumulative number of all cells that flow into each downslope cell.

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Figure 5: The average rate of erosion along the Dysynni coastline between 1888 and 2016. Points

were calculated every 200 metres Basemap from ©Wikimedia

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Figure 6: Maps indicating the areas at or below the

water level under different sea-level scenarios. The red

line indicates current Ordnance Datum

a) 0.905m OD: the new mean sea-level by 2100 under

the SRES A1FI scenario, with a sea-level rise of 0.905m

b) 2.965m OD: the mean level of high-tide by 2100 under

the SRES A1FI scenario, with a sea-level rise of 0.905m if

the tidal range remained constant.

c) 5.715m OD: the potential extreme high-water level by

2100 under the A1FI scenario if an astronomical tide the

same level as the highest astronomical tide recorded at

Barmouth between 2008 and 2016 coincided with a

skew surge (the difference between the maximum

predicted water level, and the maximum observed water

level) the same level as one experienced at Barmouth on

24/12/1997

Basemap from ©Wikimedia

c)

a) b)

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The susceptibility of LCAs to soil erosion was calculated using data provided by the British

Geological Survey, which included information such as the soil type, rate of drainage, steepness, and

susceptibility to certain threats. These criteria to identify the susceptibility to erosion in different areas

(Figure 7).

The results of this VI reveal differences in the vulnerability of different landscape character areas

within the Dysynni valley, and therefore indicate what elements of the historic landscape are most at

risk from the impacts of climate change. This information could be useful for informing the

management of the region’s cultural heritage.

Figure 7: Relative susceptibility of soil types in the Dysynni valley and uplands to soil erosion, from 0

(low) to 5 (high). The scores given were based on the criteria outlined in Table 2. Basemap from

©Ordnance Survey

Justifying a landscape-level vulnerability assessment

This paper proposes a new method of vulnerability assessment that considers the way in which

climate change, or indeed other risks, may threaten the historic character of landscapes rather than just

the sites within them.

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The choice of observational scale in a study is an important consideration, as the observational scale

chosen can influence the results and conclusions drawn (Lam 2004; Sayre 2009). For instance,

research into the most economically efficient method of coastal protection for East Anglia. When the

entire East Anglian coastline is assessed, hard defences appear the most efficient method of coastal

protection (Turner et al. 1995). However, when assessed at a higher resolution, hard coastal defences

were less efficient than other management strategies in some areas (ibid.). This exemplifies the way in

which the scale of sampling and analysis can affect the patterns that are observed or not observed

within the data, and therefore affect the results of the research. Research over a larger spatial level can

reveal processes of interdependence that may not be evident on smaller spatial levels, but result in

generalisations in the data, which can cause smaller, complex processes to be obscured (Turner 1989;

Cash and Moser 2000). On the other hand, studies with a smaller spatial extent can illuminate the way

in which global processes influence, or manifest in, a specific locality. Studies that focus only on local

level issues, however, may not be useful for policymakers operating at a higher (i.e. national) level, or

for drawing wider conclusions about these processes (Wilbanks and Kates 1999; Cash and Moser

2000). Therefore, choosing the scale and level of inquiry is an important decision, and should be

justified based on the processes or phenomena in question, and the purpose of the results (McMaster

and Sheppard 2004; Sayre 2005). In developing a methodology to assess the vulnerability of

archaeology on a broader (landscape) scale, this paper aims to shift the focus of vulnerability studies

in archaeology towards the wider impact on cultural heritage and historic landscape, rather than

looking only at sites out of context. Therefore, the decision to focus on the level of the Dysynni valley

landscape and the LCAs, rather than individual sites, will influence the results of the vulnerability

assessment. There is a wealth of information and value in the way that features are situated within the

landscape, and how they relate to other features. For example, over 430 industrial features in the HER

and NMRW records for the Dysynni valley date to the post-medieval period, such as mine shafts,

quarries, and associated buildings. It is likely that many of these features are related to one another,

for instance in their role in the growth of local industry, the materials they produce, the people that

owned them or worked in them, and the way they are perceived by local people today. Therefore,

studying these features in isolation risks obscuring information that may be held at a higher spatial

level.

In terms of heritage management, the information generated from this type of approach is useful for

informing a holistic approach to heritage management. This is because it considers the cultural

heritage of the landscape as predominantly informed by the character of the historic landscape, and

both the tangible and intangible heritage features within it, rather than just the archaeological sites.

With an increasing threat to coastal archaeology from the impacts of climate change across Britain

(and indeed worldwide), it is unlikely that the resources exist to protect all archaeological sites at risk.

Therefore, it is important to consider a broader perspective on cultural heritage management, to

identify the key areas of importance to local heritage (Landorf 2009).

Conclusion and Next Steps

This paper has proposed a methodology for assessing the vulnerability of cultural heritage to climate

change on a landscape-level, in order to inform proactive management approaches beyond identifying

the sites more or less at risk. Going forward, the VI will be applied to the features and LCAs in the

Dysynni valley to identify any limitations of the proposed approach. The limitations identified in the

simple models used in the vulnerability assessment calculations will be addressed, for instance by

including consideration of the coastal and riverine defences in the study area. The results of the VI

will also be used to inform research into potential approaches to sustainably manage the risks

identified.

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Bibliography

Bradley, A., Buchli, V., Fairclough, G., Hicks, D., Miller, J., and Schofield, J., 2004. Change and

Creation: historic landscape character 1950-2000. London: English Heritage

Cash, D.W. and Moser, S.C., 2000. Linking global and local scales: designing dynamic assessment

and management processes. Global environmental change 10(2), pp.109-120.

Chapman, H.P., 2002. Global warming The implications for sustainable archaeological resource

management. Conservation and Management of Archaeological Sites 5(4), pp.241-245.

Clarke, J., Darlington, J., and Fairclough, G., 2004. Using Historic Landscape Characterisation.

English Heritage and Lancashire County Council, 73pp.

Colette A. 2007. Climate Change and World Heritage: Report on Predicting and Managing the

Impacts of Climate Change on World Heritage and Strategy to Assist States Parties to Implement

Appropriate Management Responses. World Heritage Report No. 22. Paris: UNESCO World Heritage

Centre

Cooney, G., 2003. Social Landscapes in Irish Prehistory. In Layton, R., and Ucko, P. (eds.). The

Archaeology and Anthropology of Landscape: Shaping Your Landscape. Routledge, pp.46-65

Croft, A. 2013. Assessment of Heritage at Risk from Environmental Threat. Key Messages Report for

English Heritage. https://content.historicengland.org.uk/images-books/publications/assessment-

heritage-at-risk-from-environmental-threat/Key_Messages_Report.pdf/

Cynefin, 2017. Tywyn, visualize [online]. Available at http://cynefin.archiveswales.org.uk/en/tithe-

maps/visualize/#Tywyn&/transcribe/119235387960/&/georeference/094191668331/&/visualize/0941

91668331&&/map/298363905266/ [Accessed 18 December 2017]

Daire, M.Y., Lopez-Romero, E., Proust, J.N., Regnauld, H., Pian, S. and Shi, B., 2012. Coastal

changes and cultural heritage (1): Assessment of the vulnerability of the coastal heritage in Western

France. The Journal of Island and Coastal Archaeology 7(2), pp.168-182

Daly, C., 2013. A cultural heritage management methodology for assessing the vulnerabilities of

archaeological sites to predicted climate change, focusing on Ireland’s two World heritage sites

(Doctoral dissertation, PhD thesis. Dublin Institute of Technology).

Dawson, T., 2015. Eroding Archaeology at the Coast: How a Global Problem is being Managed in

Scotland, with Examples from the Western Isles. Journal of the North Atlantic 9, pp.83-98.

De Roo, A.P.J., 1998. Modelling runoff and sediment transport in catchments using GIS.

Hydrological processes 12(6), pp.905-922

Dunnell, R.C., 1992. The notion site. In Rossignol, J., and Wandsnider, L (Eds.). Space, time, and

archaeological landscapes, Springer Science & Business Media, pp.21-42

Dunnell, R.C. and Dancey, W.S., 1983. The siteless survey: a regional scale data collection strategy.

Advances in archaeological method and theory 6, pp.267-287.

Edwards, R., O’Sullivan, A., Brooks, A., Quinn, R., Bell, T., and Warren, G. 2007. A Vulnerability

Assessment of Ireland’s Coastal Archaeological Heritage. Report for the Heritage Council:

Archaeology Grant (Ref: TRINI 382). [poster] Available at

http://www.science.ulster.ac.uk/cma/slan/CAA_2007_edwards_et_al.pdf

15

Fairclough, G.J., Lambrick, G. and Hopkins, D., 2002. Historic landscape characterisation in England

and a Hampshire case study. In Faircloguh, G., Rippon, S., and Bull, D (Eds.) Europe’s Cultural

Landscape: archaeologists and the management of change, Europae Archaeologiae Consilium,

Belgium, pp.69-83.

Fairclough, G.J., 2003. Cultural landscape, sustainability and living with change? In Teutonico, J. M.,

and Matero, F. (Eds.), Managing Change: sustainable approaches to the conservation of the built

environment, The proceedings of the US/ ICOMOS 4th International Symposium April 5-8, 2001,

Philadelphia, pp.23-46

Fairclough, G., 2006. Large scale, long duration and broad perceptions: scale issues in historic

landscape characterisation. In Confronting scale in archaeology, Springer US, pp.203-215

Fitzpatrick, S.M., Kappers, M. and Kaye, Q., 2006. Coastal erosion and site destruction on Carriacou,

West Indies. Journal of Field Archaeology 31(3), pp.251-262.

Fujii, T., 2012. Climate change, sea-level rise and implications for coastal and estuarine shoreline

management with particular reference to the ecology of intertidal benthic macrofauna in NW Europe.

Biology 1(3), pp.597-616.

Gurtz, J., Zappa, M., Jasper, K., Lang, H., Verbunt, M., Badoux, A. and Vitvar, T., 2003. A

comparative study in modelling runoff and its components in two mountainous catchments.

Hydrological Processes 17(2), pp.297-311.

Gwynedd Archaeological Trust/Ymddiriedolaeth Archaeolegol Gwynedd, n.d. Historic Landscape

Characterisation – Dysynni [online]. Available at http://www.heneb.co.uk/hlc/dysynni.html

[Accessed 12 September 2017]

Herle, I., Herbstová, V., Kupka, M. and Kolymbas, D., 2009. Geotechnical problems of cultural

heritage due to floods. Journal of Performance of Constructed Facilities 24(5), pp.446-451.

Heywood, I., Cornelius, S., and Carver, S., 2011. An Introduction to Geographical Information

Systems 4th ed. Harlow: Pearson Education Limited

Historic England, 2017. Historic Landscape Characterisation [online]. Available at

https://historicengland.org.uk/research/methods/characterisation-2/ [Accessed 15 November 2017]

Holický, M., and Sýkora, M., 2010 Assessment of flooding risk to cultural heritage in historic sites.

Journal of Performance of Constructed Facilities 24(5), pp. 432–438

Jones, N. 2002. Description of the coast. In Davidson, A. (ed.) The Coastal Archaeology of Wales.

Council for British Archaeology, pp.9-18

Jones, P., Harpham, C., Kilsby, C., Glenis, V., and Burton, A., 2010. UK Climate Projections science

report: Projections of future daily climate for the UK from the Weather Generator. Met Office

Hadley Centre, Exeter, UK. 45pp

Kelly, B., 2009. Implications for the cultural heritage of Irelands coast and inland waterways. In Kelly

B, Stack M (eds) Climate change, heritage and tourism: implications for Ireland’s Coast and Inland

Waterways, The Heritage Council, pp.82-100

Lam, N. S-N., 2004. Fractals and Scale in Environmental Assessment and Monitoring. In Sheppard,

E. and McMaster, R.B. (eds.) Scale and geographic inquiry: Nature, society, and method. John Wiley

& Sons, pp.23-40

Landorf, C., 2009. A framework for sustainable heritage management: a study of UK industrial

heritage sites. International Journal of Heritage Studies 15(6), pp.494-510.

16

Lewis, M., Horsburgh, K., Bates, P. and Smith, R., 2011. Quantifying the uncertainty in future coastal

flood risk estimates for the UK. Journal of Coastal Research 27(5), pp.870-881.

Lowe, J. A., Howard, T. P., Pardaens, A., Tinker, J., Holt, J., Wakelin, S., Milne, G., Leake, J., Wolf,

J., Horsburgh, K., Reeder, T., Jenkins, G., Ridley, J., Dye, S., Bradley, S., 2009. UK Climate

Projections science report: Marine and coastal projections. Met Office Hadley Centre, Exeter, UK.

99pp.

McMaster, R. B., and Sheppard, E., 2004. Introduction: Scale and Geographic Inquiry. In Sheppard,

E. and McMaster, R.B. (eds.) Scale and geographic inquiry: Nature, society, and method. John Wiley

& Sons, pp.1-22

Met Office, 2011. Climate: Observations, projections and impacts. Met Office Hadley Centre, Exeter,

UK. 153pp.

Meylemans, E., Vanmontfort, B., and Van Rompaey, A., 2008. The evaluation of archaeological sites

using LIDAR and erosion/sedimentation modelling. The Archaeology of Erosion, the Erosion of

Archaeology Conference Papers, 28-30 April, pp.23-36

Mitasova, H., J. Hofierka, M. Zlocha, L.R. Iverson, 1996, Modeling topographic potential for erosion

and deposition using GIS. Int. Journal of Geographical Information Science 10(5), 629-641.

Murphy, P., Thackray, D. and Wilson, E., 2009. Coastal heritage and climate change in England:

assessing threats and priorities. Conservation and management of Archaeological Sites,11(1), pp.9-15

National Tidal and Sea Level Facility, 2017a. Storm Surge Climatology: Wales [online]. Available at

http://www.ntslf.org/storm-surges/storm-surge-climatology/wales [Accessed 12 October 2017]

National Tidal and Sea Level Facility, 2017b. Highest & lowest predicted tides [online]. Available at

http://www.ntslf.org/tides/hilo [Accessed 12 October 2017]

Pitts, M. 2011. 6 threatened sites. British Archaeology 118 [Accessed 28/10/16] Available at

http://www.archaeologyuk.org/ba/ba118/feat2.shtml

Reeder, L.A., Rick, T.C. and Erlandson, J.M., 2012. Our disappearing past: a GIS analysis of the

vulnerability of coastal archaeological resources in California’s Santa Barbara Channel region.

Journal of Coastal Conservation 16(2), pp.187-197.

Rippon, s. 2013. Historic Landscape Character and Sense of Place. Landscape Research 38(1),

pp.178-202

Robins, P.E., Skov, M.W., Lewis, M.J., Giménez, L., Davies, A.G., Malham, S.K., Neill, S.P.,

McDonald, J.E., Whitton, T.A., Jackson, S.E. and Jago, C.F., 2016. Impact of climate change on UK

estuaries: A review of past trends and potential projections. Estuarine, Coastal and Shelf Science,

169, pp.119-135.

Sayre, N.F., 2005. Ecological and geographical scale: parallels and potential for integration. Progress

in human geography 29(3), pp.276-290.

Sayre, N. 2009. Scale. In Castree, N., Demeritt, D., Liverman, D., and Rhoads, B., (Eds.) A

Companion to Environmental Geography. Wiley-Blackwell, Chichester, pp. 95-108

Trow, S. 2003. Coastal defence and the historic environment. English Heritage, London. 16pp.

Turner, M.G., O'Neill, R.V., Gardner, R.H. and Milne, B.T., 1989. Effects of changing spatial scale

on the analysis of landscape pattern. Landscape ecology 3(3-4), pp.153-162

17

Turner, R.K., Adger, N. and Doktor, P., 1995. Assessing the economic costs of sea level rise.

Environment and Planning A 27(11), pp.1777-1796.

Turner, S., 2006. Historic Landscape Characterisation: a landscape archaeology for research,

management and planning. Landscape Research 31(4), pp.385-398.

Westley, K., Bell, T., Renouf, M.A.P. and Tarasov, L., 2011. Impact assessment of current and future

sea-level change on coastal archaeological resources—illustrated examples from northern

Newfoundland. The Journal of Island and Coastal Archaeology 6(3), pp.351-374.

Westley, K. and McNeary, R., 2014. Assessing the impact of coastal erosion on archaeological sites: a

case study from Northern Ireland. Conservation and Management of Archaeological Sites 16(3),

pp.185-211.

Wilbanks, T.J. and Kates, R.W., 1999. Global change in local places: how scale matters. Climatic

change 43(3), pp.601-628.

Zlocha, M., and Hofierka, J., 2014. R.flow [online]. Available at

https://grass.osgeo.org/grass64/manuals/r.flow.html [Accessed 24 October 2017]

Appendix

Table 1 : Description of the variables used in the VI for archaeological sites and features

Variable Classes Score

Level of preservation

Good/no visible damage/buried 1

Some small damage or visible weathering to structure. Buried archaeological feature slightly exposed

2

Buried features are exposed and show signs of weathering, structures show structural damage and weakness

3

Significant weathering damage, little evidence remains of the features 4

Extremely damaged, ephemeral remains 5

Resistance of the remains

Solid built feature, actively used, managed or protected. 1

Made of resistant materials such as rock/stone, but is less fixed i.e. a drystone structure

2

Made of less resistant materials, such as organic remains, but remains buried or has a small amount of protection

3

Feature or site characterised by a collection of artefacts rather than a structure, so lacking foundations. Also made of less resistant materials 4

Features made of a less resistant or very fragile material that may have been previously buried but are now exposed. Any organic remains.

5

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Resistance of local substrate

Feature is positioned on solid bedrock, in an area of low relief (<5°) with no visible weathering or erosion nearby 1

Feature is positioned on solid bedrock in an area of medium relief (5-15°). Little visible weathering or erosion in the area.

2

Feature is positioned on bedrock in an area of high relief (>15°), or on unconsolidated sediments in a low relief area. Some visible erosion and weathering in the vicinity 3

Feature is positioned on or in unconsolidated sediments or sand in a low/medium relief area. Visible weathering or erosion nearby 4

Feature is positioned on or in unconsolidated sediments or sand in an area of high relief. Significant visible erosion and weathering near the remains 5

Susceptibility to projected

temperature change

Solid built feature, made of rock or other resistant material 1

Buried features not thought to include organic remains 2

Organic or wet-preserved remains, but located in areas unlikely to be prone to desiccation, such as the intertidal zone 3

Living features such as parks and gardens 4

Organic or wet-preserved remains, in areas susceptible to desiccation or peat fires i.e. uplands 5

Susceptibility to projected

precipitation change

Solid built feature, actively used, managed or protected. Located in very low flow accumulation area (<20), or in intertidal zone 1

Made of resistant materials such as rock/stone, but is less fixed i.e. a drystone structure. In a low flow accumulation area (20-50)

2

Made of resistant materials, but located in areas with moderate flow accumulation (50-150). Alternatively, made of less resistant materials such as earthworks or organics and/or located on unconsolidated sediments in areas with low flow accumulation (<50) 3

Made of less resistant materials such as earthworks or organics and/or located in unconsolidated sediments in areas with moderate flow accumulation (50-150) 4

Made of less resistant materials and located in valley or gully areas with high flow accumulation (>150) Organic or wet preserved remains susceptible to desiccation 5

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Table 2: Description and division of the variables used to calculate the vulnerability score for LCAs

Variable Classes Score

Mean vulnerability score of the features characteristic of this LCA

1<=x<1.5 1

1.5<=x<2 2

2<=x<3 3

3<=x<4 4

4<=x<=5 5

Number of similar features that characterise this LCA

over 50 (or none) 1

25-50 2

10-25 3

5-10 4

Less than 5 5

% of LCA at risk of flooding and storm surge

None of the LCA area at risk of sea-level rise, storm surges or flooding by 2100

1

<30% threatened by high storm surge or flooding from rivers, but none threatened by sea-level rise.

2

30%-60% threatened by high storm surges or river flooding and <30% threatened by sea-level rise alone.

3

>60% threatened by storm surges (below 5.715m OD) and river flooding, and/or 30-60% of the LCA threatened by sea-level rise 2100 (within 2.965m OD)

4

>60% at risk of inundation by 2100 (within 2.965m OD)

5

Proximity to unprotected eroding shoreline

None/<10% of the LCA is located within 100m of unprotected shoreline or eroding

1

10<50% of LCA area is between 50-100m away from the erosion buffer zones in areas of unprotected shorelines

2

10<50% of LCA area is located 25-50m away from the erosion buffer zones. OR most sites (>50%) are located within 50-100m of the erosion buffer zones.

3

>50% of LCA is located within, or within 25m of, the erosion buffer zones.

4

>50% of the LCA located sea-ward of the erosion buffer line, and so is at high risk of damage or destruction by 2100

5

Susceptibility of soil type to erosion

Very little risk, as soils are freely draining, relatively cohesive, and low relief.

1

One of the following criteria: In an area at risk of floodwater scouring or runoff Sandy/unstable soils at risk of wind erosion during dry periods Risk of sheet erosion during high-precipitation events

2

20

Shallow soils and bare rock in places Risk of soil erosion due to grazing and trampling Slow or impeded drainage Steep slopes

Two of the above criteria

3

Three of the above criteria

4

Four or more of the above criteria 5