Investigating Heritage and Climate Change in the Coastal and Maritime Environments of Wales and Ireland: A Guide to the CHERISH Toolkit

Abstract

In March 2023 the EU-funded CHERISH project published its free user-guide and methodology for investigating heritage and climate change in the coastal and maritime environment (Barker and Corns 2023). This paper provides an overview of the publication, specifically the CHERISH toolkit – the 15 approaches employed by the multi-disciplinary project to investigate at-risk heritage sites in Wales and Ireland. Using the eroding coastal hillfort of Dinas Dinlle in Wales as a case study, the toolkit which combines air, land and sea-based investigation techniques is highlighted. This article will assist users going forward in identifying relevant approaches to the study of their own at-risk sites. It is relevant to a wide-ranging audience anywhere in the world, taking into consideration a variety of requirements such as the environment, budget, and outputs.

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Ym mis Mawrth 2023, cyhoeddodd prosiect CHERISH a ariennir gan yr UE ei fethodoleg a'i ganllaw am ddim i ddefnyddwyr ar gyfer ymchwilio i dreftadaeth a'r newid yn yr hinsawdd yn yr amgylchedd arfordirol ac arforol (Barker and Corns 2023). Mae'r papur hwn yn rhoi trosolwg o'r cyhoeddiad, ac yn benodol o becyn cymorth CHERISH – y 15 dull a ddefnyddir gan y prosiect amlddisgyblaethol i ymchwilio i safleoedd treftadaeth sydd mewn perygl yng Nghymru ac Iwerddon. Gan ddefnyddio bryngaer arfordirol Dinas Dinlle sy'n erydu fel astudiaeth achos, rhoddir sylw i'r pecyn cymorth sy'n cyfuno technegau ymchwilio o'r awyr, y tir a'r môr. Bydd y papur hwn yn cynorthwyo defnyddwyr yn y dyfodol i adnabod dulliau perthnasol o astudio eu safleoedd nhw sydd mewn perygl. Mae'n berthnasol i gynulleidfa eang ym mhob cwr o'r byd, ac mae'n ystyried amrywiaeth o ofynion megis yr amgylchedd, y gyllideb ac allbynnau.

The CHERISH (Climate, Heritage and Environments of Reefs, Islands and Headlands) project was initiated to raise awareness and understanding of the past, present, and near-future impacts of climate change on the rich cultural heritage of the Welsh and Irish seas and coast. Studies of climate records in Wales and Ireland show that the long-term prevailing weather conditions (the climate) are changing, characterized by warmer mean temperatures; hotter, drier summers; warmer, wetter winters; and more frequent extreme weather events such as storms (Daly 2019:18; Historic Environment Group, Climate Change Subgroup 2020:4). The impacts of this on the cultural heritage of both countries are numerous and becoming increasingly visible, as highlighted in a CHERISH-commissioned bespoke work of art by Carys Tait (Figure 1).

Figure 1. CHERISH commissioned artwork by Carys Tait illustrating how climate change is affecting the coastal heritage of Wales and Ireland. (© Carys Tait/Carys-ink.com. Image created for the CHERISH Project. © Crown: CHERISH PROJECT.)

CHERISH brought together four government and academic organizations from Wales and Ireland: (1) the Royal Commission on the Ancient and Historical Monuments of Wales, a national body of survey and record for the archaeological, built, and maritime heritage of Wales; (2) the Discovery Programme, Center for Archaeology and Innovation Ireland; (3) Aberystwyth University: Department of Geography and Earth Sciences; and (4) Geological Survey Ireland. The project ran for six and a half years between January 2017 and June 2023 and benefited from €4.9 million of European Union funds through the Ireland–Wales Territorial Co-operation Programme 2014–2020, linked specifically to funding Priority 2: Adaptation of the Irish Sea and Coastal Communities to Climate Change.

Drawing on the shared expertise of the four partners, the principal initiatives of CHERISH were to do the following:

• • Target data and knowledge gaps to raise awareness of heritage in remote coastal locations. This form of data collection was undertaken through techniques such as lidar and Coastal Zone Assessment (CZA), producing enhanced and updated national Historic Environment Records to aid protection and management going forward—for example, through Coflein, the online catalog of archaeology, buildings, industrial, and maritime heritage in Wales.

• • Establish new metrically accurate baseline data and recording standards of heritage-at-risk sites. Baseline data collection and recording was specifically aimed at enabling future monitoring of climate change impacts and was undertaken through techniques such as uncrewed aerial vehicle (UAV) survey, terrestrial metric survey, terrestrial laser scanning (TLS), and marine survey. Alongside new 3D survey data, permanent fixed survey markers were also installed at key at-risk sites.

• • Investigate heritage at risk on land and beneath the sea. This was our adaptation response to climate change, a preemptive preservation by record where loss is inevitable and was carried out through techniques such as geophysical survey, excavation (traditional and exposed cliff face), scientific dating, and archaeological diving.

• • Reconstruct past environments and weather history through palaeoenvironmental reconstruction. Synthesizing information to reconstruct past environments provides valuable information on the longer-term context of change. Understanding changes over millennia helps to build a picture of how dynamic a site is, and how frequently it has been subject to extremes in the past, which helps inform our understanding of future risks and vulnerability.

Through (1) consultation with agencies, landowners, and local communities; (2) assessment of current and future climate change risks; and (3) the determination of both the potential for partnership working and the potential to provide valuable information about past environments and climates, the project selected 18 study areas across Wales and Ireland (Figure 2). These linked land and sea, running from the coast edge, onto the intertidal zone, to inshore waters (under 40 m depth), and out to offshore islands. In these areas, we selected a diverse range of heritage sites, landscapes, and environments spanning many millennia—from the end of the last glaciation (around 12,000 BC) to the present. This included the remains of prehistoric promontory forts (around 500 BC), medieval castles and monasteries (around AD 1300), timber and iron shipwrecks (around AD 1900), exposed peats and submerged forests (generally between 5500 and 2000 BC), coastal lakes and lagoons, wetlands, dune systems, and multiperiod island landscapes.

Figure 2. Map showing CHERISH study areas and the location of case study site Dinas Dinlle. All are located within the funding area of the EU Ireland–Wales 2014–2020 Programme (green and red shading). (© Crown: CHERISH PROJECT.)

The work undertaken in these study areas established the CHERISH methodology for investigating heritage and climate change in the coastal and maritime environment, and it is this methodology that forms the focus of this how-to article. The article is intended as an overview and showcase of a far more expanded how-to product: the free 252-page e-publication CHERISH: Sharing Our Practice: Investigating Heritage and Climate Change in Coastal and Maritime Environments. A Guide to the CHERISH Toolkit.

The CHERISH Toolkit

The four cross-disciplinary partners that made up CHERISH shared expertise and worked together as a single survey and investigation team, combining knowledge and equipment and creating an integrated toolkit approach capable of tackling a study site from every angle. A cross-disciplinary response and close collaboration is essential in the investigation and understanding of heritage sites at risk. No one organization, discipline, or approach can do this in isolation.

The CHERISH toolkit (Figure 3) integrates the disciplines of archaeology, geomatics, geography, palaeoecology, history, geomorphology, and maritime geophysics—with 15 individual approaches combining air-, land-, and sea-based techniques and encompassing both noninvasive and invasive investigations. Many of these approaches are long established, such as excavation and archaeological aerial reconnaissance, whereas others are relatively new, such as lidar and UAV survey. Used in isolation, they provide a valuable but relatively small stepping stone to the investigation and understanding of heritage sites at risk, but combined, over a phased campaign of work, they offer a powerful tool to raise awareness and understanding of the past, present, and near-future impacts of climate change on heritage sites.

Figure 3. The CHERISH toolkit approach. (© Carys Tait/Carys-ink.com. Image created for the CHERISH Project. © Crown: CHERISH PROJECT.)

Nearly all the work on the CHERISH study sites was undertaken by the CHERISH team, but where necessary, additional data acquisition was commissioned—such as airborne lidar, which was processed and analyzed in house. The project also made use of open data, such as satellite mapping, and involved the local community and volunteers as much as possible.

Sharing Our Practice: A Guide to the CHERISH Toolkit

In March 2023, as a key legacy of the project, CHERISH published its user guide and methodology for investigating heritage and climate change in coastal and maritime environments (Barker and Corns 2023).

This free, downloadable publication, available in English and Welsh, is for individuals and organizations wanting to monitor change, damage, and loss at heritage sites, and to understand broader landscape change across a range of environments—on land, in the intertidal zone, and on the seabed.

The publication is intended for a wide-ranging audience, from individuals and local community groups looking for quick and cost-effective ways to monitor local at-risk sites to heritage professionals and site managers who can advise about, provide cost for, and instigate new investigation as part of their climate change adaptation and mitigation strategies. We hope that the guidance can be used to initiate other collaborative projects and research across the world and that the CHERISH experience will provide a useful evidence base to secure future funding for such work. Although CHERISH focused on coastal and marine environments, many of the approaches explored could be adopted for other types of landscape—for example, upland environments.

The CHERISH Toolkit: Overview and Analysis

The 15 individual approaches that form the CHERISH toolkit (Figure 3) are at the heart of the publication (Barker and Corns 2023:16–239). Here, we provide an overview of the approach (links to additional resources are provided for detailed technical information), followed by an analysis across a standardized set of criteria and a case study, showcasing how the approach was employed at a CHERISH study site. The published case studies represent a range of environments, landscapes, and site type. Below are some examples:

• • The lidar survey of six Welsh Islands is used to illustrate how baseline survey data for large landscape blocks in remote locations was acquired and the variety of results produced (Barker and Corns 2023:27–29).

• • The UAV survey of Glascarrig Motte in Ireland shows the benefit of repeat UAV survey to assess and detect change in the condition of a monument (Barker and Corns 2023:42–45).

• • Cliff-face excavation at Woodstown Promontory Fort, Ireland, provides an example of the use of rope access to clean and record eroded sections of archaeology (Barker and Corns 2023:153–155).

• • Diving the Bronze Bell shipwreck off the coast of Wales provides examples of a range of survey approaches (georeferenced site plan, photogrammetric survey, repeat photographic survey, and an environmental survey) used to identify and monitor underwater heritage going forward (Barker and Corns 2023:180–183).

• • Past storminess at Llyn Coron in Wales was reconstructed with optically stimulated luminescence (OSL) and radiocarbon dating on sediment cores to build up a regional picture of the chronology of environmental change and periods of storminess (Barker and Corns 2023:224–225).

The criteria against which each toolkit approach is analyzed are presented across 10 standardized tables. Table 1 provides an overview of these tables; these were compiled following extensive discussion and mapping with practitioners.

Table 1. An Overview of the Standardized Tables and Essential Criteria for Each of the 15 Toolkit Approaches.

^a A guide value for each rating is provided.

^b A list of threats associated with each of these descriptors is provided.

Given that one of the main aims of the publication is to guide users in their selection of techniques to investigate heritage sites at risk, a summary of the individual tables for each of 15 toolkit approaches has been produced (Barker and Corns 2023:240–249). Four tables provide a visual overview of the technical criteria, the outputs, the cultural heritage value, and the climate-change monitoring value. These tables employ a “traffic light” system to highlight which approaches are appropriate to specific needs. By scanning horizontally across a requirement—for example, the type of environment in which the at-risk site is located or the survey accuracy required—users can differentiate between the approaches that are suitable and those that are not (Figure 4).

Figure 4. Overview table summarizing the technical criteria of the toolkit approach (Barker and Corns 2020:228). Red: low suitability / high cost / high difficulty; Orange: moderate suitability / medium cost / medium difficulty; Green: high suitability / low cost / low difficulty. (© Crown: CHERISH PROJECT.)

Bringing the Toolkit Together: A Case Study Example

The CHERISH toolkit represents an integrated and multidisciplinary approach as highlighted in CHERISH work at Dinas Dinlle coastal hillfort in North Wales (Figure 5). Constructed on a prominent mound of glacial moraine that dominates the low-lying coastal landscape, Dinas Dinlle hillfort is a nationally important protected site, dating from the Iron Age (800 BC–AD 43) and Roman period (AD 43–410; see Coflein NPRN 95309 for further information).

Figure 5. Dinas Dinlle hillfort in Wales. The monument is owned by the National Trust and open to the public. (© Crown copyright. RCAHMW AP_2014_0877.)

Erosion is a clear active pressure, especially on the seaward side of the hillfort. Between 20 m and 40 m have been lost over the last 100 years. Climate change projections mean that the rate of erosion is set to increase; CHERISH has calculated that the whole monument will be lost over the next few centuries (Griffiths et al. 2019). Recognizing this, work initiated by CHERISH focused on adaptation—the way a monument is managed to take account of future changes in climate. Here, adaptation means a very practical response: to recover as much information and understanding as possible before the monument is lost. The overall research aims were as follows:

1. (1) Establish metrically accurate baseline data for the monument that can be used for future monitoring.

2. (2) Initiate a new program of archaeological investigation to increase our understanding of the monument.

3. (3) Reconstruct the past environment and weather history of the monument and surrounding landscape.

4. (4) Establish absolute chronological markers for key phases in the history of the monument and surrounding landscape.

5. (5) Support the organizations responsible for Dinas Dinlle in applying the research outcomes to the management of the site going forward.

Table 2 illustrates how CHERISH used the toolkit to tackle the archaeologically and geologically complex landscape of Dinas Dinlle. Work here spanned the full six and a half years of the project and one of the additional benefits was that the initial CHERISH investment expanded into a larger collaborative project, able to deliver additional work.

Table 2. The Integrated CHERISH Toolkit Used to Study Dinas Dinlle Hillfort, Wales.

There have been many positive results from the work at Dinas Dinlle. Through UAV survey and TLS there is now a centimeter-accurate dataset and a printed and virtual 3D model of the monument, with millimeter accuracy for the cliff face. The UAV surveys of 2018 and 2021 have been used to generate digital elevation models (DEMs) and provide an assessment of change (Figure 6; McCarthy 2023). Such focused study has enabled a more detailed analysis and understanding of the erosion processes that have been communicated back to the landowners.

Figure 6. Dinas Dinlle hillfort assessment of change from 2018 to 2021. Red indicates erosion; green indicated accretion. Values are in meters. (© Crown: CHERISH PROJECT.)

The program of both invasive and noninvasive archaeological, paleoenvironmental, and geomorphological investigations has greatly increased our understanding of the hillfort and surrounding environment. Through a range of geophysical surveys (Barker 2019; Bristow and Barker 2023; Hopewell 2018; Udyrysz-Kraweć and Wajzer 2020), we have greater knowledge of structures and features within and directly adjacent to the monument; ground-penetrating radar (GPR) data provided valuable information about the depth of buried archaeology within the hillfort and the evolution and development of the coastal spit adjacent to it. Evaluating a number of these anomalies through excavation has brought the landscape to life and enabled engagement with the local community, none more so than through the discovery of the stone roundhouse close to the eroding edge within the hillfort interior (Hopewell and McGuiness 2022; Lynes et al. 2021). The roundhouse, fully excavated as part of the wider partnership over three seasons, is now stabilized and accessible to the public, with new interpretation panels and reconstructions that will serve to tell the history and climate story of the monument (Figure 7).

Figure 7. New reconstruction drawing of Dinas Dinlle hillfort incorporating the results of work undertaken 2017–2023. (© Crown: CHERISH PROJECT: Artwork by Wessex Archaeology.)

Bringing everything together, CHERISH commissioned an animation—“20,000 Years and Counting: The Evolving Landscape of Dinas Dinlle, Gwynedd, Wales”—which is available to view here: https://youtu.be/gpjgRWhynLk.

Conclusion

Planning for CHERISH began in 2015, and very early in its development, we identified the need to produce guidance as a key legacy of the project. Phase 1 of the project, from January 2017 to June 2022, was the fieldwork stage—a period in which we developed and implemented our approach and methodology for investigating heritage and climate change in coastal and maritime environments across 18 carefully selected study areas in Wales and Ireland. It was during this period that the toolkit evolved and became the obvious focus for the guidance we felt would be most beneficial—a practical and widely accessible user guide, equipped with a range of case study examples. To our knowledge this was and remains a unique resource.

The four CHERISH partners, alongside the many project stakeholders, benefited greatly from the collaborative and cross-border work that the funding initiated. Through sharing expertise and knowledge, we were able to do more to develop the toolkit and establish and mainstream new methods of working within our own organizations and sectors. We hope that the toolkit will shape and influence future work practices, not just in coastal and maritime environments, and encourage the adoption of approaches and techniques that are not currently used widely in other countries; it has global relevance.

Given that the publication could only be written toward the end of CHERISH, with its launch at the end of the project in March 2023, it remains to be seen what impact it will have, but early signs are encouraging. One of the downsides of a time-limited and funded project is that of legacy, ensuring that the work and lessons learned are not lost. The CHERISH partners are now working hard to make sure the guidance is widely promoted and used, and they are looking to continue the successful partnership. We see the toolkit as a resource that can be added to and adapted, and not just by the CHERISH partners. More can be done with some of the approaches. One example is satellite imagery. We are also aware that other approaches would be beneficial, such as the use of thermal imagery. The challenge now is how we make this happen. Sharing knowledge and practice is crucial in the climate emergency.