Shoreline Management Project

Screengrab from the 3d Model of Porth y Rhaw

The Dyfed Coastal Shoreline Management Project

Commissioned by Cadw, the historic environment service of the Welsh Government, and undertaken by the Heneb – Dyfed Archaeology, this project is a vital part of the ongoing efforts to safeguard Wales’ coastal heritage against the impacts of climate change and natural deterioration. Western Wales, with its rich tapestry of historical sites ranging from prehistoric settlements to World War II defences, faces significant threats from sea-related flooding and coastal erosion. These risks are exacerbated by the rising sea levels and increasingly extreme weather events associated with global climate changes.

Our project was initiated as a response to the Shoreline Management Plans (SMPs), strategic policy documents that guide the management of coastal flooding and erosion risks. The SMPs emphasize sustainable management practices that not only protect human communities but also conserve historical and environmental assets. In line with these goals, our project has two main components:

  1. Desk-Based Assessment: We conducted extensive research to collect and analyse existing data on vulnerable archaeological sites. This included reviewing records from the Scheduled Monument register, Listed Building register, and the Historic Environment Record (HER). By integrating these data with Flood Risk Assessment Wales (FRAW) and National Coastal Erosion Risk Management (NCERM) data, we developed a detailed understanding of the specific challenges each site faces.
  2. Fieldwork and Technological Integration: To complement our desk-based findings, we carried out field surveys, including aerial drone surveys and photogrammetry, to create detailed 3D models of the most at-risk sites. These models are not only invaluable for recording the current state of these sites but also serve as an engaging way to share our findings with the public and the academic community.

This technological approach has enabled us to establish a comprehensive digital archive and generate accurate 3D models of a number of at-risk sites. Recognising the dynamic nature of coastal erosion, these UAS surveys not only provide a current snapshot of site conditions but also lay the groundwork for ongoing monitoring plans. Regular follow-up surveys, potentially utilising the same UAS or similar technology, may be necessary to track changes and implement adaptive conservation strategies.

We invite you to explore the interactive 3D models below, which bring to life the sites we are striving to protect.

St Ishmaels, Carmarthenshire (PRN 2113)

St Ishmaels Village by Archaeoleg Dyfed Archaeology on Sketchfab

Surveyed on the 1st February, 2024. Shortly after storm Isha and storm Jocelyn.

This 3D model displays the archaeological remains of Halkim, a village documented by historical maps and destroyed by a severe storm in the early 17th century. Situated at the mouth of the River Tywi, notable findings include a silver penny of Edward I and various potsherds dating from the 14th to the 16th centuries. Recent excavations revealed four distinct structures; however, our surveys indicate that a significant portion of the southwest corner of “Building 6” has eroded, leaving no visible trace.

Searchight Battery, Pembrokeshire

Searchlight Battery by Archaeoleg Dyfed Archaeology on Sketchfab

Surveyed in April, 2024.

The remnants of this concrete searchlight battery is ingeniously positioned halfway down a cliff face. Searchlight batteries were crucial in coastal defences from the early to mid-20th century, employed to spotlight enemy ships at night, thus making them easier targets for artillery. This preserved installation, whose location remains undisclosed, illustrates the strategic efforts taken to protect coastlines during wartime. The model highlights the enduring, robust structure of the battery, underscoring its significance in historical military defence and its resilience to coastal elements.

St Ishmaels Gunnery, Carmarthenshire (PRN 30100)

St Ishmaels Gunnery by Archaeoleg Dyfed Archaeology on Sketchfab

Surveyed on 1st of February, 2024.

This 3D model presents the robust remnants of a concrete gun house constructed in 1940-41, designed to defend the Towy estuary against potential German invasion during World War II. Positioned strategically atop a substantial stone wall rising from the beach, this installation was equipped to accommodate a 4-inch gun, pivotal for long-range targeting. Additionally, loopholes built into the structure allowed for the operation of light machine guns, enhancing its defensive capabilities.

Gunneries like this were essential in coastal defenses, serving as fortified positions from which guns were fired to intercept enemy ships and protect vital estuaries and harbors. The enduring structure of this gun house not only reflects the tactical military efforts of the era but also stands as a historical monument.

As of February 2024, Dyfed Archaeological Trust staff noted the presence of graffiti, rubbish, and remnants of a campfire within the gun house, indicating ongoing challenges in preserving these historical sites against modern-day impacts.

Waterybay Rath, Pembrokeshire (PRN 2939)

Watery Bay Rath by Archaeoleg Dyfed Archaeology on Sketchfab

Surveyed on the 16th February, 2024.

Nestled along the rugged coast of west Wales, South Castle Rath stands as a testament to the architectural ingenuity of ancient fortifications. This multivallate coastal promontory fort is characterized by its strategic defensive features: its western and southern sides are fortified by high sea cliffs, while the northern and eastern sides are protected by three lines of curving bank and ditch. The most substantial inner bank is flanked by an outer ditch, followed by a smaller central bank, a second ditch, and a third bank, culminating in an outer ditch, spanning approximately 115m in length and 35m in width.

To document the current condition of this historical site and the toll taken by time and coastal erosion, a drone survey was conducted, resulting in the accurate 3D model presented here. This model not only serves as a practical tool for future monitoring but also allows for comparisons over time to track the ongoing impacts of environmental forces on the site. This snapshot captures the enduring legacy and diminishing presence of one of west Wales’ prehistoric forts.

Porth y Rhaw, Pembrokeshire (PRN 2721)

Porth y Rhaw by Archaeoleg Dyfed Archaeology on Sketchfab

Surveyed on the 29th February, 2024
Porth y Rhaw, a multivallate coastal promontory fort located along the rugged coast of west Wales, stands as a testament to prehistoric fortifications significantly reduced by coastal erosion. Positioned atop approximately 30m high sea cliffs, the fort has weathered time’s relentless forces, leaving its interior divided into two small promontories. Originally a larger, unified structure, the eastern promontory now measures 70m N-S by 25m E-W and the western one 70m SW-NE by 30m NW-SE.

The fort’s elaborate defenses utilize the natural topography, with four lines of banks and ditches arranged strategically. The innermost bank, rising 4m above the adjacent ditch, dominates the crest of the valley side, creating a monumental appearance. The subsequent banks diminish in height, with the outermost bank diverging in its course, suggesting different construction phases. Severe cliff erosion has impacted much of the site, including the entrance and defensive terminations which are now perilously close to the cliff edge.

To document and preserve what remains of Porth y Rhaw, a drone survey was conducted, capturing the current condition of this historic site. The resulting 3D model provides a detailed snapshot for comparison in future monitoring efforts. Excavations between 1995 and 1998 uncovered the remains of at least eight timber roundhouses, evidencing repeated reconstructions and use from the early-to-mid Iron Age through to the 4th century AD.

This site, primarily covered in rough grass, continues to face severe erosion, particularly at the western end of the inner defense and where the public footpath crosses the outer bank. The model not only highlights the fort’s archaeological significance and the ongoing erosion challenges but also serves as an essential tool for future conservation strategies, ensuring that Porth y Rhaw’s story endures despite the encroaching sea.

Black Point Rath, Pembrokeshire (PRN 3128)

Black Point Rath by Archaeoleg Dyfed Archaeology on Sketchfab

Surveyed on the 6th March, 2024.

Black Point Rath, once a formidable univallate promontory fort along the West Wales coast, now displays the profound impacts of coastal erosion. Documented in the 1st Edition Ordnance Survey map of 1889, this fort was naturally defended by high sea cliffs on the west and south, and a curving bank approximately 120m long with an external ditch to the north and east. Despite these formidable defenses, much of the fort had already been lost to the sea by the late 19th century, with the internal area measuring about 120m E-W and 35m N-S.

Our drone survey has captured the ongoing deterioration of Black Point Rath. The entire promontory is visibly crumbling, likened to a “blancmange sliding off a plate”, now estimated to be 5m to 10m lower than a century ago. Great fissures crisscross the landscape, rendering the site hazardous for visitors. Despite the decay, the fort’s impressive earthworks, including a bank that still stands over 3m high internally and 5m above the ditch base, offer a glimpse into its past strength.

The alarming losses documented in recent surveys paint a sobering picture of Black Point Rath’s vulnerability. This accurate 3D model serves not only as a snapshot of the current precarious state but also lays the groundwork for future monitoring plans to preserve what remains of this once-mighty fortress.

Little Castle Point, Pembrokeshire (PRN 2962)

Little Castle Point by Archaeoleg Dyfed Archaeology on Sketchfab

Surveyed on the 19th March, 2024

Perched upon a blunt promontory, Little Castle Point fort stands at 40m above sea level, embraced by rugged sea cliffs to the north, west, and south. Its univallate design offers a glimpse into its lightly defended past, with a curving rampart stretching approximately 75m on its eastern flank. The rampart, consisting of a 5m wide bank and a 3m wide ditch, offers a modest barrier, though fading towards the southern ends. A simple gap in the rampart serves as its entrance on the southeast side. While the interior reveals no distinct house platforms, subtle undulations hint at its historical significance.

Great Castle Rath Head, Pembrokeshire (PRN 2960)

Great Castle Head Rath  by Archaeoleg Dyfed Archaeology on Sketchfab

Surveyed April 2024.

Shaped by centuries of erosion and human history, Great Castle Head fort boasts imposing defenses, revealing its ancient past. The inner bank bears marks of earth construction with stone retaining walls, while the outer bank once guarded the fort’s perimeter. Rotational slumping has left the southern half lower than the rest. Excavations in 1999 revealed its complex history, dating back to the Early or Middle Iron Age. Though no clear structures remain, the site’s intensive use suggests its significance. Discovery of medieval pottery hints at re-fortification in the 12th-13th centuries AD. Despite its historical importance, ongoing coastal erosion threatens Great Castle Head. Cliff collapse on the north side jeopardises its survival. In the late 1990s, excavations salvaged traces of past inhabitants, from Iron Age settlers to potential Norman occupiers and First World War defenders.

East Block House  by Archaeoleg Dyfed Archaeology on Sketchfab
Surveyed in April 2024.

East Blockhouse is a rare defensive structure dating back to the 16th century. Sadly, it is in poor condition, with coastal erosion threatening its existence. In 2011, an excavation was conducted to document its archaeology before it succumbs to the sea.

Much of the original rubble and floor deposits were removed, likely during the Second World War.

Originally built by Henry VIII to guard Milford Haven, the East Blockhouse later saw use in World War Two for local defense. Its current state reflects its turbulent history. Recent erosion has caused significant damage, with parts of the structure disappearing since the excavation.

While little dating evidence was found during the excavation, records indicate that the blockhouse was never fully completed and had collapsed by 1546. Surviving walls, now thin and precarious, hint at its function as an annex or accommodation block.

We would like to extend our gratitude to all of the landowners who kindly gave us permission to carry out these surveys.

Heneb - The Trust for Welsh Archaeology