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Earth Science Conservation Review
| Ballycastle Beach | Antrim |
| Site number: | 1135 | ||
| ESCC: | IA | ||
| Locality Type: | Coastal section | Status: | ESCR |
| Grid Reference: | D121415,D134415 End(s) of linear site, Not Entered | ||
| Google maps: | 55.20828,-6.23908 | ||
| County: | Antrim | Council area: | Causeway Coast & Glens Borough Council |
| Period: | Quaternary | ||
| Stages: | Holocene, Pleistocene | ||
| Site Description | |
|---|---|
| Highlights: | |
The 1.5km wide Ballycastle Bay has a medium energy shoreline, 2.5km in length with a tidal range of 1.2m and is composed mainly of fluvial-derived sediments washed down from the nearby Carey Valley. Here, a large volume of glacial sand and gravel in the form of deltas from the last Ice Age (18,000 yrs) are stored and have episodically been washed down to the coast during flood events. Lower valley deposits are made up of these sediments in the form of alluvial/river terraces which have been reworked and deposited by wind and wave action into the present Ballycastle strand (Carter and Bartlett, 1988). The bay is defined in this summary by the estuary of the Margy river to the west and Pans Rock in the east, marking its western and eastern limits, respectively. | |
| Introduction: | |
Ballycastle Bay is on the north-east coast of County Antrim, O.S. Grid Ref. D121415. The bay has a smooth planform with a 1.5km long sandy beach occupying its central section, consisting of a coarse beach material backing onto an incised river terrace. The coastal sediments are the result of marine reworking of river- derived sediments over the past 4-5000 years (Carter and Bartlett, 1988). Coarse beach material is capped by recent aeolian dunes which are 600m long and 150m wide. Older dunes further inland towards the Carey river, represent an older period of dune construction at the site. The present landscape has been modified through a golf course construction, coal mining, glass making, harbour construction and roadways. Blown sand is found west of the Carey river and at the Warren where thicknesses of up to 6 metres occur. Dune bedding is occasionally exposed. Dunes are largely vegetated and currently in a general immobile phase with isolated activity at the foredune sections. The presence of two old roads, 1.2m and 2.1m below the present dune surface, and no older than the eighteenth century, indicate dune activity since that date (Wilson and Robbie, 1966). The construction of the harbour began in 1737. The inner harbour, occupies the former mouth of the Margy River which was subsequently diverted east to limit siltation in the inner harbour. | |
| Description: | |
The beach at Ballycastle is made up of two morphodynamic units; a dissipative subtidal zone, that typically consists of low elevation crescentic bars, 300m in wavelength; and a higher intertidal zone. Nearshore circulation of water/sediment is controlled by the presence of secondary waves in the nearshore region. These waves which travel at right angles to the shore interact with shore-normal primary waves. Two wave regimes are present, Atlantic swell waves and Irish Sea sea waves. Long-period Atlantic swell waves penetrate the crescentic bars, reach the shoreline and cause erosion. Increased water level due to incoming waves creating a landward water slope gradient (enhanced momentum from the moving waves) will also increase the erosive potential of the waves (Carter and Bartlett, 1988). Wave refraction studies at Ballycastle (Heaney, 1988) show the beach to comprise a series of cells which alternate in space and time with changing wave conditions. Results from this study showed a net longshore sediment drift potential to the west and a resulting accumulation at the Margy river. This can, however, reverse towards the east. Carter and Bartlett (1988) speculated that reduction in river flow would result in increased marine deposition of sediment at the present Margy river mouth in the south-west section of the bay. Carter and Bartlett (1988) observed beach cusps (with a 20-40m wavelength) in the dissipative-reflective zone. This indicates seaward reflection of incident wave energy under modal wave conditions. These features may not survive under storm conditions. If they are preserved, they may serve as guides for wave run-up to attack the back beach area at regularly spaced intervals. | |
| Importance: | |
No exact dating procedures have so far been conducted within the local dune system or elsewhere at the site, making reconstruction of its evolution more difficult. Glacial material in the Carey Valley has, however, been studied by McCabe and Eyles (1988). Ballycastle does, however, represent a possible river-controlled coastal cell on the Antrim coast, making it particularly vulnerable to changes in the river system. The beach and dunes at Ballycastle have been so disrupted by human activity, however, that it is difficult to distinguish natural and human emplaced sediment. This, coupled with uncertainties regarding the nature of the sedimentary circulation mitigate against designation of the site at present. | |
| Interpretation: | |
Fluvially-derived sediment dominates over shelf-derived sediment on the modern beach. McCabe and Eyles (1988) have suggested that the deltas from which fluvial sediments are derived in the Carey Valley are of submarine origin and thus deposited under higher sea-levels in late glacial times. Sediments at Ballycastle beach (size range 0.35-0.25mm) display relatively poor sorting compared to beaches further west along the coast. According to Carter and Bartlett (1988) this may be due to a predominance of terrestrial glacial sediments rather than offshore glacial/marine sediments, as is the case in adjacent beaches further west. It is also speculated (Carter and Bartlett, 1988) that at the eastern section of the bay, a previously wider and deeper estuary of the river occurring at the late-early postglacial period of higher sea-levels, may have now been infilled substantially by riverine sediment deposition. The river mouth is thought to exert significant influence on the Ballycastle system by creating a circulatory cell of sediments through the reduction in energy and refraction of incoming waves and also the attraction of longshore currents. Any changes in a river regime are therefore likely to be manifested in alterations of the shoreline sediment supply. The north-facing beach at Ballycastle is afforded protection from direct approach Atlantic swell waves by Kinbane Head to the west and Rathlin Island, 8 km to the north. Local wind-generated waves are instead responsible for most of the influence on the beach. A westerly, wave-induced movement of sediments along the beach during a period of large channelisation of the river terraces is suggested to have been balanced by the `pumping` mechanism of the river mouth. However, Carter and Bartlett (1988) speculated that in more recent times this mechanism has declined somewhat to allow a rearrangement of the sediments in the system. This, they believe, has lead to sediment loss at the eastern section of the beach and accretion at the river mouth to the west. Shoreline change at Ballycastle has been a subject of debate for at least the last century. The natural change in the reorganisation of sediments in the system on a longer time-scale, as mentioned previously, must be considered in any interpretation of shoreline alteration or sediment movements at the site. Human impact also appears to have been a significant cause of change at this location due to various activities over the years. Local industrial operations such as coal mining, glass making, harbour construction and sediment removal from the beaches and dunes have all had some degree of influence on sediment cycles and supply. Artificial nourishment of the beach and eroded back-beach areas has led to the present beach being composed of a high proportion of exotic clasts. Since the 1700's the onset of local industrial activities (Hamilton, 1790; Hamond, 1991) such as coal mining and glass works have resulted in some disturbance of the site. Construction of the harbour to facilitate mining industries may have had a significant influence on the site, particularly in terms of altering incoming wave characteristics and their subsequent influence on sediment circulation. More recently, sediment extraction from the beach for glass making and the local golf course have reduced sediment availability of the system. Other sediment removal practices are mentioned in Wilson and Robbie (1966) where `an unusual minor industry is the collecting of fine mixed chalk and basalt gravel which is widely used in Northern Ireland for pebble dashing. This material is obtained by sieving the beach shingle on the west of Ballycastle Harbour'. | |
| Conclusions: | |
The Ballycastle shoreline was formed by reworking of terrestrially-derived sediments by marine processes. These sediments are sourced mainly from the Carey Valley and are brought down to the shore by rivers. The river appears to have a significant influence at the site, and may effectively help to draw in longshore transport and recirculate beach sediments seaward. Wave conditions indicate westerly-sediment transport along the beach towards the river and the harbour. A small, mature dune system is present at the rear of the beach. Present dune forms are largely relict features and a limited input of fresh sand supplies the frontal foredune sections. The site is highly disrupted and the role of man in altering the system is poorly understood. It is unlikely to warrant designation at this time. | |
| Notes: | |
Although not formally designated, this site is of interest. Further study should be directed at understanding the proposed seaward return flow of sediment via the river mouth. Any further studies on coastal erosion will require more detailed wave refraction modelling and examination of how protective structures and extraction have influenced sediments at the site. | |
| Keywords | |
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| Relations: | Beach deposit, Coastal processes, Glacio-fluvial sediment |
| Geomorph: | beach cusp, crescentic bar, sand dune |
| Access | |
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| Management: | |
Carter and Bartlett (1988) discussed in detail the management history of the site and examined present management practices. The protection of the golf course at Ballycastle has involved the dumping of waste building material in front of the foredunes of the strand. This has since been reworked and distributed down the beach in the form of beach cusps (wavelength ~40 m). Since the Carter and Bartlett study of 1988, protective gabions have been placed at the eastern section of the beach along the toe of the `foredune' (now a largely artificial embankment consisting of building waste material). At November 1995 intermittent wave attack had over-topped the two-tiered gabion structure and caused erosion into the front embankment structure. Location of this wave attack appears to be aligned to the troughs in crescentic bars situated in the surf zone. The full impact of these gabions on the system is not know. The beach is heavily utilised for recreation particularly in the summer, while the dunes form part of the golf course. | |
| Threats: | Coastal erosion. |
| Uses | |
| Uses: | The beach is heavily utilised for recreation, particularly in summer; golf. |
| References (6) | |||
|---|---|---|---|
| Carter, R.W.G. & Bartlett, D., 1988. Coast erosion and management in the Antrim Coast and Glens and the Causeway Coast Areas of Outstanding Natural Beauty. In Final Report of the Coast Erosion Survey. Department of Environment (Northern Ireland). | |||
| Hamilton, W., 1790. Natural History of the Basaltes and its attendant Fossils in the Northern Counties of Ireland., London. | |||
| Hamond, F., 1991. Antrim Coast and Glens: Industrial Heritage. Countryside and Wildlife Interpretation Series, DoE(NI). | |||
| Heaney, C.J., 1988. An investigation into a coastal problem between Ballycastle Golf Club and the Moyle District Council (BSc dissertation). (Thesis) University of Ulster. | |||
| McCabe, A.M. & Eyles, N., 1988. Sedimentology of an ice-contact glaciomarine delta, Carey Valley, Northern Ireland. Sedimentary Geology, vol. 59, pp.1-14. | |||
| Wilson, H.E. & Robbie, J.A., 1966. Geology of the country around Ballycastle. Memoirs of the Geological Survey Northern Ireland. | |||
| Map(s): | See the 1:50,000 O.S. Sheet 5 (Ballycastle). | ||
| Record type: | ESCR report | ||
| Entered by: | E M Porter | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Ballycastle Beach, County Antrim, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=1135. Accessed on 2026-11-05. |
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