2008:366 - Broadmeadow River at Lissenhall Bridge and Ward River at Balheary Bridge, Balheary Demesne, Dublin

A non-disturbance assessment was undertaken on behalf of the Railway Procurement Agency across two waterways, the Broadmeadow River and the Ward River, in an area that is to undergo development as part of the proposed Metro North Project. The Ward River flows north-eastward through Balheary Demense before turning eastward and flowing east-north-east through the assessment area to conjoin with the Broadmeadow River at NGR 31885 248152. Balheary Bridge, a two-arched bridge structure, crosses the Ward River at NGR 318744 248140 (centre-point). Balheary Bridge is a protected structure and is noted in the National Inventory of Architectural Heritage (RPS340, NIAH no. 1335018). The Broadmeadow River is located 91m north of the Ward River and flows south-eastward through Balheary Demense to its confluence with the Ward River within Lissenhall Great townland Lissenhall Bridge, a five-arched bridge structure, crosses the Broadmeadow River at 318760 248245 (centre-point). Lissenhall Bridge (DU018–011–4081) is a protected structure (RPS 341, NIAH no. 1335019). A bridge is first recorded in this location on the Down Survey map of 1656 and the central section of Lissenhall Bridge may retain structural evidence to suggest a late 15th-century construction. Both river assessment areas are located adjacent to the N1 link-road, c. 700m north of Swords, Co. Dublin.
The on-site assessment comprised a systematic visual inspection and magnetometer survey of the riverbed and attendant bank structures at both river locations. A 100m section of the Ward River was surveyed, between NGR 318649 248114 and 318757 248141, and a 70m section of Broadmeadow River was surveyed, between NGR 318724 248237 and 318786 248236. The assessment included a detailed survey of the bridges, the riverbed, and attendant bank structures at both river survey locations. Balheary Bridge and Lissenhall Bridge were recorded in plan, cross-section and elevation. The survey data was gathered and position-fixed using a differential GPS unit and a total station EDM. In addition, a c. 90m (north–south) by c. 90m area of parkland that forms the flood-plain between the two rivers was field-walked.
Three features of archaeological significance were documented as part of the assessment: Lissenhall Bridge (Feature 1), its adjacent single-arched culvert (Feature 2) and Balheary Bridge (Feature 3). In addition, several riverine features of historic interest were documented, including: a weir location and associated walling (Feature 4), five sections of river revetment wall (Feature 5), and a single-arched bridge structure located 91m west of Balheary Bridge (Feature 6).
The results of the assessment work indicate that Lissenhall Bridge the adjacent culvert and Balheary Bridge form part of the same continuous structure that was built across the Broadmeadow and Ward river channels. John Rocque’s map of County Dublin (1760) clearly depicts a single structure as described and visual inspection confirmed the presence of an earlier build phase (Phase 1) at Lissenhall Bridge, the single-arched culvert and Balheary Bridge. This initial build phase forms the middle section of each structure comprising Features 1–3. These mid-sections are aligned with each other on a north–south axis and display a similar construction methodology throughout. Later build phases abut the eastern (downstream) and western (upstream) side of each structure. It has previously been noted that the middle section of present-day Lissenhall Bridge is thought to date to the pre-1600s, a date that can be extrapolated to encompass the mid-sections of the adjacent culvert and Balheary Bridge. A second build phase (Phase 2), dating to the 18th century, was also identified, forming the bridge extensions at Features 1–2 and the downstream extension at Feature 3. A third build phase (Phase 3) is present at Balheary Bridge, the upstream bridge extension being constructed in the 19th century (c. 1850) in response to the collapse or partial collapse of the upstream (Phase 2) bridge extension that preceded it. It is following this 19th-century addition that the three bridge phases that form Feature 3 are collectively named ‘Balheary Bridge’. This, in name, partitioned the extended structure that formed Lissenhall Bridge, with Balheary Bridge and Lissenhall Bridge now being clearly marked as separate structures on the OS second-edition mapping of 1906.