2001:421 - THE WEIR, Firhouse, Dublin

Monitoring was undertaken at Firhouse following the discovery of timber pipes during the extraction of silts from above the weir. These works were undertaken primarily as flood relief but also as part of a more integrated long-term landscaping and linear park development along the Dodder River. Although much of the weir was remodelled during the Victorian period, it owes its origins to a 13th-century structure.

Monitoring of the removal of spoil from above the weir at Firhouse took place between 4 and 26 September. As groundwork had been initiated without the presence of an archaeologist, it was recommended by Dúchas that metal detection be carried out on the extracted river deposits mounded on both the north and south banks of the river. This was carried out by Ian Elliot of Cultural Resource Development Services Ltd under licence no. 01R076.

During the unsupervised removal of materials above the weir, eight hollowed-out tree trunks were recovered from the riverbed running alongside the south-western revetment wall. These were not identified from a secure context and have been assigned an 18th-century date on the basis of similar historical water pipes recovered in Dublin City.

The monitoring of the area surrounding the weir included a watching brief of the extraction of bank material along the northern bank upstream of the weir and the deepening of the channel with subsequent levelling and battering of the bank. An area to the north-east of the weir, where the city watercourse exits the weir, was cleared of some debris and the channel was cleared of undergrowth to expose masonry revetment along the southern bank.

The results of the monitoring and the metal detection failed to produce anything of archaeological significance as the weir was systematically cleared of river gravels for use as building material up until the 19th century.

8 Dungar Terrace, Dun Laoghaire, Co. Dublin