2022:918 - River Barrow, Mortarstown, Carlow, Carlow

Underwater Archaeological Impact Assessment (UAIA) was undertaken of the River Barrow at Mortarstown Upper, Carlow Town, where an upgrade to the existing Mortarstown Waste Water Treatment Plant (WWTP) is to take place. As part of the upgrade works, it is proposed to insert a new outfall structure on the east bank of the River Barrow at ITM 671120E, 674929N (centrepoint); positioned at a point 15m downstream of the existing WWTP outfall.

The assessment sought to provide a detailed account of riverbed topography, to assess the potential of riverbed deposits to retain archaeological material, and identify any additional features/structures of archaeological or historic significance that may be present. This work included a walkover survey of the attendant bank structure. In addition, targeted metal detection was employed to help assess the bankside/riverbed area and highlight any metallic concentrations present.

The UAIA comprised systematic visual inspection of the River Barrow, extending 45m upstream and 20m downstream of the river impact location, ITM 671135E, 674967N - ITM 671059E, 674913N. Water depth of between 2.5m (channel sides) and 4m (centre of channel) was encountered for much of the watercourse on the day of survey.

No archaeologically significant features, structures, or deposits were encountered for either the immediate impact location or the wider assessment area. Likewise, metal-detection across a series of riverbed areas did not yield any items of interest.

The on-site work was carried out on 9th August 2022.