2009:700 - ERRIT LOUGH, DERREENAMACKAUN, Roscommon

Underwater and lakeshore survey took place of the footprint of the proposed public amenity development at Errit Lough, Derreenamackaun, Co. Roscommon. The proposed development seeks to improve an existing public amenity site located at the south-west corner of Errit Lough. The site currently comprises a small car-parking area, swimming area, pier structure and two wooden jetties. A ruined 18thcentury structure, Errit Lodge, is located within the development footprint.
The area under assessment is located within an archaeologically rich landscape, the RMP listing four crann)g sites for Errit Lough, two of which are located within Derreenamackaun townland. The first site (RO019–011) is located c. 300m east-north-east of the proposed inwater impact, the second (RO019–009, possible crann)g) is located c. 900m to the north-north-west.
Systematic visual inspection of the lakebed and adjacent shoreline surrounding the proposed development was undertaken. A buffer zone was incorporated into the assessment and both the underwater survey and lakeshore field-walking extended beyond the boundaries identified for the inwater and land-based impacts, the underwater survey extending across a 120m north-west/southeast by 60m area and the field-walking extending across a 70m north-west/south-east by 50m area.
Nothing of archaeological significance was encountered as part of the field-walking and the survey revealed a shoreline that has been adapted since the establishment of Errit Lodge in the 18th century. The remains of Errit Lodge are of historic and architectural interest, as the existing structure may retain elements of the original 18th-century building. This potential is highlighted by the presence of the NIAH desk-based factsheet for Errit Lodge, which is listed in the NIAH archive as RO–32Ms43845.
Nothing of archaeological significance was encountered as part of the underwater assessment. However, lakebed deposits were found to have a good holding-content and provide conditions suitable for the preservation of in situ subsurface archaeological material. The presence of a submerged, in situ, tree-trunk at NGR 158652 283778 is of interest, as it is an indicator of past water-level changes within the lake; it is anticipated that the current shoreline is c. 30m inland (west) from the original shoreline. While it is clear that a water-level rise has taken place within Errit Lough, it is also evident from the study of the historic maps and recent satellite imagery that this event took place in antiquity, no discernible changes to the lake extent being evident during the 19th and 20th centuries. Moreover, increased water levels within Errit Lough could have potentially resulted in the preservation of any archaeological remains situated along the shoreline in antiquity.