2011:214 - ST BRENDAN’S HOSPITAL, GRANGEGORMAN, Dublin

This monitoring licence relates to enabling works undertaken prior to the construction of a Mental Health Care Facility, developed under the auspices of the Grangegorman Development Agency at the north-western corner of the extensive Grangegorman campus. The site is defined to the north by the North Circular Road, to the west by a shopping centre and garage on Prussia Street, to the south by the playing fields attached to St Brendan’s Hospital and to the east by the hospital premises and a residence formerly attached to the hospital fronting the North Circular Road.
The site is not within the constraint area of an archaeological monument per se, although the designation for the historic city core (DU018-020) extends up Prussia Street, a continuation of the medieval Stoneybatter and the old thoroughfare leading to the north-west from the city. In addition, the site lies within the historic curtilage of the former Richmond District Lunatic Asylum, developed in a piecemeal fashion from 1851 onwards in the fields between Grangegorman, the Bradoge Water (now flowing under Grangegorman Upper) and the North Circular Road.
The enabling works involved ground reduction in the region of 0.7–0.8m over the entire site in order to remove the toxic roots of the Japanese knotweed (Fallopia japonica) and giant hogweed (Heracleum mantegazzianum) which had infested the area over the past number of years. The work was thus undertaken as an archaeological exercise, with grading buckets used on all machinery to ensure that all the roots were exposed and removed. As the roots tend to extend further into the ground over pits and negative features, the whole area was reduced to natural subsoil to ensure total eradication, with an archaeological presence at all times in accordance with the planning condition.
The monitoring was undertaken over a seven-week period from 16 February until 31 March 2011. The operation was undertaken by stripping off the topsoil to expose the upper surface of an introduced deposit of garden soil. This was in turn removed, along with a sequence of modern pits which cut through to the subsoil. Another layer of soil was subsequently removed to the surface of the subsoil when it became clear that the roots had penetrated further than expected. Several field drains were encountered over the monitoring operation, all of which are associated with the occupation of the site by the asylum in the late 19th century.
The results of the unusually comprehensive ground reduction programme did not succeed in locating any evidence for the medieval or early modern grange of Grangegorman. Where a pre-1850 ground surface was located, there were no significant archaeological features cutting this level or, indeed, the surface of the subsoil below. This is perhaps in itself significant, indicating that the fields depicted here on the early edition of the Ordnance Survey were not enclosed by ditches. The several medieval references to the ‘great field’ may well relate to the area under discussion.
The modest finds assemblage comprises material introduced onto the site with the garden soil, some of which may be derived from the cleaning out of ash-pits or urban latrines. To this can be added clay pipe stems, ceramics and glass dating from the 19th- and early 20th-century cultivation of the site.

Archaeology and Built Heritage, 79 Queen Street, Dublin 7