Watching Brief
Date 22 September 1998 - 23 September 1998
Event ID 1028088
Category Recording
Type Watching Brief
Permalink http://canmore.org.uk/event/1028088
A watching brief was carried out over the two days of the 22nd and 23rd of September 1998 while a series of seven test pits were excavated within the confines of the largest of two adjacent water towers situated in the upper part of Edinburgh Castle.
The tower consisted of a reused masonry structure 11.50m along each side forming a roughly squared structure into which had been inserted a vast iron water tank. Following the disuse of this facility the roof of the building had been removed and the tank cut up and lifted out. The result was to expose the foundation of the water containment which consisted of five concentric rings of masonry standing approximately 1m above a soil infill layer and occupying the whole of the interior of the building. A narrow gap existed in each ring of masonry at a point towards the NE allowing access to the underside of the tank for purposes of repair.
The various excavations within the old water tower building have revealed that in order to put in place massive foundations for an extremely heavy water tank it was considered essential that the masonry was founded in all places on bedrock. The extent of the foundations required that all internal deposits in the building be removed prior to construction of masonry. Perhaps a few small areas of original early occupation material survived this activity, as in trench 1, but in general terms the inside of the building was cleared in totality. Following the building of the concentric rings of foundation masonry, dated to the first decade of this century, the gaps between the rings were filled up with imported soil to a level 900mm below the wall tops. This level coincided with the highest point of the natural bedrock as seen in trench 4.
The excavations have proven that there is no great depth of infill to be removed within the square water tower. To be precise the bedrock comes to within 300mm of the general walking surface within the two towers. The greatest depth from the same surface is 1280mm. Consequently any plan to substantially lower the floor level of this building will require quarrying of the bedrock.
Sponsor: Historic Scotland
Kirkdale Archaeology 1998
