Dunedin Botanical Gardens
(45d, 51`,30S, – 170d, 31`, 14E).
Whilst visiting Dunedin’s beautiful Botanical Gardens and walking past the hilltop, Aboretum area, my attention was drawn to the profuse growth of what I call giant rhubarb plant. The real name of the plant is Gunnera. This plant only grows in wet conditions and thrives on added nutrients. At home in the Lake District, it is the bane of my life, as it bestrides a footpath I look after, well watered by the local beck, and with nutrients galore from the outlet of our village sewage plant., it requires cutting back at least three times a year. Therefore, Gunnera on a hill indicated a spring fed water course, plus added nutrients.
A survey of the arboretum area indicated that most of the area had been walled to form a 100m x 72m (NS) enclosure. It was easy to follow the outline of the walls on the north and east faces adjacent to the park paths, as the underlying stone had inhibited the grass growth and created a brown line. The SE corner of the wall (Aviary corner) (45d, 51`, 31S, – 170d, 31`, 18E) being the site of a Eucalyptus Kartzofianca.
An internal survey indicated the presence of eight barrack blocks, each with 8 + 1 rooms,
providing accommodation for 512 men. A 6m x 6m ablution block, marked by a Nyassa Sinensis, was located alongside the hollow which contains the remains of the harbour. (probably puddled clay-lined and devoid of stone) The Petasites (rhubarb plants) grow profusely in this hollow. Within the hollow, MAS located the outline of the harbour wall, within the narrow outlet from the hollow, a canal system, connected by ladder locks down to the creek below.
Three aqueducts entered the site, one at the SE corner of the enclosed area, and two at the western end of the south face. One discharged directly into the ablution block, which in turn discharged into the harbour, (unlike the Roman system which discharged solids into the harbour outlet, but liquids into the harbour.) The third aqueduct discharged directly into the harbour to make up water lost to leakage, evaporation and when the punts locked up or down, to the adjacent creek. No doubt the nutrients enter the aqueduct system from the very well-stocked aviaries, upstream of the harbour.
T.C.Bell UK Feb 2003
