The Hydro Walk above the Te Waikoropupu Springs is a circuit around Campbell's Creek formed from the access road and water race developed for gold sluicing in the area.
It goes through interesting forest and bush. It ascends steeply to 200m and follows a loop at or around the 200m contour through lowland beech and podocarp forest.
The South side is open to the sun with taller mature trees. The north side follows the water race and is damp and dark with a profusion of ferns, mosses and liverworts and a dense understory of tree ferns.
There is a very active trapping programme to try and control possum, rats and stoats predating birds, damaging the trees and laying waste to the carnivorous Powelliphanta snails that populate this north-western corner of the South Island.
A volunteer we met said that the controversial pesticide 1080 had been air-dropped on neighbouring forests and that it had wiped out a lot of bird life in the upper valley. See my To Air Drop or Not for more on the 1080 controversy in New Zealand.
The area was part of the Golden Bay goldfield and the impressively engineered water race was built to sluice out gold-bearing gravels. The race was completed in just six months by eight men in 1901. It had an 123 metre head that gave it the required pressure for the sluicing hoses. The mine, run by Charles Campbell until 1910, was the richest (in terms of dividends paid) in Golden Bay.
In 1929 the water race was used to run a small hydroelectric power station. Apparently Golden Bay residents were suspicious of the new technology and had to be persuaded to hook up to the mini-grid.
In 1981 the station suffered a 'flashover'. that severely damaged the generating gear. Abandoned it was re-instated by the Pupu Hydro Society and began generating again in 1987 (See DOC).