Gold-mining sites and contemporary wild-flooding at Northburn, near Cromwell, 1968

From left to right across the photograph are the modern bed of the Clutha River, the rise to the high terrace, and then the hill country. The wild-flooding is marked by the darker water-soaked ground on the high terrace. The water is flooding out of a supply race and storage ponds originally designed in the 1860s by gold-miners for sluicing the high terrace. Head races from the ponds to the gold-sluicing area (marked by 'herring-bone' tailings) show clearly. The wild-flooding water from the supply race has flowed into and gathered in the original head races and the storage ponds, and is beginning to flow down the terrace face, mimicking the flow pattern of the older miners' ground-sluicing.

Several eras and systems of alluvial gold-mining are represented here. On the high terrace 60 m above river level, supply races feed into a number of small holding dams created by an earth embankment constructed on the slightly sloping surface of the high terrace; these show as dark patches at bottom right. During working hours the water from these dams was fed into the head races and then across slight slopes down to the work faces, marked here by fainter linear traces of tailings upslope from the herringbone tailings. The final work faces were at the edges of the herring-bone tailings. Tail races carried water away from the tailings area. In the bed of the Clutha River which runs from top to bottom are the tailings of dredges, dating from about the turn of the century.