In 1888 the Waihi Gold Mining Company captured Mill Stream at a dam near Barry Road to provide water, and later water power, for the Waihi Battery on Union Hill.
The small valley through which it used to flow was much modified. Three tailings impoundments were established where once there was a stream. It was from these impoundments that the Cassel Tailings plant took their tailings, and also the Waihi Mill as it was closing down. Mining spoil and discarded machinery were added.
The tailings were easily washed away, so a cut-off drain was created to the west of the ponds to intercept surface run-off and direct it away from the ponds. A continuous drain ran from the top pond to Clarke Street. This drain still exists, though much modified, as do the three tailings bunds or embankments.
Mill Stream Walkway follows this drain from the south of the bamboo to the boxed steps. The drain behind Charlie’s seat, and the present Mill Stream course below the upper walkway bridge (ie including the gorge), were the lower part of this cut-off drain (they line up well).
The drain behind Charlie’s seat was also used to accept the by-wash water which flowed down from the end of Baker Street.
After the Waihi Battery closed (circa 1913), the water of Mill Stream was no longer required for power, and a course for Mill Stream had to be re-established. This meant creating a new channel, more or less from Speak’s Quarry to Clarke Street. The middle tailings bund has a distinct hand cut channel through which Mill Stream has been directed. The lower section of cut-off drain, from just below the upper walkway bridge to Clarke Street, became the new stream course.