Have you ever wondered what the hollow and pond are at Puka and Grotto Streets in Onehunga?
Interpretive signage will soon be taking the mystery out of the site at 36 Grotto Street, explaining the area’s history and detailing why Hochstetter Pond is officially noted as a Significant Ecological Area and an Outstanding Natural Feature.
Located on the map as 36 Grotto Street and 26-30 Heretaunga Avenue Onehunga, there are two visible hollows which remain recognisable features of the area. As early as 1867 these were described as ‘the grotto’ and ‘the pond’.
Research indicates that these formations are the result of lava caves which broke and had collapsed thousands of years ago, leaving steep edged holes in the landscape.
In the 1940s and early 1950s, diatomite - fossilised algae used as an abrasive and filler - was mined from the pond and used the construction of walls and drains to help manage water flows. Part of these structures remains today.
On 6 June 1973, the Central Leader published an interview with William, the son of the mine operator:
“The site, which looks like a crater with volcanic rock sides was once occupied by the Donaldson family, who are said to have allowed breweries access for a time to the diatomaceous earth for filtration.
"The family later operated a nursery from the site, selling the earth as a side-product. William Donaldson is said to have marketed the earth as a cleaning product, known as 'Grotto Maid'.
In 1973, Onehunga Borough Council tried to buy the Gotto Street section for use as a wildness reserve, but it wasn’t until 2006 that it passed into Auckland City Council ownership.
Maungakiekie Tamaki Local Board approved recommendations to protect and preserve the wetland area, including the placement of interpretive signage to better inform the public and community of the value and history of the area.
The interpretive signage is expected to be installed before the end of 2019.