Spijkerbosch says the fourth sculpture was carved two years ago by local artist Shannon Wafer and was due to be uplifted from Sulphur Lake.
"Given that it refers to the historic grindstones situated at Sulphur Point this was a wonderful opportunity to acknowledge the site."
Spijkerbosch says that, aside from enhancing the Sulphur Point area, these pieces acknowledge and celebrate Rotorua's rich natural and cultural environment.
"These sculptures have been created by leading national carvers.
"They are a tremendous addition to the city's public art collection, and give more opportunity for locals and visitors to engage with and share in our stories."
Rotorua sculptor Shannon Wafer's Hinetuahoanga – (the Lady of the Sandstone) is made from Oamaru stone.
Wafer says this piece represents the grindstones found around the lake.
This is particularly in two places - one behind the Energy Events Centre, and the other at Waiteti Stream.
These places have been used for stone manufacture for generations.
Wafer says he made the piece in the 2016 Rotorua Sculpture Symposium, and since the 2016 works at the Rotorua Sulphur Lake Sculpture Trail were being replaced with this year's symposium works, he decided he wanted to gift it to the community.
He says this was on the condition that it was installed at the location it was designed for, so it felt good to have the sculpture at Sulphur Point.
"It's one of those artworks were you made it with a specific place and kaupapa in mind.
"I can't imagine it going anywhere else, so I'm really happy it's ended up where I intended it to be."
Wafer says it is nice to subtly educate and inform the viewing public about history through artwork.
Waters of Rotorua was sculpted by Hokitika's Rory McDougall - the winner of this year's Rotorua Sculpture Symposium.
This work depicts a map of the Rotorua region.
Made from Taranaki andesite stone, the grooves and concentric rings represent the 13 main bodies of water alongside the rivers and hills of the Rotorua area.
People may also associate the sculpture with water ripples, mud pools and topographical maps.
Taranaki's Steve Molloy's piece is titled Taniwha, with the description - "From the deep swirling pools in our rivers and the depths of our lakes, the Taniwha will rise. Kaitiaki of our waters."
Whangārei's Trisha Fisk's piece is titled Waiwera.
This work is about bliss and the total relaxation and contemplation possible in Rotorua's thermal pools.
Its use of stone variety places Rotorua as central.