The Stony Batter walk on Waiheke Island starts at the car park at the end of Stony Batter Road. The walk takes you along a private road between vineyards and farmland to the Stony Batter Reserve, with its amazing boulder field and historical WWII fortress.
The walk is 2 km, and reaching the reserve takes about 20 minutes. It starts with a short, sharp climb to almost 200 metres above sea level, with a forest remnant on the left. This is followed by superb open views of rolling hills down to the Hauraki Gulf to the north. The farmland quickly gives way to a boulder-filled hillside on the south side of the road.
The boulder field consists of rounded boulders, remnants of an 8-million-year-old basalt volcano. Some boulders exhibit karst features (shapes created by water flow erosion), a process rare with basalt rock and only known to exist in a few places. Examples include boulders in the Hokianga at Wairere Boulders and Wairere Heights.
Before people arrived, the boulders were covered in forest. Humus accumulated around the roots on top of the boulders. This material, combined with rainwater, formed a weak acid. As it dribbled down the sides of the boulders, it created funnels and flutes. These processes of water-based erosion were known to occur with limestone and marble rocks, creating karst features, but the discovery that this happens with basalt is relatively recent. Another odd feature of some boulders is the regular shape of lichen patches that mimic the boulders' roundness.
Once you reach the reserve, there is an entrance onto the hill with the boulders. You can wander around them at your leisure and continue over the hill on the Opopo Bay Track. Due to lambing, access is barred from 1 August to 30 September. Continue on a short distance for the shark head rock and the entrance to the Stony Batter Fortress.
You will also notice the concrete base of the workshop alongside the road. This is all that remains of the work camp that supported the construction of the Stony Batter Fortress in the 1940s.
To reach Stony Batter from Onetangi, take Waiheke Road to Man O’War Road, then Stonybatter Road. Park at the end of the road in the car park.
