Access to the Pillars of Hercules is signposted off Kaimanawa Rd. While we would not put a Truck/RV attribute on the cache page, when you arrive at the car park at the end of the gravel road you will see signs stating that Self-contained Campervan overnight parking is allowed here.
The Tongariro River makes a sharp S bend at the Pillars of Hercules. Flowing approximately north-east it turns back on itself before cutting through the Pillars and then turning once more to the north-east. The deep gorge through the Pillars has a complex history of formation. The river has eroded a narrow channel through ancient flows (350,000 years and older) of andesite and ignimbrite rock.
This Earthcache
For this earthcache you will need to describe what you see at GZ and at the Stage 2 waypoint, and do some Google research to answer some questions.
The Posted Co-ordinates
Task 1: At the bridge there is a plaque (look above head height). When was this bridge built? Email the answer to the CO.
Task 2: Walk out onto the bridge and look down. Estimate the length of the gorge passing through the Pillars.
Task 3 (Optional): Take a photo of yourself on or near the bridge, with your GPS clearly visible. Upload this photo with your online log.
Stage 2
To get to Stage 2 take the track from the carpark. Leave the track at the Trailhead waypoint and follow an unmarked trail.
When you reach the Stage 2 waypoint please enjoy the view, but don’t get too close to the edge. There are no safety rails here and it is a very long way down. The questions from here can be answered without doing anything silly. Please do not post any photos from here that may include spoiler information.
While you are here don't forget to find the Traditional cache hidden nearby.
Task 4: Estimate the width of the gap through the Pillars as a percentage of the pool in front of the cliffs.
Task 5: Describe the cliffs that make up the Pillars of Hercules. Colour, texture etc.
Task 6: What is ignimbrite?
The largest ever recorded flood in the Tongariro River occurred last century. A flow of 1470 tons of water per second was recorded (cf 1440 t/sec in February 2004). It was big enough to destroy the Red Hut bridge and significantly alter the river. It was believed to have been caused by a blockage of the Pillars of Hercules. Standing at the Stage 2 waypoint it is easy to imagine the area below you acting as a dam and holding an enormous volume of water before the blockage was breached.
Task 7: In what month and year did this flood occur?
The answers for the questions in Tasks 1, 2 and 4 to 7 should be emailed to the cache owner while the photo from Task 3 should be uploaded with your online log. Any online logs that do not accompany an email with the correct answers will be deleted.
You can log this cache straight away after you have emailed your answers to the cache owner, no need to wait for confirmation. Please include the name of this earthcache in the email. Also, when contacting us with answers, if you want a reply, please include your email address. Any problems with your answers we'll be in touch.