RANGIHAU TRACK BOG BRIDGES

Coromandel Forest Park – Summer 2021-22

​The Rangihau is a neglected backcountry track at the head of the Kauaeranga Valley in Coromandel Forest Park. Running north from the popular Pinnacles Hut, the track provides access to several historically significant sites – including the main Kauaeranga Kauri Dam site and work camps. This area was the site of some of the last significant kauri milling in the country, during the mid-1920s, with important relics remaining.

​The Kauaeranga Tramping Club (KTC) wanted to improve access to the main dam site, and in particular, a boggy section of track about halfway between the Kauaeranga River ford and the turn-off to the Pinnacles turn. The Backcountry Trust arranged funding. KTC’s Greg Laslett provided the details for this summary.

US Forest service bog bridge design

​The KTC decided to build ‘low elevation walkways’ also known as a ‘bog bridges’ or ‘swamp bridges’, based on an original United States Forest Service design. Similar bridges have worked on the Tararu Track, also in the Coromandel Range.

one of the boggy locations

bog bridge in place

​The high voltage power lines crossing the Coromandel Range prevented a helicopter drop directly into site, so instead materials were manoeuvred into a small area that members prepared about 150 metres away.
 
To build a bog bridge, you first have to lay spans on top of which the main planks are secured. Finding old dam timbers on the swamp floor gave us the opportunity to use more natural material than originally anticipated. However, the team underestimated the effort involved in the uphill walk to the site (and then back), laden with tools, meaning several more trips than originally planned. Club members were certainly fitter after the effort!

boggy section before bridging

​Altogether the four KTC volunteers spent some 131 hours completed the bog bridges, including travel, planning, DOC liaison, quotes, funding application and on-site labour.
 
Finally, at an informal opening, KTC President Chris Browne had the honour of removing the last piece of caution tape and commencing the first tramp along the new swamp bridge.
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Many thanks to Carters Thames for offering quality materials at a good price, and especially for providing really dry timber, which weighs considerably less than wet timber. Thanks to the pilot Caleb from Sky Works Thames and his team for their ever-professional approach. Thanks to the local DOC Hauraki staff for helping make the project happen, especially for flying in additional materials during a Pinnacles Hut re-supply. Grateful thanks to KTC club members, local trampers and hunters who helped out.

Kauaeranga TC president Chris Browne at the informal bog bridge opening