History The Ruamāhanga River is the largest river in the Wairarapa, flowing through the Wairarapa Valley for about 130 kilometres. The Waihenga Bridge is located in the middle reaches of the Ruamāhanga catchment, just after it joins the Huangarua River. The bridge is an integral part of State Highway 53 and services the huge hinterland of the South Wairarapa as well as providing access to the Coast.
The designer of the Waihenga Bridge was G Laing-Meason, a Wellington Civil Engineer. It was signed off on 21 October 1910, with tenders closing a month later. Sir Joseph Ward, the Prime Minister opened the bridge in January 1912. Testing of the bridge was carried out by running two 14 ton traction engines over it. It has remained in use from its construction to the present day so is now 112 years old.
Flooding
Flooding is a perennial problem. The table below illustrates the number of closures since 2008.
Bridge Closures
| Year | Date | Max River Height |
| 2008 | 30th July
26th August 7th October | 4.88m
4.90m 5.12m |
| 2009 | 24th July
31st August | 4.9m
4.69m |
| 2010 | 6 September | 5.14m |
| 2011 | 11th July | 4.61m |
| 2012 | 3rd March | 5.07m |
| 2013 | 12th July
12th September 25th October 28th November | 4.89m
4.78m 4.63m 4.61m |
| 2014 | 5th January
18th April 3rd August | 4.73m
4.73m 4.97m |
| 2015 | 20th -21st June | 5.01m |
| 2016 | – | – |
| 2017 | 3rd February
5th April 13th July 26th September | 4.58m
4.69m 5.17m 4.78m |
| 2018 | 12th – 14th June
26th – 27th November 27th – 28th November | 5.00m
4.56m 4.7m |
| 2019 | – | – |
| 2020 | 18th September
27th September | 4.470
4.512m |
| 2021 | 21st June
18th July 17th August 14th September | 4.832m
4.726m 4.681m 4.630m |
On the 13th February 2022 the bridge closed yet again. Due to heavy rain in the Tararua catchment area the Waihenga Bridge was closed. The East West Access Rd was closed due to flooding at Kahutara. Longbush Rd was closed due to a tree falling on the road. The widespread flooding at Kokotau prevented access to the Huangarua/ Ponatahi Bridge. Effectively Martinborough and the Coast were isolated once again.
Mountains of debris have piled up on both sides of the bridge and will need to be removed. According to Waka Kotahi the Waihenga Bridge is one of fifty bridges needing clearing. Clearing the debris for our bridge is on the To Do list sometime.
Over the years the South Wairarapa District Council has made several representations to NZTA for a new bridge citing the problems; the bridge is too narrow; it is a long span to cross and the height of the bridge above the river is less than it was in the past owing to the riverbed rising. The bridge has recently been checked by an engineer and deemed fit for purpose. With a ballpark figure for a new bridge costing around 50 million there is not a lot likely to happen in the foreseeable future. Lyle Griffiths
Out of interest; in around 2008 a replacement was approved for the Waihenga bridge. This was quite well up the NZ Transport to do list, estimated to start in a two or three years. There was much excitement at Council.
It was subsequently dropped down the list, then was reassessed. It has now been deemed strong enough to last for the time being – that is, not structurally at risk. So off the priority list for now as traffic numbers don’t warrant an upgrade. Mike
