Burnside Bridge in Takapau was badly damaged during Cyclone Gabrielle in February 2023 and closed due to its instability. It is one of three remaining cyclone-damaged bridges in our district.

We don’t have enough money to replace or repair Burnside Bridge, but we do need to make it safe.

The site has been allocated up to $560,000 government funding as a result of the bridge's low traffic demand and short five-kilometre detour. This is not enough to fund major repairs or a rebuild.

The only viable option available to us, with the funding we have, is to remove the bridge and make the site safe for community.

So, how have we got here?

We cannot afford to fund the recovery from Cyclone Gabrielle on our own, the impact on rates would be too significant. We rely heavily on New Zealand Transport Agency Waka Kotahi (NZTA) to co-fund transport repairs caused by weather events, so it is crucial that we align with NZTA's funding requirements and processes, which include assessing the cost benefit analysis of potential work options.

We have explored options to make the currently closed, damaged bridge safe. These include:

• building a new bridge, which is estimated to cost up to $16 million. NZTA has assessed this to be uneconomical given the bridge’s low user rate and current five-kilometre detour.
• building a drift-deck (low-level) ford. This solution also exceeds NZTA's funding parameters and has been assessed as uneconomical.
• removing the bridge and making the site safe.

The damaged bridge is not safe to cross and is closed to all vehicles and pedestrians so presents a great risk to community if left as it is.

Demolishing the bridge and making the site safe and secure would cost: $560,000

Burnside Bridge is a 99-metre single-lane bridge built in 1921. It was badly damaged by the high-river flows and excess flood debris snagging on the bridge during Cyclone Gabrielle. It has been closed to all traffic since the cyclone.

Extensive cracking is evident at the piers and in the bridge deck, making it unstable for any load and expensive to repair.

This option is not viable.

The significant cost to build a new replacement bridge far exceeds the $560,000 funding we have from NZTA for this site, with no further co-funding available due to the bridge’s low traffic volume, ongoing maintenance costs, and short five-kilometre detour.

Council has looked at options for Burnside Bridge with NZTA, landing on a high-level estimate for replacing the bridge. This did not include site investigations, flood assessments, or geotechnical investigations to understand bridge pier depth or bridge form, such as the number of lanes. A high level of contingency was applied.

Note that Council assessed the estimate and the consultant fees, and concluded that they are within market expectations for this kind of project. However, these are unknown and could be quite complicated for a bridge rebuild of this nature.

Burnside Bridge crosses the Makaretu River but is currently closed to all traffic. We have investigated the option of building a low-level ford (similar to the one in construction in Wairoa below) to allow vehicles to cross the river when the water levels allow.

This option is not viable.

The cost far exceeds the $560,000 funding NZTA has allocated for this site, with no further co-funding available due to the bridge’s low traffic volume, high ongoing maintenance costs, and five-kilometre detour.

While cheaper than rebuilding the bridge, this option was assessed by NZTA to have a benefit cost ratio (BCR) of 0.12 and a ‘very low’ efficiency rating under NZTA’s investment prioritisation method. A project requires a BCR of greater than 1 to support any spend over $2 million.

The structure for the ford option was designed and tendered, giving a good market indication of price to build.