The Spillway needs to be upgraded as it is part of the Rangitāiki Floodway, a key piece of infrastructure to help protect the community in a flood event.

In a flood event, the Floodway and Spillway upgrades, will help divert water away from the Rangitāiki River. This helps reduce the risk of significant flood damage to both rural and urban areas. (For example, the economic damage of the 2017 event was estimated to be $95M).

Check out this short video explaining what a floodway and spillway are:

In a flood event, the Spillway enables water from the Rangitāiki River to pass over the lower fixed crest weir and into the Floodway.

Through the design process, we do our best to predict what the water level could be at the Spillway during operation. This is because the water level determines how much flow will go over the Spillway. However, in an actual flood event, if the water level does not reach this predicted height, the Spillway could underperform, resulting in not enough water spilling into the Floodway to have the desired effect.

Having contingency gates provides ‘back up’ if the river doesn’t act as predicted by allowing controlled flow into the Floodway. It gives the operator and the community reassurance that pressure can be taken off the Rangitāiki River and the flood defences down stream of Edgecumbe, and better protect lives and livelihoods.

The community discussed the importance of having contingency 'back up' during the 2020 consultation process, which is why this has been included in the detailed design.

The current estimates to construct the revised designs are:

• Construct the Fixed Crest Weir and the Contingency Gates from 2023/24 at an estimated cost of $7.8M.
• Construct the Fixed Crest Weir only at an estimated cost of $3.8M. This option would mean there is no contingency 'back up'.

These estimated costs will be less the grant funding and are inclusive of project management, construction management, consenting and contingency. These increased costs will be passed to the ratepayer via targeted rates.

*Footnote: Please note this project has attracted Central Government Climate Resilience funding of $2.1M.

We want to consult with you about how we can help limit the impact of the cost increase in a challenging economic climate – particularly those of you living in the Rangitāiki-Tarawera River Scheme, as you will be directly impacted through your targeted rates.

As such, we are presenting two options (and asking for feedback):

• Construct the Fixed Crest Weir and the Contingency Gates from 2023/24 at an estimated cost of $7.8M.
• Construct the Fixed Crest Weir only at an estimated cost of $3.8M. This option would mean there is no contingency 'back-up'.

Targeted rates scenarios will be discussed at the community meeting and will be available on our website after that session.

The following graphs indicate the impact of the cost increases on a typical residential or rural property in the Rangitāiki-Tarawera Rivers Scheme.

The rates are based upon paying off a loan over 20 years, which is Council policy.

These graphs demonstrate the impact on rates each year over the next 10 years. We have also included a comparison graph for the 10-year mark. For example: for a residential property, rates would increase by $86 in the year 2032/33 for constructing the full $7.8M build.

If you have questions about these figures, please contact engineering@boprc.govt.nz

Click on the image below to zoom in.

NB: Rating effect is subject to change, pending the adoption of Regional Council’s Annual Plan and rates setting process in June 2023.