Following the impacts of Cyclone Gabrielle in February 2023 and previous significant flood events, we're investigating a programme of flood resilience improvements for Tolaga Bay Uawa, Tokomaru Bay, Makarika and Tikitiki.
East Coast catchment areas
Tolaga Bay - Mangaheia, Hikuwai and Uawa rivers
Tokomaru Bay - Waiotu Stream and Mangahauini River
Makarika - around the school
Tikitiki - Poroporo River
This project aims to safeguard lives and reduce flood risk to property and community facilities.
The focus is on cost-effective solutions to reduce flooding risk to 38 impacted dwellings. 13 dwellings were classified as FOSAL Category 3, and 25 as Category 2, with 14 to be lifted if viable.
While the project's in its early investigation stage, solutions to enhance flood resilience may include a combination of:
- stop banks
- hazard mapping
- channel widening/deepening
- flood storage measures
- managed retreat
- capacity improvements at culverts and bridges
What's happening now?
We're at Stage 1
The initial investigations phase - hydraulic modelling and optioneering are underway.
We'll also develop flood hazard maps, sediment models, risk assessments and prepare a cost/benefit analysis for flood mitigation options.
Early engagement with community, iwi and infrastructure owners is underway to share a long list of options for all catchment areas.
Then the most cost-effective option/s can be progressed to resource consent, detailed design and construction/delivery.
Considerations will include climate change, civil defence evacuation plans, land use, operation and maintenance activities, changes in rivers and interventions to mitigate the risk of flooding.
Programme and costs
Since the start of Stage 1, this has been accelerated by around 3 years by delivering flood resilience projects as solutions are identified and developed rather than waiting for investigations to be completed for all catchment areas.
Acceleration opportunities beyond this are limited, due in part to availability of local technical specialists and contractors in these isolated areas.
*The PARA framework and resilience—each of the 4 main approaches has the potential to contribute to the “big picture” of community flood resilience: Protect, Accommodate, Retreat, Avoid.