Following the impacts of Cyclone Gabrielle in February 2023, we're investigating flood resilience improvements for the Turanganui, Waimata, Taruheru rivers and the city suburbs of Whataupoko and Mangapapa (city north).
The Gisborne city area was severely impacted with more than 170 homes flooded, 48 dwellings classified as FOSAL Category 2 with 24 being lifted if viable and 14 impacted due to land instability. To address this, we're investigating a programme of flood resilience improvements.
Gisborne city
Taruheru, Waimata and Turanganui rivers and Whataupoko and Mangapapa suburbs
The project will identify and deliver cost-effective interventions to reduce the risk of inundation to around 150 dwellings across the Gisborne city catchment.
It aims to safeguard lives, protect property and community facilities, and improve the resilience of the city's water, wastewater, and stormwater systems.
What's happening now?
We're at Stage 1 - investigations
Updated: August 2025
A draft hydraulic model has been completed and will undergo a series of internal workshops. The model has identified constraints within the piped and waterway networks, pinpointed secondary flow paths, and informed a cost-benefit analysis of potential flood mitigation options.
Consultation with the community, iwi and infrastructure owners will help shape the preferred mitigation options. The most cost-effective option(s) can then be progressed to resource consent, detailed design, and construction/delivery.
The design service level will be equivalent to a 1:100-year event, with allowances for climate change and sea level rise. Key considerations include climate change impacts, interaction with the stormwater network, land use, existing assets, changes in river behaviour, and interventions to reduce flood risk from Gisborne's 3 city rivers.
While the project is in its early investigation stage, potential interventions may include stopbanks, channel widening or deepening, capacity improvements at culverts and bridges, and upgrades to the piped network.
Detailed design work is currently underway to widen the Taruheru River between Taruheru Cemetery and Gray's Bush. Significant excavation work is anticipated, beginning at the downstream end. Resource consenting has commenced, with physical works planned to start from 2026 onwards, subject to consent approvals.
Stage 2 is being finalised and expected to start in late-2025 and mid-2028.
Estimated cost $13.95m.
