Flood protection networks across our region have been significantly affected by persistent heavy rainfall and the impact of 2 cyclones.
The resultant build-up of silt has considerably reduced the capacity of drain channels, exacerbating the vulnerability of many residents to
compromised drainage systems and increasing the risk of future flooding.
Focus areas
Our flood protection efforts are set to intensify during the spring and summer months. However, realistically, completing all necessary work within the next three years is unlikely. It may take up to seven years to address all areas adequately.
Our immediate focus will be on the most critical flood-prone areas:
Silt and debris management
Ongoing removal of silt and large woody debris around key structures is critical for maintaining the functionality of our drainage systems.
Stopbank enhancement projects
We'll continue to advance our stopbank projects to bolster resilience against future flooding.
Infrastructure planning and modelling
Comprehensive planning, reviewing, and modelling efforts will guide us in reinstating, reinforcing, and enhancing our flood protection
infrastructure to heighten the resilience of our networks.
Focus on Waipaoa River
Particular attention will be given tothe middle reaches of the Waipaoa River, especially around Te Karaka. This focus will help us understand the causes of flooding and shape future flood protection strategies for the area.
Rural land drainage network
Priority is being given to clearing drains in flood-prone areas such as Patutahi, Muriwai and Manutuke to prevent overflows and property damage during heavy rainfalls.
Mangahauini River stopbank repair
Staged repairs and erosion protection measures on the Mangahauini River stopbank. This project is crucial for protecting the Tokomaru Bay township from flooding.
Budget for 3 years 2024-2027
We had $64 million approved from government, as part of the $204 million Cyclone support package. As part of this agreement, we need to fund an additional $7.1 million.
We're forecast to spend $56.2 million over the next 3 years. The remainder of works will be completed post 2027.
Work that started immediately following the cyclones
We needed to urgently develop a plan to repair and rebuild the flood protection system to ensure the safety and well-being of our residents, as well as invest in new schemes to prevent further damage to public and private property.
The impacts of the cyclones across the flood protection system are from reduced capacity in the channels due to siltation, woody debris build up at structures and stopbanks that have either failed or are no longer fit for purpose.
Te Arai River - clearing log jams
Updated June 2023
Recovery work removing major log jams in the Te Arai River following Cyclone Gabrielle began but it has been put on hold now due to difficult access for machinery into the river, affecting safety and efficiency of works.
Central government have allocated a significant fund ($30 million +) toward removal of Large Woody Debris (LWD) and silt in Tairāwhiti. This enables a major regional project requiring significant planning to ensure success.
An Expression of Interest (EOI) process calling for contractor's interest in removing LWD has closed mid-June and is currently being assessed.
Site assessment and prioritisation is underway.
Realistically reasonable access to river sites will be gained in Spring or Summer to undertake removal of LWD.
What’s happening at Te Karaka?
Staff are analysing all the survey data of the middle reaches of the Waipaoa River, upstream of Kaitaratahi Bridge at Te Karaka.
This work involves identifying the reasons for flooding and making long term flood mitigation proposals for Te Karaka.
Flood spread mapping work is also in progress for modelling and then staff will come up with solutions for Te Karaka
Work has started clearing silt from Council’s rural land drainage network.
Following Cyclone Gabrielle, the drains at Manutuke and Patutahi were fully flooded including some areas in Muriwai.
Contractors have started work at the Whatatuna Drain at Manutuke and from Opou Road early June. Work will also start in Patutahi from mid June.
One excavator can clear around 200m of drain each day, with some places needing more digging.
It’s estimated to take 25 days to clear 5km of drains, weather permitting.
Our plan is to clear 5km of drains in Patutahi, 4km in Manutuke and 2km in Muriwai initially at critical locations and then continue work in other areas.
We’re thankful for the recent fine weather to be able to start the work. The clearing work will be extended if the weather continues like this.
The high-water tables and soggy ground conditions has made it difficult for heavy machinery to get in and do the work until last week and we’re still experiencing difficulties at some sites.
Making the most of the fine weather, at the same time we’re weed spraying the drains as this was missed due to the wet summer and cyclones Hale and Gabrielle.
Usually, the drains are dug out and the silt is carted away. But due to the volume of silt, the huge workload and not enough work crews, we’ll dig the drain and leave the silt on the side as we need to use the resources and fine weather while we can.
We’re committed to clearing the rural drainage system before the winter and this is the quickest way to get the work done.
Updated June 2023
Reconstruction of the Mangahauini River stopbank and erosion protection will help protect Tokomaru Bay township from flooding.
Site 1 - Required construction of a 230m section of rock armouring from the campground to 24 Mangahauini Street. This was completed in May 2023. The stopbank has been temporarily reinstated along this length awaiting drier conditions to fully complete.
Site 2 - 175m section of rock lining along Toa Street from Marotiri Street to the transfer station. This was completed in June 2023.
Site 3 - 135m section of rock lining at 19 Taro Street. This was completed in June 2023.
Site 4 - 195m section of rock lining from SH35 Bridge to the Kura. This is currently under construction. Expected completion mid-July.
Back filling of all the sites has been put on hold awaiting drier conditions.