The $3 million third stage of improvements to the Awanui flood scheme is progressing well, according to the Northland Regional Council.
Councillor Colin Kitchen, the regional council's Te Hiku representative, said the third annual construction season of the $15m scheme upgrade was now expected to be completed in 2022/2023.
About $1.1m worth of work had been done last construction season, but a subsequent multimillion-dollar injection from the Government as part of its Covid-19 recovery response package was allowing the project to be completed more quickly and at less direct cost to ratepayers.
This construction season's schedule was costing about $3,050,000, including extensive earthworks for southern spillways under way over about 2.4ha of former farmland behind Rongopai Place, in Kaitaia, including construction of 280m of new stopbanks to better protect 29 flood-prone homes in Rongopai Place, and about 900m of new spillway.
Kitchen said the $1.1m spillway work would account for more than a third of this season's programme, and was now 90 per cent complete, although the spillways would not be used for the next year or two, to allow grass to become well-established.
Church Rd scour protection and stopbank stabilisation was about 60 per cent complete, and work at Allan Bell Park work was about 10 per cent complete.
The weather-dependent construction season typically ends in May, but timber had been ordered for construction of the Milky Way floodwall, near the SH1 Waikuruki Bridge, which could progress irrespective of wet weather.
In an additional community benefit, some of the excess fill had been used to improve the nearby A&P showgrounds and equestrian track.
The council also has $4m of work scheduled to begin late this year for the new 2021-2022 construction season, and another $5m, which should mark the completion of the upgrade, for the year after that.
Kitchen says the upgrade was designed to help future-proof the decades-old scheme, including predicted climate change impacts, as well as delivering a considerably higher level of protection for Kaitaia and surrounding areas.
"The upgrade collectively is designed to protect urban Kaitaia in a once in a century-type flood and a 1:20-year event in surrounding rural areas," he said.
Already Northland's most common natural hazard, flooding would likely become more intense as climate change continued, increasing risks to communities in flood-prone areas and to critical infrastructure such as roading.
"One of the key drivers for the Awanui scheme upgrade is to make sure we're collectively doing as much as we can now to prepare and adapt for what the future is predicted to hold," he added.
The council had previously warned that without the added protection offered by the upgraded Awanui scheme, a large flood in urban Kaitaia could cause tens of millions of dollars' worth of damage and potentially put lives at risk.