Start soon for $5M-plus of long-awaited floodworks

25 Feb 2022, 12:07 PM

More than $5 million of long-awaited staged works designed to substantially reduce the flood risk to Otiria and Moerewa are to begin in earnest shortly.

Northland Regional Councillor Justin Blaikie says about $5.1 million of works will be carried out over three stages, beginning with a $500,000 project to construct a 150 metre lower spillway from Pokapu Road to where it meets the Waiharekeke River.

The councillor, who co-chairs the Taumārere River Liaison Working Group, says the three-month project effectively began Friday, 25 February, with a dawn blessing near the Pokapu Bridge.

He says in a big flood, about 80 percent of the water from the Otiria Stream spills over nearby land as does 70% from the Waiharakeke Stream.

The NRC plans to restore the streams’ natural flows by replacing the existing Pokapu Rd Bridge and building a new three-span, 60-metre-long single-lane bridge.

The spillway will skim the flood flow from the Otiria Stream and restore natural flow towards the Waiharakeke Stream. (Currently the railroad, Otiria and Pokapu Roads deflect the flood flow towards houses and two marae and then eventually flows to the Waiharakeke after going through houses and the marae.)

Local kaitiaki Wiremu Keretene says the project has “demonstrated and shown us what a true partnership looks like from a hapu mana whenua point of view when referring to Te Wakaputanga 1835 & Te Tiriti o Waitangi 1840”.

“We are working together to achieve a solution where both tangata whenua and local government agency are in agreement with the final decision”.

Mr Keretene says locals’ knowledge has been intergrated into the overall project plan and importantly for them, they have had the opportunity to be included at the discussion table and in the decision making process.

Councillor Blaikie says the first stage of this work (the lower spillway) should begin in earnest shortly and is being carried out by Kaitaia Contractors Limited, which has already successfully carried out works on the Awanui flood scheme in Kaitaia.”

Councillor Blaikie says Stage II of the works is a significant undertaking – expected to cost $3.9 million. Pending agreement with the landowners involved, it will begin in May this year and run until December.

“Subject to landowner approval, this will involve construction of the new 60-metre-long bridge to handle a 1:100 year plus climate change flood event. The new bridge will replace a smaller 18-metre existing bridge and will help reduce flooding to Otiria and Moerewa.”

The third and final stage will begin in December this year and run until June next year.

Expected to cost about $700,000, it will see construction of an upper spillway and stopbank from the new bridge to the Otiria Stream to block overland flow and direct floodwaters to the Waiharakeke River.

Councillor Blaikie says the project is being carried out by working downstream to upstream to ensure the receiving environment is ready before opening the spillway.

While the works will not stop flooding altogether, they will deliver ‘enormous’ benefits, including reducing the severity of a typical flood by about 75% and importantly reduce the risk to currently flood-prone marae and the local rugby club.

The council says $2.8M of the project cost will be met by central govt via Kānoa - Regional Economic Development & Investment Unit, another $1.6M from the NRC and the balance – about $600,000 – via a local rate on about 2300 properties in the affected area.

Men with nets and equipment in a stream.

Kaitiaki Wiremu Keretene, left, and local community volunteers carry out electric fishing as part of pre-works stream health checks at Moerewa’s Otiria Stream.