ACROSS THE REGION

August 2021, River Management edition

CHAIR’S MESSAGE

Tēnā tātou i ēnei rangi o Hine-takurua, me te kino o hūpē tautau i tēnei tau. Ka mahue ake a Mākeremumu, kei kō iti atu a Kōanga; me aro atu ki ngā hua, ki ngā pua ka puawai mai. Āpā ia nei ka rari noa mai, engari kē he mea kūmanu e te ringa mākohakoha. Tama tū tama ora, tama moe tama mate.

Welcome to the latest edition of Across the Region. This issue focuses on river management - a crucial part of Horizons Regional Council’s core business. Our region’s communities and land assets are built around waterways and Horizons’ river management team are responsible for managing the region’s rivers to help prevent flooding and erosion.

As part of our ‘business as usual’ we manage 34 river and drainage schemes, maintain over 500 km of stopbanks, 1,100 km of drains, 22 pumping stations and 53 dams. Our flood protection and land drainage assets have a replacement value of $680 million. Other river management work includes erosion control, land drainage, engineering design and asset management. All this works towards the common goal of achieving natural hazard resilience and long-term economic, social, cultural and environmental wellbeing for our communities.

A recent example of our river management assets at work was the late June flood event earlier this year. While our stopbanks kept water within the river channel as designed, the event highlighted areas that require attention. This event reiterated the important role river management plays in keeping our infrastructure and communities safe.

In this newsletter you will also find information on four Infrastructure Climate Resilience projects, which central government has provided significant funding towards as part of their response to the economic impact of COVID 19.

If you’d like to learn more about our river management, beyond what’s included in this edition, please visit www.horizons.govt.nz

Noho ora mai rā.

Rachel Keedwell, Chair

FLOOD RESILIENCE

Floods are the most common natural disaster experienced in New Zealand. With three main river systems, the Whanganui, Rangitīkei and Manawatū, in our region we are especially vulnerable.

To help protect our communities from floods, Horizons’ river management team does a broad range of work such as planning, flood control, river safety and managing resources for resilience and future proofing.

Many things impact on rivers, their flow, and course. For example, as our towns grow and more homes are built, a lot of soil which would have previously absorbed water, is now covered by structures and concrete pads. Instead of being captured in the soil, rainwater flows into gutters and drains and then into our rivers during rain events, increasing the volume and the risk of flooding.

With much of our urban communities located on flood plains it is essential to have an appropriate standard of flood risk mitigation. By protecting the flood plains we are protecting not just our communities but also productive land and key infrastructure such as roads, telecommunications, hospitals and schools.

It’s important to note that Horizons’ role is river management and community resilience – not river control. Inside we explore this further looking at the Rangitīkei River enhancement project which is aiming to create a resilient river system that has ‘more room’ to follow its natural path.

Climate resilience and flood protection

In 2020, central government’s budget included $210 million for climate resilience and flood protection projects across New Zealand. This funding formed part of government’s response to the economic impacts of COVID-19. Horizons received $26.9 million of this funding from Kānoa, the government’s Regional Economic Development and Investment Unit. We estimate the total cost of these four projects to be $35.9 million with Horizons making up the 25 per cent balance. This collaborative funding has enabled Council to accelerate work on four Infrastructure Climate Resilience projects, which were already planned or underway, to increase our river communities’ resilience to the effects of climate change.

The funding will also create new employment opportunities - we’ve conservatively estimated the number of jobs created as 36 across Horizons, external consultants and contractors. These projects will not only assist in keeping our communities safer but will help boost the region’s economy
as work on maintaining and building new infrastructure progresses. The completion date for all four projects is March 2024.

INFRASTRUCTURE CLIMATE RESILIENCE PROJECTS

Funding received in 2020 from Kānoa, the government’s Regional Economic Development and Investment Unit (REDIU), has enabled Council to accelerate work on the four Infrastructure Climate Resilience Projects listed below, increasing our river communities resilience to the effects of climate change.

Foxton East flood mitigation project

In recent years Foxton has experienced flood events which have highlighted the inadequacy of the current drainage system.

Horizons and Horowhenua District Council have been responding jointly to this issue, with funding set aside in both councils’ current Long-term Plans. Kānoa-REDIU funding has enabled Horizons to explore options including a mitigation strategy which diverts water away from Foxton Township and stores it on rural land south of Foxton. The water will then either drain through gravity or be pumped back into the Foxton Loop.

Horizons has started to meet with affected landowners and is meeting regularly with local iwi to identify the impact of this work on taonga, whenua, and wahi tapu. Once this first round of consultation is complete, Horizons staff and councillors will be talking to the wider Foxton community about the project.

Lower Manawatū scheme resilience project

Horizons has been investing on behalf of ratepayers in increased flood protection standards for the Lower Manawatū area since 2006, as a result of the impacts of the devastating 2004 floods. This has included raising/rebuilding stopbanks, replacing the Kopane Bridge and constructing the Burkes Pump Station.

Following the injection of additional funding from Kānoa-REDIU, the Lower Manawatū scheme (LMS) resilience project was established. This project includes further strengthening of the stopbank network and building resilience at key locations. This project is anticipated to take three years and will create local employment opportunities.

The LMS resilience project encompasses several sub projects along the Lower Manawatū scheme. Work is currently underway for flood mitigation and general maintenance along the Hartley Street sea wall in Foxton. This includes restoration of the existing rock armouring with new natural rock. Similar work is planned for Te Matai Road, Palmerston North. Work is also in the planning stage for upgrading the Moutoa floodway outlet (Piri Harakeke). This will be jointly undertaken with the Foxton East flood mitigation project.

Palmerston North flood protection resilience project

The scope of the Palmerston North flood protection resilience project work includes upgrades to flood defences (primarily stopbanks) and the replacement of a number of aging assets, along with new work which will include additional amenities, such as pathways and signage, and enhancing public access to the Manawatū River and Mangaone Stream.

One of the key enhancement projects Horizons is working on, in consultation with Rangitāne and Palmerston North City Council, is upgrading the area around the northern end of the Manawatū River bridle path. Plans include changing the current shady and often damp area to a river access path with bright open spaces, riparian planting, artwork and signage identifying the significance of the site. This work began in July 2021, with removal of some of the poplar trees currently shading the site.

Along the Mangaone Stream several pieces of ageing infrastructure are also being upgraded – from below Flyers Line to the confluence of the Manawatū River. Work will include realigning a section of the Mangaone Stream stopbank near Pioneer Highway.

Rangitīkei River enhancement project

We are currently developing a new management strategy for the Rangitīkei River that recognises the dynamic nature of the river. The intention is to moves towards a more resilient river system that has ‘more room’ while accommodating goals of greater river character, greater river biodiversity, and enhanced public access and recreational opportunity.

This project focuses on only the Lower Rangitīkei River from Bulls to the sea and includes:

Addressing the risk of river avulsion against the Parewanui stopbank through channel widening activities such as removing non-native vegetation mechanically, and aerial spraying and gravel management which creates multiple river channel options;
Slowly transitioning pastoral land into a continuous native plant corridor alongside the river;
Flood resilience work - for example the Scotts Ferry Rock Lining Repair;
Wetland options along the Parewanui No.1 Drain; and
The creation of pathways for recreational use along some parts of the stopbank.
The project is intended to have positive environmental and social outcomes for the Rangitīkei River and its users.

What is a 1% AEP or 1/100 year flood?

An annual exceedance probability (AEP) is the likelihood of an event occurring in any given year. If the AEP is 1% this means there is a 1% chance of the event occurring in every 100 years. However, this is a mathematical probability not a definite so we could experience three 100 year floods in a 100 year period, two in two consecutive years, or we might not experience any. If you’d like to learn more about flooding probabilities and how they are calculated visit the Flood Protection section on our website and check out our “What’s a 100 year flood?” video.

WHAT RIVER MANAGEMENT STAFF DO DURING A FLOOD EVENT

MetService provides severe weather watches, warnings and forecast rainfall to our environmental data team. The team combines this information with data collected via Horizons’ rain and river level monitoring network and feeds it into our flood forecasting system. All of this information enables the team to assess what state the region’s rivers are in and forecast what impact forecast rain might have. If you’re interested in our monitoring data visit envirodata.horizons.govt.nz

Horizons’ automated flood warning alert system operates off Horizons’ river level network and provides automatic alarms to internal and external subscribers. To find out more about subscribing to this service visit horizons.govt.nz/flood-emergency-management.

River management staff will check assets such as floodgates to ensure they are ready to respond, touch base with staff and contractors that may help with a response, and identify what points in the network may need extra attention. During an event, river management staff are based in the Emergency Operations Centre (EOC) and out in the field. In the field they are monitoring the flood and inspecting assets to ensure they are performing as they should be, reacting to any emerging situations (such as if a stopbank is going to be over topped or a culvert blocked), and deploying pumps. The current state on the ground is reported back to the EOC via the river management representative. Staff can also be involved in the operation of flood gates and flood barriers, as directed by the EOC.

After a flood event, the team will visit assets to assess any potential damage and prioritise any repairs. They will also evaluate what went well during the event and what they may need to keep in mind for next time.

Your representation on Horizons Regional Council

Later this year, we will be consulting with our communities about how they would like to be represented on Horizons Regional Council. A representation review is normally done once every six years however, following a decision
in May to establish Māori constituencies in time for the 2022 local government elections, Council will now be seeking public feedback on their proposal sooner. Things that will be considered is how we achieve fair representation for each of our communities, including how many councillors and where constituencies (districts or boundaries) should be. This will also include one or two Māori constituencies. By establishing Māori constituencies, voters enrolled on the Māori electoral roll will vote in a Māori constituency, and voters on the general roll would continue to vote in their general constituency. As no one can be enrolled on both rolls at the same time, no one gets to vote in more than one constituency.

UPCOMING COUNCIL MEETINGS

AUGUST AND SEPTEMBER 2021

Passenger Transport Committee 17 August, 10am
Regional Council Meeting 24 August, 10.00am
Audit, Risk and Investment Committee 24 August, 1.00pm
Climate Action Joint Committee 6 September, 1.30pm
Regional Transport Committee 7 September, 11.00am
Strategy and Policy Committee 14 September,10.00am
Environment Committee 15 September, 9.30am
Regional Council Meeting 28 September, 10.00am

Unless otherwise stated meetings are open to the public and will be held at Regional House, 11-15 Victoria Avenue, Palmerston North. Strategy and Policy and Regional Council meetings are also live-streamed on our Facebook page. Please note all details were correct at time of sending. However, for the most up-to-date dates and times for council meetings please check our website.