28 January, 2021


Wakamoekau project to protect and provide

By Robyn Wells, Wairarapa Water Ltd chief executive

Back-to-back scorching hot days this week have pushed the mercury up into the 30s. It is a big change from what the summer had been delivering with some less than festive temperatures over the Christmas & New Year holiday period.

This is what climate experts have been telling us to get used to, particularly on the east coast of the North Island. These big swings in the weather, with the potential for long hot dry spells, put considerable strain on water supply.

It affects us all. It puts our natural environment most at risk however, as water is taken from rivers and aquifers for everyday uses - with demand set to increase with population growth by more than 20,000 people expected - and to support the region’s two biggest GDP earners, primary production and manufacturing.

But even without growth, according to the Wairarapa Economic Development Strategy (WEDS), water demand will increase 15% by mid-century, and 30% by end-century, simply due to climate change. Higher summer temperatures and less frequent rain will result in increasing water loss from evapo-transpiration with limited replacement.

At the same time as this predicted pressure on water availability from both climate change and population growth, new regional freshwater plans mean less water can be taken from the rivers to adhere to new higher minimum flow requirements. While this is absolutely necessary for river health, it will further exacerbate water supply issues.

The Wakamoekau Community Water Storage Scheme (WCWSS) is an infrastructure-based solution to help ease this pressure, and provide reliability and relief to the environment, our communities and our regional economy.

The project is about doing water storage differently, and seeks to protect Wairarapa communities by ensuring benefits of stored water are shared across environmental, economic and cultural considerations.

To help ensure we deliver according to this, the project is being guided by Te Mana o te Wai, now a Government requirement. This means that the water will be prioritised to maintain the health of the water, then provide water for the community, and then for consumptive uses.

An illustration showing how Te Mana o te Wai will be incorporated into the Wakamoekau Community Water Storage Scheme, ensuring the protection of the health and mauri of the water.

Following debate and investigations over twenty years with the last six years funded in more earnest by local and central government, the culmination of this work - the Wakamoekau - which is supported by many in the community, will be submitted for resource consent application early this year.

The Wakamoekau consists of a reservoir in a natural valley basin of pastureland located in the hills north-west of Masterton. It will be filled primarily with water harvested from the nearby Waingawa River and upper Wakamoekau Creek only during periods of high flow, and stored to distribute in the dry months when required.

The site of the proposed reservoir was selected following lengthy processes where numerous sites were identified and deliberated by the Greater Wellington Regional Council alongside local stakeholder and governance groups. It has been farmland since the 1940s with only a handful small, predominantly man-made wetlands which are heavily modified and generally exotic species dominated.

We plan to regenerate and develop hectares of wetland, plant indigenous forest, and develop much of the reservoir border in natives and wetlands as part of the project. Similarly, we hope to protect and enhance the Opaki Water Race for amenity value and ecological benefits.

In times of significant heat, the Wakamoekau creek flow slows significantly with a resultant detrimental impact on downstream flora and fauna. The WCWSS will ensure that a minimum environmental flow is released consistently from the reservoir even in these dry times helping downstream.

Regenerating the site area from its near century-long life as pastureland will create ecological and educational benefits and will hopefully link into other native planting corridors being developed in the Wairarapa region.

But while there are many positive opportunities and benefits, this project is complex and not without risks. For example, building to withstand the region’s well known seismic profile and keeping costs practical will be a challenge, and we will share more on this with the community soon.

Indeed, hearing from the community is very important, and over the past 12-months we have sought to engage with a wide range of people, to listen to concerns and to share information compiled by experts. This is a community project, we have been committed to being open and transparent, sharing information via our website (www.wwl.net.nz), newsletters and newspaper advertisements. But, of course, as with any significant project, not everyone agrees.

As we hit the hottest time of the year, I think it is timely we remind ourselves that the Wairarapa comes out at the extreme end of climate change predictions, according to NIWA (Water and Atmospheric Research) and many of us are becoming increasingly concerned about water reliability in the future. We all need to work together to find multiple and optimal ways forward - which can be as simple as turning off the tap when we brush our teeth, to investigating and supporting a combination of nature-based and infrastructure-based solutions. WWL looks forward to continuing to progress an initiative that can make a difference for our future.

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