Low water levels at the Mangatangi Dam in the Hunua Ranges, in June this year. Photo / Simon Runting, Watercare
Low water levels at the Mangatangi Dam in the Hunua Ranges, in June this year. Photo / Simon Runting, Watercare
COMMENT
Right now, Auckland needs more water from the Waikato River. But Auckland Council and Watercare have agreed it can't be the long-term solution.
That hasn't stopped the likes of David Clarke and Tony Lanigan, both formerly of Watercare, from coming out swinging with their opinion on theissue (NZ Herald, July 15). They make it sound like a simple fix. But this is a complex issue.
On the one hand, there's a seemingly unlimited supply of water in the Waikato River that some believe should be available to those who need it, when they need it.
At the same time, Waikato Regional Council is being hammered to improve Waikato's environment, but taking more and more water from the awa inevitably impacts its health.
That's why I called the water summit in Hamilton earlier this month – so an agreement could be reached by stakeholders on the short- and long-term solutions for Auckland's water supply.
The Waikato River runs into the Tasman Sea. Photo / Watercare, file
There's been a focus in the media – and by Clarke and Lanigan – on Watercare's 2013 application to Waikato Regional Council for 200 million litres per day (MLD) for population growth later in the decade. What Clarke, Lanigan and others haven't told you is Watercare's own asset management plan says this additional amount is not needed until 2028.
Let me be clear. This application has been a distraction from finding real solutions to Auckland's current potential crisis if the rains don't come before next summer.
That's why I welcome the Government's Board of Inquiry. It will determine whether that water is in fact needed now to meet Auckland's needs, or in the future. But we know that locking up water now for Watercare's future needs means others can't use it in the interim. The inquiry will also investigate other viable options for supply, such as the treatment of wastewater.
As a result of the summit the focus is now in the right place – on Watercare completing the upgrade it started this year on its Tuakau treatment plant to use all the 25 MLD over winter granted by Waikato Regional Council in 2017. The agreement with Hamilton City Council, once Watercare has sought consent, extends the availability of that water over summer.
Watercare is doing its bit, too. It's now talking to other consent-holders who may have spare water to share to get another 50 MLD, which it'll be ready to treat by this time next year. Water-sharing is only possible because Waikato Regional Council's policies allow it to happen.
Once Watercare has completed discussions with iwi, Waikato Regional Council staff will push ahead with processing the consent received in May for another 100 MLD, which seeks to take water during the period of October to April when the river is above median flow and there is ample water. It would also provide for 100 MLD during the months of May to September when there is water available to allocate. It will be some time before Watercare's plant and pipe into Auckland can take this extra amount, if granted.
Taking this all into account, it will be interesting to see if Watercare still needs all the 200 MLD for the future. Because Watercare has told us it doesn't want to increase capacity if it can decrease demand.
The limit on how much water can be taken from the Waikato River was determined by the Environment Court in 2012 at 10 per cent of the five-year low flow. This totals 18.79 cumecs.
During the drier months over summer, 15.88 cumecs is now allocated from the Waikato River, leaving some 2.91 cumecs, or 251 MLD, left when allocation pressures exist.
Russ Rimmington. Photo / supplied
This limit is set to meet the ecological needs of the river and marine environment into which it flows, iwi values articulated through Te Ture Whaimana o Te Awa o Waikato (Vision & Strategy), and to assimilate impacts of discharges and land use in the catchment. It also ensures there's enough water for recreation and electricity generation, while also meeting domestic, municipal, agricultural, cultural and industrial needs as far as possible.
Auckland's water needs vary throughout the year, with typical demand an average 450 MLD.
Watercare currently takes around 165 MLD from the Waikato River at Tuakau, with upgrades due to be completed in August enabling it to treat and transport 175 MLD into Auckland.
Watercare can also take an estimated 250 MLD from the reservoirs in the Hunua ranges, formed through the damming of the Mangatāwhiri and Mangatangi rivers, tributaries to the Waikato River. There's no limit on how much water can be taken from these reservoirs, so long as there remains a small residual flow left in the rivers below the dams.
While much is made of the seven years that has passed since Watercare's 2013 consent was lodged, no comparisons have been made with other similar consenting processes. For example, the consent lodged with Auckland Regional Council in 1999 for the Mangatāwhiri River was completed in 2012 – taking more than 11 years.
• Russ Rimmington is chair of Waikato Regional Council.
