Central Plains Water decision

Graeme Wilson summarises the impacts on kayakers arising from the conditions applied to the Central Plains Water resource consent for water from the Rakaia and Waikmakariri Rivers.

The independent commissioners have released their report into the Central Plains Water consent application. The biggest issues for kayakers are the impacts on flows and the presence of intake structures in the Rakaia River and Waimakariri River (just above the gorge bridge).

The original proposal provided for a massive storage dam, and a year-round take of up to a maximum of 40 cumecs from each river. It was proposed that CPW take all Waimakariri water once the flow at their intake exceeded 63 cumecs.

There have been huge numbers of submitters against CPW, kayakers and otherwise, and the appeal process is only just beginning. In short the kayaking outcome is much improved as the Commissioners propose a maximum 24 cumec take, and CPW will only be able to take half of whatever water is available above an unmodified flow of 66 cumecs. The intake structures pose less of a hazard than originally proposed.

Excluding the holiday rule (described below), the key points are:

  • there will be very little take outside the irrigation season as CPW can only take to top-up on farm storage.
  • the take is subject to one-for-one flow sharing from commencement of take at an unmodified flow of 66.1 cumecs as measured at the Old Highway Bridge - that is, CPW can only take one of each additional two cumecs above that flow.
  • no take during the Coast-to-Coast race.
  • restrictions to ensure the first fresh after a period of low flows stays in the river.
  • Rakaia water is to be taken in preference to Waimakariri water - when sufficient water is available from the Rakaia no water will be taken from the Waimakariri.

The Commissioners have imposed a "holiday rule" to apply for all weekend days and public holidays between 1 October and 15 March; and all weekdays from 21 December to 15 February; and Easter weekend (Friday to Monday inclusive).

With the holiday rule in operation, if the unmodified flows are at 80 cumecs above the CPW intake then 55 cumecs would remain instream at the Old Highway Bridge (OHB); at 85, 60; and at 95, 65 respectively.

So what does it mean for paddlers? The impact of CPW unmitigated by the Holiday Rule is that days per annum in the marginal paddling band of 55 cumecs or below, as measured at the OHB, would increase in an average year by around 16 days, from 106 to 122. The Holiday Rule in a “typical year” would reduce this by 7 or 8 days - so there would still be a significant increase in days in the marginal range.

Also, the impact of CPW unmitigated by the Holiday Rule is that days per annum in the next flow band, 55 to 65 cumecs, as measured at the OHB, would increase in an average year by around 3 days, from 34 to 37. The Holiday Rule in a “typical year” would further increase days in this band by about 6 per annum.

The Commissioners stated: the proposal may not maintain amenity values of the Waimakariri River at their current level. However, we do not see this as an absolute requirement. We are now satisfied that with the changes to the scheme proposed by CPW and the conditions we have included the take regime will maintain recreation and intrinsic amenity values of the Waimakariri River at a similar level to present. We are satisfied that the values of the river will not be significantly compromised by the scheme.

They also note We are satisfied that the applicant’s proposed take regime along with the so-called “holiday rule” condition will largely avoid adverse effects on boating amenity and will adequately mitigate the effects which might occur in some flow conditions.

The Commissioners have stated that We are satisfied that potential impacts on the safety of kayakers in the vicinity of the Waimakariri intake can be addressed as a matter of final design. The applicant has agreed to a condition which requires a safety audit of the final design by a suitably qualified expert.

Broadly, the conditions provide for any intake structure to minimise the risk to a swimmer or of a boat becoming pinned; seek to minimise intake velocities; provide trash screens to enable a swimmer to climb off; and require certification of design and construction and an operational review by independent parties in consultation with Whitewater NZ.

In summary, this is a much better outcome than we faced when the scheme was first proposed but there is still a negative impact on kayaking flows and days. We are considering our options.

Thanks hugely to all the individuals who submitted against CPW, who attended the hearings, and who submitted on the various interim reports over the last two years. Hundreds of hours of effort from kayakers have had a major effect, reducing the impact that the scheme will have on us.

A huge thanks to the team from Whitewater NZ, Arawa and the Whitewater Canoe Club, and Maree Baker from Anderson Lloyd, who contributed to this result.