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The Tukituki: Always a Taonga

Minimum flows must be raised

Minimum flows are supposed to retain sufficient water within rivers to protect environmental, social and Mãori cultural values. However, as a river falls below its minimum flow, these values are compromised. In practice, the needs of livestock grazed on irrigated pastures are prioritised over environmental and Mãori values, as water is still taken from rivers for stock purposes when a river is below this environmental bottom line.

Water for stock use was previously included in abstraction volumes and subject to resource consents for use in stock water races. These races meandered across the farming landscape and farmers accessed water from them as required. They increased habitat availability for a range of wildlife and fish species, replenished some ground water zones and unused water flowed back into the river. Water from races was also stored in tanks or farm dams for use during drier parts of the year.

Over the last decade, the stock water races have been closed down. This water has been transferred by various councils and the purpose changed from stock use to irrigation. This has had a compounding effect with irrigation and stock water volumes increasing and stock water going from a consented activity to an assumed permitted activity. This puts more demand on our water resources.

Additionally, many orchards and some cropping enterprises are required to gain a resource consent through a publicly notified process for amounts of water ranging from 350 to 1000 cubic metres per week, while dairy farms that use similar amounts for their stock water are not required to have a consent. The cropping activity is assessed as having an effect on our rivers, but not the stock water takes.

In May 2013, 75 consents to take water from the Tukituki expire, and another 33 shortly after. When considering these renewals it will be interesting to see if HBRC takes into account the effects of all groundwater takes from the Ruataniwha Plains on the Waipawa and Tukituki Rivers. There is mounting evidence confirming that the combined ground water takes from the Ruataniwha Plains have a negative impact of more than 1000 litres per second on the lower Tukituki. The NPS for Freshwater envisages setting limits on total abstractions from rivers and for water quality.

The flow setting criteria in background reports for the proposed National Environmental Standard on Ecological Flows and Water Levels (2008) recommended a default minimum flow for rivers of a similar size to the Tukituki, somewhere in the region of 80% of Mean Annual Low Flow (MALF). Using the MALF as a baseline helps average out any extremes over time and this figure is often used as guidance for habitat requirements for aquatic species. If applied to the Tukituki, the minimum flow at Red Bridge would need to increase from the current 3,500 to 5,300 litres per second.

Pro rata reductions of existing consents would be the logical and common sense approach to expect from our water managers to reduce over-allocation in the Tukituki River and Ruataniwha groundwater zones.

Enter water storage

The goal posts for the water storage dam in Central Hawke’s Bay keep moving. Initial discussions with Tamatea hapu indicated that there would be flow augmentation during summer low flows, leading to a healthier river and gaining tentative agreement.

This however, has changed with HBRC now stating no flow augmentation and letting the river “potentially” return to natural flows. The problem with this scenario is that the Ruataniwha aquifers have declined by around 70 million cubic metres over the last decade due to unsustainable ground water pumping, so flow loss will continue to occur through the riverbed gravels until groundwater levels are sufficient to maintain or re-activate the natural spring flows which historically replenished the rivers.
Dam-fill, we’ve been informed, would involve capturing the top 10-15% of flows from heavy rainfall events. The rest of the water would continue to flow naturally down the river channel. This would allow the HBRC Water Company to be in control of determining what the natural flow should be exiting storage, while retaining the rest of the river for on-selling.

I can’t see Mãori backing this option unless we are part of governance and management of the dam, as in the past, commercial activity and profit has always been achieved at cultural and environmental cost. Regulators seem to ignore the Treaty guarantee of the right for Mãori to develop our own resources and the Makaroro dam proposal and its governance structure risks alienating Mãori from participation in management of a natural resource. It also makes a mockery of the new era of co-management.

Once water is taken from the dam, either in a pipe or man-made channel, to all intents and purposes it becomes a commodity and subject to a different legal regime, some of it outside the scope of the RMA, public control or input. The proposal also assumes Mãori don’t have an interest in the higher river flows targeted for filling the dam, nor rights to the riverbed similar to those of the Tuwharetoa Trust Board in relation to their lake and its tributaries.

To date no invitation has been received by tangata whenua to be part of the Water Company, which ought to be a given, with the dam and future water use likely to have some major downstream effects on our taonga.

Of course lake edge property soon becomes prime real estate over time, as happened with Lake Dunstan in Otago after they put in the Clyde dam. If the Makaroro dam goes ahead it will create similar opportunities but also drown significant remnants of indigenous flora. Environmental offsets may be the order of the day as envisaged by the proposed NPS on Indigenous Biodiversity. Riparian planting should be a pre-requisite anyway to help prevent slips and sedimentation.

As capacity of the proposed dam has expanded to 90 million cubic metres, the issue of dam encroachment onto lands subject to Treaty claims has arisen. Leaving the riverbed debate aside for a minute, the northern side of the (potential) lake created by the dam adjoins land blocks that were dubiously acquired by the Crown during New Zealand’s colonial period. Covering them in water rather than using them as part of Treaty reconciliation may not be tenable to Treaty claimants.

Regulating farm run-off

Around 60-70% of nutrient in the Tukituki River is derived from agricultural run-off, from so-called non-point source discharges. Regional councils regulate point source as in what flows from a pipe or drain, but seem reluctant to put the brakes on the main contributors to surface water pollution. Nitrate levels in ground water are also on the rise across the Ruataniwha Plains.

There seems to be an acceptance by some that a right to farm includes a right to pollute through nutrient run-off. The contention promoted by our regulators is based not on how to prevent nutrient loss to rivers or ground water, but on how much should the public be required to put up with from these commercial activities. Excessive phosphorus and its contribution to the acceleration of aquatic weed growth in the Tukituki is partly attributable to excessive agricultural run-off from fertilised pastures.

There is a move afoot to create markets around water and nutrient trading. Part of this is aligned with a “whole of catchment” approach to water management, which is how catchment boards used to operate before they morphed into regional councils in the 1980s. In the early 2000s, the Ministry for the Environment commissioned Australia’s CSIRO to come up with a report on using market-based instruments for managing water (CSIRO, Jan, 2004). This idea has received more focus over recent times, with calls to increase flexibility around water transfers, with Irrigation New Zealand leading
the charge.

Of course trading has occurred in the background for some time anyway, with the RMA actually encouraging it in some circumstances. Also being considered is a management fee or levy whereby regional councils or their successors charge for water by the cubic metre.

Mãori would prefer to be included within these conversations because where an abstraction (or nutrient) permit is transferred between sub-catchments there is a likely impact on a different hapu group than previous.

But of course, as has been outlined, this is just one of many conversations about the Tukituki catchment that must include appropriate and knowledgeable Mãori. Sensible, sustainable Tukituki management solutions must be arrived at and implemented. Continuing down the failed path of economic advancement at the cost of our iconic river is no longer acceptable.

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