Of water, grass and fish

Probably not many Hawke’s Bay people appreciate the significance of the Tukituki River catchment to trout anglers of New Zealand. There is no doubting Hawke’s Bay people value it as a recreational resource or a place to seek solace from the pressures of life, but for anglers it is right up there.

In fact, it is nationally significant.

In the last survey that Fish and Game New Zealand (F&G) ran on trout fishing throughout the country, the Tuki came in as the seventh most fished catchment in New Zealand! Not a bad effort for a catchment that is currently facing huge pressures.

Part of the reason this catchment supports such a large amount of angling is its proximity to urban centers and the great access that people have to it. The other reason is that it currently supports a productive, wild brown and rainbow trout fishery. This is the key facet that F&G are seeking to protect as pressure mounts on water quality and quantity.

Understanding the Tuki

The Tuki originates in the geologically young Ruahine Range. It then traverses the Ruataniwha Basin, goes through the Raukawa Range and down to the sea. The most interesting and complex part of its journey is that part across the Ruataniwha Basin (RB).

Historically we understood that the Basin was much like a stack of pancakes, layered on top of each other. In between these pancake layers was water and the water in the different layers would not mix. These were known as confined aquifers.

In 2004 the Hawke’s Bay Regional Council (HBRC) commissioned an investigation in the Basin to make sure this assumption was correct. What they discovered has changed the way we have to view the Basin forever. The new research shows that the layers of pancakes are not flat, they are tilted, and the water that was thought to be confined between them is in fact freely mixing through the layers.

Previously irrigators were told that if they sunk deep bores there was “all the water in the world” and they could irrigate for as long as they wanted to pay the power to pump it.
This new information tells us that people with bores (even deep bores) many kilometers away from the surface waters of the Tuki and Waipawa Rivers could be affecting flows in these rivers. The modeling suggests that this may be adding up to a further 500 litres a second to the takes from the surface waters of the Tuki.

What we do not know and what the HBRC is currently investigating is how long the delay or lag is before water taken from these bores affects the surface water of the Tuki or Waipawa systems. If the lag is only a matter of a few weeks, then the effect of abstractions from deep bores will be to lower river levels during critical summer months. In essence this means that the rivers will be over allocated and at risk of serious depletion during the summer. If it is several months, then the effects might not occur until mid- winter when flows are high and the results could be less significant (as long as it rains during the winter!).

HBRC seemingly adopts precautionary approach

Given this new information, the Regional Council agreed in 2007 to put a very high burden of proof on people presenting new applications to take water from the Tuki catchment. This recognized that we all knew less than we thought about these resources, and therefore needed to take a precautionary approach to allowing more water to be abstracted. The HBRC said that new applications would need to be supported by extensive information demonstrating that their takes would be sustainable and not affect the surface waters of the Tuki.

From a F&G perspective we were happy with this approach and thought that it set a very high bar to reach for new irrigation consents. However, the proof of the pudding is in the eating, and this appears now to not be the case, as the following outcome will show.

Firstly we should consider minimum stream flows and how they are set. In Hawke’s Bay the HBRC uses a process called Instream Flow Incremental Methodology (IFIM). This is a process that works through a consideration of all the factors around water allocation (economic, ecological and cultural) and then arrives at a (hopefully) balanced position. The key part of this process for F&G is the hydrological model that determines how altering stream flows affects the amount of habitat available for trout.

The current models in use were developed for North American rivers and in our view do not reflect circumstances in NZ. This concern was brought forward during the development of the Regional Resource Management Plan (RRMP) where we had lodged appeals on the minimum flows for the majority of the Region’s rivers. The RRMP is used by the Hawke’s Bay Regional Council (among other things) to manage the region’s natural resources. All this was way back in 2000. As it worked out, the final matter to be resolved before making the RRMP “official” was our appeal on the minimum flows.

To allow the RRMP to become operative, we agreed to ‘park’ our appeals on the minimum flows through an agreement with the Regional Council and Federated Farmers. Part of this agreement was that a programme of research would be concluded to better inform the debate on how minimum flows should be set.

Given this the HBRC, F&G and the Cawthron Institute (working under funding from the Foundation of Research Science and Technology) have spent the past two summers collecting data in the field to improve the model and make it applicable to the type of river we find in NZ. The thinking is that this information would then feed into a debate on how our water resources are managed across a range of catchments. This work has yet to be concluded.

So reflect for a moment on what we know about the Tuki catchment. We currently do not have a clear picture on the effects of flow alterations to instream habitat and we have no idea on the lag time for the stream-depleting effects of deep bores in the Basin. All this in a system that supports a nationally significant recreational trout fishery.

Or do they? New consents granted

On this basis and given the HBRC’s clear indication that a high burden of proof was required for new consents for irrigation, we were surprised to see applications hit the table for this catchment.

The consents under consideration have a convoluted history. They began as the ‘sale’ of rights for water from the Tuki and Waipawa rivers for stock water through water races. Central Hawke’s Bay District Council (CHBDC) were notified in 2002 that the consents they held for the water races were to expire in 2004 and were unlikely to be renewed as they were not an efficient use of water.

CHBDC then decided to close the races and put the water out for tender in 2003. Four companies or individuals successfully sought that water. The new ‘owners’ of the consents thought they would eventually use this water for irrigating pasture and crops, despite an agreement they entered with CHBDC and the new consent holders that they would not pay CHBDC for the allocations until the consents were successfully renewed in 2004. This arrangement suggests that the new consent holders were aware consent for the transferred allocations might not be granted.

In 2004, when the consents for the whole catchment came up for renewal, F&G said that we would entertain a roll over of existing consents to allow the research and debate outlined above to occur, but would oppose any applications for new consents. On this basis we opposed the consents to use the stock water for irrigation and took the matter to a HBRC hearing.

During the hearing it was revealed that some applicants had sought and were granted short term consent to use the stock water allocation for irrigation. This was done on a non-notified basis with no affected party able to have input to it. On the basis of this short term consent the applicant invested a considerable amount of money in infrastructure. Subsequently this investment was a significant part of the reason the HBRC hearing panel approved their consent to continue taking water. Other applicants who had not invested in infrastructure were declined consent.

The granting of three consents at the hearing in May this year to allow an additional 265 litres a second or 242,223 cubic meters a week of water has therefore come as a surprise to F&G. Even more surprising was that these consents were granted where others were declined, and that the hearings panel went against the advice of their own staff and direction of the HBRC. To top it all off, none of the applicants presented any supporting evidence or assessments of effects of their proposed new activities on the instream values of the catchment, despite the requirement to do so under the RMA.

What is even more fascinating is that existing consent holders in this catchment do not appreciate now what lays before them. The additional pressure on already fully or even over allocated rivers will reduce the certainty of supply for many existing irrigators. This being compounded by the clear directive from the HBRC to “use it or lose it”. So, many irrigators who had previously not turned the taps on will be doing so this summer or the next. This will result in the current minimum flows (that F&G are still contesting) being reached more often and for longer than has ever occurred.

Hence F&G has reluctantly decided that the only option is to ask the Environment Court to review this decision. It is our view that the hearing panel got it badly wrong, but time will tell.

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