How Environment Canterbury Regional Council resource consents have destroyed the outstanding habitat(s) of Great Rakaia Island


, How Environment Canterbury Regional Council resource consents have destroyed the outstanding habitat(s) of Great Rakaia IslandNo unmodified habitat remains at the margin of this section of the Rakaia Island

 A resource consent is permission from the local council for an activity that might affect the environment, and that isn’t allowed ‘as of right’ in the district or regional plan


 Recognising the outstanding values of the Rakaia River were under threat from those wishing to exploit the water resource contained within the catchment of this iconic braided river, anglers, jet boaters, acclimatization societies and others successfully sought the Rakaia River 1988 National Water Conservation Order.

In 1994, the Rakaia Island run comprising of 921 hectares of freehold land and a further 1757 hectares of leasehold land comprising of (public) soil conservation reserves and several small titles of DOC reserves was purchased by new owners who have converted an extensively farmed property of 16,000 stock units, (SUs), of sheep and beef cattle into an irrigated dairy platform comprised of four dairy farms milking a total of 5,600 cows, the equivalent of 40,600 SUs.

The Rakaia Island, roughly 17 km long and up to 4 km wide, is situated in the middle of the Lower Rakaia River between the main braids and the North Rakaia River.

, How Environment Canterbury Regional Council resource consents have destroyed the outstanding habitat(s) of Great Rakaia IslandMap from walking access New Zealand. Freehold title is contained within the centre of the green soil conservation reserves

The island is in the middle of a large braided river protected by a NWCO that recognises its outstanding values including the outstanding habitat above and below the gorge, the outstanding fisheries, recreational fisheries, and jet boating.

The Island is central to the hapua or coastal zone of the Rakaia River where 90% of the fish and many coastal and riverine birds exist.

Development of the Island began in conjunction with extensive river works along the margins of Rakaia Island.

From 1994 until 2005 the owners were given permission to carry out the river works by the Canterbury Regional Council’s Regional Engineer.

In 2005, after 10 years, the owners were advised that such activities required resource consents.

The decision making process

 From documents provided by Ecan following LGOIMA requests regarding the decision making for  the resource consents the following can be determined;

Permission to carry out river works from 1994 to 2005 was contained in a letter from the regional engineer following a phone call to Ecan by the new owners.

The investigating officer for the 2005 resource consent application did not visit the site, relying instead of advice from staff familiar with the Island and the documents supplied by Aqualinc on behalf of the owners.

The consent process was not notified.

The applicant asserted that the river works would have minor environmental effects in the context of the size of the whole Rakaia River catchment.

The applicant asserted that the river works would not affect the river’s flows or increase the risk of flooding to other parties.

The applicant asserted “where practicable” the river works would not have any adverse effects to the braids, fishery, or birdlife.

The applicants assertions and proposed mitigation provided the basis for the twenty year resource consents issued; CRC052103 and CRC054650.

, How Environment Canterbury Regional Council resource consents have destroyed the outstanding habitat(s) of Great Rakaia IslandRemoving shingle from the river fairway to build berms along the Island margins

, How Environment Canterbury Regional Council resource consents have destroyed the outstanding habitat(s) of Great Rakaia IslandA google earth image from 2023 showing how extensively the natural river margins have been destroyed.

 Some of the adverse environmental/ecological effects of developing the Rakaia Island

 In response to local angler concerns, Ecan tasked one of its ecology scientists to monitor monthly surface water quality of spring fed tributaries arising from the flood plain of the lower Rakaia River from 2009 – 2014. (1).

“Braided river habitat is multi-dimensional, with strong links between the surface water and underlying alluvial groundwater of the floodplain. A number of small spring-fed tributaries arise from upwelling groundwater in the floodplain. These spring-fed streams often provide more stable stream habitat compared to the main channels which are subject to physical disturbance from flooding flow. As a result, spring streams often have greater invertebrate species diversity and abundance than the main river braids (Gray et al. 2006; Gray and Harding 2007; Gray and Harding, 2010”. 

 Mathias Stream which arises from the floodplain of Rakaia Island was one of the streams studied;

“Rakaia Island has undergone a progressive increase in land use intensity with much of the island now used for dairy farming. A small riparian margin remains alongside the stream, however much of the shallow groundwater zone/drained wetland is converted to pasture land”.

 The study found several measures of water quality were worse in Mathias Stream than the other two streams between Rakaia Island and the Rakaia Huts settlement;

  • Nitrate levels were more elevated
  • E. Coli levels were above the levels considered safe for swimming
  • Quantitative macroinvertebrate community index (QMCI) values were indicative of mild to moderate pollution

My observations

Mathias Stream once held a healthy population of large brown trout. This is no longer the case.

One evening I observed a number of dead silver sea trout in the lagoon near the confluence of Mathias Stream?

While Mathias Stream is fenced and planted with narrow margins to maximize the available pasture, the planting has choked what was once an open stream with grassy margins.

In winter when the river mouth is partially blocked, and following heavy rain, much of the lower paddocks through which the stream flows becomes waterlogged and pugged by cattle and vehicles.

The fencing no longer marks the stream margins.

I obtained a copy of the raw data and noted the study ceased shortly after the nitrate (NO3-N) levels peaked at 6.9 mg/L.

My own infrequent monitoring shows levels between 2 and 2.6 mg/L NO3-N which is lower than many streams and drains I monitor in the Selwyn District, but still high given the close connection to the main river flows.

Adverse impacts of the river works

 The river works are extensive with most of the circumference of the 17 km long island modified at some time.

Most of the ongoing river works occur along the margin with the main river.

This has wiped out many hectares of springs, wetlands, and cover for birds and game animals.

This is due to bulldozers pushing out into the river fairway to temporarily divert major river braids away from the margin. These barriers may extend several hundred meters into the riverbed.

The furtherest I measured from the boundary fence was just under one kilometre.

As is illustrated in the image above, whatever “outstanding habitat” that existed has been wiped out in the farm’s attempt to protect their productive land.

Along with other witnesses, I have photographed and reported apparent non-compliance with the resource consents to Ecan to no avail.

Ecan seem expert at finding excuses or devices not to take action.

This council is demonstrably on the side of those who exploit the natural environment rather than those interested in its conservation.

NWCOs deserve greater protection

 While many might see the (personal) wealth created by two brothers who took advantage of the Canterbury Regional Council as a good thing, and see the development of Rakaia Island as of net benefit to the community, I am disappointed that Ecan issues consents in such an uncritical manner, especially when the Rakaia Island is an integral part of the Rakaia River protected by a National Water Conservation Order.

The Rakaia Island serves as a case study of the agricultural encroachment/development and river works that the Canterbury Regional Council has consented along the length of the Rakaia River from Te Pirita to the sea.

A massive amount of outstanding habitat including riverbed, springs, wetlands, native and exotic trees and shrubs has been destroyed in the process along with the biodiversity that was contained within this habitat.

While water allocation has changed the river’s flows causing increased water temperatures and increased deposition of sediment, development and river works have similarly adversely affected the ecology of this iconic braided river.

The net result is the near extinction of a keystone species of native fish, a massive drop in the numbers of recreational fish, and loss of the primary food source for breeding colonies of coastal gulls and terns.

These are not “minor” effects as stated in the various consent applications.

It is not the one single consent that is so damaging, it is the cumulative damage caused by the sum of these consents.

Until Ecan recognises this and stops viewing consents as an “output” required of council, the destruction will continue.

No wonder Ecan is so unwilling to to accept its role as the agency that must enforce the Rakaia River NWCO.

Dr Peter Trolove
NZFFA Executive
Rakaia Huts resident


 Surface water quality of spring-fed tributaries arising from the floodplain of the lower Rakaia River: Boat Creek, Clear Stream and Mathias Stream, Kimberley Robinson, Ecology Scientist, Environment Canterbury

, How Environment Canterbury Regional Council resource consents have destroyed the outstanding habitat(s) of Great Rakaia IslandLooking out from the site of river works to the remains of a breached temporary diversion about 600 meters away in the middle of the photograph. The boundary of the farmland is about 300 meters behind me.



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