Work carried out on the Waingawa in February 2016

The destructive effects of the river erosion control programme

 David Famularo, February 2016

The Waingawa is a typical braided river that constantly shifts its flow
The Waingawa is a typical braided river that constantly shifts its flow
Work carried out on the Waingawa in February 2016
Work carried out on the Waingawa in February 2016

While going for one of my semi-regular early Saturday morning walks (and occasional swim) at the Waingawa River by Hood Aerodrome, a beautiful braided river system running from the Tararua range down to the Ruamahanga River, I came across the latest work of Greater Welling Regional Council and the contractors it uses in their river erosion prevention programme.

A single vehicle track had been bull dozed into a two lane road with vegetation and rubble pushed into a pile along the way. But this was a minor piece of work compared to the latest channel the bulldozers had gouged out of the river bed in an attempt to create a drain like direct channel for water.

As grand as this work was, it is only the tip of the iceberg of the work that has been carried out over the past nine years or so. Almost all of the Wairarapa’s major rivers have had bulldozers digging and scraping the river bed, wiping out flora and fauna along the way and making it impossible for them to become re-established.

But this is only one aspect of the problems created by this programme which very few Wairarapa residents know about and which has never had any public input or notification. I have had long time fishers like Graham Howard (see below) explain the catastrophic effect the work has had on fish life, a Fish & Game employee say that they are ripping open the river bed leading to greater loss of water underground, and another person who was in charge of south Wairarapa catchment in the 1980s and 1990s explaining how all the loosened gravel and silt is going further downstream creating potential future flooding hazard.

Then there is the aesthetic issues where once attractive spots have been made into ugly wastelands as is progressively happening.

The sole beneficiaries of this work are owners of land beside the rivers who contribute around half the cost of the work while Greater Wairarapa Regional Council (AKA Wairarapa rate payers) pays for the other half.

Following is an earlier article on this subject which highlights some of the problems the work is creating along the rivers.

While Wellington Regional Council along with other organisations is asking the public to become conscious of the Wairarapa’s eel population, in particular Tuna Kuwharuwharu (Longfin Eel), it seems the council has become the eel’s worst enemy, sanctioning the bulldozing of a straight channel all the way along the Ruamahanga River from Mount Bruce in Tararua District down to Lake Ferry at Cape Palliser – the main highway for all eel migration along the Wairarapa valley.

Wairarapa fisher and fishing journalist Graham Howard has been almost a lone voice in speaking out against what he says is the destruction of vital fish habitat in not only the Ruamahanga River but its tributaries, the Waipoua, Waingawa and Waiohine Rivers.

Graham says this is due to the straightening of the river for erosion control which has removed the pools, runs and meanders which are the habitat of elvers (baby eels) crayfish, bullies and other aquatic life that need them to survive.

“Every eel in the Wairarapa Valley, from Lake Wairarapa to the headwaters of the Ruamahanga River pass through the river as elvers.

“They live, as they pass through the system, in the rocks that form the pool ‘aprons. (aprons are the collections of rocks and boulders deposited just downstream of the pools).

“They would have killed thousands of eels when the bulldozers went through where all the elvers live. They would never have survived that.

“By law they are supposed to have so many pools per kilometre of river but this isn’t happening.”

Ironically, Graham says, he enjoyed the best fishing ever at the end of the summer of 2009 downstream of the bulldozers as all this dead fish matter fed fish further downstream, for one season only.

It is not just these river’s fauna is affected by erosion control, Graham says. The work is also quickening the flow of the Ruamahanga, with other impacts like lowering the aquifer (80 percent of a river’s water flows underground).

He also notes that the road that runs alongside Lake Ferry is suffering from erosion for the first time in the history because the lake bed is being filled by sediment from the run off which increases the height of the waves created by the regular north westerly winds that hit the area.

Following are excerpts from a Letter to the Editor of the Wairarapa Times Age which was written by Graham in 2009.

While there have been great strides made by many organisation and individuals (in improving the ecology of the Wairarapa), there has been a concerted effort by the Wellington Regional Council to destroy the natural beauty, ecology and wonderful trout fishing resource that is our Ruamahanga River and its tributaries, the Waipoua, Waingawa and Waiohine.

For the past two years a large number of locals and visitors have observed with growing alarm the blatant vandalism that has been visited on our rivers.

Gone are the pools, runs and reaches. Now the river is wide, featureless and barren in many of its past fish-filled reaches.

Gone are the little eels, crayfish, bullies and bottom dwelling fauna that lived in the aprons of the many pools.

Eels are a special case. They are reportedly under huge stress in the Wairarapa with numbers in serious decline.

Every eel in the Wairarapa Valley, from the lake to the headwaters of the Ruamahanga, pass through the Ruamahanga as elvers. They live, as they pass through the system, in the rocks that form the pool “aprons.”

How do you think they survived the bulldozer rippers that have totally destroyed kilometres of this crucial habitat?

Earlier this year there was an article on the front page of the Times Age detailing the concerns of the residents of Lake Ferry where the road to the outlet is being eroded away.

This road has been in existence for a hundred years. What has changed? I have been reliably informed that the lake bed has risen sharply since they started remedial work upstream.

Guess where the sediment that used to hold the gravel and rock beds together came from – there-s none left where I have fished for the past 40 years.

NB Here is an interesting comment from on Facebook on this subject from Rob Kennedy

After fifty years of river straightening there has been a considerable reduction in river complexity and riparian habitat. Although this practice reduces flood risk in this area the risk is exported down-stream. However this is a risky strategy because the flood peak is larger and faster and leaves down-stream communities with greater vulnerability. this down-stream risk then needs more infra-structure for protection e.g. Ruamahanga Diversion.
However flooding is not the only concern, and since a 1-in-100 year event is much less common than droughts, under enlightened water management systems a more balanced approach to managing flooding without harming water availability is taken. Within this approach, referred to in scientific literature as “Integrated Water Resource Management” the ecological and habitat values are secured within the management framework by choosing methods which reduce the risk of flooding by denaturalising floodplain areas and allowing rivers to display more natural fluvial geometry (meandering and migrating) which boundaries where valuable assets do not occur (or are removed).
There is much more than can be said about why the rest of the world is trending their water resource management towards the “IWRM” model while NZ is not. Perhaps the most pertinent comment is that IWRM is about the managers proving they can cooperate while the NZ model is about the community being made to do what each management group thinks is best …

This story from the Tasmanian Times does a very good job of giving a general outline of what current river management river practices are doing to the Wairarapa’s rivers here.