Lower Hutt: Floodway bites into Riverbank Trail

Accusation lowest cost is council’s prime driver

Rotarians have delivered a strong message to floodway engineers that green space along the Hutt River is regarded as one of the city’s treasures.

Debate over floodway improvements between Kennedy-Good and Ewen bridges, and a ‘preferred’ design that will bite deeply into the River Trail and popular dog walking area alongside State Highway 2, looks to be boiled down over dollars.

The option of a 20-metre vegetation buffer along the western bank of a realigned river course is estimated to cost $4.5 million. But in places it would swallow between one third and one half of the existing open grass space.

Other options, which would preserve most of the present open space and deliver the desired flood defences are more expensive: a series of rock groynes would cost $6 million, or rocklined river banks (as currently exist for about 150 metres immediately north of Melling), $8 million.

Last week, three Greater Wellington Regional Council officers outlined to the Hutt City Rotary Club the state of play.

Engineer and project manager Jacky Cox said upgrades to achieve the flood ‘design standard’ (defences capable of holding a 2,300 cumec/one-in-440-year flood) in the Boulcott area are to happen on a number of fronts.

Higher and stronger stopbanks are to be built adjacent to Hutt and Boulcott Golf Clubs, “essentially following the (current) residential boundaries.”

Mills St has been in the headlines recently because the stopbank upgrade is likely to require the demolition of four or more houses.

But there are also issues to do with the river channel, with the big problem being a pinch point in the river next to Transpower’s large Melling substation, Ms Cox said.

Today’s floodway is about 600m wide near Kennedy-Good Bridge, narrowing to 150m at the substation. Along that stretch the river changes in grade and the river channel decreases in width from 100m to 50m. At the narrowest part by the substation during floods, the water velocity and turbulence and thus erosive power is a major issue.

The Hutt River advisory sub-committee two months ago approved in principle, with the proviso there be more consultation with the community, a design that would establish a 100m wide river channel from Kennedy-Good to about 200m upstream of the substation. It would then reduce to about 70m for the next 600m or so. A big payoff is that with the straightened and wider channel, the Boulcott stopbanks needn’t be as high as they would otherwise have to be.

A strengthened 20m vegetation buffer zone of mainly willows would chew up a big chunk of the dog walking area green space and the existing River Trail. But Ms Cox said GWRC has listened to community concerns about minimising the need for in-stream work, and keeping ‘view shafts’ through the trees so walkers and people on the highway could see the river.

It’s quite possible that a new River Trail could in parts wind its way through these trees.

Bank rocklining or groynes along this western bank would not need trees or take up the 20m band of grass land. But that will cost $1.5m to $3.5m more.

Ms Cox said rocklining is generally reserved for stretches of river ”adjacent to high value assets” (such as city streets, the substation).

Robin Maud, a Rotarian who has devoted countless hours to establishing the River Trail over the last 16 years, said the value of the open space to future generations of Valley people is being ignored.

”It appears to me that the decision has been made purely on the lower dollars.”

Past club president Allan Brown said Hutt people ”have a huge emotional connection to this piece of space” and are intensely interested in how it will be developed into the future. Rotarians had tried to get the message through to GWRC politicians and officers that the river vista and the preservation of green space is vital, ”but clearly we are not there yet.”

>via stuff.co.nz


Last updated 13:12 22/09/2009

Ok I’m not a Rotarian, but I am a dog owner, lets get that out of the way first.

This subject is a pet (no pun intended) issue of mine, given I am a frequent user of the area and take the dog for a walk there often. Also the primary reason I live in the Hutt is because of the river and the greenspaces it provides.

I greatly appreciate the work that has been undertaken by Rotary in this area over the years, and it is of great credit to them this area is so well utilized now by walkers, commuters, and dog owners. Also good on them for presenting a campaign for the residents of the Lower Hutt on the importance of this area, the vistas of the river and gaining low level support for their concerns from officials who make these decisions.

But, and I say but

Do the people of Lower Hutt really care if this area is lost to them?

Is the key issue that this city is built on a flood plain, and if a large scale flood occurs, is protecting personal property of greater concern to the average citizen than a pretty place to walk, or look at?

Should the whole issue, of the Hutt River development be placed before its citizens as a holistic view, rather than individual bites, that are pushed through. Both the regional and local councils have a decision process over river development. I feel those concerned individual voices are lost on each separate case concerning issues around the river. Illustrated only recently by residents of Mills Street concerns, the water quality of the Hutt river, water extraction from the Hutt River, recent 1080 posionings to name but a few.

There is no doubt in my mind that from the perspective of council both local and regional that their primary concern is taming the Hutt River, whilst exploiting its value from a commercial viewpoint.

The attractiveness of the Hutt Valley is based around the value of a River Valley, period. In my 30 years of appreciating that I have seen the value of it diminished from an individual perspective that I probably would not swim or drink from it now, it is a but a trickle of its former self.

There is a midpoint of compromise here, but perhaps all the cards need to be shown from everyone who controls this river. If we continue on the same path Hutt City council needs to stop fooling themselves and give up on the idea of developing the City Heart to incorporate river views, if their goal in conjunction with the GWRC is to destroy the capabilities of the Hutt to have a river.

What is decided in the next year will set in perpetuity, whether this area will have a narrow or wide berm area. It needs to be placed in consideration given a wider viewpoint of river development and the impact this will have on further developments in the future. At no stage have I seen an overall model / plan for what the councils see the river being like in the years ahead.

I feel we really do need to care about our river, its what makes the Hutt different from other parts of Wellington. It created flat river plains, large areas of native greenbelts and both geographically and historically created the Hutt we live in today.