Big dreams and blue car­bon in the red zone

Plans for the Avon red zone are com­ing back to or­di­nary uses like hous­ing, parks and water­sports. Could there be some­thing more am­bi­tious? re­ports.

The Southland Times - - FEATURES -

No idea is too big, they said. Yet, maybe this one is. Wayne Alexan­der, an Ilam en­gi­neer and John Brit­ten’s for­mer mo­tor­cy­cle rac­ing team man­ager, takes a deep breath and launches into his pitch.

The re­cov­ery agency, Re­gen­er­ate Christchurch, is look­ing for a re­ally smart postquake use for the 600-hectare Avon res­i­den­tial red zone – a project unique and am­bi­tious enough to put Christchurch on the world map.

The talk has been of row­ing lakes, eco-sanc­tu­ar­ies, green belt parks. Cer­tainly all nice-to-haves, Alexan­der agrees.

But pretty much what ev­ery other New Zealand city has to of­fer. Not es­pe­cially unique.

Even the $100 mil­lion Eden Project pro­posed for the Avon Loop is not a first.

So what is Alexan­der’s big idea? In a nut­shell, he says, turn the lower Avon into a giant fish hatch­ery by carv­ing up the aban­doned red zone into a lat­tice­work of canals.

Make it a refuge for white­bait, eel and salmon. Ac­tu­ally, it is big­ger than that. The es­tu­ary and en­tire Pe­ga­sus Bay could be­come a fish farm and ‘‘blue car­bon’’ scheme.

Alexan­der says dust the water with sol­u­ble iron sul­phate, and pro­duc­tion would take off. Christchurch would have fish com­ing out of its ears.

The red zone could an­chor an aqua­cul­ture scheme on a truly grand scale. On top of all that, it could be a pioneering blue car­bon project too.

The red zone process has be­gun to frus­trate some. The de­ci­sions ap­pear to be tak­ing for­ever.

Un­der Re­gen­er­ate Christchurch, the fu­ture of the Avon red zone – an area four times larger than Ha­gley Park – is meant to emerge from a com­mu­nity-led de­bate.

There are the many well-aired pro­pos­als now, like an in­ter­na­tional row­ing course for Horse­shoe Lake, and a fenced eco­sanc­tu­ary next to Travis Wet­land in Bur­wood.

Some newer ones have also been pop­ping up, like the pos­si­bil­ity of Avon­dale and Rawhiti golf clubs do­ing landswaps.

In ex­change for giv­ing up their own good land for af­ford­able hous­ing, they might get a new salt­marsh golf links some­where like Bex­ley.

A clever way to use the red zone to bring peo­ple back to East Christchurch with­out ac­tu­ally hav­ing to build on it.

But de­spite so much be­ing said about in­di­vid­ual projects, it has be­come dif­fi­cult to know what is in, what is out.

So far, Re­gen­er­ate Christchurch has only been pre­pared to talk in terms of high­level ab­strac­tions.

The re­cov­ery agency fi­nally pub­lished the first con­crete out­come of its con­sul­ta­tions in May – a ‘‘vi­sion and ob­jec­tives’’ state­ment.

This month, it de­liv­ered a batch of maps meant to present 10 dif­fer­ent ways the red zone could be carved up.

Yet th­ese were just colour-coded blocks mark­ing pos­si­ble cat­e­gories of land-use, not the nam­ing of ac­tual projects.

Re­gen­er­ate Christchurch chief ex­ec­u­tive Ivan Iafeta says the next big pub­lic en­gage­ment – an ‘‘expo of ideas’’ to be held late this year or early 2018 – is when the many pos­si­bil­i­ties should be boiled down to some more def­i­nite set of choices.

It is slow go­ing. But it means some­thing new and un­thought of may cap­ture the pub­lic’s imag­i­na­tion – some­thing as left­field as a fish farm per­haps. In his liv­ing room, Alexan­der grins as he un­folds a map of the red zone.

Most peo­ple will think it is a crazy no­tion on first hear­ing, he ac­knowl­edges. But it is a plan he has been work­ing on for sev­eral years now.

He has met with Re­gen­er­ate Christchurch of­fi­cials to dis­cuss it. And pre­lim­i­nary hy­dro­log­i­cal mod­el­ling has been done by a lo­cal firm.

Alexan­der got in­volved with the Avon red zone through white­bait re­search and the Nga¯i Tahu-backed Mahinga Kai ex­em­plar project in An­zac Drive Re­serve.

A tidal pump run­ning ei­ther side of the high­way to con­nect Travis Wet­land to the Avon River, the re­serve has been one of the few ac­tual red zone projects to be started so far.

To show what could be pos­si­ble in terms of eco-restora­tion and cus­tom­ary food gath­er­ing, the re­serve has been planted with thou­sands of na­tives.

Then there and else­where in the red zone, straw bales were put out as a method to en­cour­age inanga or white­bait spawn­ing. It was at that point that all the bits of the jig­saw came to­gether for him, Alexan­der says.

Think about it from a global per­spec­tive. The world knows it needs to get se­ri­ous about com­bat­ing cli­mate change through car­bon cap­ture, Alexan­der says. And the land-based op­tions like forestry are al­ways go­ing to be lim­ited by space.

So the next ob­vi­ous thing to do is use the ocean as a great big car­bon sink – seed it with iron sul­phate and get the plank­ton bloom­ing.

How­ever, that kind of geo­engi­neer­ing is risky and un­tried. There are in­ter­na­tional laws against it be­cause who can be trusted safely to run a blue car­bon project way out at sea?

Alexan­der says Christchurch could of­fer a con­trolled set­ting where iron fer­til­i­sa­tion was be­ing tri­alled in­shore next to a ma­jor city. A place where thou­sands of eyes would be watch­ing it con­stantly.

‘‘The prob­lem is that there’s no such thing as cer­tifi­cated blue car­bon schemes as yet,’’ says Alexan­der. But a 1990s Niwa coastal sur­vey showed Pe­ga­sus Bay had, at that time, an av­er­age chloro­phyll den­sity of 6 mi­cro­grams per litre. There is a Ky­oto Pro­to­col era base­line to work with.

‘‘If you could say it was 6 mi­cro­grams, and you had dou­bled it to 12 mi­cro­grams, then that is an ad­di­tion­al­ity just the same as plant­ing a for­est af­ter 1989.’’

In like fash­ion, ev­ery­where in the world there are coastal cities with big sewage farms, says Alexan­der.

And most not even as clean as Bromley. So Christchurch could be­come an in­ter­na­tional ex­am­ple of how to go a step bet­ter in us­ing nu­tri­ent-laden waste­water to cre­ate an ac­tu­ally health­ier lo­cal eco-sys­tem.

Alexan­der says it sounds like mon­key­ing with na­ture. But the truth is Pe­ga­sus Bay was long ago de­nuded by com­mer­cial fish­ing. It is many years since trawlers gath­ered off New Brighton beach.

Get­ting deeper into the tech­ni­cal de­tail, Alexan­der says on the red zone side of things, he imag­ines carv­ing 26km of me­an­der­ing chan­nels into the bro­ken land stretch­ing from the es­tu­ary up as far as Por­ritt Park – the whole length of the tidal prism.

That would cre­ate a ton of new habi­tat which recre­ates the swampy lower Avon as it used to be.

The cost of ex­ca­va­tion should only be $2m to $4m, he says. Of course, there would be se­ri­ous en­gi­neer­ing is­sues to con­sider.

His hy­dro­log­i­cal study, pro­duced by DHI, says the es­tu­ary would be pump­ing more water be­cause of the ex­tra vol­ume of wa­ter­ways be­ing filled.

Flow rates could be a third faster on the in­com­ing tide.

But then earth­quake dam­age means the es­tu­ary hasn’t in fact been filling so well.

That has been prompt­ing calls for costly dredg­ing any­way, he says.

Then when it comes to the prac­ti­cal­i­ties of us­ing Bromley and its 3km ocean out­fall to man­age the fer­til­ity of the bay, Alexan­der says by his guessti­mate, only about 250 grams a day of added iron might be needed.

That could be mixed with the waste­water stream to get the pho­to­syn­the­sis go­ing as soon as it hit the open sea.

An­other step that might be re­quired to max­imise the ef­fec­tive­ness of the scheme is seed­ing the water with the right types of plank­ton in suf­fi­cient quan­tity.

Yes, his plan is start­ing to get hazy at this point, he says. How­ever the idea is that Christchurch would be do­ing the ba­sic sci­ence to dis­cover what it would take to make it all work.

If Christchurch went to the world say­ing it was go­ing to use its red zone to tackle some re­ally global problems, that would at­tract the in­ter­na­tional fund­ing to pay for the whole ex­er­cise.

‘‘You’d be able to raise $100m or $200m for do­ing the nec­es­sary re­search.’’

Christchurch could wind up with both a new pro­duc­tive in­dus­try – a fish farm – and also lead­er­ship in the prac­ti­cal knowhow of blue car­bon projects and eco-friendly waste­water sys­tems.

And then think of a fu­ture Christchurch where white­bait again turn the streams milky with their milt each breed­ing sea­son, where a salmon run is es­tab­lished that goes right through the heart of town, he says.

Back at Re­gen­er­ate Christchurch’s head­quar­ters, the eyes start to dart when the ques­tion is put di­rectly.

Is this an idea too big, or in fact some­thing quite pos­si­ble?

Res­i­den­tial red zone gen­eral man­ager, Rob Kerr, says he has talked the scheme over a cou­ple of times with Alexan­der.

Cut­ting a net­work of mahinga kai chan­nels all the way up to Kerr’s Reach could best be de­scribed as ‘‘chal­leng­ing’’, Kerr says. If noth­ing else, there is the lat­eral spread risk to con­sider.

The chan­nels would be vul­ner­a­ble to next big shake.

Also, strictly speak­ing, the sewage plant/fish farm­ing project would be out­side Re­gen­er­ate’s red zone re­mit, Kerr says.

Re­ally, Alexan­der is talk­ing about two projects – what to do with the red zone and some­thing else hap­pen­ing out in Pe­ga­sus Bay.

The plan is to first build a gen­eral pic­ture of the pos­si­ble uses. Alexan­der’s scheme would come un­der the head­ing of pro­duc­tive ac­tiv­i­ties, or ecorestora­tion.

How­ever, it is still to be de­ter­mined where new stop-banks are go­ing to go. And while the re­cov­ery agency is in­deed ask­ing for big ideas that will put Christchurch on the map, and at­tract in­ter­na­tional in­vest­ment, it could be ar­gued the red zone it­self as a whole is go­ing to do that, says Iafeta.

He says the world will be in­ter­ested just in the red zone as an ex­am­ple of how a large area of ur­ban land can be re­pur­posed to an­swer a va­ri­ety of com­mu­nity needs, while also deal­ing with a range of land-use risks, such as quake-prone­ness and ris­ing sea lev­els.

The bal­ance of uses is as im­por­tant as it hav­ing some flag­ship use. So cau­tious sup­port. But Iafeta says it is cer­tainly good to have voices like Alexan­der to up the level of am­bi­tion.

Avon-O¯ta¯karo Net­work spokesper­son Evan Smith is also sup­port­ive, say­ing Alexan­der’s grand ap­proach does tick most of the boxes of the stated red zone vi­sion.

It would be a mas­sive ecorestora­tion project that could also pay for it­self. Smith warns that if the red zone is treated as just a new pub­lic park, the main­te­nance cost is go­ing to fall back heav­ily on rate-pay­ers.

Smith says there is the ob­vi­ous con­cern 26km of canals sounds too much. How would that fit with other lower Avon projects like a golf course in Bex­ley or eco­sanc­tu­ary in Bur­wood?

‘‘Hav­ing lots of trib­u­taries run­ning through a sanc­tu­ary would seem a con­flict, as each one would be a hole in the preda­tor­proof fence­line.’’

But also, Smith ad­mits, some of the early-favoured projects like the eco-sanc­tu­ary are get­ting a harder look now pub­lic con­sul­ta­tion is un­der way.

Is it re­ally right to build a pro­tected habi­tat for dry­land na­tive species – kiwi, ka¯ka¯ and tu­atara – in what is in fact an es­tu­ar­ine en­vi­ron­ment? Nice idea, wrong con­text, is the com­ment be­ing heard on that.

How­ever, Smith says Alexan­der is an ex­am­ple of the cre­ativ­ity be­ing un­leashed by the red zone de­ci­sion be­ing put out to the pub­lic.

The idea may go nowhere or hap­pen in a sim­pler form. Eco­log­i­cal restora­tion is go­ing to be a prime ob­jec­tive, re­gard­less.

Yet, it is the kind of pro­posal that should wake peo­ple up to the fact that Christchurch is in a happy po­si­tion of be­ing able to make some big and in­ter­est­ing choices, Smith says.


En­gi­neer Wayne Alexan­der sees the Mahinga Kai ex­em­plar project in Bur­wood as the start of some­thing big.


A new com­mer­cial fish­ing in­dus­try is pos­si­ble.


Chris Mene, Ivan Iafeta and Robb Kerr.

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