We are in familiar territory again – scribbling dreams of future Christchurch on bright Post-it notes and sticking them to the wall.

On a Saturday morning, a roomful of community representatives are gathered at Christchurch Bridge Club for Joining the Dots – a go at figuring out a common plan for the Avon River residential red-zone organised by Eastern Vision.



As convenor and former Dean of Christ Church Cathedral, Rev Peter Beck, says at the start of the day, the city's recovery has had a rather top-down "done to us" feel about it so far.



But what the Government does next with the 5500 sections and 430 hectares it red-zoned in July 2011 – an area two and half times the size of Hagley Park – is now meant to be a "done with" exercise.



READ MORE:

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* Green dreams for river red zone

* What will become of the Avon River red zone?

* Regenerate Christchurch to investigate red zone water course



The concern hanging in the air is the Government is still determined to get part of its money back by fixing land and flogging it off.



As one economist remarked after the red zone was purchased for about $140,000 a section, it represents either a billion dollar parkland gift to the city – or two Ashburton's worth of property development.



Yet the official promise is this recovery decision is going to be an open-minded choice. Nothing has been pre-determined.



A joint Crown and city council master-planning authority, Regenerate Christchurch, has been formed, and its biggest piece of work will be deciding the best long-term use of the damaged land.



Today is intended to be a start on that. So let's begin.



"THE AGILE AMPHIBIOUS CITY"



The meat of the day is going to be the constraints. Experts will talk about what possibilities can't fly due to the physical and economic realities of the red-zone.



First, however, the fun. The invited groups all have some pet project they have been hatching for the past four or five years, hoping to claim their spot in what could be a river corridor park stretching from city to sea.



A microphone is passed around from table to table so each can give a speedy one minute elevator pitch outlining their idea.

There are the big bits of furniture. Landcare ecologist Colin Meurk talks about building a 150ha fenced Eco-Sanctuary that could extend Travis Wetland through Burwood to the river – a forested refuge for kiwi, takahe, tuatara, and even kakapo, he says.

JOHN McCRONE/FAIRFAX NZ Community representatives posting their ideas at Eastern Vision's Joining the Dots forum.

Sport Canterbury's Julyan Falloon describes East Lake, the proposal to dig out Horseshoe Lake for a 2km competition rowing course complete with beaches, room for sailing and triathlons, and possibly a pumped white water course for kayaking nearby.

Lincoln tourism professor David Simmons speaks about EdenNZ, an eco-education venture similar to the Eden Project which has proved such a tourist draw for Cornwall.



But not a giant set of enclosed domes like the English one, Simmons reassures. The Avonside version would sit light on the landscape.



There are other projects for particular red-zone locations. A heritage garden park in Richmond. A surf pool with a pumped artificial wave in New Brighton.



But in fact most of the rest of the proposals in the room are about the general recreational and ecological use of the land. Groups speak to the need for cycleways, walkways, art trails, "places of tranquillity", wetland areas for stormwater treatment, nature playgrounds for children.



Canterbury astronomy professor John Hearnshaw calls for a general "dark sky park" policy with lighting controls to encourage star gazing.



Nutritionist Janne Pasco says a tapestry of community gardens and allotments would help educate a city in affordable living. "Christchurch could be the greatest edible garden city in the world."



After this sketch of the projects, we are into the first workshop – identify the benefits of getting the red-zone decision right.

It is pretty clear, if money and politics are no problem, an Avon-Otakaro river park would be a real legacy for the city. The excited chatter around the table is how it may be the one thing most remembered about Christchurch's earthquake recovery in another 30 or 50 years.

AVON-OTAKARO NETWORK/SUPPLIED Where the river park projects might go: Urban Farm (a), Heritage Park (b), EdenNZ (c), Rowing Lake (d), Food Growing (e), Eco-Sanctuary (f), Bexley Wetlands (g).

The park could forge a new identity for Christchurch as a true river-based city.

The west has its Hagley Park and Botanic Gardens, which give it a certain character. But an urban native forest filled with community farms and eco attractions would become a living example of modern sustainable thinking.



It would rebalance Christchurch's energy by giving a focus to the east, and also put the city on the world map in a way that any number of shiny new convention centres and retail precincts never will.



The felt-tips are frantically scrawling out the positives on Post-its. On the wall, notes are shifted about so the common themes emerge. Red dots are added to those that best seem to sum it up.



"The agile amphibious city". "Exemplar to demonstrate sustainability and environmental adaptation". "Education opportunities, awareness, environmental engagement".



However the talk is also turning quickly to the problems and practicalities.



One of the organisers, Environment Canterbury's (ECan) Chrissie Williams, says there are plenty of wonderful ideas. But the next step is spending real money to produce some detailed feasibility studies. And for the smaller groups, it is not clear where that will come from.



Williams says there are also some really important technical decisions yet to be made about the red-zone – like where its flood stop-banks will go.



Everyone assumes they will be hard to the river. But it might make sense for them to be halfway back in the red-zone, or even right on the outside of this area of sunken and liquefiable land.



Former ECan chief executive and Canterbury University water researcher Bryan Jenkins says the ground is very unstable. So building anything by way of permanent structures could have unexpected cost.

This may be bad news for big projects like the competition rowing lake, he says. There is talk it could take $320 million to carve out a suitable stretch in the muddy silt of Horseshoe Lake. The same facility built somewhere on gravel beds to the west of the city would cost maybe only $80m.

PERCEPTION PR/SUPPLIED How it could look: Artist impression of a "rainbow room" for the EdenNZ project in Avonside.

"So is the red-zone really the best location for that lake? You'd have real issues with the sides slumping in. You'd need water treatment plants if you really wanted to use it for swimming and recreation."

A simpler training area – an expanded Kerr's Reach – still seems a likelihood, says Jenkins. But as the red-zone thinking gets serious, even some of the more popular and obvious-sounding ambitions may suddenly find themselves being knocked on the head.



SWAMPY FLOODPLAINS



The next workshop and set of presentations is designed to get into that larger picture. Dreams are fine, but the red-zone may be such fragile land that it can only support a low impact and perhaps temporary use.



Canterbury University environmental hazards expert David Bell stresses what everyone should already know. The suburbs of the lower Avon are naturally a dynamic landscape – a near sea-level mud flat formed only during the past few thousand years.



The Waimakariri River dumped gravel to form the west of Christchurch, silt to form the east. "The shoreline was in Hagley Park just 6000 years ago. So in the east, we've got very young sediments with channels, infills, and all sorts of issues."



Bell is blunt about the prospect of ever building much on red zone land. He says while from an engineering perspective anything is possible, really the best Christchurch can do now is let the land return to what it wants to be.



The message was echoed by the other experts. Heed the story already written in the ground.



Ngai Tahu's Te Marino Lenihan says the river and estuary were rich swamp land – prime kai territory supporting seven Maori settlements. There were duck, eel, whitebait, freshwater crays and mussels.



Lenihan says physically, mentally and spiritually, most people seem on the same page about a return to these natural values. "We're looking to work the land in respect of the water so that it feed us."



Landscape architect Di Lucas brings out geographic maps she helped produce for the council decades ago. Lucas says the Avon area is a criss-crossing of old water channels.



In our modern way, we thought we could just carpet over them with houses and roads. But especially with climate change and sea-level rise, it is time to understand that the red zone is too unstable for permanent settlement.



A young French geologist from Canterbury University, Chris Gomez – who has been studying the somewhat similar situation of the Tamagawa River floodplain in Tokyo – paints probably the clearest picture of how the authorities may in the end need to view the proposed Avon-Otakaro river park.

Gomez says Christchurch is like every other modern city in building over its natural hazards. Even today, Auckland is looking to release risky land because of the pressures to allow for new housing.

KIRK HARGREAVES/FAIRFAX NZ The Avon-Otakaro Network delivering its petition in 2012 calling for the red-zone to be made a park.

Christchurch is unique simply in having had so much of that change revealed all at once by its earthquakes. With much of the east sunk by up to a metre, it has become an international test-bed for what to expect, how to cope, when you are a pancake-flat city almost level to a large ocean.

Gomez says there is some bleak news for Christchurch because it is far more at risk of flooding than it realises. It had a taster with the 2014 rainstorm which exposed St Albans' Flockton basin in particular. But much worse could happen at any time.



And building new stop-banks at the estuary end of the Avon could in fact increase the future flood risk higher up, says Gomez.



It is basic hydrology. If you create a ponding area where water fills to a higher level at the bottom, the water at the top can no longer drain away fast enough and will spill over its banks there. "It'll flood in places where you've never seen flooding."



So really, the red-zone needs to be considered as a giant flood management project. The focus has to be on plumbing it right – doing things like creating the open ground and wetlands that can soak up water.



That is how Tokyo rethought its Tamagawa floodplain after the city started expanding across it rapidly after the Second World War, says Gomez.



The government paid to turn it into a flood protection reserve. But then it left it in the local community's hands how to actually use the area. And that use has evolved with time.



"It started in the 1960s and 1970s with lots of sports grounds because people were younger, in their 20s. Now that they are older, it is community gardens. Imagine when you are in your 60s, you don't play baseball. You'd rather be gardening."



BUILDING BRIDGES



So is there a clear consensus on the Avon red zone? Dynamic nature now wants to tell its own tale. And Christchurch would be smart to make that the red-zone's point.



It is 430ha of rather expensively acquired Crown property. But logic seems to say its best uses will be community-centric and light on the landscape. The question then is whether the money and politics will go along with this conclusion.



Regenerate Christchurch's newly-appointed chief executive, Ivan Iafeta, ends the Joining the Dots day by assuring his job is to build a bridge between community and officialdom in writing the city's regeneration plans.



And while the shape of the central city is largely a decision already taken, Regenerate Christchurch really is in charge with the residential red-zone.



However Iafeta adds the room represents a small collection of people who have been passionately living their ideas for a number of years, and Christchurch's community is of course much larger. The city has its youth, its disadvantaged, its business interests, and other groups.

"There are many in Christchurch who haven't been a part of this conversation yet. So we have to think about how we go about approaching that."

JOHN KIRK-ANDERSON/FAIRFAX NZ Ivan Iafeta of Regenerate Christchurch: Crown is in open-minded discovery mode as to the future of the land.

The Joining the Dots forum breaks up into last chattering knots as the tables and chairs are tidied away. Just time to buttonhole Iafeta for a few final insights on the realities of the red-zone's political constraints.

It is plain from many comments that a frustrating part of the process has been the Government's apparent unwillingness to spell out whether it is indeed ready to write off the cost of the red-zone for the public good.

Some are convinced the land is so wrecked it has to be off the market. Others can imagine Asian consortia swooping in with heavy engineering ground stabilisation plans.

Why not recoup cash with housing developments where areas of the land are passable? If commercial interest is invited, perhaps someone will want to build luxury river-side apartments safely up on stilts. Or maybe even a semi-permanent mooring for houseboats like they have in Europe.

Iafeta says the central city was largely about rebuilding civic and business assets. Its needs were clearer. But with the red-zone, the Crown is genuinely in "discovery mode".

Iafeta says there has already been a smaller scale public consultation between the Canterbury Earthquake Recovery Authority (Cera) and Waimakariri District Council over Kaiapoi's red-zone. That ended up with community-focused projects like food forests and BMX parks.

The council's draft plan does not rule out some future commercial development, but restricts it to low impact "yard businesses" like nurseries.

So the only requirement is that the whole of Christchurch is part of forming an outcome, Iafeta says. "We don't want to push the green 'go' button too quickly here."

And with today's brainstorming meeting, at least the green 'start' button on that long awaited public discussion has at last been pressed.