Goodbye lake, hello river as Cromwell reclamation plans revealed

The beaches, boat ramps and lakebed close to Cromwell's Old Town have been filling up with silt carried down the Kawarau, but a bold new plan to stop fighting nature and help it along instead has been presented by Clyde Dam operator Contact Energy.

The power supplier has been given a rev up by the community in recent years to better maintain the stretch of the manmade lake from Butchers Drive to the Junction.

Part of the company's fresh commitment to keeping the area of lake looking good and usable is to work with locals on a design plan for it.

It is one of the actions listed in its finally signed-off latest version of its management plan for the Kawarau Arm of Lake Dunstan, a requirement of its resource consents to operate the dam.

The result, officially released at two community drop-in sessions in Cromwell this week, is the first draft of a design plan that includes a mix of reclamation, boardwalks, plantings, pontoons and even a paddling pond come ice-skating rink in winter.

The project, which started in the first half of last year with a series of community brainstorming workshops lead by Shaping Our Future, signals a shift in the narrative from 'sort the silt' to 'it's inevitable, so how do we work with it?' for many who have involved themselves with the process.

"We're working with the transition to silt that's happening rather than trying to endlessly dig it out," Shaping Our Future's John Glover says.

Arrowtown-based landscape architects Blakely Wallace have been contracted to flesh out ideas collated from the original community workshops.

Key designer Philip Blakely says "it wouldn't be a natural thing to keep excavating the lot".

He sees an opportunity to work with what's happening naturally - the elephant in the room here being there is little that is natural about the hydrology of a river turned lake after the construction of a dam - but it will need "community buy-in", he says.

Contact Energy's community relations boss Neil Gillespie says despite recent extreme weather events, the volume of sediment emptying into the lake from the Queenstown direction hasn't really changed over the years.

He sticks with the often-cited one-million cubic metres a year on average - as much concrete as was used to build the 100-metre-high Clyde Dam.

"From the information we get from analysing the lakebed, it's still there or thereabouts."

Some people have described the section of lake outside Old Cromwell as being in an awkward transition phase, a bit like a kid needing to go through pimply teenage years before finding their groove.

By the time the Kawarau Arm 'finds its groove' in front of Old Cromwell, Mr Gillespie says people should expect a landscape more like "an alluvial river" than a lake.

"The transition phase, when it will end, we don't know, but we're going to help it along the way."

He thinks the once much-used Butcher's Drive boat ramp is redundant.

"We've survived without it for a while already. Let's take away the expectation of it being usable."

Its carpark has been revisioned in Contact Energy's plan to include attractive native plantings, a children's playground and an only-in-Central-Otago paddling pool/ice-skating rink combo, all within cooee of the Cromwell Community Board's ambitious planned new events centre.

There's no deep water under the jetty now, so Contact's vision (right) involves reclamation to widen the grassy area and shift the present lake edge out.

A little further around the lake the plans show a wooden boardwalk over a wetland area planted with native grasses, while in front of the heritage buildings the grass area is widened by way of reclamation, with the pontoons from Butcher's Drive given a new home at the end of the existing jetty to provide a mooring spot in the channel for boats - as well as a potential launching point for swimmers wanting to reach deep water without wading through sludge and weeds.

A recreational boatie was one of approximately 130 people at this week's reveals of Contact's draft design plan.

He says he is pleased to see Contact Energy thinking about boat access to the Old Town, but wants the company to go further.

He thinks it's too early to call it a day on the navigability of the lake between Cromwell and Bannockburn.

It is his opinion the original channel of the Kawarau River provides a safe passage for boats, and he thinks work could easily happen to mark it.

He says he's done a DIY job himself using his kayak, a depth finder, and temporary milk bottle floats, and it has enabled him to enter coordinates to a route finder for use on his wooden hulled boat.

He wants to see Contact Energy and local authorities committing to this alongside any plans to beautify the lake edge.

Mr Glover says the next step for Contact Energy is to do a "reality check".

While Mr Gillespie says this week was about checking in with members of the community that Contact and Blakely Wallace had interpreted their ideas and aspirations for the area correctly, there has as yet been no consultation with any other stakeholders such as the Central Otago District Council, the Otago Regional Council or Land Information New Zealand.

"The key thing is this is not all going to happen overnight."

Whether or not the community-sourced ideas are feasible from an engineering, consenting or environmental perspective is still up for discussion, but Mr Gillespie seems set on one thing: money to fund them, will not be a problem.

Although he could not put a dollar figure on the overall project, he did have this response to Crux's "Are you good for it?".

"We've said we're going to do it."

The should-be floating pontoons at the Butcher's Drive boat ramp in Cromwell sit on silt (file photo).

Cromwell lake guardians the Lake Dunstan Charitable Trust have long lobbied local authorities and Contact Energy to better manage Lake Dunstan for the benefit of residents and holidaymakers.

Speaking with Crux last year at the onset of Contact's latest project, trustee Karleigh Hoera said the group's mindset had changed.

More than three years ago Ms Hoera spoke to Crux about the town's disappointment as it watched its lake disappear.

"Back when we first spoke, we were still thinking that potentially dredging was an option, so silt removal and getting the lake back to what it was.

"I think in the following years we've accepted that it's never going back to where it was...but that probably is not necessarily where all the community is at.

"Potentially there might be some instances where silt can be removed, just to maintain some sort of access, but it would be minimal."

Main image: Contact Energy's draft design for the edge of Lake Dunstan outside Old Cromwell includes a boardwalk over a wetland area with native plantings.