Nelson City Council will take another look at plans for its $46 million riverside library, as new data shows sea level rise will affect the region sooner than anticipated.
Nelson City Council's possible concept design for a new riverside library. Photo:
Recent figures from the SeaRise Programme show land subsidence is affecting urban Nelson at a rate of around 2mm per year.
It also takes into account the latest International Panel on Climate Change (IPCC) projections on sea-level rise and shows Nelson is predicted to face between 0.4 to 0.7 metres of relative sea-level rise in the next 50 years.
That is an increase of between 10 to 20cm over previous Ministry for the Environment projections.
Over a 100 year timeframe, the more conservative projection used for planning purposes has increased by 30 to 50cm and now sits at 1.4 to 2.0m of sea-level rise.
The new library, beside the Maitai River on the corner of Halifax St and Trafalgar St has been proposed as a major asset in the Riverside Precinct development - and a modern hub for the community.
The $46.3m project, which will be funded by a loan and paid off over 65 years, is more than the council has ever spent on one project.
The council voted last year to go ahead with the riverside location, over refurbishing the existing library or building elsewhere.
Nelson City Councillor Rachel Sanson has long been concerned about the development being in a vulnerable location - where it's at risk of coastal inundation, river flooding and liquefaction.
She said the SeaRise data provided an opportunity to take another look at the library development.
"I think it's incredibly important and deeply concerning data. I think it has serious implications for everybody in the country and I think that a reasonable person would question the proposed project and its current location."
Sanson said the library would be a game-changer for the community - and she wanted it to last.
"There is just such incredible potential for this, but I also think that we have an immense responsibility with the level of investment that has been proposed that we should be seriously assessing alternative sites that we know you're going to be resilient for generations to come."
There were 342 submissions on the library redevelopment during Nelson City Council's 2021-31 Long Term Plan consultation last year.
Of those, 234 supported some form of library redevelopment or refurbishment, 93 did not support any development, while 15 did not indicate a preference either way.
The Elma Turner Library on Halifax St. Photo: RNZ / Samantha Gee
The option to build a new library on the Halifax and Trafalgar streets received 101 submissions in support.
Of the 241 submissions that did not not support that option - cost (120) and flood risk (78) were cited as the biggest concerns.
Zero Carbon Nelson Tasman had also raised concerns about the site and said it would rule out managed retreat and other adaptation measures.
But Nelson City Council chief executive Pat Dougherty said the new library had been engineered to withstand the impacts of climate change and would remain "high and dry" for the next century.
The library has been designed to adapt to climate change, with a floor level that can be raised to prevent the building from storm surge and river flooding at 2m of sea-level rise.
Dougherty said staff were working out what the SeaRise data would mean for some of its projects and were to be required to report back to elected members on the data's impact on projects - including the library development.
"I am confident that we can make a case to demonstrate that the library can still be built on that site and get 100 years under the worst case scenario at the moment, but what I can't put myself in the position of is deciding what the councillors will do with that information."
Dougherty said the new data meant under the most conservation sea level rise projection - the library building would be flood resilient up to 2130 as long as the floor level is raised
Council staff are now looking more closely at the data, it's impact on the library project, and will report back to elected members and the community in the coming months.
The council's existing modelling shows 4170 properties worth $5 billion could be at risk from 1.5m of sea-level rise, 20 years sooner than expected.
Council climate change manager Rachel Pemberton said from next month the council would be talking to the community about that impact.
"The objective for that engagement is to understand what the community wants to achieve for adapting our coasts and also to be able to present the types of solutions that are available for climate change."
The council is waiting for New Zealand's first National Adaptation Plan to be released in August before it tackles measures to mitigate the effects of climate change in the region.