Changes to a coastal hazard map for the West Coast's new combined district plan is open to submissions from June 27.
Residents are being urged to have their say on the new mapping, which has meant some households will now be considered at risk of rising seas, while other homes will move out of the inundation zone.
The hazard information for the Te Tai o Poutini Plan (TTPP) will be updated with with new technical survey data, which was undertaken by NIWA for the West Coast Regional Council in early 2023.
The new modelling, using LIDA surveys for coastal inundation, means the shape of the current hazard maps notified in mid-2022 has to change.
TTPP principle planner Lois Easton said it was vital to carry out the mapping change now because some properties previously considered at risk under the TTPP may no longer be restricted.
Conversely, other properties not previously caught in the zone now had a designated coastal hazard risk over them.
"The current maps are wrong and we need to have accurate maps," Ms Easton said.
"We're trying really hard to make people aware of it -- anybody can make a submission on it," she said.The council would have a six-week submission period, more than the statutory requirement.
The changes apply to the entire coastline from Jacksons Bay to Hector but excludes Hokitika, the Grey District including Greymouth from the Taramakau River to Point Elizabeth, and the town of Westport.
Those areas each have their own particular coastal zones based on previous detailed hydrodynamic modelling.
Ms Easton said the area north of Hector to Karamea was yet to be surveyed.
Designating the coastal hazard zone in the TTPP was really about protecting life and property, she said.
That meant having the right hazard maps to ensure future planning assessed the level of risk when it came to residential building.
Ms Easton said anyone, aside from previous submitters, could make a submission.
TTPP project leader Michelle Conlon said advice on the coastal hazard mapping variation was being sent out from today.
All those who had previously submitted on that aspect of the TTPP and any affected property owners under the variation would also be contacted.
Ms Conlon said over 4000 letters have been posted advising the variation and how to make a submission.
People could also go the TTPP website [TTPP.nz] and click on the 'plan variations' tab on the left of the web page to find further information on the proposed variation.
Earlier this month, a legal opinion from Haast ratepayer Vance Boyd was canvassed by the TTPP Committee.
He advocated against the threshold of a 100-year return period event for building and planning requirements in the coastal hazard zone.
Instead, he wanted a more foreseeable 50 years.
Ms Easton reminded the committee those issues were previously put before them.
"These are the sort of concerns that are not a barrier to progressing the variation," she said.
However, concerns such as Mr Boyd's could be advanced through submissions for the coastal mapping variation.
Council chief executive Darryl Lew said the 100-year timeline was in line with legislative requirements.
The presentation by NIWA scientist Dr Cyprien Bosserelle can be found at: https://ttpp.nz/wp-content/uploads/2024/06/WCR-Coastal-Hazard_2024_Bosserelle-NIWA-1.pdf
Ms Easton's report recommending notification of the coastal hazard variation can be found at: https://ttpp.nz/wp-content/uploads/2024/04/Agenda-Te-Tai-o-Poutini-Plan-Committee-29-April-2024-Memorandum.pdf