Incoming tide . . .
Report analyses sea-level rises and impact on shore
The council has released a report that will help inform future infrastructure investment decisions and support community conversations about how to respond to future coastal hazards resulting from sealevel rise.
Infrastructure services group manager Sean Mallon said the coastal hazards assessment will be a valuable input to decisions about where and when to invest in utility upgrades, like wastewater pumping stations, and projects like the renewal of the Raumati and Wharemauku seawalls.
“It will also underpin community conversations about what needs to be done to adapt to future changes to our coast resulting from climate change and sea level rise.”
The report by independent coastal engineering and environmental experts Jacobs New Zealand Ltd is titled Coastal hazard susceptibility and vulnerability assessment for the Ka¯piti Coast District coastline.
“Ka¯piti is facing significant challenges due to rising sea levels and the erosion and flooding this causes.
“This report provides guidance on where and when we can expect increased coastal erosion and flooding in future.
“We accept that scientific models are not perfect predictions or guarantees but they are our best tool for planning for the future, as long as we keep updating them as conditions evolve over time.
“The report provides an excellent basis for future decisions about where and when we invest in infrastructure and our community discussions about climate change and our coast.
“Grappling with coastal science has been a difficult issue for our district in the past but the debate has moved on. We have learned from previous work in this area and the report has been subject to two independent reviews with issues raised with regard to previous historical work also addressed by Jacobs in this current report.”
Since 2017 the Government has provided clear guidance for councils on planning for climate change.
The Climate Change Commission, Insurance Council of New Zealand, and the media have also done a lot to highlight the need for communities to work together on how to respond to climate change.
“There’s also far greater public awareness of the impacts of climate change and sea-level rise because of the increased frequency and intensity of storms that we’ve all experienced, and the efforts of local groups like Low Carbon Ka¯piti and our young people, so I’m confident this assessment will be received for what it is — essential technical projections that will enable the council to make
good long-term decisions about protecting, maintaining, or moving public assets and infrastructure in the future.
“The council made a commitment to our community to work on coastal challenges in its 2018-2038 and 2021-41 long-term plans because they affect the services and lifestyle of our whole district and impose costs on all of us. This technical assessment supports that commitment.”
Mallon said the report shows which parts of the district will be vulnerable to coastal erosion and inundation under two to four different sea-level rise scenarios over 30, 50 and 100 years. The 30-year timeframe is important for long-term council asset planning, 50 years is used for considering building consents, and 100 years is the minimum timeframe Government guidelines recommend for climate change planning.
“Obviously, the sea-level scenarios for the nearer timeframes have a higher degree of certainty attached to them just like a weather forecast. Tomorrow’s forecast is more certain, but understanding the long-term outlook is useful for planning ahead.
“There’s no denying that sea-level rise is changing our coastline and these changes will affect everyone who wants to access our beaches for recreation, and people who own or plan to buy property here. This report provides the council and the community with the technical information we need to help us maintain and protect the assets and infrastructure our ratepayers pay for and will provide useful base hazard data for future District Plan change processes.
“As a community, we need to understand our choices so we can plan effectively.
“The longer we delay, the more limited and expensive the options become for everyone.”
Read the report on the council website at kapiticoast.govt.nz/ coastal-science along with the report methodology, and other information on coastal hazards.