Warmer Central Otago has many implications for climate change

What does the future hold for Central Otago? Photo: Gerard O'Brien

When it comes to climate change, there is more to consider than sea-level rise, warmer temperatures and more pests for councils.

The Central Otago District Council commissioned Bodeker Scientific to look at climate-change effects on the region in the next 80 to 100 years.

The report, ''The Past, Present and Future Climate of Central Otago: Implications for the district'', looking at worst-case or highest-warming scenarios, was released in October.

CODC executive manager for infrastructure services Julie Muir said the report would be used as a baseline and platform for input on the region's long-term plan.

It was commissioned to enable council staff and the public to better understand the implications for Central Otago.

She said the report predicted more hot days, warmer average temperatures, fewer frost days, an increase in drought risk, reduced snow storage, higher intensity extreme rainfalls and possibly more landslips and flooding, and higher snowfall.

That had implications for roading - replacing bridges, culverts, stormwater systems and other infrastructure.

''When it comes to replacing items like bridges and stormwater systems, they need to be able to cope.'' she said.

Although drains were expected to have a life of about 80 years and bridges about 100 years, when it came time to replace them she said it did not necessarily mean designing bigger bridges, but rather designing secondary flow systems for them.

She said they also had to consider whether stormwater systems for subdivisons could cope with extreme rain events and whether a secondary flow system was required.

The council would also need to consider increasing overall storage capacity in reservoirs and putting in additional bores and booster pumps, especially if the predicted drought conditions eventuated.

It would also consider upgrading water treatment to withstand the cloudiness caused by floods.

Julie Muir.

Roads would also be affected, by both hot and freezing events, and would need to cope with snow dumps.

While there might be less snow on the tops, it was likely there would still be adverse snow events at lower levels.

''Although the winter might be short and not quite as cold, there may well be heavy snowfalls. We might not have to deal with ice on the roads in the future, but we might have a bit more work dealing with snow so it is a trade-off with financial planning''.

Mrs Muir said the report might also start generating discussion on the long-term plan, based on a set of assumptions and scenarios which might need revisiting.

The council would also be documenting emergency response procedures and plans, as well as management procedures for maintenance activities during high fire-risk periods, and health and safety requirements for staff working outside during high temperatures.
-By Yvonne O'Hara