Some Huon Valley roads are not high above tidal water.
This is significant given that sea level rise has reached an astounding 5mm a year, and is likely to accelerate further.
The road from from Huonville to Cygnet is already being cut off during floods, while the Huonville-to-Franklin route and Huonville-to-Judbury have low spots which will be a problem in future.
The report in the above link notes an acceleration in global warming, not unexpected given the vast increase in greenhouse gas output over the past 30 years.
Sea level rise will bring more flooding to Huonville. The Huon River floods quite regularly, and higher sea levels will worsen the effects.
Parts of some Huon roads will eventually go under during high tides.
Global warming and sea level rise will speed up further as Antarctic, Arctic and Greenland ice caps melt and the sea warms.
Check out polar ice melt trends here.
Road managers need to make plans, perhaps by creating future funds to pay for the required costly roadworks.