Sea level warnings for canals and coastal properties

SBS sea level rise new website Coastal Risk Australia 15 04 16 CLICK

SBS has reported on a new website called Coastal Risk Australia , designed to help home buyers work out the risks involved with purchasing coastal properties.

Sea level rise is happening faster than expected.  But people are still buying in low lying coastal and river areas and our State and Local Governments are still approving them with gay abandon, despite the warnings?

But who cares what happens in 100 years, right?
Think again, sea level rise is expected to affect some places sooner than that, like in  Mandurah for example.
This is a modelling of the Mandurah/Murray areas expected to be underwater by the year 2100 if the sea level rises by 1.1m as predicted. NOTE: Maps are based on a simple ‘bucket fill’ approach and should be considered as approximate only, source ozcoasts.gov.au.

This is a modelling of the Mandurah/Murray areas expected to be underwater by the year 2100 if the sea level rises by 1.1m as predicted. NOTE: Maps are based on a simple ‘bucket fill’ approach and should be considered as approximate only, source ozcoasts.gov.au.

But isn’t just  sea level rise itself that we have to worry about. Combined with other factors, including warm ocean and surface temperatures, tides, atmospheric pressures, just small differences in sea levels can seriously exasperate the impacts of cyclones and big storms coming in off the ocean.
In Western Australia, like everywhere else, we can expect more extreme weather events going forward.  Cyclones are predicted to come further south, to be more intense and more frequent.  WA has had many cyclones and Perth certainly has been hit by cyclones before;
Cyclones Affecting Perth BOM

Tropical Cyclones Affecting Perth – Australian Bureau of Meteorology (BOM)

Cyclone Alby in 1978 was a category 5 cyclone and caused the most wide spread storm damage in WA’s history. “Storm surge and large waves caused coastal inundation and erosion from Perth to Busselton”, according to BOM.
Cyclone Alby erosion _floreat

Erosion caused by storm surge and waves by Cyclone Alby at Floreat Beach – BOM

 The image above gives and indication of how high waves/storm surges can reach during cyclones.
It is important to understand the terminology that insurance companies use for the different types of flooding.  In the  major insurance company policies that we checked,  “flooding” refers to flooding caused by rain, but flooding from the ocean is referred to as “inundation from the ocean“, “storm surge“, “tidal surge” or “tsunami“, for example.
All policies happily cover for “tsunami“, because they don’t happen in WA.  The term “tsunami” is  related to earth quake activity and not considered a risk.  Flooding from rain, seems to covered by most, though it is important to check individual policies, because policies are customised to different areas.  An area prone to flash flooding from heavy rain is likely to be more expensive or not cover for flooding at?  Mandurah for example is prone to flash flooding from rain.
It is very hard to find a policy to cover for anything related to flooding from the ocean.  A few still do, we found a couple, but not for anyone, only if you have your home loan with them and only in certain areas. Insurance companies are experts in working out climatic risks. If something is not covered by insurance or if it is extremely expensive to insure, that means they perceive that there is a high likelihood of it happening.
Apart from flash rain flooding in areas with poor drainage (often in built up areas due to poor drainage systems and or a lack of trees and vegetation), major flooding on a large scale from heavy rain events is unlikely in Perth you would think, as our dams are so low now,  it would take rain fall of biblical proportions to fill them to over flowing, as they have in the past?  See this Perth Now article which describes some of the flood events Perth has experienced in the past.
Perth Now (The Sunday Times) tends to trumpet developer propaganda and developers in WA want to build canals and other coastal developments as do their crony politicians.  This could be why this Perth Now article was mainly about less likely rain flooding?  They only mentioned this tiny bit about ocean flooding incidentally,  “sustained strong westerly or northwesterly winds can also cause a build up of water on the coast, flooding parts of the river’s foreshore on high tide with storm surge.   In addition, tropical cyclones are also responsible for flooding.”  Reading this article you wouldn’t get the impression that flooding from storm surge was a significant risk?
The way we see it, the concern is not water rushing down the river from the hills towards Fremantle because of  heavy rain, but rather the other way around, as occurred with Hurricane Sandy in NY, when storm surges pushed in from the ocean up the Hudson River causing devastating inundation.  This is very common with cyclones and hurricanes.  They spin around in one direction, forcing walls of water up onto the  coast.
Storm surge
Storm surge pushing into harbour New York

Storm surge pushing into the harbor New York – Hurricane Sandy

Coastal areas and especially all of the canal developments built in the low lying  estuarine swamp areas between Fremantle and Busselton are especially vulnerable to storm surges and inundation.  Canal houses are built up high off the water, but not as high as decent storm surge.s or high enough to protect surrounding infrastructure and facilities.
Cyclone Alby in 1978 , “Caused the most widespread cyclone damage in Western Australia’s history. Destroyed a large portion of the Busselton Jetty. Affected Perth with the 3rd highest recorded wind gust in the city’s history, 130 km/h (81 mph), and Fremantle with a 143 km/h (89 mph) gust.”
Below is a photo of the Safety Bay Jetty in normal weather, next to two photos take by a resident of Safety Bay during cyclone Bianca, on the 25th of January 2011, with the comment below.
Safety bay jetty - storm surge cyclone Bianca 2011 “Cyclone may have fizzled but we still got a bit of a storm surge, here are two pics of the Jetty at Safety Bay taken about an hour apart, this is the first time I have seen it go under.”
 
Bianca was  a category 4 cyclone, which fortunately ended up changing direction and caused very little damage to WA’s coast line.  But one can only imagine how high the sea levels would have been if the storm had hit with full force?
Those who do still have insurance in low lying coastal areas for inundation from the ocean, could find that it becomes prohibitively expensive going forward and if they try to sell their properties, the new home buyers may not be able to get it at all?
Floods don’t always happen were they are supposed to happen. As the people of South Carolina have found, you can’t trust Governments to get the risks right . Nearly every major flood or storm that has occurred in Australia or overseas, large numbers are caught out, thinking they were insured, when they weren’t.
Perhaps in other parts of the world, as is apparent in WA, politicians are more interested in the short term profits of their developer mates and/or the short term profits to be made in selling public coastal land to developers for coastal developments and  canal estates (i.e. Point Peron in Rockingham)?  The well being of ordinary citizens seems to be the last thing on their minds a lot of the time?
Approving new high risk developments could bankrupt Local Governments going forward, if their Local Government indemnity insurers refuse to cover claims made by members of the public made against them, should a big cyclone cause a lot of damage?  Government planning authorities have a duty of care to protect citizens, this is the main purpose of Town Planning, to ensure safe orderly development.  The public have right to assume that if planning authorities approves a development, then it must be considered to be safe, based on the best science available to them at the time?
Erosion at Seabird is a continuing nightmare for the Shire of Gingin and ratepayers.  The State Government can’t be counted on to pick up the pieces?
Property boundaries are crumbling in Seabird. Photo: ABC News, Bonnie Christian

Property boundaries are crumbling in Seabird. Photo: ABC News, Bonnie Christian

Just encase you would like to visit the new Coastal Risk Australia website , you may have to wait a few days?  We have been trying for the last couple of days and it is still busy.  Hardly surprising.
Coast Risks Australia website 16 04 16
This entry was posted in Canal Developments, Climate Adaptation, Climate Change, Extreme Weather, Planning and Public Health, Point Peron, Storm Surge, West Australian Government and tagged , , , , , , , , , , , , , , , . Bookmark the permalink.

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