The team estimated that the [Gulf] coast would suffer $134 billion of losses over 20 years if no preventive measures were taken. Elevating homes could prevent $39.4 billion of those losses, but it is incredibly expensive. At an average of $83,300 per house, it would cost $54 billion to prevent that $39 billion in damages. The six-meter-high dikes being built in Louisiana were a worse option; at $33,000 per meter, they were an absurdly expensive way to protect a relatively limited amount of property, returning just $1 in savings for every $4 of expense. Smaller levees built on land in front of many low-lying coastal communities prevented much more damage for almost the same cost.The thrust of the article is that natural forms of shoreline protection are more cost-effective than armoring the coastline with concrete seawalls. Those that pay for things such as shoreline protection and for damages after major storms are starting to pay attention. Which combinations of protection measures are used may have a lot to do with how much it costs to buy flood insurance. That, in turn, has a lot to do with who can afford to build what near the coast.
In terms of bang for the buck, sandbags were the best investment, saving $8.4 billion of damages for a mere $0.84 billion in expense. Natural defenses ranked high as well. Wetlands restoration, which could prevent $18.2 billion of losses, would cost just $2 billion. Oyster-reef restoration could prevent $9.7 billion in losses for $1.3 billion. Barrier island restoration offered $5.9 billion of prevention for $1.2 billion. And “beach nourishment” (replenishing depleted beaches with sand dredged from the seafloor) in the eastern Gulf could save $9.3 billion for $5.5 billion.
Saturday, April 6, 2019
Protecting the Shoreline From Storms
It turns out that that "hard construction" is the worst alternative.
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4 comments:
Most flood insurance is Federally subsidized, which just encourages people to build where they shouldn't.
If they had to pay rate commensurate with the risk, few would be able to afford a home on the shoreline. And no bank would give a loan unless someone would provide insurance coverage.
My friend in Pennsylvania owned a house by a creek . In the 20 years that he owned it he had four 100 year floods that just filled his basement with sediment that he cleaned up and went on with life . In 2011 they had a 500 year flood . Thats more flooding than the house endured in the previous 80 years . He looked at all options and tore the house down . He took the 70k from flood insurance and built a new house on an engineered base and pillars . That alone used up the 70k , but he has a new house 9 feet in the air and a mortgage .
His gov't flood insurance on the old house would have been $500 a month on the old building ,it's less than a tenth of that on the new one .
His neighbour on the other side of the creek did the same thing . Since 2011 the neighbour has lost about 40 feet of creek bank to erosion . My friend has lost none because he encourages the plants and trees that stabilize the bank .
Flooding is the main cause of property damage claims here and I expect it is in the US as well . There are neighbourhoods in Toronto that are on high ground that repeatable flood because the storm sewers that were adequate for many years can't handle the volume they get now .
Flooding isn't what it used to be .
Interestingly enough, until 2004, the National Flood Insurance Program was paying its own way. After Katrina and Sandy, both having huge damage caused by State and Federal poor decisions on flood protection, the program moved into the negative, where increasing flooding from 100 and 500 year events are costing more than predicted. Could that be climate change, why sure, the climatologists show a definite link at over 99% probability (whataboutism or “bullshit” posts to follow).
The actual requirements of the participation in the NFIP, in terms of State and local ordinances and building requirements are actually pretty significant and result in an inability to rebuild in many cases unless mitigation activity occurs. The majority of NFIP policies are in place in Texas and Florida, with the majority of the exposure in Florida on grandfathered properties. The simple reality is the Government (at all levels) encouraged building in locations that are at risk and are becoming at risk, and until that changes fully, these loses will continue. As an example of the problem, the passage of a bill in North Carolina (2012) prohibiting any law or actions recognizing Climate Change and rising water levels, results in unavailable flood insurance in much of NC, and the possibility of the withdrawal of NFIP polices in NC.
I remember reading that the continuing wetlands loss and the added intensity of future storms because of higher ocean temperatures pretty much guarantees that New Orleans will get wiped out again.
They said they were trying to hold on to what wetland storm protection they had, but the disappearance was at best slowing down.
The way I remember it, the maintenance of the shipping lanes wasn't helping, either.
-Doug in Oakland
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