- Not related to tides - high fatalities - NSW at low risk bc big continental shelve - fast multiple waves with long length and period

Rob 2 Flashcards by Sammie Chilton

What is a main coastal hazard

we live to close to the coast

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What is the key criteria for a natural coastal hazard?

A natural process -Cost expense and lives

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How long do short term coastal hazards last

sec/min -> hours/days

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Bodysurfing and the law

Shore break is dangerous - guy swain - break neck - sue- red/yellow flags - now said that the individual has to recognise obvious and foreseeable risks

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Short term coastal hazards

Water depth

breaking waves
shark
tsunami
storm surge
Rip currect

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Explain how breaking waves are a short term coastal hazard

After car accidents, beaches are the 2nd most common location/cause of spinal injuries in Aus. Dependent on beach morphology, e.g. coogee biggest amount of spinal injuries because it has a lot of plunging waves

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Shark fatalities in Aus and global

Aus - 0.8

Global - 4

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Tsunami

Not related to tides
high fatalities
NSW at low risk bc big continental shelve
fast multiple waves with long length and period

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What are tsunami’s a consequence of?

Under sea earthquakes, volcano’s and landslides

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E.g. of tsunami

Thailand Boxing day 2004

-Japan 2011

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Indicator of a tsunami is -

-> oceans getting sucked out!

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Curious case of maldives

Tsunami just went straight over the maldives - corruption - govt. exaggerated the problem to get money!

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Storm surge : cyclone /hurricane

Cause huge waves

Elevate sea level/wave set up
Related to air pressure and wind stress

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What do storm surge include

Hurricanes and cylones

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What can storm surge cost

Life’s and $$

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What type of coastal hazard is a rip current?

A short term hazard

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Rips role in surf rescues..

In Aus rips are estimated to be a factor in ~80% of the estimated yearly 15,000 rescues

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How many people die from rips each year

20-30 fatal drowings in Aus each year

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What is the problem with rips-

most beach goers don’t know what they are!

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surf zone

the region of breaking waves

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Rob’s suggestion on rips

Instead of teaching people how to get out of rips! teach them how to avoid them in the first place

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What is the conventional advice if u get caught in a rip

-dont panic -dont swim against the rip - swim parallel to the beach -stay afloat and signal for help

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What did robs gps and swimmer research study find?

Floating can lead to exits or long periods afloat

-swimming parallel is a coin toss in terms of if it will be effective!

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What did rob’s study suggest about rip currents?

That rip current flow behaviour is very complex

On the same beach there are large variations between rips
There are different types of rips
a single rip can change over time and space

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What message did rob's research suggest was appropriate?

A combined approach! No single message is good enough!

Describe the social research project..

Look at the demographics, surf knowledge and behavioural responses and experiences of rip current survivors! In order to aid appropriate rip current safety messages and education

How was the social research project conducted

online and face to face surverys at coastal parks and beaches ect. Interviewed all abilities of swimmers!

Science of the surf (SOS)

presentatons since 2001 now given to over 50,000 adults - awards - media coverage - visually powerful explanation of surf safety

Social research found

-most people are ignorant /uneducated on rip currents -most people are unaware of the severity of the hazard -some just dont care BUT THE AVERAGE BEACH GOER DOESNT WANT TO DROWN!

2 challenges with the science communication

- how to communicate complex info to public | - how to make beachgoers care and motivate them to follow instructions

DArk gaps =

rips

good way to teach people about rips

- visuals -dye

Seems to be working

..there has been a confirmed drop in rip current induced fatalities since 2004!

How long do long term coastal hazards last

Months, years, decades, centuries and longer

What are long term coastal hazards

-Sea level rise -Storminess -Erosion

Sea level rise as a long term coastal hazard

Problem isn't that the beaches are going to disappear because they will just move back! The problem is that we have built to close to the sea

Storminess as a long term coastal hazard!

The magnitude and frequency of storm events and the relationship with the volume of sand on beaches and the recovery times

Key e.g. of storminess

East coast cyclone - damage coogee and bondi

Storminess and climate change

Storminess related events have increased with climate change

Erosion as a long term coastal hazard quote

there is no erosion problem till a structure is built on a shoreline

Erosion costs .. (e.g.)

money and lives (narrow sand spit in the gulf of mexico)

Why is coastal management important?

Because 80% of the worlds population lives on the coast!

What makes up the framework for coastal management

Policy, planning, practice

Policy

Politics/administration/legislature

Planning

Resource allocation

Practice

needed to implicate a idea

What happens if policy and planning isn't happening?

You have 4 options

What are the 4 options of policy and planning coastal management stratergies aren't working

-No action -retreat and relocate -hard solution -soft solution

What are hard and soft solutions ?

Shoreline (coastal) engineering

What are shoreline coastal engineering?

Methods of changing or altering the natural shoreline in an attempt to stabilise it

What is a soft engineering strategy!

more natural method

e.g. of soft shoreline coastal engineering

1) dune replenishment, revegetation, renourishment, rehabilitation 2) beach nourishment

What is the advantage of dune replenishement/revegetation as a soft shoreline coastal engineering

quick, cheap, easy

Beach nourishment

Requires a sand source

Analysis of beach nourishment

Expensive - short term answer - requires top up - intial erosion rate is increased by 10% -need to tailor nourishment strategy to the beach

Hard shoreline coastal engineering

Involves construction and structures

e.g. of hard shoreline coastal engineering

- breakwaters - storm surge barrier - groynes and jetties - sea wall

Breakwaters

detached barriers which sit off shore parallel to the shoreline

Groynes and jetties

walls which extend into the ocean - aiming to trap long shore drift - made of rock, timber, steel

Sea wall

Vertical wall built back from and parrallel to the shore to protect proerty

-ve impacts of sea walls and groynes..

- reflect the wave energy which increases its turbulence - enhance long shore and rip currents = more erosion - ruin beach - dont have long life spans (repair/replacement)

New jerseyisation of a coast

First place to have a beach resort --> build --> erosion --> build sea wall !end up with a resort but no sea wall