Understanding the Beach @ Venus Bay

Why is the beach eroding?

 

The beach along Venus Bay has been eroding significantly this year, with many high scarps left around beaches 1, 2 & 3, So what is going on? Superficially it looks like it might be evidence of sea level rise, perhaps strong evidence of global warning. However if that were the case the beach should be higher and narrower, whereas the beach is wider than normal for this time of year and lower.

 

The erosion has been occurring at specific location associated with specific high tide events. The king tides (higher spring tides) and some storm tides (mainly due to strong onshore winds & swells rather than storms) have been responsible for specific stretches of erosion rather that a continuous event along the beach. At the same time the beach profile has deepened exposing shell beds in many locations and is clearly lower at most locations,

 

I suspect that many of these changes started last spring with the king tides, when a few erosion scarps occurred in only a couple of places along the beach, At the same time the normal change of the profile from its winter shape to summer shape did not occur along much of the beach at all last summer. The winter berm, (the beach’s winter shape) has a distinct parabolic shape with a steeper gradient at the back of the beach. The same winter profile appears to be continuing this year. The summer berm, (the beach’s summer shape) has a flat upper dry section at the back of the beach and long flat foreshore with extensive development of sandbars. This flatter profile in the tidal zone now seems to be occurring at many places but under an obvious winter berm at the top of the beach.

 

I have been trying to work out the source of all the sand that builds the venus bay spit and direction of sand drift for a few years now. I have also noticed that last year the dominant sand drift direction has been fluctuating locally from a general northern drift over previous years. My current thoughts are that the beach is not washing away, the sand is just being moved up and down the coast but that the beach profile has been rotated down a little, I suspect that the shape of the coast is trying to adjust to a subtle change in the equilibrium of the forces that shape it, currents, swells, tides, storms and climate generally.
 
What are the consequences of the extra erosion?

What can we do about this?

 
It is important that everyone interested should start recording these changes and observations along our coast.
 
This is a "citizen science" project but to particpate you do not need to be a scientist, university trained, or qualifed you just have to be interested in what is happening and know how to use a web tool so share your observation.
 

Photographs

 
Take photos and send them to VBOPing,  flickr, photobucket or picasa web albums, use the tag VBOP, take part in the groups discussion threads. 
 

Blogs

 
Use your existing blog, or contribute to the ObsBlog in VBOPing, get a link badge and post into and about this project as often as you want.
 

Short Field Notes

 
Use the ObsBlog or twitter, or other microblogs, to send in short field observations. Use the hash tag #VBOP and share your observations with us all.
 

Artwork & Writing

This project should not be limited to just "scientific" observations, there is plenty of creative inspiration along the beach and venus bay area.
 
Some suggestions of wher to post, there is a beach art group on redbubble, which gives you the opportunity to sell your work and the flickr VBOP group, but tag your works VBOP and ART so we can find them. 
 

What else is happening?

 
There is a lot more than erosion to learn about our beach. What are the other occupants of the beach, the birds, the shells & other aquatic life. the dunes, the vegation and the animals that live there up to. Sublte changes in any of these areas could be very useful warnings of deeper changes.
 
So there will be a special tags and places to recorded all this related information with a special empassis on phenology, the timing and cycles of natural events