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my beach is changing

PostPosted: Wed Oct 19, 2016 6:48 am
by oldmansurfer
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Here is my beach from 2012 when it was in a sand removing mode
IMG_1013.JPG
Here is my beach from a week ago. It's in a sand depositing stage and it's not been good for the sand break. What needs to happen is some really big waves at the right angle which will sweep it into a long slanting sandbar which make waves that break from way outside all the way inside. Big change HUH? We only get 1 to 2 feet change in tides so that isn't it. But the way it is now there doesn't appear to be much sand outside so it doesn't break very far outside and when the waves are small the whole middle part is mostly shoredump. But I guess fortunately there are reefs on both sides that catch some swells and the rivermouth has often a little better sand distribution because the river pushes it out. Beaches are always changing. I am sure it will be good again ....sometime

Re: my beach is changing

PostPosted: Wed Oct 19, 2016 7:40 am
by jaffa1949
Sand beaches are a fully dynamic situation, and can vary greatly season to season , and changes in sea level or primary swell direction can remove or build a beach entirely.

Cool zones that were once glaciated can rise from below sea level after the glaciers have receded , river sediments can change a coastline, damming a river can stop deposition, and seas take away old beach deposits.

Casual observance may not notice change but daily beach going will acquaint you with the climatic and season changes.
For surfers know and appreciate your local sandbank at its best! :lol:

Re: my beach is changing

PostPosted: Wed Oct 19, 2016 9:33 am
by dtc
Jaffa, did you lost a lot of sand in June or so when those big swells came in (when narrabeen was washed away)? Up where I am the beach was almost gone in places, lots and lots of rocks exposed, high tide running up to the dunes

Now, 4 months later, beaches are back, rocks covered up. I thought it would take a few years maybe, but only took weeks. Amazing

Re: my beach is changing

PostPosted: Wed Oct 19, 2016 9:46 am
by Big H
I had to reassess after June here....everything was different.

Re: my beach is changing

PostPosted: Wed Oct 19, 2016 11:23 am
by jaffa1949
dtc wrote:Jaffa, did you lost a lot of sand in June or so when those big swells came in (when narrabeen was washed away)? Up where I am the beach was almost gone in places, lots and lots of rocks exposed, high tide running up to the dunes

Now, 4 months later, beaches are back, rocks covered up. I thought it would take a few years maybe, but only took weeks. Amazing


The fore dunes at one beach full exposed to the swell have been cut back to the the second line of vegetated dune, the rock platform is fully exposed with 2 to 3 metres of sand gone and now forming a wide bank about 300 metres out to sea. Boulders about the size of VWs were moved around up to 100 metres on the normal rock platform.

Merimbula bar was washed both in and out. The whole foredunes system was washed into the lake and the bar itself widened and the tidal channel changed by 90 degrees, lots of landslides of the cliff face, but the bar now has a deep hole halfway down the normal run only long boards or really good power surfers get across the fattening of the wave. A second quality bar has formed. About a kilometre further south, the double underhead conditions have preserved the whole new set up for much longer than normal

Re: my beach is changing

PostPosted: Wed Oct 19, 2016 5:03 pm
by BoMan
The sandbars and channels of Bolinas shift with every visit, and it's important to note the changes before going out. Yesterday the shore break was bigger than the waves out back which made entry and exit an adventure!

BolinasKingTide.jpg
BolinasKingTide.jpg (121.46 KiB) Viewed 2045 times

ThePatch.jpg
ThePatch.jpg (118.75 KiB) Viewed 2045 times

Re: my beach is changing

PostPosted: Wed Oct 19, 2016 5:28 pm
by oldmansurfer
I grew up at this beach and at it's very worst there was no beach for that whole stretch except at the ends and the ocean was eroding the road that runs along the beach. And in the years before that you could walk out about 100 yards because there was so much sand. The sand comes and goes not so much with season but more complex stuff like if there is sand being moved from another area to where the waves will push it in. What needs to happen to groom the sandbar is a huge swell that pushes a lot of water over the reef on the left side. When the water runs off the reef it goes out at an angle which creates a nice long right breaking wave. It might also help to have a huge rain so the river pushes the sand in the rivermouth area toward that sandbar reinforcing it. Sometimes a heavy rain will push the sand out from the rivermouth to form a nice (smaller) right breaking wave of it's own. There was once a pro surf contest held at that beach back when longboards were the only thing.

Re: my beach is changing

PostPosted: Wed Oct 19, 2016 6:42 pm
by DreamSurf
oldmansurfer wrote:
000_0005.JPG
Here is my beach from 2012 when it was in a sand removing mode
IMG_1013.JPG
Here is my beach from a week ago. It's in a sand depositing stage and it's not been good for the sand break. What needs to happen is some really big waves at the right angle which will sweep it into a long slanting sandbar which make waves that break from way outside all the way inside. Big change HUH? We only get 1 to 2 feet change in tides so that isn't it. But the way it is now there doesn't appear to be much sand outside so it doesn't break very far outside and when the waves are small the whole middle part is mostly shoredump. But I guess fortunately there are reefs on both sides that catch some swells and the rivermouth has often a little better sand distribution because the river pushes it out. Beaches are always changing. I am sure it will be good again ....sometime



it changes yeah. some parts of tahadart in morocco were all sand. and the sand was dragged by time. all the sand is gone now and its a stony place. full of old antique ruins under water and graves of jews and portuguese. also its really sharp. i wonder when the sand will come back(not in my lifetime) it changed really fast. like in 3 years you could slightly see old stony homes and beachrocks. crabs would housevest the holes and urchins everywhere.

as for your beach it seems really clean. if the waves are there then thats all that counts. perhaps swimpaddle a little further. shoredump huh :p
i get beaches here LOL the further you go the undeeper. there are some places here where you desperately go faaaaaaar and far and u notice you can still stand on your feet.

a question. how is the underwater map there oldman?

Re: my beach is changing

PostPosted: Wed Oct 19, 2016 7:05 pm
by oldmansurfer
On the top picture I would be happy with those waves. The bottom picture was taken on a day when the break over the far reef was inconsistent so at the time of the photo no waves in that area but the waves there were fun. Also what isn't shown is the reef on the right side which has waves and the rivermouth area which also has rideable waves