3rd upper launch erosion - done 2016

[behindThePeak]

let the beach go and focus your efforts on improving the place instead of maintaining it. if you're going to ask for something this complicated why not ask for a floating dock or low pier running east perpendicular to the wind.

It could start on the northeast corner of the golf coarse and extend to the channel blocking the wind at water level and making that whole area a buttery flat water paradise.

make the structure wide enough to launch from and we won't need the beach anymore.

a few derelict barges should do the trick. or better yet, some kind of heavy but flexible floating structure that rode the tide up and down but still deadened the chop. complex and ambitious? sure, but probably less effort than fighting erosion long term.

you could get a sponsor to pay for it all and call it "Aunt Jemima Land". Problem solved. You're welcome.

[behindThePeak]

Tell me you don't love that idea Phill

[le noun]

Phil loves aunt Jemima.
Last time we saw her she was hanging out at HMB harbor.

[Aloha]

I'm way too local and missing kiting with you both to even post up on that one

[le noun]

[adamrod]

isn't this exactly the kind of thing the SFBA was created for? a lot of us have donated....seems worth a try to get them involved.

[Thor29]

I wrote an e-mail to SFBA asking about this when I saw this thread. I included a link to it. No response so far, Do any of you members have an inside contact? I am certainly not going to join if they are going to ignore this. But I agree with Adam, this is exactly what a group like SFBA is made for.

[dpca10]

Ok back on topic, I think the erosion is caused by the tidal wash through the north bay inlet. There is a line of rocks you can see at low tide but it is incomplete. This allows a rapid ingress and egress of water. I think rocks or sandbags to raise the height of the wall and slow the flow in the north bay would probably slow erosion considerably. On those huge high tides we get the upper launch gets hammered when waves can roll in unchecked. Just my thoughts.

[Tony Soprano]

Statement of the SFBA

I agree that this is a problem, but of very substantial scale. My background is in coastal engineering and shoreline retreat on the open coast. The beaches on the West Bay in this area are highly disturbed, and the shoreline is both retreating and adjusting, as well as responding to sea level rise. There was a pretty good look done at Coyote Point as part of the County's efforts to build a beach there. Essentially, the shoreline was pushed out with fill over the mudflats. (It is also altered by other nearby fill areas, like that to the up coast of the power lines.) All of this alters both the supply of sand and the wave energy. David Lyon has poked around a bit, and I asked two technical experts--Bob Battalio, ESA's coastal engineer, and Peter Baye, who has worked on beach restoration (e.g Aramburu Island in Marin County) for a little informal help.



There are two problems. First, long term erosion and sea level rise has eroded not just the beach, but areas up wind (up wave energy direction), so shoaling of waves occurs closer to the beach, bringing more wave energy and accelerating erosion. Second, but not so clear to me, the shoreline was perhaps filled many years ago and is now seeking a new equilibrium. Unless we understand the issues, and have the City behind us, any restoration efforts are doomed.



The good news is that the agencies who regulate the shoreline now understand that soft solutions--eg. restored beaches--are better habitat than rip-rap. So there are some prospects for eventual support and solutions, but the price tag is in the millions, and the time scale is in the five to ten year horizon.



Sorry to not have better news.



Jim McGrath
Vice President San Francisco Board Sailing Association
Board Member San Francisco bay conservation and development commission

[Aloha]

Luckily to launch a polesail all you need is carpet covered rip rap - windsurfing may not be cancelled afterall