SEA WALLS CAUSE LOSS OF BEACH IN PACIFICA
We've already seen it at Rockaway Beach, where 56 years ago the beach was "armored," that is, rocks were put in to hold back the sea. They are at least temporarily holding back the sea, but there is no beach anymore. And we're going to see it again at Sharp Park, Linda Mar, and Esplanade: Every beach that is "armored" will lose near-beach habitat, so that in 10 to 20 years the beach will erode completely.Watch the video [2 minutes]:
Discussion of this well-understood phenomenon in Terrain Magazine:
Sea levels are rising all over the world. On the California coast, it is still subtle but insistent. Because of global warming, sea-level rise will accelerate. Instead of trying to hold back the sea (an impossibility), we should plan for habitat to "migrate," and work around it. The general public will not approve using federal tax monies to keep out the ocean. To answer Shakespeare, we may not really oppose a sea of troubles. We need to work with nature, for we have no equal force to oppose it. Nor do we wish to lose wildlife habitat, which we surely will if we mistakenly armor our beaches.
DOLORES DE CABEZA
Ocean Beach does not have waves crashing at every high tide against a rip-rap seawall in a desperate attempt to keep the waves from reclaiming a handful of private houses, as in the case of much of Pacifica.
The Ocean Beach parking lot has a concrete wall about 50-100 feet away from the low-tide point, which as I recall is there to raise it off of the beach to the level of Great Highway (which is on a berm), to keep the wind from blowing sand all over the parking lot (which it does anyway), and possibly to protect from storm surges. It's not getting pummeled all day and night, all year long.
The berm is there because that whole section of the Sunset is below sea level, due to the water being pumped out of what were then marshes and dunes by the quaint Dutch-style windmills that are still there, around 100 years ago.
I have been to Ocean Beach many times. I don't recall ever seeing signs there that say "CAUTION! WAVES MAY BREAK OVER SEAWALL"... because there isn't one, and they don't.
Posted by: ken restivo | December 30, 2009 at 03:35 AM
There's got to be more to this than meets the eye. Ocean Beach in SF has been "armored" for at least 50 years and the beach there looks like it's doing fine. I also remember in 1970 going to the end of Rockaway Beach Avenue with a friend to watch the waves crashing against the seawall. To me it doesn't seem to be proved that putting the rocks on the beach is going to cause the beach to disappear. (Unless you count the fact that the rocks are now on top of the beach.)
I've also looked up information on the formation of beaches with the Army Corp of Engineers. According to what I read, beaches are formed by the sand coming out of the river systems being deposited on the coast.
Posted by: Gil Anda | December 27, 2009 at 02:14 PM
The Dutch have an unusual situation. The land is pretty much entirely reclaimed from the ocean. There are no naturally occurring flora or fauna. Every plant and stone was placed there by a human being. No offense to The Netherlands, but I can't see the whole world trying to fit that model.
Posted by: Dan B. Underhill | December 23, 2009 at 08:29 PM
Tell the Dutch to "work with nature" and tear down their dikes. I'm sure they'll benefit from that.
Posted by: Steve Sinai | December 23, 2009 at 06:05 PM
When my wife and I bought our first and only property in Linda Mar, we were adamant about going to open houses. One house we visited in Montara was about 200 feet from the ocean. The street that divided the house from the ocean was buckled as if a major earthquake had just rippled through the area. I asked the real estate agent if there was any danger of the house collapsing into the ocean. I was assured that there was no such danger. I am not blaming real estate agents for selling tomorrow's ocean floor, but why should the public lose out because someone didn't do their homework? I don't see an easy solution, just a win-lose situation.
Posted by: Jim Currie | December 23, 2009 at 05:29 PM
It's a fine sentiment until it's your own home that's in danger.
Posted by: Alan Dodds | December 23, 2009 at 08:55 AM
California law states that all beaches are public property. When sea walls are built, the beach washes out, and the public loses. We lose while property owners are rewarded with private oceanfront property. One local example is Nick's Restaurant. The parking lot at Nick's should be the beach. I used to have a good photo of this from atop the hill south of Nick's. One can clearly see how the parking lot has destroyed more than a third of the beach.
Posted by: Jim Currie | December 22, 2009 at 03:06 PM