Sunday, April 12, 2009

PreSand Diversion Bluff Erosion

Our coastal bluffs were exposed to erosion long before humans impacted the sand budgets. The biggest man-made monkey wrench is probably the Oceanside Harbor. It is important to note that it opened in the early 60s.

Here is a historic photo from Solana Beach. It was taken long before the harbor opened.

Notice the seaweed up to the bluff's toe (the high tide line?) and the two caves carved out by erosion.

See Also: Historic Encinitas Beaches and Bluffs

4 comments:

  1. Of course. Is this shocking?

    Just look a the coastline the trails San O.

    The difference in N. County is we armored 90% of the coastline and dammed all the sediment travel with the railroad berms crossing the rivermouth openings.

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  2. The sand peddlers want you to believe that bluff erosion is a man made problem and that wide sandy beaches is the wild condition for our town, so that's not shocking.

    What might be shocking is saying that the railroad berms aren't the big problem people think they are. I remember a columnist for the Coast Dispatch that would write a lot about straightening out the San Elijo rivermouth. He led people to think that the roads and bridges were keeping sand from pouring onto our beaches. I bought that idea then, but I don't buy it now.

    Why should we think that San Elijo and Batiquitos could be important net sources of sand for our beaches?

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  3. "Why should we think that San Elijo and Batiquitos could be important net sources of sand for our beaches?"

    Hey Kevin- I think you need to take some course in SDSU on sediment transport in Hydrologic water sheds. Our at least go talk to some of the professors. You will likely learn that the huge RR berms are acting as a particle dam and do hold back a percentage of the sediments. Complete dams like hodges on the san dieguito water shed are even worse, they level the first flush velocities which really effect the sediment transport. Anyway- Keep up your interest and you will continue to learn.

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  4. "Our at least go talk to some of the professors."

    I have. If you give me names of a few I haven't already spoken with I will make an effort to speak with them too.

    ReplyDelete

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