| HomeJoin & DonateFAQImportant TopicsOther ResourcesTake ActionAbout UsContact Us
|
Tide Beach Park, August 1989  |
 |
Save the bluffs,
|
|
FAQ
Don't sea walls cause beach erosion and contribute to the disappearance of sand off our beaches? We have interviewed a number of expert witnesses at institutions including Scripps Institution of Oceanography and the University of California, Berkeley that have hard evidence that this is a vicious and self serving myth. These scientists and experts tell us that the hard factual evidence says that the movement of sand on our beaches is directly related to the storms and littoral cell action of the ocean. The long term studies of beaches like Torrey Pines, La Jolla at Scripps Institution of Oceanography and Mission Beach, where sea walls have existed for 25 to 50 years, prove that the sand activity is completely independent of the fact that a sea wall exists.
Studies have shown that cliff derived sediment has only been a small fraction of the supply to the Beaches. The Solana Beach bluffs could be expected to yield a mere few thousand cubic yards per year compared to the input from sediment of the region's rivers of about 200,000 cubic yards per year. Bluff erosion is not the answer to beach erosion.
"Planned retreat" is literally the process of giving up under the guise of attaining natural beauty. "Planned retreat" is a lie. There is no beauty in the process of losing the bluffs or collapsing infrastructures. This is a concept which has been frequently discussed, but never successfully implemented anywhere. The concept has no long term logic. When existing development falls into the sea, the movement of the bluff will continue eastward. Where does it stop? "Planned retreat" would be a disastrous policy for Solana Beach. There are other options.
Isn't there any alternative to sea walls? The BEST way to prevent the ocean from eroding the bluffs, is to have a wide beach. A wide healthy beach naturally absorbs the energy of the waves and prevents accelerated erosion, not to mention it provides a place of beauty with unlimited recreation for all.
Why isn't there more sand on the beaches? Nature's sources of sand supply are from the inland streams and lagoon bottoms working its way down to the sea and into the littoral system. These sources have to a very great extent been shut off by human development, such as dams for flood control and roads and rail access across lagoon mouths. The mining of sand for concrete, including that required to build these blocks to sand migration, has further depleted the sand available. Today, less than 10% of the sand required for natural beach replenishment ever gets into the system.
Where does the sand come from for beach replenishment? There are large deposits of sand just off shore which can be dredged and returned to the beach. Dredging of local harbors for maintenance, or near shore construction projects are also potential sources of high quality sand.
Won't the winter storms just scour the sand from the beaches each year? The long term impact of winter wave action varies from beach to beach. On most, the profile of the beach changes seasonally, making it seem as if the beaches disappear in the winter and return in the summer. These require only minimal replenishment every few tears to maintain a healthy sand beach. Others, and notably Solana Beach, are subject to very high erosion rates, and require installation of sand retention devices in order to stay healthy from year to year.
What is a "sand retention device"? Basically it is a man made structure on or just off the shore which alters the action of the waves and reduces their erosive impact on the beach. Some are "groins" which are built perpendicular to the shore, other forms are artificial reefs or chevrons, which are placed parallel to the beach slightly offshore. While there is difference of opinion as to which type is most effective, there is general agreement among coastal engineers that in spite of their cost, these devices are in the long run the most effective and economical way to keep some beaches healthy.
What can I do to help make sure this all happens? The BBC was formed to do just that! Add your support and voice to make sure we have beautiful beaches and a safe environment on the bluffs. For membership information and/or to volunteer your time, please complete our Membership Form or call the BBC directly at 858-481-1011.
|