Not long ago, I went down to the shoreline along the California coast. In this area, beach-adjacent, there were lots of breakwater rocks and big boulders. I am sure you’ve seen this before, if not, you have seen pictures online. In any case, it was very interesting to see that wherever the breakwater rocks ended, the beach right next to it was eroded. Why? Well, because of rip tides, rip heads, currents, and the flow of sand and water.
Now then, with all that duly noted and understanding that I probably won’t get any disagreements here from oceanographers, surfers, maritime professionals, or those who study geology – I’d like to discuss some other issues with you on this topic if I might. You see, all too often policymakers that work at municipalities, county agencies, harbor districts, port districts, or for the state or federal government make poor choices in where they put the breakwater. In some cases they are wise and call in the Army Corps of Engineers to help them decide.
These experts take surveys of the area and take all of the factors into consideration along with their special computer modeling. They determine exactly how to place the breakwater as to not cause unintended consequences of future beach erosion. Unfortunately, as sophisticated as these programs are, they are not perfect. Further if another component changes along the way, such as an undersea buildup of sand, or a slight change in where the water works to get back into the ocean, the riptide, this can change the dynamics entirely.
This is why I say when placing boulders and breakwater it is very much an art and a science. It must look good and aesthetically pleasing to beachgoers and those who run harbor districts; otherwise it defeats the purpose and hurts tourism. But making the breakwater look pleasing and putting everything in the proper place is only a start, as the dynamics will change as future goes on. Remember water wants to be free, and it will always find a way to flow to and from.
When I was surveying one of the beaches out in California I noticed that where the breakwater ended, at that point the beach started an erosion pattern – that is to say that unfortunately wherever the breakwater ended the sand had eroded right afterwards. The city then wanted to put more breakwater rocks out; more boulders, but that only meant that the sand would erode further down the beach. You can’t put breakwater or boulders across the entire West Coast all the way to Mexico. In some places the sand will build up outside of the breakwater, and in other places it will wash over and erode the sand behind breakwater. Click here www.channelislandschamber.org for pictures of breakwater.
Consider this also, if mankind goes away for 50 years and comes back what will that breakwater look like? Probably whatever the ocean decides it should look like, which might have nothing to do with what mankind had intended when they put forth the stones, rocks, and boulders. It takes more than proper planning and engineering to get this right, sometimes it takes a trial and error period – and more costly repairs to the modifications done to the coastline.
Indeed I hope you will please consider all this on a philosophical level so that if you are in charge of such a project you don’t make the same mistakes that humans have so often in the past.