Saturday, May 20, 2006
This was a new one for me. It's a log crib, bolted together with stainless cable and hardware, extending out in front of the base of the bluff. It was built within the last year or so, presumably as a softer approach to erosion control than a conventional bulkhead. I'm still struggling with what to make of it. If nothing else, I wish it didn't extend so far onto the beach and that it had incorporated soil and plantings. Functionally, it appears equivalent to a failing timber seawall -- maybe that's a good thing. I wonder what the hardware will look like in 20 years?
The north side of Samish Island is a great place to talk about human impacts to beaches and we've been bringing the CTP class, and other groups, here for years. Bulkheads, bluff modifications, and groins. Sediment supplies have been heavily impacted (some material still comes from farther northwest) and what sediment that's left is heavily compartmentalized by two large projecting fills that act as groins. The spit (Samish Beach) at the distal end has undergone a variety of changes over the decades and was most recently the site of a large (by Puget Sound standards) private gravel nourishment project.
Tuesday, May 16, 2006
Our approach to beach nourishment on Puget Sound is really pretty lame. Down here folks know how to do it right. Dredge it, barge it 20 miles, pump it to the beach, repeat. Do it for 9 miles of beach and then a few years later do it again. The project we got to visit is on Sand Key in St. Petersburg, from Clearwater down to Redlington. They weren't pumping today on account of possible bad weather coming in, but we got to see lots of big yellow equipment on the beach and lots of 24" pipe. Just like on Puget Sound, if you build the beach too high or too steep, a scarp develops. Bluff erosion, Florida style. Must be a pain if you're a sea turtle trying to crawl up the beach in the middle of the night with 120 eggs to lay.
More Florida beach photos at my other site (hshipman) - as usual, sometimes it's tough to separate business from personal.
Sunday, May 14, 2006
The Flagler whom Fort Flagler (previous post) was named is NOT the same one who built the Breakers Hotel in Palm Beach and the railroad out to Key West. But that's where we are now. This is definitely not Puget Sound. Everything here is made out of calcium carbonate or some derivative of it. The rocks, the beaches, and the buildings.
Just like I suppose I should visit Glacier Bay (fast forward two years - Glacier Bay) while there is still a glacier in the bay, I thought I better visit South Florida while there's still a South Florida. For two days, the only time I was more than a few feet above sea level was on highway overpasses, hotel rooms, and observation towers. I wonder what it will look like 100 years from now?
Note the use of 20-story hurricane deflectors along the backshore of many of these beaches.
Saturday, May 06, 2006
I swung by Fort Flagler SP late Wednesday. Marrowstone Point continues to intrigue me - it appears very similar in form and evolution to Point Wilson to the north. Both are cuspate forelands, both seem to be receding on their northern sides and building immediately south of their points. Both have been armored heavily on the north side to protect structures from the inevitable southward march of their northern beaches. I'll rattle on more about these points another time -- maybe after the Fort Worden workshop in June when I'll no doubt get some new pictures of the Point Wilson lighthouse.
This winter saw lots of action along the northern bluffs of Marrowstone Island, with continuous fresh slides and block falls below the old gun batteries. It's too bad we don't have an easy way of watching how all this new sediment redistributes itself along the shoreline over the next few seasons.
This shoreline south of the mouth of Chimacum Creek was filled and used for log storage for decades. This winter, WDFW (who acquired the site several years ago) removed much of the old fill, restoring over 10 acres of intertidal shoreline. The work focused on the excavation of fill and the lining of the landward bank with large wood - the new intertidal area is being allowed to restore itself. This is already proving to be a great opportunity to observe how an area like this evolves, both geomorphologically and ecologically.
A sandy berm has already begun to build along the outer edge of the site, pretty much along the edge of the original fill. It is forming as a bar or low spit extending northward toward the creek. If there is sufficient sediment to allow the feature to continue building, I suspect it will create a large lagoon with a fringing salt marsh - though this will take several years. If a spit continues to form, the south end of Indian Island might be a good reference (although far more complicated). Jetty Island in Everett might also be a good analog, although that completely artificial site has an abundance of sediment (nourishment with dredged sand) and the plantings were done as part of the project. Chimacum is on its own, although there might be a way of assuring continued sediment with a small feed source at the south end and there might be some ways to actually foster the development of marshy areas.
The amount of large woody debris placed along the inner shoreline of the new project is remarkable. What that bank needs the most is live wood, not dead wood, though hopefully that will come with time. It might be nice to have sprinkled a few large logs out into the prospective marsh area, although I bet this happens by itself within a couple years.
This is one of the larger nearshore restoration projects I can think of, other than dike breaching in the larger deltas. The folks involved in this one deserve lots of credit for making it happen. This and Jimmy-Come-Lately Creek (Sequim Bay) make a great pair of projects for many restoration field trips over the next few years.