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| Waves topping bulkheads! |
Some bulkheads did better than others. Our
bulkhead lost several pilings where the termites had been eating away at the
cores. Betty's bulkhead fared very well because they had a layer of
landscape fabric and large cobbles directly behind the pilings.
Consequently, they didn't have much erosion, although the large cobbles were thrown 15 feet back from the bulkhead. This is in contrast to
Larry's lot next door, where pilings were backed by sand and there are now
enormous pits of erosion where the flushing water took the fine particles away
with it. The piling bulkheads that did not have any landscape fabric, but
had coastal dune ryegrass did a much better job retaining soil than those that
were ryegrass free. The extensive root system of the coastal dune
ryegrass, combined with a plywood barrier, was most effective at retaining the soil in our lot even after the
pilings had broken away.
Another notable example of bulkheads working well
could be found in Brad's tall rip-rap. Brad's contractors did an
admirable job because there is not any damage at all. On the other hand,
it is clear that the shorter rip-rap (found by George and Joe's) allowed in a
great deal of higher energy water with every wave. If that bulkhead had
been built one course higher, it would have functioned much more effectively at
breaking up the wave energy. The rip-rap bulkheads by Ralph's had a great deal of erosion behind them, and the foundation rocks have dislodged.
All bulkheads were challenged when they contained boat ramps. The gradual slope of the bulkhead is an invitation for
water to flow up onto the land. Many of the boat ramps have large erosion
points on the east sides where the water flowed back out. In many cases
the concrete is undercut.
Lessons learned:
1. Bulkheads do best when backed by landscape
fabric or plywood.
2. Bulkheads do best when they have a healthy
network of coastal dune ryegrass to stabilize the soil.
3. Bulkheads need to be high enough to deflect
strong wave energy.
4. Old, termite infested bulkheads are not strong enough to deflect high wave energy storms and must be replaced.
5. Boat ramps flood, so a path for receding water
should be designed in.
6. There is no path for the water to escape once it comes over the berm and must percolate through the soil. Low lying lots bear the brunt of this. If those lots bring in fill for building, a similar event's saltwater will flow across the road to the hill-side ditch system.
Septic Systems:
We'll all want to have our septic systems pumped
out. They are all filled with salt water now, and this will kill the
correct microorganisms that break down waste products. The drain fields
also got a good flushing out with salt water. It was interesting to
locate the ends of our drain field lines by watching for the bubbles emerging
into the standing water. Everyone with mounds systems should be happy to know
that the drain fields stayed clear of the standing water, but the tanks were
usually underwater - so those should be pumped too.
Plants:
Most of my new landscaping (new grass and rhodies)
is probably shot. We'll have to see which trees will be able to withstand
the salt shock. Luckily many plants are dormant, so if we have enough
rainfall this winter, some plants may make it. Our experience with
flooding down at Thompson Spit shows that many trees can take the flood once in
a while, but if there is a repeated inundation, they cannot survive.
Salal, oceanspray, coastal dune ryegrass, gumweed, sea thrift, Oregon
grape, some ferns, iris, daffodils, and pines should be ok.
Community Boat Ramp:
The boat ramp looks like it fared just fine, but
there are some enormous logs washed up on it that will have to be pulled off.
Beach Height:
The sand height is unusually high on the beach side
of the bulkhead right now indicating that a lot of sediment was deposited in
this storm. That makes sense because the water color of the crashing
waves was amazingly brown.
Sheds:
Elevate them!
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