opinions... are jetties good/bad/necessary?

Discussion in 'All Discussions' started by johnnydon'tsurf, May 5, 2013.

  1. johnnydon'tsurf

    johnnydon'tsurf Active Member

    Mar 10, 2013
    good morning...

    i'm interested to know your personal experiences/opinions on jetties, specifically around inlets. the reason i ask, is that Ocean Isle Beach NC is expecting to install a jetty on the west side of the Shallotte Inlet, between the beaches of OIB and Holden Beach, probably within the next 5 years. we've always had erosion problems on the tips of our island, which wouldn't matter too much, but that's also where we've got people with homes. the extreme eastern end of the island (where the jetty will go) has about 10 homes at the moment where the high tide mark is now encroaching under the foundations of houses. these homes reside on third street, because first and second streets no longer exist; they're a 100 yards out under water actually.

    as far as i know, the legislation has passed and we will be getting this groin. right now, the state is supposedly "inspecting" the area to better understand how they will go about installing it. i believe it will be just one structure on the Ocean Isle side of the inlet, without a companion jetty on the Holden Beach side. i would prefer that the beach stay natural, but... whatever.

    so i'd like to ask for your opinions on jetties and what's been your experience in dealing with them. have they performed as they were intended? pros/cons? the sand next to them is stabilized, but way down the beach at the next inlet has taken a turn for the worse/better? i'd appreciate as much response as possible. thanks

    i would be surfing right now, but it's not 23 feet yet, so it's tough to get motivated for these sissy waves... maybe later.
  2. LBCrew

    LBCrew Well-Known Member

    Aug 12, 2009
    While you could make some generalizations about what the likely effects of the jetty will be, every spot is different, and results will vary. There are a lot of factors, and all of them need to be considered when a structure is designed and constructed. Whether or not the engineers have "done their homework" is the question, and if I was someone in your position, I'd be asking a lot of questions. Projects like this often have public comment opportunities, and I'd be sure to take the opportunity to get some details.

  3. brewengineer

    brewengineer Well-Known Member

    Jun 22, 2011
    Charleston harbor jetties caused rapid erosion of Morris Island, along with addition sand loss on Folly. In that case, I would say they were bad. There are examples out there where they are good.
  4. zach619

    zach619 Well-Known Member

    Jan 21, 2009
    I would say regardless of the effects on the surf, that particular jetty seems necessary. Regardless of if you live in the SE or the mid-atlantic, all these sandy barrier islands are on a time clock. Without installing jetties, pumping sand etc, these areas would or will no doubt become unlivable. So for the local economy's sake, not to mention the millions of coastal home owners up and down the coast, these Jettys are very important and usually do what they were intended to do... My dad used to always say, some day in 50 years, Ocean Pines (OC MD) will be the new ocean front... It was a half joke, but it is what it is... Most of the coastal areas in the Mid-A and SE are not ideal to populate with structures and people. We all know this... Same goes for HHI where I live... Any season, this place could get ripped in half again the same way it did early in the last century... Same thing happened to OC MD way back in the day... Same thing happened dozens of times in the carolinas... OBX etc.... We are all on borrowed time living in these regions, so sometimes I try and put my surfing aside and accept what is best for people living in my area...
  5. Mitchell

    Mitchell Well-Known Member

    Jan 5, 2009
    Inlet jetties are necessary when we develop too close to natural barrier island inlets. Warning: Huge Generalization: Barrier island inlets are naturally migrating features that send to move in one direction for a while (driven by net littoral sand drift), until the bay or river is taking such an inefficient path into the ocean that a storm cuts a more efficent and direct route and the migration process begins again. This is obviously a fluid landform that just begs to be avoided with immovable development. Jetties are mans way of stabilizing the inlet to hold it in one place, and end the perpetual migration.

    In the illustration below, the likelyhood is a new inlet forming during a storm up around the 1738-1808 location, and with that new more direct water flow the 1987 inlet will silt in and close. Can you believe this is the kind of landform that we have chosen to develop? Amazing!

    Last edited: May 5, 2013
  6. Erock

    Erock Well-Known Member

    Aug 6, 2011
    Johnny: The Masonboro Inlet jetties are a good case study for what you might expect to happen with the Shallotte Inlet. I'm pretty sure they will end up going with a jetty on both sides eventually because it's the only really navigable, deep water inlet in the HB/OIB area and needs to remain that way.

    Put it this way, the waves on the North End of Masonboro would not be nearly as good if the jetty wasn't there. The inlet has caused shoals to form offshore there, the bathymetry tends to bend the waves into the nice peaky lines that spot is known for... sort of the same effect that makes Duranbah (around the corner from Snapper Rocks) such a world class beachbreak.

    The MBI jetties are also great for fishing and spearfishing thanks to the crystal clear water we enjoy in this area, although the water is usually too brown around OIB to make for good spearing visibility you will still be able to land some doormat flounder around it.
  7. Koki Barrels

    Koki Barrels Well-Known Member

    Aug 14, 2008
    In 1933, there was a hurricane that created the Ocean City inlet in a matter of 36 hours...a jetty was built a year later at the new end of Ocean City. Before the hurricane, Ocean City and Assateague were connected. Since the building of the jetty, it has prevented the natural flow of sand south to Assateague, and the island continues to diminish and push further towards the mainland.

    "The jetties were constructed by the Corps of Engineers in 1934, after the inlet formed during a
    major storm in 1933. Since it formed over 60 years ago, the inlet has functioned as a
    thoroughfare for boating traffic between the ocean and the coastal bays. In addition to
    providing access to the coastal bays, the jetties have disrupted the sediment supply
    between Ocean City and Assateague Island. Prior to the formation and stabilization of the
    inlet, the sand generally traveled from Ocean City south to Assateague Island. Since
    construction, the inlet and jetties have prevented a large portion of sand, which would
    otherwise have reached Assateague, from reaching the island. Consequently, the northern
    11 km (6.8 miles) of the island shoreline have been seriously affected. The disruption in
    the natural longshore transport of sediment between Ocean City and Assateague Island
    has resulted in adverse physical, biological, and economic impacts to the area. The result
    is an island that is not being maintained in a natural condition and that lacks the geologic
    integrity of a healthy barrier island. A substantial portion of Assateague Island, which has
    always been known for its natural beauty, has also suffered significant aesthetic impacts.
    The island overwashes frequently, and the shoreline has eroded back towards the mainland
    at an accelerated rate. This erosion has caused a loss of salt marshes, an infilling and
    reduction in size of Sinepuxent Bay, and a decrease of habitat diversity on the island. It
    has also created navigation difficulties near the inlet and through the back bays, and has
    increased the vulnerability of mainland communities to storm damage.
    Due to the lack of an adequate sediment supply, it is expected that northern Assateague
    Island will continue to be degraded, and a breach will most likely occur on Assateague
    Island, which could cause additional inlets to form. This could occur during the next
    substantial coastal storm. An additional inlet would change the dynamics of the area and
    would create more environmental and economic problems. Most importantly, the
    Assateague Island National Seashore, a national treasure, would suffer significant loss. In
    addition, it is expected that considerable losses to wetlands would result, as well as losses
    to recreational opportunities, damage to property, and hazards to navigation."
    excerpt from http://www.mdcoastalbays.org/files/pdfs_pdf/restoration-of-assateague-appendix-d_Part1.pdf

    This article shows pictures of the aftermath of the storm and a picture that shows how much Assateague has moved since 1933....http://www.baltimoresun.com/news/maryland/eastern-shore/bal-1933storm-pg,0,6378003.photogallery

    Jetties have their pros and cons, there will be changes to the coastal area, no doubt. Anytime, we try to control or inhibit the ocean and land from it's natural progression, we can expect it to backfire in our faces. I'm just glad that I won't be around to see Assateague fall off the map, fingers crossed.
    Last edited: May 5, 2013
  8. Erock

    Erock Well-Known Member

    Aug 6, 2011
    Sounds like they need to have a bypass pump in that case, Koki. I think something like that would help out at most jettied inlets.

    For the record, I am a proponent of jetties protecting navigable inlets.
  9. zdsurf4422

    zdsurf4422 New Member

    Jul 8, 2011
    Jetties in general can be beneficial for surf breaks I believe and many people have sited the masonboro/ south end wb jetty. However, do you research on the OIB jetty. The reason I am opposed to the OIB jetty is that nearly all of the property that is being "saved" is owned by one individual. Should we use public funds to save only one individuals property?? They chose to own these locations and the associated hazards I am not too sure that it is fair for the taxpayers to protect only his property. I will do more research and put down some citations.
  10. NJshredmachine

    NJshredmachine Well-Known Member

    Jan 17, 2013
    Hey koki. Looks like you copy and pasted brahhh.

    Here's the scoop. Jetties are great up her in NEW JERSEY. it makes the waves bigger and better than anywhere.
  11. ThatSlyB

    ThatSlyB Well-Known Member

    Aug 20, 2012
    Looked at a map of your area and couldn't help but laugh. Google actually shows those underwater streets. Was there houses there? Were they destroyed? When did you lose those streets?

  12. johnnydon'tsurf

    johnnydon'tsurf Active Member

    Mar 10, 2013
    yo zdsurf... i'm not exactly in favor of it either, but at the same time, i've got bigger fish to fry. i've got things in my life to worry about, whether or not a jetty costing millions of dollars gets built or not, to possibly save the beach or not, isn't all that high up on my list. with our town, what the mayor/town council want, the mayor/town council usually get. i'm not even looking at it from the standpoint of creating a new break or anything like that, just the standpoint of is it necessary/beneficial to justify it being built in the first place. as erock stated, the natural flow of sand from east to west is going to be cut off, so that's not good. a ton of the sand OIB has renourished in the past decade, is now sitting on the east end of Sunset Beach... that end of their beach has grown exponentially over the last few years.

    alright zdsurf, i got sidetracked... i'm not aware of any one person owning that end of the beach, unless you are referring to Chauncey Cooke or the Williamson family. if it's someone other than those two, then i'm out of the loop. i agree with you, that why is it the needs of the few outweigh the needs of the many, but around here money talks. i'd rather not see it built, but i'm not as proud of my beach anymore as i have been in the past... everything's a money grab, aesthetics be damned. which brings up a new thread i'm gonna start... what's up with all these Israeli faux surf shops getting built all over SE NC? i've heard some bad things about what's really going on behind these "businesses." but that's for another thread, so if that pisses anybody else off too, feel free to start it. Tsunami surf shop and all that crap, what a joke. OIB sold us out on that one, and for what? a little bit of tax money? they said we'd never look like Myrtle Beach here, that this was the quiet beach... well, if there's money involved, i guess they can overlook that statement. i'd like to see your research zd, thanks for your input!
  13. Koki Barrels

    Koki Barrels Well-Known Member

    Aug 14, 2008
    Totally agree, Erock...actually was about to go into that at the end of my post, but had to run out.

    As for you, JerkOffMachine, I'm not sure why i feel the need to explain to you, of all people...but since you asked for it....notice how i wrote "excerpt from" and then listed the source...what are you? A re-todd?
  14. ClemsonSurf

    ClemsonSurf Well-Known Member

    Dec 10, 2007

    Those jetties aren't the best example. They're in place to maintain the depth of the shipping channel. I think OP is talking about jetties (rock outcroppings) going out into the surf from the beach like you see on Sullivan's island or on Folly beach.
  15. Mitchell

    Mitchell Well-Known Member

    Jan 5, 2009
    A bit of terminology:

    The rock structures built to stabilize inlets and prevents sand from washing into the naviagational channel are called jetties.

    The timber or rock structures built on beaches to trap moving sand and reduce erosion (like Folly Beach) are called groins.

    If the OP is talking about structures primarly intended to stabilizing a naturally moving inlet, then those are jetties.


    Last edited: May 5, 2013
  16. Erock

    Erock Well-Known Member

    Aug 6, 2011
    I look at jettied inlets more in terms of a system rather than just how they affect a surf break. A stable, protected inlet is greatly beneficial to the local economy in terms of commercial fishing, charter fishing, pleasure boating and becoming a welcoming port for transient long distance cruisers. Yes, it stops the natural movement of an inlet but in many cases will stabilize the islands.

    Of course there will always be a question of "who's" property it is protecting, but that is just one part of a larger equation. Anecdote: The South End of Wrightsville has grown a lot--back to where it was when the island was originally plotted for development. All of a sudden there were all sorts of folks claiming rights to the land due to family history and the sort... even though it was non-existent for a couple decades. Luckily the town stepped in and turned it into a park.

    I'm trying to dig up some scientific info explaining why the MBI jetties have not caused any severe erosion or damage to Masonboro. I'll post it up when/if I find it.
  17. brewengineer

    brewengineer Well-Known Member

    Jun 22, 2011
    Yeah, wasn't sure what exactly his area was doing, but I thought I should mention the bad.
  18. titsandpits

    titsandpits Well-Known Member

    Sep 4, 2012
    manaquan inlet in NJ is a good example of this. it has jettys on both north and south sides of the inlet. before hurricane sandy the north side manasquan side was a killer spot even on 15-20 mph winds onshore winds it was still rideable and decent...now with the sand erosion from hurricane sandy it sucks.

    now for the southside "jenkinsons" jetty those waves that hit that break was a real gnarly spot. it mostly wedged up against the jetty on the sand bar and offer crazy pits but they were close to shore...now after hurricane sand theres like a inner break next to the rocks kinda like before, then another break about 100 feet to the right and about 100 from beyond the jetty(pretty far out break for NJ)

    my point is that everywhere is different and one big storm completly changed two spots one two sides of ONE jetty completly jenkinsons possibly for the better but squan for the worse