Question regarding beach nourishment

Because not all beach nourishment projects are the same by a long shot. Some actually improve surfing, if the sand pumped on shore is of higher quality than previous material, but that's rare. In Delaware in the mid 1990s two of our towns were actually filled with material that almost immediately improved surfing due to sandbar formation. The Delaware chapter of the ESA was able to hold contests in Dewey Beach for the first time ever due to this finer grained sand pumped from Hens and chicken Shoals. Due to complaints from fishermen, that borrow site is no longer used and we all know how well the coarser grained newer beachfills have worked out.

There are other factors:
Did the beach nourishment bury the ocean ends of groins or jetties that formed breaks?
Did the beachfill extend the beach into really deep water so steep bottom slope just offshore becomes an almost permanent state?
Is the sand so coarse grained that it basically is never pulled off the beach to form bars?

 

i live at a inlet area, what happens is the dredging that they put on the shore erodes after a few years of big northeast swells and hurricane swells then they have to dredge again, i did notice this last time they did put some really coarse grained sand (shell) on the beach, people dont want to go there, its to rough to even walk on, and many years of dredging have really messed up some really nice (used to be) breaks, its just too deep now, it has screwed up the beaches 5 miles south of the jetty...and we stupid humans call it progress

 

http://www.surfline.com/surf-news/s...-at-one-of-australias-best-beachbreaks_47637/
like he said, sand pumping can make great waves if done right

 

I think it all comes down to how much sand gets filled in. Best example I know of firsthand is 7th Street in OCNJ. Used to be soooooo good. but they filled SO MUCH SAND in there... I don't think it can ever come back.

Used to ride waves under the boardwalk up to the seawall on high tides... now theres a dune system between the boardwalk and ocean covering up the L part of the jetty. Its all washed out now too, so theres just a huge cliff with no beach. Why can't they just leave **** alone?

 

Mitchell is right... every project is different, tailored to meet the specific needs of the area. Major factors include bottom contours offshore, whether there's any supply of sand coming into the area, dominant swell direction and size, longshore vs. cross-shore sand transport, the location/size/orientation of structures like jetties, whether sewalls are present, whether dunes are present, grain size, current erosion rates... and a bunch of other stuff.

I don't know the specifics about nourishment projects in Florida, but the problem we have here in NJ is that, put simply, there's a shortage of sand being supplied to the beach system. Instead of natural dunes, lagoons, beaches... we've cut off the flow of sediments to the beaches by damming sediment-carrying creeks and rivers that flow into the ocean to create oceanfront lakes, and paved over and built upon the dune areas that should keep our beaches in balance. Sediment sources from rivers that flow into the ocean are the source of material that help supply sand to keep beaches in a state of equilibrium. Cutting off that sediment input into the system, and removing dune material that would naturally erode to supply the beach with sand, starves the beach of sand input. So the system is open on one end only... out... erosion without deposition.

Sandbars that make good surfing along beachbreak shorelines are formed by cross-shore sand transport.... the movement of sand from the dune toe and beach to offshore during high wave action seasons (winter) and storms. That sand moves back up onto the beach during depositional periods of low wave action (summer and flat spells). Meanwhile, longshore currents transport all sands parallel to the shoreline. So sand should sort of zig zag from beach to sandbar and back, many many times, all the while shifting down the beach with the longshore flow. The deeper the water is offshore, the greater the longshore flow, because the longshore flow is generated by wave and wind energy. We all know that deep water offshore means more wave energy coming into the beaches. In Monmouth County, we have the deepest water at the shortest distance offshore than anywhere in NJ. So our longshore sediment transport dominates the movement of sand, and erosion rates are very high because of a lack of sand supply updrift. So when the ACOE pumps a bunch of sand up onto the beach, the unnatural slope created under water is far too steep for an equilibrium state conducive to bar formation. Instead, the longshore current quickly grabs that sand and sends it north, scouring out the slope of sand below the intertidal (littoral) zone, maintaining a steep drop-off, and creating a feeback loop that perpetuates itself. That means shorepound for all but the biggest swells we might get. Sandbars do not begin to form until the beach once again reaches equilibrium... when most of that new sand is gone and the beach returns to its natural profile. And that can take years.

Many who study the beach dynamics and nourishment projects in NJ agree that nourishment alone has never and will never be the long term solution to our problems at this point. It must be a combination of nourishment and hard structures, like jetties and/or artificial reefs. NJ has three artificial reefs designed specifically for erosion mitigation, and they all work, to varying degrees. That's the direction we need to go in. We need to stop taking the quick and easy way that results in short-term gains in property protection and "towel space," but with steep costs in money, habitat, and recreational resources, knowing we'll have to do it again... and again... and again. And soon, too. We need to start using 21st century technology, like they do in other places around the world, and engineer a more efficient, effective, sustainable solution without the social and environmental costs of outdated, traditional nourishment methods.

Fortunately, there are some organizations working hard on our behalf, and the authorities are - for the first time - starting to listen. Surfers and fishermen are now being included in the dialog, and are having an influence (as small as it may be) on project design and implementation. We have our foot in the door. I hope that things improve from here.

 

Good read, something that almost every EC surfer can relate to since we all pretty much have the same breaks. I grew up surfing in FL, and I can say that nourishment does create shorepound here. They filled in my spot recently, and the two early storms that brushed through sucked the recently filled in sand in the water and created some double-up shorepound which made for a frustrating session during a good swell weeks ago. It happens.

From my experience growing up here, I've been pretty good at predicting what will happen to the breaks during a major event like a dredge, noreaster, hurricane/TS, but I could never tell how it will be months after said event.

 

LBCrew - your post is excellent and well-conceived! I'm always amazed that the ACOE never seems to "get it" when it comes to managing natural beach processes. There is also a tremendous amount of politics played when million dollar properties are involved.

Last year I read the transcript of a very interesting town hall meeting involving Topsail Island, NC residents and the ACOE. The northern part of topsail is highly unstable, but that didn't stop people from building palacial homes there. Of course, now they want someone to save them (check out Google Earth, North Topsail Island to see some of these houses sitting in the water!), but any actions at the north end of Topsail will have a huge domino impact on residents of the southern part of the barrier island. No one could agree how to proceed because of diametrically opposed positions.

Research has shown that over a long period of time, natural beach restoration processes do their job if left alone. Unfortunately, eliminating dunes/shoreline vegitation, building structures, and changing shoreline characteristics interfere with the natural course of things. A big land management feedback loop is created because the more the land is managed, the more it has to be managed in the future! Finally, land owners don't have much patience when their taj mahals wind up heading for the drink after a couple hurricanes or nor'easters.

The whole thing is sad, but at least it sounds like there's some hope on the horizon as everyone realizes we can't go on like we are without completely ruining one of our greatest natural resources.