In this article, which you had posted earlier, there's a great discussion on the geologic history of the coastline.
Today's geomorphology is discussed, as well as the processes of erosion and deposition as they relate to natural and man made structures. My argument is based on what's said in the discussion of south jersey. Particularly...
"Tidal inlets divide the barrier islands from each other. These inlets serve to segment the littoral distribution of beach sand into cells roughly corresponding to the distance between the individual inlets... Strong tidal currents move sand into and out of the narrow inlet channels between two barrier islands. As current flow slows down in either the bay behind the barrier chain, or in the open ocean, the sand is deposited in what are termed flood- or ebb-tidal deltas (respectively). The more significant of these two features relating to beachfront changes is the ebb-tidal delta. The delta is essentially a shoal surrounding the inlet and extending up to several thousand feet along the oceanfront beaches on either side of each inlet. This shoal produces shallow water seaward of the beach on the adjacent barrier islands. All waves slow down as they enter shallow water. This, coupled with the refraction that occurs as the wave reaches the delta, results in substantial alteration to the wave energy and approach direction to the barrier beach in the immediate vicinity of the inlet mouth. The delta shoal acts to shield beaches that lie behind the arc of the shoal from some of the approaching wave energy. Larger waves break first on the delta margin, losing energy. This combination of effects yields very complex equilibriums, which vary from year to year and even seasonally. The inter-relationships of wave energy distribution and beach changes around inlets have only been recognized in the past 30 years. These relationships are only now being quantified so that management decisions on inlet navigation dredging and beach nourishment projects can take inlet-beach dynamics into account."
Many inlets have been stabilized by huge jetties which essentially block the flow of sand into the inlet, and eventually deprive these shoals of material supply. Indian River Inlet in Delaware has been stabilized for 75 years, and sand has been pump-bypassed around the inlet for 20 years. This combination of management practices has largely prevented material from spilling into the inlet. As a result, the ebb tidal shoals just off the end of each jetty (both south and north) which used to produce good waves, have shrunk and the water is now much deeper where these bars used to be, resulting in a deterioration of what used to be the two best spots in Delaware 20 years ago.
Last edited by mitchell; Nov 22, 2011 at 01:56 AM.
Where I live, a number of smaller inlets ,and perhaps marshes/wetlands/lagoons, would exist except for the fact that the flow of these streams have been dammed to create oceanfront lakes with adjacent buildable lots. The banks have been stabilized (bulkheaded) and their interaction with the ocean has been channeled and restricted. The lack of shoals, even smaller scale, localized shoals that may have helped stabilize local beaches, have forced wave energy to be focused on the beaches, exacerbating erosion. Larger inlets have been stabilized as well.
IMO, the solution to the problem is not simply building up the beaches, only to be washed away again. This quick fix approach is not addressing the cause of the problem, only the manifestation of the problem. Create structures that shield the beaches from wave energy and you will significantly slow the beach erosion process.
I would tend to agree and would I think that a permanent sand nourishment system that somehow re-creates the effects those smaller inlets would have had should be considered. Simply pumping sand on to a beach with no consideration for bathymetry of the shoreline is complete stupidity. If you spend even just one year observing our beaches you should be aware of the natural process of sand movement that wave energy creates. The building of a natural berm by small longer period waves during the summer and then the re-dispersion of that sand by storms. Pumping a large amount of sand and creating a berm during the time of year when the process is at the dispersion step must disrupt the process. Even just a shift towards consideration for the bathymetry of the shoreline would make a huge difference in the effectiveness of sand pumps. Seems obvious to everyone but the people pumping the sand.
its on its way...
yeah but thats not the problem sand pumping is trying to solve...sand pumping solves the problem of politicians looking for a recurring-revenue model Boondoggle, that is all this is.IMO, the solution to the problem is not simply building up the beaches, only to be washed away again. This quick fix approach is not addressing the cause of the problem, only the manifestation of the problem. Create structures that shield the beaches from wave energy and you will significantly slow the beach erosion proces
http://www.deallake.org/images/Deall...Hills_1781.jpg shows a section of Monmouth County where numerous rivers flowed into the ocean in the late 1700s. Deal lake was created around 1890, when the inlet was closed off from the ocean to create lakes and ponds.