Beach Erosion in New York City
By Leah Biel
 

    Beach erosion is an ever-present threat that affects the lives of people living or working near any beach.  With every inch that the water comes inland, the dilemma increases, causing loss of land, loss of environmental quality, and even loss of life.  Residents who use the beaches and the government must deal with this problem. Statistically speaking, New York City has over 600 miles of coastline, and 47% of New York State’s shoreline is eroding constantly. With such a threat looming various resources and preservation methods have been established to help decrease the effects of this problem.

     The Division of Coastal Resources is doing many things in order to try to deal with the issue; correcting mistakes of the past and make better decisions.  The DCR is placing sand bypasses at inlets to reinforce the natural process of protecting the shore, as well as using monitoring programs to put more information in coastal processes databases and offering assistance in problems regarding specific sites.

    A major local monitoring project is the Atlantic Coast of New York Monitoring Program.  The program began as a model patterned after similar programs in other states and feedback from local officials.  With help and resources from NY Sea Grant, the New York State Department of State Division of Coastal Resources began to collaborate with the US Army Corps of Engineers to put the program into action.  With legislative support, the Federal Water Resources Development Act included a  $1.4 million annual funding for the program.

     This program, active since 1995, uses 426 stations all down Long Island’s 125-mile south shore, from Coney Island to Montauk Point, spaced 0.6km apart, to collect various forms of data twice a year, in spring and fall.  These stations take beach measurements, analyze waves, and examine the impact of storms.  Beach profile surveys and aerial photographs are also taken, as well as beach cross-section surveys approximately every 1000ft.  After collecting this data from the stations, the findings are put together with tabulated historical information to deal with long-term costal changes along the south shore produced by erosion.


(The fencing in the background helps to limit erosion)

     For the south shore, coastal erosion poses a large problem for every governmental level.  The historical information from maps and aerial photos show differing shoreline changes all along the coast.  While some areas remain stable or even get more sand, other areas are prone to erosion rates upwards of ten feet per year.  There are several different causes of erosion, and different causes may explain the differening erosion rates.  One main cause of erosion is wave action. It can be especially bad if the slope the wave breaks on is steep and the water is deep.  Some warning signs of this cause are prevailing winds, a beach covered by waves during storms, and frequent flooding during storms.  Since the south shore has had a fair amount of major storms in recent years, this may be the primary, if not the only, culprit.  This problem is one that not only has deep environmental effects but also seems to devour alot of expensive property. The value of the properties prone to erosion total over $10 billion.

    A second main cause of erosion is surface runoff, where water falling across the face of the beach dislodges soil particles.  Warning signs of this type of erosion include water falling over the slope in a sheetlike pattern, channels cut into the surface of the slope, and runoff flowing uncontrolled over the slope.  A third main cause of erosion is groundwater seepage.  Signs for this type include landsliding, mudflows on the slope, and wet-looking dark soil layers that remain after a rain has dried up.  People can also impact the rates and patterns of erosion, especially those who dredge and stabilize inlets in order to navigate.

    For the ocean beaches that are open in New York, annual erosion rates generally range from 0 to 7 feet.  The beaches on the south shore show signs of long-term erosion, but areas that are down-drift of inlets, such as Fire Island’s eastern end, experience a significant amount of erosion.  Positions of the shore in sections of Long Island have been in flux over the past 160 years, but overall have only receded about 350 feet.

   The New York State Department of State has set up some erosion hazards policies.  On lands that are considered to be coastal erosion hazard areas, structures are to be placed far enough back from the shoreline to minimize the damage of the oncoming erosion.  The only structures allowed in the hazard areas are ones that have the capability of being moved.  Natural protective features such as barrier islands, bluffs, and dunes are seen as safeguards of property damage and reducing danger to human life caused by erosion.  Doing anything to these features without care could result in destruction of those features, and must not occur.  Coastal processes like mining and excavation, which can deprive the shore of its natural resources, must be done in a fashion that would not reduce supply, and therefore cause erosion to the shores.

     Regarding erosion control, the Department of State has also put up some guidelines.  The state decrees that structures shall be made or reconstructed that will prevent erosion and flooding.  However, the only structures that will be erected or reconstructed to prevent erosion are ones that have shown a possibility of controlling erosion for at least thirty years in demonstrations and construction standards.  In paying for these structures, public funds should be used for structures where it is imperative to protect the life around it.  This appropriation of funds should only be given after careful consideration and analysis of long-term costs.

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