There are places where the beach has been gradually widened, as well 

 as narrowed, by natural processes over the years. This is evidenced by 

 lighthouses and other structures that once stood on the beach, but now 

 stand hundreds of feet inland. 



In their eagerness to be as close as possible to the water, developers 

 and property owners often forget that land comes and goes, and that land 

 which nature provides at one time may later be reclaimed by the sea. Yet 

 once the seaward limit of a development is established, this line must be 

 held if large investments are to be preserved. This type of encroachment 

 has resulted in great monetary losses due to storm damage, and in ever- 

 increasing costs of shore protection. 



lo52 NATURAL PROTECTION 



While the sloping beach and beach berm are the outer line of defense 

 to absorb most of the wave energy, dunes are the last zone of defense in 

 absorbing the energy of storm waves that overtop the berm. Although dunes 

 erode during severe storms, they are often substantial enough to afford 

 complete protection to the land behind them. Even when breached by waves 

 of a severe storm, dunes may gradually rebuild naturally to provide pro- 

 tection during future storms. Continuing encroachment on the sea with 

 manmade development has often taken place without proper regard for the 

 protection provided by dunes. Large dune areas have been leveled to make 

 way for real estate developments, or have been lowered to permit easy 

 access to the beach. Where there is inadequate dune or similar protection 

 against storm waves, the storm waters may wash over low- lying land, mov- 

 ing or destroying everything in their path, as illustrated by Figure 1-8. 



1.53 SHORE PROTECTION METHODS 



Where beaches and dunes protect shore developments, additional pro- 

 tective works may not be required. However, when natural forces do 

 create erosion, storm waves may overtop the beach and damage backshore 

 structures. Manmade structures -must then provide protection. In gene- 

 ral, measures designed to stabilize the shore fall into two classes: 

 structures to prevent waves from reaching erodible material (seawalls, 

 bulkheads, revetments); and an artificial supply of beach sand to make 

 up for a deficiency in sand supply through natural processes. Other 

 manmade structures, such as groins and jetties, are used to retard the 

 longshore transport of littoral drift. These may be used in conjunction 

 with seawalls or beachfills or both. 



Separate protection for short reaches of eroding shores (as an indi- 

 vidual lot frontage) within a larger zone of eroding shore, is difficult 

 and costly. Such protection often fails at its flanks as the adjacent 

 unprotected shores continue to recede. Partial or inadequate protective 

 measures may even accelerate erosion of adjacent shores. Coordinated 

 action under a comprehensive plan that considers erosion processes over 

 the full length of the regional shore compartment is much more effective 

 and economical. 



1-14 



