alternatives to the revetments depend- 

 ing on the site specific circumstances. 



Beach nourishment from onshore or 

 offshore locations can be used to widen 

 and raise the beach profile. This, in 

 turn, will dissipate the wave energy 

 and may reduce erosion of the upland 

 areas. This solution is temporary as 

 the wave energy causing erosion will be 

 focused on the new beach and, in time, 

 transport the sand either offshore or 

 alongshore, thus re-exposing the erod- 

 ing area. Beach nourishment can also 

 be used in conjunction with groins as 

 an alternative to revetments. 



Vegetation can also be used to re- 

 tard erosion. Vegetation is particularly 

 suitable against wind- or rain-caused 

 erosion. Vegetation cannot withstand 

 constant action of waves or currents 

 and would need to be supplemented by 

 other structures, or means, to prevent 

 erosion. Vegetation is often used well 

 above the surf zone for stabilization 

 and accretion of sand on dune areas. 

 In areas of relatively low wave energy, 

 the establishment of a fringe marsh 

 might be an alternative to revetment 

 construction. 



Most structures exposed to sea 

 conditions are ultimately subject to ero- 

 sion and failure. Th-is problem can be 

 avoided by zoning against development 

 of foredunes, cliffs, or other areas sub- 

 ject to erosion by the sea. Setback reg- 

 ulations are another means of assuring 

 that structures will not be threatened 

 by shoreline erosion at a future date. 

 One problem is that it is not always 

 possible to forecast the extent of possi- 

 ble erosion over the life of the struc- 

 ture. This is particularly true in cases 

 where groins, jetties, and breakwaters 

 are being constructed in adjacent areas 

 which might lead to rapid accretion or 

 erosion of the shoreline. Also, unusual 

 storm and wave conditions can have 

 drastic effects on a shoreline that has 

 been reasonably stable in the previous 

 years. Assuming an upland building or 

 facility is threatened by an eroding 

 shoreline, an alternative to revetting 

 the shoreline is to move the building or 

 facility back on the lot, leaving the 

 forward part of the land to erode. 

 This, of course, requires sufficient 



land to allow relocation of the endan- 

 gered building and a structure which can 

 be economically moved. This remedial 

 action might have to be repeated in the 

 future. 



Regional Considerations 



Riprap revetments are a common 

 means of protecting eroding shorelines 

 in Puget Sound (Coastal Region 1). They 

 are also common in estuaries and harbors 

 along the coast of Washington, Oregon, 

 and northern California. Riprap revet- 

 ments are used to protect railroad 

 tracks, roadbeds, residential lots, and 

 uplands from erosion. Heiser and Finn 

 (1970) studied chum and pink salmon in 

 marinas and bulkheaded areas in Puget 

 Sound. These authors recommended using 

 riprap revetments with irregular, 40° or 

 less angle facings in lieu of vertical 

 bulkheads as this type of revetment pro- 

 vides protective habitat for young sal- 

 mon. 



No information sources concerning 

 revetments unique to Coastal Regions 2, 

 6, 7, or 8 were found. Physical and bio- 

 logical impacts are similar to those 

 previously described. 



Limited quantitites of hard igneous 

 rock in peninsular Florida (Coastal Re- 

 gions 3, 4, and 5) make riprap revet- 

 ments expensive as rock must often be 

 shipped in from other states. Coquina 

 rock, mined from quarries in the St. 

 Augustine area, has proven to be a dur- 

 able construction material for marine 

 structures; however, this source of sup- 

 ply is almost exhausted. Limited sup- 

 plies of hard native limestone are 

 available in the Tampa area (Collier 

 1975). 



RAMPS 



Definition 



A ramp is a uniformly sloping plat- 

 form, walkway, or driveway. The ramp 

 commonly seen in the coastal environment 

 is a sloping platform for launching 

 small craft. A launching ramp will nor- 

 mally slope continuously from above the 

 high water line to below the low water 

 line to allow launching of boats or air- 

 planes under varying tidal or water 



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