4.3.5 Alternatives 



As alternatives to bulkheading for erosion control purposes, 

 eroded shores and banks can often be stabilized by grading the shore- 

 line and planting salt-marsh grasses, mangroves, or other vegetation. 

 Such an artificial marsh barrier is preferable to other types of 

 shore erosion structures where feasible and may prove to be the least 

 expensive. In protected water bodies where erosion rates and wave 

 action are low, an artificial marsh may be an effective method of 

 shoreline protection, since wave forces are absorbed and sediments 

 are trapped by the planted vegetation. It has the added benefit of 

 creating a more biologically productive shoreline, as well as one 

 with higher natural aesthetic appeal. In Florida, mangrove species 

 lend themselves well to shoreline protection [53] [54] as does cord- 

 grass species ( Spartina ) in temperate zones. 



4.4 BEACH STABILIZATION - SUBPROJECT 4 



The risks attached to development on the ocean beachfront encourage 

 the building of protective structures to stabilize and safeguard beach- 

 front, facilities. Experience shows that these structures may serve only 

 a temporary purpose and provide a false sense of security, therefore, 

 nonstructural programs, such as building setbacks, are now more often 

 proposed. 



The incentive to place major OCS facilities on the open beach is 

 small because most of them require protected shorefronts of coastal 

 bays. Nevertheless, the subject of beach protection is so important that 

 it needs to be considered in relation to even so minor an activity as a 

 pipeline crossing and secondary development which may result from OCS. 



4.4.1 Summary 



Beaches and dunes shift with changes in the balance between the 

 erosive forces of storm winds and waves, on the one hand, and the 

 restorative powers of tides and currents, on the other. The natural 

 beachfront exists in a state of dynamic tension, continually shifting in 

 response to waves, winds, and tide and continually adjusting toward a 

 point of equilibrium (Figure 16). 



These natural forces at work at the beachfront are immense, and the 

 power of man to hold the beach at a higher than natural angle of repose 

 (slope) to protect property is limited. Long-term stability is gained by 

 holding the slope or profile intact through balancing the sand reserves 

 held in various storage elements--dune, berm, offshore bar, and so 

 forth (Figure 17). Each component of the beach profile is capable of 

 receiving, storing, and yielding sand, depending on which of several 

 constantly changing forces is dominant at the moment. Stability is 

 fostered by maintaining the storage capacity of each of the components 

 at the highest level . 



103 



