I.On 



0.5 



£ 0.0' 



-0.5 

 1.0n 



0.5 



(U 



,E 0.0' 



-0.5 



t=6 hrs 







- Initial 



— D- 



- measured 





-GENESIS 



6 8 10 12 



Distance Alongshore, m 



— 1 1 — I 



16 1i 



Figure 18. Case 4 physical model/GENESIS comparison 



advanced to the tip of the T-head structures, causing the model to cease opera- 

 tion. GENESIS does not allow tombolo formation at detached breakwaters (T- 

 heads in the present case). 



GENESIS showed promise in the modeling of shoreline response to T-head 

 groins in comparison to the physical model study. Limitations related to tombolo 

 formation in the present version of GENESIS prevent application of the model to 

 the evaluation of T-head structures in the field. Application and influence of T- 

 head groins will be considered qualitatively in the evaluation of design 

 alternatives. 



Model Evaluation of Design Alternatives 



With concern over the anomalously high erosion rates of the beach fill at 

 Monmouth Beach, a study evaluating alternatives to mitigate the rapid erosion 

 was undertaken. The purpose of the design was to maintain a protective berm 

 75-ft wide fronting the seawall for the duration of the 6-year renourishment 

 interval. Effectiveness of each shore-protection design alternative was evaluated 

 with the shoreline-change numerical model GENESIS. Design alternatives were 

 composed of three CP&E (1997) design alternatives and two variations on these 

 designs. Evaluated design alternatives are presented in Table 2. 



Chapter 3 Functional Design 



19 



