depth below datum (m) alongshore transport (m^3/m) 



6 

 4 



— Initial Profile 



A A h 





2 



Cohesive Profile 

 " ■■ Iritermediate Profile 



\ 



1 



/ 



\L 



-100 





 -2 

 -4 



Alongshore Transport 





w 



-200 



_ 



V 





nr 





-300 



-6 









-8 



- ^^^^.^^^^^^^^--^^^ 





-400 



-10 



- ^^^^-^^^^^^^^^^Z--^^ 1 







-12 



^^^-^^^^^^^^^^^^ 



-500 



-14 



I.I 1,1,1,1 



at>>r\ 



-16 -wwu 



200 400 600 800 1,000 1,200 1,400 1.600 



distance (m) 



Total Transport -68,254 m ^3 



k. Profile R23 3-D modeling for the 14 January, 1993 storm, dgg = 0.2 mm actual W.L. 



Figure 20. (Sheet 6 of 6) 



3-D model results. Sand eroded from the beach south of the Waterworks 

 revetment (and from the south end of the feeder beach) is deposited at the 

 fillet beach. 



The predicted change for the 24 January 1992 event is not that much differ- 

 ent from the changes predicted under the 2-D modeling, which is a result of 

 the relatively low net alongshore transport values associated with this storm, 

 which swings from southwest to northwest. However, erosion in the southern 

 section of the feeder beach is predicted with increasing southerly transport in 

 this area (from Line RIO to Rll). This erosion is balanced by some minor 

 deposition in the vicinity of Lines R12 to R14. 



The increased "volatility" of the sand cover that occurred in the NW and 

 SW storms results in both more and less exposure of glacial till compared to 

 the 2-D cross-shore results of the section titled "Results of Cross-shore 

 Modeling with Multiple Grain Sizes" (i.e., where only the inner surf zone fea- 

 tured significant changes to profile shape). With the 3-D results, larger areas 

 of till were exposed where a section of the profile was subject to erosion due 

 to increasing alongshore transport, whereas depositional conditions occurred in 

 other areas, burying till that was previously exposed in troughs between bars. 



Chapter 4 Analyses of Coastal Processes and Geomorphology 



47 



