Discussion of test results 



Wave heights obtained for existing conditions indicated rough and turbulent 

 wave conditions along Camp Ellis Beach for storm waves from 101, 88, and 

 75 deg with the higher swl's (+2.7 to +4.1 m (+8.8 to +13.6 ft)). Wave 

 heights ranging from about 2.4 to 2.7 m (8 to 9 ft) will occur adjacent to the 

 beach during storms with mean high water conditions (el +2.7 m (+8.8 ft)). 

 Increases in water level due to extreme storms will result in wave heights 

 along the beach reaching almost 3.4 m (11 ft). Tests also revealed little wave 

 energy along the shoreline during low water conditions (el 0.0 m (0.0 ft)). 



Sediment tracer tests for existing conditions revealed sediment movement to 

 the north for waves from 101, 88, and 75 deg with the +2.7-m (+8.8-ft) swl. 

 Larger test waves moved the material out of the area more quickly than smal- 

 ler, everyday wave conditions. Extreme storm waves with the +3.7- and 

 +4.1-m (+12.0- and +13.6-ft) swl's resulted in high levels of onshore move- 

 ment of sediment tracer material onto the model overbank. The model was 

 constructed in cement and could not erode; however, these extreme conditions 

 would probably result in severe shoreline erosion of the Camp Ellis Beach area 

 in the prototype. Test waves from 101, 88, and 75 deg with the 0.0-m (0.0-ft) 

 swl did not move the tracer material out of the immediate vicinity of Camp 

 EUis Beach, nor did the small test waves from 56 deg for either the 0.0- or 

 +2.7-m (0.0- or the +8.8-ft) swl. Since waves arrive at the site predominantly 

 from 101 through 88 deg and high tides occur daily, net sediment movement 

 in the area is expected to be toward the north. Current patterns obtained for 

 existing conditions also indicated northerly current movement for aU test 

 directions. 



Results of wave height tests for the roughened breakwater of Plan 1 indi- 

 cated, in general, a slight but not significant decrease in wave heights along 

 Camp EUis Beach, as opposed to those obtained for existing conditions. In 

 some cases, waves reflected off the north breakwater were not as apparent for 

 Plan 1; however, maximum wave heights along the beach for the various swl's 

 did not vary significanUy. Wave-induced current patterns and magnitudes also 

 were similar for existing conditions and Plan 1. A comparison of sediment 

 tracer patterns for existing conditions and Plan 1 reveals, in general, very simi- 

 lar movement to the north for corresponding test conditions. Test results indi- 

 cate that Plan 1 roughening of the inner portion of the north breakwater does 

 not appear to have any significant beneficial effect on erosion of the beach. 



Test results for the beachfill plans for both the existing (Plan 2) and pro- 

 posed roughened (Plan 3) breakwaters indicated that sediment tracer material 

 would migrate north and after a time erode to the existing shoreline which 

 indicates erosion would probably occur. The roughened breakwater was not 

 effective in lessening erosion at the site. In light of these test results, it was 

 determined that beachfiU plans would be only temporary solutions to the ero- 

 sion problem at Camp Ellis Beach (i.e., periodic nourishment would be 

 necessary). 



Chapter 4 Tests and Results 



31 



