13. ABSTRACT (Concluded). 



b. Sediment tracer tests for existing conditions indicated that erosion would occur along Camp Ellis Beach 

 for the higher tide levels with net movement of sediment generally in a northerly direction. Larger wave 

 conditions would result in an increased rate of erosion. For the lower tide levels, however, test waves would not 

 move sediment out of the immediate area of Camp Ellis Beach. 



c. The roughened breakwater plan (Plan 1) would not significantly reduce wave heights, alter current 

 patterns and magnitudes, or prevent erosion in the vicinity of Camp Ellis Beach. Test results were very similar 

 to those obtained for existing conditions. 



d. For the beachfill plans with existing (Plan 2) and roughened (Plan 3) breakwaters, sediment would move 

 north, and beachfills would eventually erode to the existing shoreline. The beachfill plans would only be 

 tempcffary solutions to the erosion problems at Camp Ellis Beach (i.e., requiring periodic renourishment). 



e. The 152,920-cu-m (200,(XX)-cu-yd) Plan 4 submerged berm configuration initially would result in reduced 

 wave energy reaching the beach and a slightly reduced rate of erosion along Camp Ellis Beach. The 

 76,460-cu-m (100,000-cu-yd) Plan 5 submerged berm configuration provided minimal wave protection and would 

 initially result in erosion along the beach similar to existing conditions. Sediment from both berm configurations 

 would migrate toward, and feed, the beach. After continued exposure to wave action, the berms would erode to 

 a point where they provide little or no protection and sediment will migrate north; thus, the submerged berms 

 would only be temporary solutions to the erosion problems at Camp EUis Beach. 



/. Of the spur plans tested, the +4.6-m (+15-ft) crest elevation, 914-m-long (3,(XX)-ft-long) structure of 

 Plan 7 was most effective in significantly reducing wave heights along Camp Ellis Beach. Both Plan 7 and the 

 +4.6-m (+15-ft) crest elevation, 457-m-long (1,500-ft-long) structure of Plan 8 would be effective in preventing 

 erosion of the beach. For both plans, sediment would remain in the immediate vicinity and not migrate in a 

 northerly direction. The longer Plan 7 spur jetty would provide a more stable shoreline and protect a longer 

 reach than the Plan 8 structure. 



g. Removal of the north ta-eakwater (Plan 9) would not significantly reduce wave heights, alter current 

 patterns and magnitudes, or decrease the erosion rate along Camp EUis Beach. Since the north breakwater's 

 impact on hydrodynamics off Camp Ellis Beach is minimal, the presence of the structure should result in 

 insignificant changes in the northerly migration of sediment along the beach. Breakwater removal would, 

 however, significantly increase wave heights in the navigation channel. Test results also indicate that the 

 91-m /s (3,200-cfs) Saco River discharge would have no impact on the erosion rate along the beach. 



h. Pre-breakwater conditions of 1866 indicated that the ebb shoal at the river mouth would meander, 

 forming offshore bars and building the beach. These bars would severely hamper, if not stop, navigation. The 

 original +3.0-m (+10-ft) el breakwater constructed in 1873 resulted in similar shoaling patterns, since sediment 

 moved over and through the structure. The raised +4.6-m (+15-ft) el breakwater, completed in 1897, reduced 

 navigation channel shoaling and resulted in offshore bar formations north of the structure and seaward of Camp 

 Ellis Beach. All conditions tested with the historical alternatives resulted in sediment constantly moving north 

 out of the Camp Ellis Beach area, thus suggesting eventual erosion without nourishment or replenishment of the 

 beach. 



