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RETURN PERIOD (YEARS) 
LEGEND 
SELECTED NOPTHEASTERS 
SET A 
———— SET B 
STAGE FREQUENCY 
STILL WATER LEVEL 
COMPARISON BETWEEN SETA AND SETB 
GAGE 12(E FRONTAGE & EXT. OF HACEN 
Figure 68. Variability in stage frequency for the two 
northeaster data sets at gage 12 
hurricanes and northeasters are presented in Appendix G for each of the 20 
numerical gages. Locations of all gages are shown in Figure 53. 
221. The required final product is a single stage-frequency curve for 
the combined hurricane- and northeaster-induced water level. This combined 
frequency curve was obtained by adding the exceedance probabilities of hurri- 
canes and northeasters at each stage increment. Combined regressed frequency 
curves for gages 6 and 12 are shown in Figures 69 and 70; curves for all 20 
numerical gages are presented in Appendix G. 
222. The combined stage-frequency curves discussed above do not in- 
clude any additional still-water level increase due to wave setup or wave 
crest overtopping. Most channels within the river system are narrow and do 
not provide adequate fetch lengths for these processes to occur. However, the 
upper reaches of the Navesink and Shrewsbury basins are susceptible to such 
wave impacts. Standard methods given in the SPM (1984) were applied to esti- 
mate the maximum wave setup and wave crest elevation that can be expected in 
these areas. Results for these estimates are shown in Figures 71 and 72 for 
numerical gages 15 and 18. 
130 
