data and interpretations contained in Appendix D. In recent years, the rate 
of shoreline change on this highly protected coast has been low, but exhibit- 
ing a tendency for erosion. As an example, the average recession rate along 
the project reach in the time interval 1953-1985 was 0.17 m/year (Table D-18). 
The recession rate is low because the beach has effectively retreated to the 
seawall along much of the reach. For specific sections with existing sandy 
beaches, such as the northern portion of Sea Bright and north Long Branch, the 
recession rates in the same time interval were 0.84 and 1.18 m/year, respec- 
tively. These rates of shoreline retreat are comparable to historic rates 
existing prior to the modern era of significant shore protection. For exam- 
ple, Table D-7 shows that the average shoreline recession rate for the period 
1836-1932 was 0.85 m/year, with several sections of the coast experiencing 
rates twice the average. Based on these and other data contained in Appen- 
dix D, the potential rate of shoreline recession can estimated to be on the 
order of 1 m/year. The potential rate applies to a sandy beach; for the 
numerous areas where the beach has eroded to the seawall, the recession rate 
will approach zero. 
31. Other reports. Two unpublished reports (PRC Harris, Inc. 1980; 
Farrell 1981) also contain longshore sediment transport rate analyses. PRC 
Harris developed longshore transport rate estimates for Manasquan Inlet using 
four methods: adoption of best known rate at a nearby site, historical 
changes in topography, wave energy flux, and an empirical predictive method. 
Although some lower transport rates were obtained, most calculations for vari- 
ous time periods resulted in rates of 300,000-400,000 cu yd/year, and this 
range of values was recommended for sand bypassing design. 
32. The report of Farrell (1981), based on original analysis of pre- 
and post-survey dredged volumes measured during the interval 1968-1980 for 
Manasquan Inlet and Shark River Inlet, presents longshore sediment transport 
rates much lower than other estimates. The annual rate for the recent 13-year 
period is 22,200 cu yd/year. Farrell compared his results with those of PRC 
Harris (1980) and discussed possible reasons for the order of magnitude dif- 
ference. It is noted that transport rates calculated using the shoreline 
change numerical model developed in the present report (Part IV) lie between 
the rates determined by Caldwell (1966) and Farrell (1981) 
33. Sea level rise. The scope of this study did not include an 
investigation of sea level rise. Based on data from the Sandy Hook tide gage 
22 
