2 Summary of Acting Coastal 

 Processes 



This chapter contains a summary of acting coastal processes at the 

 Monmouth Beach erosion hot spot. An analysis of directional wave data col- 

 lected at Long Branch, New Jersey is presented, as well as a description of beach 

 sediments, information about vertical datums, and a description of beach-profile 

 adjustment. 



Long Branch Gauge Analysis 



This section presents statistical information derived from directional mea- 

 surements of waves at Long Branch. New Jersey. The Long Branch gauge 

 (40.30° N, 73.97° W) is located approximately 2.7 km south of the hot spot at 

 Monmouth Beach at a water depth of 10 m. A slope array, deployed by CHL for 

 the New York District in 1994, was replaced with a directional wave gauge 

 (DWG) in July 1 995. Directional wave data are collected at a rate of i Hz for 

 1,024-sec-long bursts. Bursts of data are collected hourly during stonn condi- 

 tions and at 4-hr intervals during calmer wave conditions. Peak energy-based 

 wave height (//„,„), period, and direction are determined and recorded for each 

 data burst. 



Wave periods and directions are not recorded for conditions in which the 

 measured wave height is less than 0.2 m. Gaps in the wave record exist because 

 of instrument failure and malfunction (approximately 23 percent of gauge 

 deployment) with extended gaps in the data occurring between mid-November 

 1994 to mid-July 1995 and October 1 996-February 1997. A summary of 

 statistical parameters derived from the DWG measurements from January 1994 

 to March 1998 is presented in Table 1. A statistical description and tabular 

 summar>' are presented in Appendix A. 



Table 1 



Wave Statistic Summary 





Season 



Ha.g, m 



H„a«, m 



Tmode, sec 



e^o* 



Spring 



0,68 



4.1 



8.5 



SE 



Summer 



0.62 



2.6 



8.5 



SE 



Fall 



0.72 



4.2 



9.5 



ESE 



Winter 



0.76 



3.9 



9.5 



ESE 



Total 



0.69 



4.2 



8.5 



ESE 



Chapter 2 Summary of Acting Coastal Processes 



