Table 2. Shoreline Undulation Wavelengths
Date of survey/
Shoreline Undulation Wavelength (m)
st
nd
rd
photography
1 Peak
2 Peak
3 Peak
Photo Interpreted HWL Data
December 1979
1090
1705
NA
April 1983
1705
1110
NA
March 1988
1350
1090
2560
April 1995
1045
1830
NA
GPS Survey Data
August 1993
3010
1970
1220
September 1994
1045
1830
1465
August 1995
1045
1830
NA
November 1996
2050
1315
980
January 1997
2135
1315
1090
May 1997
1385
1090
NA
September 1997
1310
1065
NA
Individual Wave Analysis
This section discusses an analysis of individual undulations that was performed to obtain
statistical estimates of the seaward and landward amplitudes as well as the total shoreline
undulation "height" (Fig. 4). The seaward and landward shoreline undulation amplitudes
become important in evaluating the impact anticipated shoreline undulations would have
on typical beach fill design plans. The shoreline undulation data were processed using a
zero up-crossing analysis routine that employed a minimum 5-meter seaward or landward
amplitude threshold. That is, shoreline undulations with less than a 5-meter seaward or
landward amplitude were considered in the noise range and did not enter in the statistical
calculation of the shoreline undulation amplitudes. Root mean square (rms), significant
(average of the largest third), and 1/10th (average of the largest tenth) amplitudes were
computed for each data set. The results of the individual wave analysis are summarized
in Table 3. The data in Table 3 indicate that the average rms
Table 3. Shoreline Undulation Amplitudes
Date of survey/
Shoreline Undulation Amplitudes (m)
photography
total " eight"
h
seaward
landward
rms
1/3
1/10
rms
1/3
1/10
rms
1/3
1/10
Photo Interpreted HWL Data
December 1979
21
30
40
12
17
26
10
16
20
April 1983
34
48
59
19
28
38
18
27
41
March 1988
27
39
51
14
21
31
14
20
27
April 1995
35
49
60
20
29
39
18
25
32
GPS Survey Data
August 1993
20
30
37
10
15
18
13
20
31
September 1994
18
25
31
10
14
17
10
14
19
August 1995
37
53
65
21
31
42
19
27
38
November 1996
26
36
45
14
20
26
15
21
34
January 1997
23
31
39
13
18
25
12
17
22
May 1997
20
27
31
11
15
20
11
15
22
September 1997
25
33
43
16
22
31
11
15
18
All Data
Average
26
36
46
14
21
28
14
20
28
Standard Deviation
6
9
11
4
6
8
3
5
8
Gravens
8
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