Analysis
Waves were sampled during all tests. After completion of a test, the data files
were analyzed for the time- and frequency-domain characteristics of the
measured waves and velocities. Summary plots of wave and current time-series
and tables of summary descriptive parameters were produced. Damage to the
structure was monitored during testing. After each test, photos were taken and
damage summaries compiled. The changes in profile of the sediment-control spur
were measured intermittently.
Analysis of waves and currents
Standard Generalized Data Acquisition Package (GEDAP) spectral and time-
domain analysis programs were used to analyze the waves measured in the
model. Details are provided in Davies (2001, Section 6.1). Current measurements
were made for Test Series D onwards. Data are summarized in Davies (2001,
Appendix 3) in terms of mean, maximum, and minimum velocities measured at
Gauge 1 (center of water column at center line of spur) and Gauge 2, 2 m
landward of the spur.
Damage
Damage was measured by visual analysis of stone (or geobag) mobility,
supported with both video and digital still photography. Stone counts were made
in two ways:
a. The number of stone movements observed during a 100-wave interval
was recorded to provide an estimate of the average number of stones
moving per wave. This was performed over the entire test section so the
stone counts provided in this report represent stone movements that
would occur over a 40-m-wide section of the sediment-control spur in
nature.
b. The total number of stones removed from the structure was counted at
the end of each test segment. This number is reported as a total for the
40-m-wide section of the spur being tested in the flume.
Overview of Test Program
The test program started on 16 January 2001 and continued through
23 February 2001. Approximately 160 tests were run on seven test configurations
(Davies 2001, Section 6.1). Configurations are identified by a letter, A through
G. The test series are summarized in Table A3.
A sequential test log and detailed description of the tests and associated
results are presented in Davies (2001). Results presented relate to stability and
stone mobility, structure-seabed and structure-sand interactions, geobag stability,
influence of offshore bathymetry on wave field and structural stability, and wave
transformations and transmission.
A21
Appendix A
Stability Analysis of a Submerged Spur, North Jetty, Grays Harbor, WA
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