Case study 1 Flashcards
(23 cards)
What was the objective of the Estuary study?
To assess how wind and ship waves affect hydraulic forces on dikes, sedimentation and erosion patterns, and ecological health.
location
Scheldt Estuary (Belgium/Netherlands).
key idea:
Wind waves: dominate near the mounth of the estuary
ship waves: dominate in the mid/upstream estuary
What wave type is dominant at Hoge Plaat?
Wind waves.
What wave types affect Saeftinghe?
Wind and Ship waves.
What wave types affect Rupelmonde and Dendermonde.?
inland shipwaves
What sensors were used ?
Pressure Sensors (20 Hz).: water level
aquadopp adcp: flow velocity profiles every 10min
sed sensors: daily sedimentation/erosion measurements
What was the campaign duration per site?
2–4 weeks including spring-neap cycle.
What is the site layout?
2 cross-sections, deep channel on left, undeep secondary channel
What are the steps in data processing?
Atmospheric pressure compensation
conversion to TAW
correction for pressure attenuation
low-pass filtering
Wave characterization
What does low-pass filtering do?
Removes long-period tides, isolates short-period wave signals.
What wave parameters were calculated?
H₁/₃, Hmax, Period, Frequency Spectrum.
What was the dominant wind wave frequency?
0.4 Hz (~2.5–3 s period).
What was the maximum wind wave height observed?
1.5 m at Hoge Plaat.
What are primary ship waves?
Sudden drawdown & rebound caused by water displacement (seegoing vessels)
What are secondary ship waves?
Turbulent waves following ships, occur at all sites.
How were events isolated?
No ships =isolate wind
one ship = isolate ship waves
multiple ships = discard due to interference
Where were primary waves observed?
Only at Saeftinghe & Hoge Plaat.
Where were secondary waves observed?
At all sites.
Where were wind waves strongest?
At Hoge Plaat.
What is the trend of wave impacts inland?
Wind wave impact decreases, ship wave impact increases.
What was a key ecological finding?
Ship wave events caused sediment movement and marsh erosion.
What is the main conclusion of the wave impact study?
Waves affect safety, sediment, and ecology in the estuary.
