A series of large-scale experiments are conducted at HR Wallingford. Froude scaled tsunami waveforms are produced with periods (T) in the range of 40 – 230 s and wave amplitudes (a) between 0.03 - 0.14 m in water depths of 0.5 – 1.0 m.
The waves propagate over a 1:30 sloping bathymetry that extends onshore over which their runup is recorded. The obstacles are represented by circular cylinders (wooden dowels). Variation in diameters (D) from 0.05, 0.08 and 0.1 m and coverage inland (relative to the incident shoreline) of 1 – 2 m (Figure 1).
Results show that relative to a smooth slope, these configurations can reduce normalised runup (R/a) by < 20% for T < 100 s. For T > 100 s R/a shows no appreciable reduction compared to the smooth slope. For certain combinations of obstacle geometry and T, a small increase in R/a is observed.
