For many people an overtopping discharge is simply a figure without any physical feeling. This is not very surprising as real overtopping is random in time and with different individual overtopping volumes. Now, testing with the wave overtopping simulator at real dikes (see Section 4.8 of the Manual) has made it possible to simulate mean overtopping discharges for all kind of wave conditions, and to video the results.
These videos have been prepared in the following way. In total 18 conditions were prepared, being for mean overtopping discharges of 1; 5; 10; 30; 50; and 75 l/s per m and for wave heights of Hm0 = 1; 2; and 3 m. Each distribution of overtopping wave volumes was calculated for a smooth 1:3 slope, wave steepness of sop = 0.04 and duration of 1 hour. The simulation of overtopping events by the overtopping simulator was by choosing randomly volumes from the distribution. Then the first three minutes of the steering file of one hour was taken, simulated and the test was recorded on video. We judged that a video of three minutes would be long enough to give a good impression of a mean discharge, coupled to a certain wave height.
Videos were recorded from two locations, one beside the lower slope looking upwards and one next to the wave overtopping simulator looking downwards.
Besides taking three-minute videos, specific overtopping wave volumes were captured, from 100 l per m up to 3000 l per m. In summary the following videos were prepared for the website:
Three-minute videos looking up-slope, with the distribution of overtopping wave volumes
Three-minute videos from the crest of the dike looking downwards
For conditions:
Hm0
= 1 m; 2 m and 3 m
and:
q
= 1; 5; 10; 30; 50 and 75 l/s per m
Individual overtopping wave volumes of 100; 150; 200; 250; 300; 400; 500; 600; 700; 800; 1000; 1200; 1400; 1600; 1800; 2000; 2250; 2500; 2750 and 3000 l per m.
The objective of making the videos available is that people interested in wave overtopping may get a clear view of a given mean overtopping discharge. Moreover, the videos can be used alongside guidance in the manual to make a judgement on whether these overtopping discharges can be tolerated, depending on the actual situation. It should be noted that wave heights larger than 3 m always give large overtopping wave volumes if the mean discharge exceeds 1-5 l/s per m. These volumes exceed the capacity of the wave overtopping simulator and videos for these circumstances could not be made.