​AUR Flume Test for Pier with Armor (Czech Hedgehog) Units:

As expected, the scour occurs at the pier nose and is developed around the nose due to the horseshoe vortices, which might cause the loss of armor unit foundation. Therefore, the armor units (Czech Hedgehog) under the bed level are exposed. 

The armor (Czech Hedgehog) units are not able to prevent the scour.

Before Flume Test

Unsuccessful Armor (Czech Hedgehog)

Units Countermeasure