**3. Scour around Bridge Foundations**

Comprehensive studies on the variables controlling the maximum scour depth have been conducted since the state-of-the-art paper by [28]. The available information mostly corresponds to the case of scour in sand, with few exceptions for cases of scour in fine sediments [29–32] and gravel bed rivers [33–38]). Further, researchers have concentrated on the dynamics of scour [39–42]. A detailed description of the functional relationships between scour and its controlling variables [43,44] are out of the scope of the present paper. In this section, we focus on scour patterns.
