Evaluation of Bank Protection Methods

The design of riprap protection for channel banks is based on empirical and semi-analytical methods. In this paper, alternative methods of riprap sizing are presented. In practice, the design value is selected by judgment within the range of values computed by different methods. The design of riprap protection at the bank toe is based on potential scour depth in the channel in the immediate vicinity of the bank toe. Alternative methods of estimating channel bed scour are included. The estimated scour depth is used to design a launching apron for the protection of riprap at the bank toe. The design procedures are illustrated by field examples. As additional means of bank protection, conceptual measures are described to direct the main current and erosive forces away from the vulnerable portion of the channel bank.