River and Canal Engineering, the characteristics of open flowing streams, and the principles and methods to be followed in dealing with them.

by E. S. Bellasis

Fig. 14.

Fig. 15.

Sometimes the pitching or loose stone is not carried up to the top of the bank, or even up to high flood-level, and the bank above the pitching is protected by turfing—the pieces of turf being placed on edge normally to the slope if very steep ([fig. 14]) or laid parallel to the slope if it is not very steep—or, above ordinary water-level, by plantations of osiers or willows which obstruct the water and tend to cause silting, and whose roots bind the banks together.

Fig. 16.

Another method of using fascines is to lay them on the slopes with their lengths normal to the direction of the stream. The upper end of a fascine is above low water, and the lower end extends down to the bed of the stream. Sometimes large ropes made of straw, or rough mats made of grass, are laid on the slopes and pegged down, or mattresses of fascines are laid on the slopes and weighted with stones.

Fig. 17.

A deep recess in the bank ([fig. 16]) can be filled in, before the protection is added, with earth well rammed. On the Adige the filling material consisted ([fig. 17]) of faggots filled with stones, small cross dams being made at intervals, as shown by the dotted lines, to arrest flood water and cause it to deposit silt. At the back of the berm, poplar or willow slips were planted, and these grew up and their roots held the bank together. This system succeeded well.