Three kinds of toe walls are shown in [Figures 17], [19] and [20]. The kind shown in [Fig. 19] contains, for a given depth below the bed, far more masonry than the one shown in [Fig. 17]. It is also liable to be displaced and broken if scour occurs.
Fig. 20.
The earth should in all cases be carefully cut to the proper slope, so that no made earth has to be added. If the slope has already fallen in too much, well rammed earth should be added. The flat brick and rammed ballast can be varied as the work proceeds, more being used in soft places and less in hard.
In some parts of the Punjab, large bricks, the length, breadth, and thickness being about twice the corresponding dimensions of an ordinary brick, are made, and are extremely useful and cheap for pitching. Where the soil is sandy such bricks can be burned without cracking.
Sometimes the curtain wall which runs across the bed at the downstream end of the pitching is carried into the banks and built up so as to form a profile wall ([Fig. 21]). This is not very suitable, because the pitching of the sides is apt to settle and leave the profile wall standing out. It is better to lay a row of blocks on the slope. If a hole tends to form in the bed downstream of the curtain wall, blocks of masonry or concrete can be laid and left to take up their own positions ([Fig. 22]).
Fig. 21.
Fig. 22.