Q. Evaluate dimensions of apron according to Spring and Gales?

Dimensions of apron according to Spring and Gales. Gales and Sethi favoured uniform thickness of laid apron while Spring advocated tapered design. Spring's design has been found deficient near the toe and hence uniform thickness appears superior. Sethi has omitted berm but recommended extension of soling for 3 to 6 m beyond. Width of apron when laid equal to 1.5 times the depth of scour below riverbed has been found to permit satisfactory launching. Since apron is assumed to launch on a side slope of 2:1, the thickness of apron when laid is given by 'quantity of apron' / 'width of apron laid.'