An earthen embankment of trapezoidal cross-section, having top width B, and height d above ground level with a side slope z : 1 (horizontal : vertical) is to be formed on one bank of a river for flood protection, for a length L. It is proposed to provide turfing over the embankment. The surface area of turfing the embankment will be:
1
\(\)L(B + 2d\(\sqrt{z^2 + 1}\))
2
L(B + 2 z d)
3
L(B + 2d\(\sqrt{z + 1}\))
4
2 L(B + d\(\sqrt{z^2 + 1})\)