Let us assume shape of well is like a solid circular cylinder

Radius of cylinder, r = 2/2 = 1m

Depth(height) of well, h = 14m

Volume of right circular cylinder, V’ = π r² h

---------(I)

Given that, length of embankment, l = 40 cm

Let width of the embankment be x m

Volume of the embankment, V’’ = π r² h

= π ((1+x)² – 1)² x 0.4 -----------(II)

Since well is spread evenly to form the embankment, so their volumes, V’ = V’’

⇒ π × 14 = π ((1+x)² – 1)² x 0.4

⇒ x = 5m

∴ Height of the embankment, x = 5cm