The upstream slope of the dam is protected by soil cement and the downstream slope is protected by a 12-foot horizontal layer of topsoil and grass.
(The upstream slope of the dam; is protected; by soil cement and the downstream slope is protected by a 12-foot horizontal layer of topsoil and grass) (the downstream slope; is protected; by a 12-foot horizontal layer of topsoil and grass)
The upstream slope of the dam the downstream slope
is protected is protected
by soil cement and the downstream slope is protected by a 12-foot horizontal layer of topsoil and grass
by a 12-foot horizontal layer of topsoil and grass