When the floodway is obstructed by buildings, structures, or debris, flood waters will be dammed up and will flood even greater areas upstream.
(the floodway; is obstructed; by buildings, structures, or debris) (flood waters; will be dammed up; T:When the floodway is obstructed by buildings, structures, or debris) (flood waters; will flood; even greater areas; upstream; T:When the floodway is obstructed by buildings, structures, or debris)
the floodway flood waters flood waters
is obstructed will be dammed up will flood
by buildings, structures, or debris
T:When the floodway is obstructed by buildings, structures, or debris
even greater areas upstream T:When the floodway is obstructed by buildings, structures, or debris