In the mid-1980s, the most vulnerable areas of the riverbank were protected by rock "riprap" and special jetties designed to minimize erosion.
(the most vulnerable areas of the riverbank; were protected; by rock "riprap" and special jetties; L:In the mid-1980s) (special jetties; designed; to minimize erosion)
the most vulnerable areas of the riverbank special jetties
were protected designed
by rock "riprap" and special jetties L:In the mid-1980s
to minimize erosion