Before the present system of levies was constructed, heavy spring floods would cause the river to overflow its banks.
(the present system of levies; was constructed; ) (heavy spring floods; would cause; the river to overflow its banks; T:Before the present system of levies was constructed) Context(heavy spring floods would cause,List([53, 84))):(the river; to overflow; its banks)
heavy spring floods would cause,List([53, 84))
the present system of levies heavy spring floods the river
was constructed would cause to overflow
the river to overflow its banks T:Before the present system of levies was constructed
its banks