70 ILCS 615/3

No more of the water of the Des Plaines river shall be diverted by any such cut-off than the excess above the ordinary water mark in said stream. At the point of diversion there shall be constructed and maintained such dams and sluices as shall control and regulate the amount of such diversion at all times. During dry weather no water shall be diverted into Lake Michigan and during floods no more water shall be allowed to pass said point of diversion down the river than three thousand (3,000) cubic feet per second.