NEORSD installed the 18 inflatable rubber gates between 1974 and 1981.
NEORSD originally considered replacing the seven gates that failed with traditional steel gates, but aside from the manufacturing defect, the inflatable gates had performed according to specification.
NEORSD was aware that Bridgestone/Firestone (Nashville, Tennessee) had introduced ExpanGate, a product similar to the original inflatable rubber gates, and that two had been installed in Detroit in 1987.
NEORSD chose stainless steel bolts and galvanized plates, a decision based on economics.
NEORSD contracted with local firms for the gate installation.
The operation of the automated regulators, remote flow and level monitors, and rain gauges is monitored and coordinated from NEORSD's Central Sewer Control Facility.
This proved to be too long for NEORSD, so the first gates installed are kept inflated to one psi for four hours, then completely deflated for one hour.
So far, NEORSD has not operated its gates in the fully closed position even though both types are in the system.