A National Historic Mechanical Engineering Landmark

In 1888, E. P. Allis & Company built and installed a horizontal screw pump of a unique design by Edwin Reynolds, the largest in the world when set into operation. It faced a task also unique: Flushing the Milwaukee River.

Flushing Pump

E.P. Allis Co. pioneered the large axial flow pump with the installation of the Milwaukee River flushing station.

In 1888 the population of Milwaukee was rapidly approaching 200,000 and the city had nearly 165 miles of sewers. With much of the sewage flowing directly into the Milwaukee, Menomonee and Kinnickinnic Rivers the odor was extremely unpleasant. Resentment increased as the populace recognized the public health danger of sewage flowing through the most populous section of the city. To remedy this problem it was proposed that lake water be pumped into the Milwaukee River to increase the flow rate and flush the river. Although some of the greatest engineers in the country condemned his plans, most Milwaukeeans trusted Reynolds, and he was commissioned to provide the pump for the project.

Reynolds proposed a “screw’ pump with an impeller fourteen feet in diameter and a hub of six feet, a configuration now referred to as axial flow. It was driven by a vertical compound engine at fifty-five revolutions per minute, with a capacity at that speed of over 40,000 cubic feet of water per minute. Mr. Reynolds had originally developed the idea of the screw pump many years earlier when he built a very small pump for raising a wrecked steamer on the Ohio River.

The Milwaukee screw pump approached very nearly to plunger or piston pumps in efficiency, performing about double the amount of work with the same fuel and costing half as much as centrifugal pumps adapted for the same service. It exceeded the contract capacity of 500,000,000 gallons in twenty-four hours, pumping a greater quantity of water than any other such machine in the world. The new pump eased the situation in Milwaukee until the City built an elaborate intercepting system to pump the sewage one thousand feet into the lake.

Sectional View

Sectional view

In 1912 the original steam engine and four fire-tube boilers were replaced with an electric motor.

During 1955, a large tree stump found its way into the impeller chamber, badly damaging the pump. Two blades were damaged beyond repair and were removed. After repairs the two blades were salvaged, and operation resumed. Depending upon dissolved oxygen levels in the River, the pump ran more than another twenty-five years for two to five days a week and from 8 to 16 hours a day

The need for the Milwaukee River pump has passed, as improved sanitation and pollution control along the river has lead to cleaner water. The pump house still exists on Lincoln Drive, where it now houses an Alterra coffeehouse. The pump room is still maintained by the Milwaukee Metropolitan Sewerage District as an education center.

In 1952, the pump was designated a National Historic National Engineering Landmark. Read the commemorative brochure (pdf 8483kb) which further describes the station, its operation, and history.