Milwaukee Journal Sentinel
Dec. 20, 2018
Just four years before Waukesha plans to make the switch to a Lake Michigan water supply, the city will be spending up to $325,000 in 2019 to rebuild or replace the motor of its highest-capacity well pump.
The emergency repair comes two years after the same motor — one of the largest submersible units in the world at 700 horsepower — was rebuilt, and it is the latest in a frequent and costly series of well pump malfunctions to hit the city before it can receive lake water from Milwaukee.
The Waukesha Water Utility Commission meets Thursday to declare an emergency and authorize installation of a smaller spare motor so that well No. 10 can operate at half-capacity for the six months needed to either repair the old unit or replace it, Water Utility General Manager Dan Duchniak said.
Well pump motor failures have become increasingly common, an average of one a year since 2007, as the utility continues to draw groundwater from a sandstone aquifer several hundred feet beneath the surface, Duchniak said.
Well 10 pulls water up from a depth of 600 feet. After fixing this well’s motor for the fifth time since 2007, the city will have spent about $2.5 million in 11 years on all pump motor repairs.
Motors that should operate five years are breaking down after just two or three years of heavy use and that is one reason the utility intends to stay on schedule for building the pipes that will bring Lake Michigan water to Waukesha by April 2023, Duchniak said.
Waukesha is dependent on three deep wells pumping groundwater contaminated with radium out of sandstone aquifers to provide up to 85% of its supply. Three shallow wells also are used.
In June 2016, delegates to the governors of the eight Great Lakes states unanimously approved the city’s request for a Lake Michigan water supply so it could halt use of the groundwater wells. The states agreed Waukesha groundwater supply was not sustainable and that it did not have a reasonable alternative to the lake.
The utility will be able to provide the city’s winter season water needs of 5.2 million gallons a day and continue to meet federal limits on radium in drinking water by using other available wells, according to Duchniak.
Well 10 will be shut down Jan. 2 and should be restarted at half capacity by the end of the month.
The 700-horsepower motor in that well powers a pump that provides up to 3.8 million gallons of water a day, or 63 percent of the city’s average daily demand, Duchniak said. Water from the well is treated to remove radium.
The pump’s motor was repaired two years ago after a malfunction in 2016 and utility records show it was rebuilt in 2013, 2011 and 2009.
In November, well No. 8 was shut down for 15 days after a pump failure.
Well 10’s motor was tested in early December after two separate electrical faults temporarily prevented workers from restarting it, according to a report to the Water Utility Commission. The motor operates 24 hours a day now to avoid the need to restart it and prevent a possible failure.
The Milwaukee and Waukesha common councils last year approved a 40-year agreement that will pipe Lake Michigan water across the subcontinental divide to Waukesha beginning in 2023. Milwaukee will deliver up to an average of 8.2 million gallons a day by mid-century, under the agreement.
Connecting to Milwaukee’s water supply and returning fully treated wastewater to the Root River, a lake tributary, will cost an estimated $286.2 million.