Evanston aldermen this week approved spending $86,000 to come up with a cost-efficient long-term strategy for storing water at the city's water plant.
The vote came despite complaints from two residents that the study was unnecessary.
Barbara Janes of 802 Colfax St. and Junad Rizki of 2784 Sheridan Rd. both aregued that the city had conducted enough studies and should simply take the lowest-cost short-term solution and repair the roof of the existing reservoir.
But Richard Lanyon, of 1019 Mulford St., the chair of the city's Utilities Commission, said
the study would be money well spent "to integrate the prior studies and provide guidance to the city on the replacement of this vital infrastructure."
Utilities Director Dave Stoneback said repairs now could extend the life of the 80-year-old reservoir for perhaps 20 years, but that it would then have to be fully replaced.
Estimates for repairing the roof have run around $4 million, while a full replacement has been estimated to cost about $26 million.
And Stoneback says borrowing costs are very low now, and may be higher in 20 years.
An image from a 2012 report of the interior of the reservoir while it was drained for the study.
In addition to the 5 million gallon reservoir under a Northwestern University parking lot off Lincoln Street, the city has a collection of eight clearwells at the water plant, some dating back to 1913, which provide an additional 4.4 million gallons of storage.
A 2010 engineering study indicated that the oldest of the clearwells need extensive repair work. Studies in 2012 and 2013 revealed extensive cracking in the roof of the reservoir and recommended that it be repaired or replaced within five years.
Stoneback said the total reservoir capacity is now considered adequate — but that because not all the water can be pumped from the reservoir and it's generally not filled to capacity — the city could run out of water in the event of an extended production shutdown.
In recent years the city has on occasion had to reduce water production when icing conditions partially blocked the intake pipes in Lake Michigan.
While Rizki has repeatedly claimed that city officials are planning to find a new location for the reservoir to be able to return the property to university control, Stoneback, in response to a question from Alderman Coleen Burrus, 9th Ward, said the university has not asked him to move the tank.
"I anticipate that there weill always be a city water reservoir on that property," Stoneback added.
Alderman Delores Holmes, 5th Ward, said she supported the study because "we have to think beyond 20 years in terms of preserving our water system in the city."
Vote postponed on reservoir study (3/25/14)
Quinn offers hope for reservoir cash (2/27/14)
City makes case for new reservoir (10/28/13)