Waukesha defends water use projections in Lake Michigan diversion bid

By Don Behm of the Journal Sentinel

Forecast increases in water use by local industries over the next 40 years is the primary reason Waukesha cannot reduce the volume of its Lake Michigan diversion request, city water utility officials said Thursday in a report delivered to the state Department of Natural Resources.

Industrial customers currently make up 13% of annual demand so any change in water use by even a small number of them could have a major impact on the city's water needs, the report says.

Overall, industries are projected to boost water demand by 1.2 million gallons a day by 2050, according to the report by consultant AECOM.

So the city's request to divert up to an average of 10.1 million gallons a day from Lake Michigan by mid-century will not change, Waukesha Water Utility General Manager Dan Duchniak said Thursday.

The consultant's analysis was done in response to a Dec. 3 letter to Duchniak from DNR officials. In the letter, the department asked Waukesha to justify its projected water needs or revise volumes in the diversion request.

The city's population is forecast to grow 36% by midcentury, from 71,797 in 2012 to 97,400 in 2050, diversion request documents said.

Water use is projected to increase 45% in the same period, from an average of 6.95 million gallons a day in 2012 to 10.1 million gallons a day in 2050.

Additional analysis determined the 10.1 million gallons a day is an appropriate forecast for planning purposes, according to the new report.

A revised diversion request submitted to the DNR in October already cut the city's projected water needs by 7.3%, down from an estimated average of 10.9 million gallons a day, included in the May 2010 draft request.

Residential and other customers will reduce water demand by 10% — about 1 million gallons a day — by midcentury through conservation measures, Duchniak said.

The Wisconsin DNR is reviewing the city's application. Should the department decide the request complies with all requirements of a 2008 Great Lakes protection compact, it would be sent to the other Great Lakes states for review and a vote.

The compact requires unanimous approval of the eight states. If the request is approved, Waukesha would stop using deep wells drawing radium-contaminated water from sandstone.

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About Don Behm

Don Behm reports on Milwaukee County government, Milwaukee Metropolitan Sewerage District, the environment and communities in southeastern Wisconsin. He has won reporting awards for investigations of Great Lakes water pollution, Milwaukee's cryptosporidiosis outbreak, and the deaths of three sewer construction workers in a Menomonee Valley methane explosion.

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