Clean Water:

Metro Water Search: More Than a Divining Rod

Topic: Clean Water

When the Minnesota Legislature approved $400,000 in funds from the Clean Water, Land and Legacy Amendment this year for metro water supply planning, it was trying to stave off a crisis that might not occur for a generation or longer. The fundamental issue: how will communities in the seven-county region find adequate water for 1 million new residents, about as many people as currently live in Denver, by the year 2030?

The answer lies underground. With the notable exception of Minneapolis and St. Paul, most metro communities obtain water for drinking, industry and other purposes from groundwater. Because it’s out of sight, this resource requires careful monitoring to determine enough water is available in the right places to accommodate expected population growth.

The funds provided by the Legacy Amendment supplement a larger amount of money spent by the Metro Council to draft the master water supply plan over the last four years.

“The Legacy funding will help fill in some gaps in our data,” says Chris Elvrum, the Council’s manager of water supply planning. Among other projects, he says the Minnesota Geological Survey will map glacial deposits that can be a source of water in some areas of the region. Communities in the metro’s western suburbs have “limited” choices on where to increase water pumping and the MGS study will provide critical information on that topic.

In addition, Metro Council is in the process of analyzing the base flow of area rivers and streams – to determine how much groundwater empties into them and what the effects would be on the streams if that amount was increased. That and other data and will be incorporated into a sophisticated computer model of all groundwater aquifers in the area.

As of 2004, 110 municipal water suppliers served 123 communities. In 2004, nearly 2.5 million residents received their water through a municipal system, while approximately 290,000 residences relied on private wells. In 2004, an average water demand year, the metropolitan area used approximately 520 billion gallons of water. While power generation accounts for about 350 billion of these, only about 1% of the water used for power generation was actually consumed; the remaining 99% was returned directly to the source from which it was obtained

Elvrum says there is no danger that the metro’s aquifers will run out of groundwater in the foreseeable future, but in some southwestern suburbs, groundwater levels could sink 30 to 40 feet by 2050 if current practices and population growth continue. In this and other areas, declines could have adverse impacts on surface water features. The plan lays out steps including monitoring and development of supply options to ensure these impacts are avoided.

The plan details demand management strategies that communities can employ to help offset local water supply limitations to reduce the potential declines, . These include:

    * Summer sprinkling restrictions
    * Leak detection and repair
    * Conservation education
    * Topsoil requirements
    * Turf area limitations

These practices are likely to become standard as supply issues increase, Elvrum said.

A copy of the draft metro water supply plan and other information is available here.

Metro Water Search: More Than a Divining Rod

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