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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

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April 2006

Using groundwater

Wisconsin is water-rich.

Natasha Kassulke and Laura Chern


Getting a clean glass of water isn't as easy as turning on the tap!
The worth of water | Thirsty cities
A fluid economy | Wet and wild | Aquaculture?
Map of agricultural irrigation in Wisconsin

When it comes to water, there is no place like Wisconsin. We are water rich. Between the mighty Mississippi River and the Great Lakes of Michigan and Superior, there are more than 15,000 lakes, 7,000 streams and five million acres of wetland. And that just scratches the surface. Below our feet Wisconsin has a buried treasure – 1.2 quadrillion gallons of groundwater. It is hard to grasp just how much water is stored underground unless you look at how much we use every day.

Daily groundwater use
(From USGS statistics estimates)
Municipal drinking water (all uses) 330 million gallons/day
Commercial/Industrial use 256 million gallons/day
Livestock 100 million gallons/day
Irrigation (summer only) 182 million gallons/day
Home use 205 million gallons/day
TOTAL 1,073 million gallons/day

Each year about 29 trillion gallons of water fall as rain or snow on Wisconsin's 36 million acres. Plants and animals consume some, some is returned to the atmosphere by evaporation and transpiration by plants, and some flows into rivers, lakes and streams. The rest becomes groundwater by seeping through the soil and into groundwater aquifers.

If you could somehow pour all the water below ground on top, you'd need to trade in your ranch house for a houseboat: Wisconsin's bountiful groundwater could cover the whole state to a depth of 100 feet!

Getting a clean glass of water isn't as easy as turning on the tap!

Contents

In Wisconsin, the quality and quantity of groundwater varies from place to place. The difference is caused by a combination of geology, varying precipitation and use. Cities and towns in the north central and northeastern third of Wisconsin receive the most precipitation in the state, but they are underlain by crystalline bedrock, a type of rock formation notorious for yielding only small quantities of water. Even though there may be plenty of rain, finding enough groundwater to supply municipalities in these regions can be difficult.

Groundwater levels have been going down by hundreds of feet around some of Wisconsin's growing metropolitan areas.

At last estimate, there were more than 850,000 private wells in the state. In areas where water moves through aquifers very slowly, private wells can still yield enough water for residential use. You can drill a hole just about anywhere in Wisconsin and find water. But is this water drinkable? Groundwater can be contaminated in several ways, which you'll read about here. But you'll also read about how you can take action at home to protect Wisconsin's buried treasure.

The worth of water

In Wisconsin, about three-fourths of us draw nearly 205 million gallons of groundwater daily at home to slake thirsts, scrub pots, boil spaghetti, and shower. Per person, that's 55 gallons of groundwater per day.

How do you use Wisconsin's ample buried treasure?

Personal water use averages 55 gallons a day. © Robert Queen
Personal water use averages 55 gallons a day.

© Robert Queen

Fifty-five gallons of groundwater per person per day may not seem like much, but there are hidden costs for excessive water use. Your community may have to install new wells or water and sewer pipes to accommodate increasing demand. Pumping more water from private or public wells requires more energy, which costs more money. Treating used water (referred to as "wastewater") to stringent standards of purity strains every budget.

Thirsty cities

It's used to fight fires, clean streets, fill the local pool, sprinkle golf courses and parks, drench shade trees, supply commercial customers and satisfy the needs of thirsty residents at home or at bubblers (drinking fountains, to non-Wisconsinites) around town. Ninety-seven percent of Wisconsin's cities and villages count on groundwater to provide basic water-related services often taken for granted.

The top counties and main users:

  • Dane County (Madison) area, 48 million gallons per day
  • Waukesha County (City of Waukesha), 27 million gallons per day
  • Rock County (Janesville and Beloit), 20 million gallons per day
--(USGS statistics estimates)

The average daily cost to a family of four in 2005: between 26 and 35.2 cents – an increase only a few cents since 1983 when "Groundwater" was first published.

A fluid economy

Water is vital to Wisconsin's economic health. It's part of countless manufacturing processes, from metal fabrication to paper production to leather tanning. Some of our most important industries – fruit and vegetable processing, cheese-making, dairy farming, meat processing and brewing – need pure, clean groundwater to make the goods for which Wisconsin is famous.

Big operators aren't the only ones who need this valuable resource. Consider your local laundromat, car wash, water bottlers, restaurants, health clubs, hairdressers and scores of services and products we use daily depend on groundwater.

Food processing soaks it up: processing one can of corn or beans requires nine gallons of water. Cars, fast or slow, also guzzle it up: six gallons of water are needed to produce one gallon of gasoline. And to manufacture that car and put four tires on it takes 39,090 gallons of water!

Commercial and industrial companies draw over 106 million gallons of groundwater each day from their own wells and use about 150 million gallons more provided by municipal water systems, according to USGS. Groundwater is a silent but important partner in Wisconsin's economy because it provides more than one-third of Wisconsin's business and industrial water needs.

Wet and wild

Thousands of tourists travel Wisconsin each year to enjoy our fabulous water resources. They spent an estimated 11.8 billion dollars in 2005 alone. That's a lot of fishing, boating, and swimming. What most see is a favorite fishing hole, a secret pond with an expanse of cattails perfect for observing herons, or those wild rapids waiting to devour the raft or roll the kayak. What we don't see is the groundwater flowing into those water bodies. After seeping through the soil and rock, groundwater discharges in low places where the water table meets the land surface – streams, lakes and wetlands.

Aquaculture?

Map of agricultural irrigation in Wisconsin

Take a short test: A dairy cow producing 100 pounds of milk daily slurps 50 gallons of water each day to wet her whistle. There are roughly 1,235,000 dairy cows in the state. On average they each produce 17,800 pounds of milk per year. How much water will they drink in a year?

If you said over 10.9 billion gallons, you pass. For extra credit, how much of that water was groundwater? Ninety-six percent? Good guess!

The demand for groundwater rises as farmers install irrigation systems to increase their chances for a strong crop, especially in times of limited rainfall. © DNR Photo
The demand for groundwater rises as farmers install irrigation systems to increase their chances for a strong crop, especially in times of limited rainfall.

© DNR Photo

Wisconsin's farms use about 100 million gallons of groundwater a day to water stock, maintain a high level of sanitation in the milk house and provide all-around cleanliness on the farm. Dairy farmers know that bringing a quality product to market means starting with quality materials – wholesome, nutritious feed and pure, clean water.

The demand for groundwater on the farm continues to rise as increasing numbers of farmers install irrigation systems to make the risky business of farming more certain. In 1969, Wisconsin had an estimated 105,526 acres of irrigated farmland. According to the U.S. Department of Agriculture, that figure has risen to over 390,000 acres.

Irrigation equipment uses about 182 million gallons of water per day during the growing season, almost all of it groundwater. On average, 80 percent of the water is consumed – it is used by plants and not returned immediately to the soil under the fields.

Much of Wisconsin's irrigated acreage is in the relatively flat 10-county Central Sands area, where potato is king. The tuber grows well in the sandy, loose soil, which needs less plowing and seedbed preparation than heavier soils and makes for an easy harvest. Water quickly seeps into this permeable soil and drains away almost as fast, allowing the plant roots to breathe and preventing rot. But the sandy soil doesn't hold water well, so irrigation is almost essential to ensure a good crop.

While irrigation has helped formerly marginal lands turn a profit, there is a cost: Excessive irrigation may leach nutrients, fertilizers and pesticides into groundwater and lower the water table.