Minnesotans are paying increasing attention to the potential that climate change could have on everything from asthma and allergies to lake temperatures to crop production.

The latest effort to generate that conversation came Sunday night when the Minnesota Department of Health and Twin Cities Public Television combined to produce “Health and Climate,” a documentary encouraging better understanding of what a changing climate might mean.

One topic not touched on by the film was groundwater, something that could be dramatically affected by climate change.  Three-quarters of the state gets its drinking water from wells and how much we can take without taking too much depends on how fast precipitation recharges the water underground.

Beneath the Surface: Minnesota’s Pending Groundwater Challenge

And the speed of recharging can vary dramatically, depending on how much, how hard and when rain falls, according to the ninth installment in our groundwater Q&A series.

FROM THE PUBLIC INTEREST NETWORK: What impact will climate change have on groundwater?

Ray Wuolo,  Vice President and  Principal Hydrogeologist, Barr Engineering Co.

For the past seven years, I have been leading the team that has developed the three-dimensional groundwater flow model of the Twin Cities metro area (as a consultant for Met Council), upon which most of the current planning is based.  As part of that project, we developed a model of groundwater recharge for the period 1995-2010 for the metro area.  What we are finding is that precipitation patterns seem to be more focused in local areas (i.e. do not cover the entire metro area as much as in the early parts of the simulations) and precipitation tends to be more in the growing season.

This has several ramifications.  (1) more high intensity storms cause the formation of a “boundary effect” at the ground surface, which promotes more runoff and less infiltration (2) precipitation in the growing season is mostly used by plants and does not migrate below the root zone and become recharge and (3) regional precipitation values may not be useful indicators of how a particular community is fairing with regard to recharge.  Most importantly, skewing precipitation from the Feb – April period to the June, July, August period means that less recharge is occurring for the same amount of annual precipitation.  Nearly all of the metro areas groundwater recharge occurs in March, April, and May – that water reaches the water table in June, July and August.  But if there is less precipitation in March, April, and May, we may have similar annual rates as years past but less recharge.

Recently, we used the metro model to perform some 100-year future simulations, based on a well-recognized climate model.  Simulating one scenario of temperature and precipitation predictions, we predicted groundwater level reductions in groundwater recharge over the metro area of between 1 and 3 inches per year (compared to the current annual rate of 7 inches per year).  During this period, precipitation is predicted to actually increase but an average temperature increase of about 8 degrees F causes longer growing seasons and more evapotranspiration, resulting in less total recharge to the groundwater system.

So, if you believe in such things as climate change, impacts to future groundwater supplies could be very dramatic.  What is happening with White Bear Lake (which I do believe is the result of increased groundwater use in that part of the Twin Cities) will be nothing compared to what we will experience if climate changes as some predict.  Therefore, it will be even more important to begin to think about how to augment groundwater storage with flood water.

Previous questions:

Question 1. Should water cost us more?

Question 2. Should farmers be forced to change?

Question 3. Why would a farmer drain land and irrigate it?

Question 4. Does Minnesota water law make it easier or harder to deal with conflicts?

Question 5. Can we fill up our underground water supply with stormwater?

Question 6. Do you know how much water your neighbor uses?

Question 7. Why not just fill up White Bear Lake from one of the rivers?

Question 8. Can we use grass that needs less water?

3M Co., Pentair, Ecolab and other Minnesota businesses see great potential in the growing worries over the supply and demand for water, as MPR News reporter Martin Moylan pointed out earlier this week.

But there’s a flip side to the money-water question.

The Lincoln Pipestone Rural Water District is one of many rural water districts and small-town water systems in the increasingly expensive hunt for more water. Jackson Forderer for MPR News

Water issues threaten to throttle economic development in places — mainly rural — where the costs of delivering good water and carrying away sewage are set to overwhelm taxpayers,  the Mankato, Minn.-based Center for Rural Policy and Development warns in its newest report, “The State of Water.”

Beneath the Surface: Minnesota’s Pending Groundwater Challenge

The center is a non-partisan, non-profit research organization that has generated a variety of research in the state, looking at issues from a rural perspective.

For many reasons — water scarcity, increased demand, contamination, old and leaky pipes — a lot of Minnesota communities from Worthington to Two Harbors need water infrastructure help, the center says. Without it, the chance for economic growth is dim.

The irony, though, is that to make those infrastructure improvements, cities need a tax base from which they can raise funds to pay off infrastructure loans. And to get that tax base, they need economic development. The smaller the city, the smaller the tax base, and therefore, a decreased ability to pay for the necessary improvements.

Upgrading facilities raises water and sewer rates, which makes it harder for a community to compete with neighbors, the report argued.

The report took note of MPR News reporter Mark Steil’s coverage last week on the hundreds of irrigation wells that lack permits, making it harder to figure out the status of Minnesota’s groundwater.

Likewise, it notes that many small cities similarly have something out of whack. Of the 264 small towns with state permits to pump water for their residents, more than two-thirds failed to report to the state either how much water they pumped or how much end users used or they reported delivering more water than they actually pumped.

It’s hard to get a handle on things if that’s the case.

Is it time, the report asked, “to invest again in an overhaul of the way we handle water and wastewater infrastructure in Greater Minnesota—particularly in how it’s funded? If so, who has the will to lead the way?”

The center makes several recommendations:

  • Establish a Legislative Water Commission that would try to coordinate information about water, particularly if it has rural representation. Such a plan has been proposed in the Legislature.
  • Recognize that as water contamination requirements get tighter, they place disproportionate burdens on small communities. And be aware of the long-term decline in federal funding for infrastructure.
  • Start planning long-term for re-working small-city infrastructure.
  • Support state agencies’ efforts to get more information about the state’s water.
  • Think differently about some of the smallest communities with troubled water infrastructure

“It is hard to admit, but there are some towns that do not have a realistic chance of growing,” the report says, but adds:

However, it does not have to be an all-or-nothing future for them. There are alternatives to a traditional full-scale wastewater treatment facility. Encourage state agencies like the Pollution Control Agency and the Public Facilities Authority to continue working with the smallest communities and their engineers to explore these alternatives first.

Kraemer Mining and Materials limestone quarry in Burnsville. The cities of Burnsville and Savage use water treated after it is drawn from the pond at bottom.

Ten years ago, Kraemer Mining and Materials could see complications coming at its limestone quarry in Burnsville.

Groundwater seeping into the quarry had to be pumped into the nearby Minnesota River — more than 3 billion gallons a year. The pumping cost money, but more significant was that the company was bumping up against limits set by the Department of Natural Resources for how much it could pump. That put constraints on expansion.

Beneath the Surface: Minnesota’s Pending Groundwater Challenge

In the meantime, the people supplying drinking water to residents and businesses in the growing cities of Burnsville and Savage also had a problem. They, too, were being constrained by the state in their desire to tap groundwater.

They could see water levels dropping in the Prairie du Chien-Jordan aquifer, and they knew they couldn’t stay on the same path for another 10 or 20 years and continue to plan for growth. What’s more, groundwater pumping was threatening an unusual kind of wetland in the area. Known as a calcareous fen, it and others like it are protected under state law, much like trout streams are.

The result? People in Burnsville and Savage have been drinking quarry water for the past five years. The cities updated the Metropolitan Council on the project last month and expect to renew their partnership soon for another five years.

It’s an example of thinking differently about water and coming up with a solution that both helps preserve a sensitive environmental area and gives some assurance for a long-time supply of drinking water. Read more