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How can Minnesota achieve sustainable water use? Agriculture holds the key

Courtesy of Deb Swackhamer. Source: Metropolitan Council

To judge from the audience reaction, two charts presented by Deb Swackhamer in a talk Tuesday on the future of Minnesota’s water resources made compellingly clear why the Land of 10,000 Lakes might have some scarcities looming beyond the horizon.

The one above shows how the water supply in the Twin Cities metro area has shifted from surface sources, like the Mississippi River, to groundwater pumping in the decades since World War II – an almost complete reversal in a couple of generations.

At the left edge, as the bars begin, most of the metro population is in Minneapolis and St. Paul, which drew their water supplies from the river and still do. But as the 1950s got under way, Swackhamer said, “We began to build the outer-ring suburbs, and the next-outer-ring suburbs, and then the next-next-next, outer-outer-ring suburbs ... and all the suburbs drink groundwater.”

The problem with that, she explained, is that “groundwater is like a savings account you save for a rainy day – you want to save it for when you have a drought.”

Unlike surface water, which she likened to a checking account, you can’t count on regular deposits of seasonal rains. Groundwater is replenished on geologic time scales, which means “it might take 10,000 years to replace a year’s worth of use.”

Which brings us to the second chart, below:

Courtesy of Deb Swackhamer

This is a hydrograph of the water level of the Prairie du Chien-Jordan aquifer, measured in feet below the surface at an observation well near Orono.

Each year is represented by a vertical blue bar, whose high side is summertime use, and the band of bars shows a steady downward march of unsustainability, toward a crisis point whose arrival date is difficult to predict though impossible to deny.

But based on state-of-the-art modeling by the Metropolitan Council, Swackhamer said, it seems likely that a continuation of current population and usage trends will bring significant shortages as early as the year 2030.

There is a simple alternative: Getting strategically selected communities in the metro, and in other designated “areas of concern” around the state, to build new pipelines that can bring them water from surface sources instead of underground.

Simple, but neither cheap nor politically palatable.

A gift for synthesis

Deb Swackhamer

Swackhamer has a serious gift for synthesizing complex scientific material in ways that non-specialist listeners can grasp, and it’s paired with matchless expertise on this subject:

She directed the University of Minnesota’s Water Resources Center from 2002 to 2014, and led the effort to produce the massive Minnesota Water Sustainability Framework, commissioned with funds from the Legacy Amendment to provide policy guidance for decision-making over the next 25 years.

She has served in leadership roles on scientific panels advising the U.S. Environmental Protection Agency and the International Joint Commission, and has just begun a three-year term on a National Academy of Sciences panel focused on environmental science and toxicology, recognition of her focus on toxic-chemical pollution.

And she does not shrink from controversy. For example, she had much to say about the fraught connections between large-scale agriculture and Minnesota’s water problems, some of it quite provocative.

If we shift from issues of water quantity to issues of water quality, she observed, we see that more than 4,100 lakes and stream sections across the state – or more than 40 percent of the total – are classed as “impaired” because they fail to meet federal quality standards.

The major driver of these impairments is excessive inputs of nutrients, primarily phosphorus and nitrates from fertilizers, and the major source of those nutrients is row-crop agriculture.

Courtesy of Deb Swackhamer

Since Minnesota banned phosphorus-based lawn fertilizers, the amount of phosphorus contributed by nonagricultural (and chiefly urban/suburban) runoff has fallen to about 11 percent of the total. Agriculture contributes almost four times that share of this pollutant, which fuels algal blooms.

With nitrates – which carry public health risks and are the only major water pollutant, she said, whose levels are still increasing in Minnesota – agriculture contributes 78 percent of the overall load.

If these chemicals were flowing from factories, sewage plants or most other sources, the problem could be readily addressed through permits and other limits.

“The regulated community has these boundaries, and they live within them,” she said. “Agriculture’s tougher. Through a quirk in the law, row-crop agriculture is exempted from regulation under the [federal] Clean Water Act.

“So our hands are kind of tied unless we can find some other way to incentivize the agricultural community to participate in cleaning up the water. My personal opinion is, there has to be an investment from the public in bringing about those changes.”

At other points, Swackhamer said:

I don’t mean to malign agriculture in any way. ... They’re business people, so they do what they do to make their business work.

But there’s no limit on how much they can use, nobody to say they're using too much, and it’s cheap insurance to make sure their crops will grow.

One possible but partial solution, she said, is wider use of reservoirs to catch and retain water removed from fields with drainage tile. Presumably these could also become sources of water for irrigation, which has been the fastest-growing use of Minnesota groundwater in the last 20 years.

Another, she said, would be a serious effort to protect lakes and streams with buffers of minimally cultivated land, as proposed by Gov. Mark Dayton.

The current buffer standard of one rod, or 13 feet, could remove only 2 to 5 percent of nitrate  runoff even if it were rigorously enforced, which it is not. The 50-foot buffers Dayton wants to require would immediately raise the filtration capture to 50 percent.

Signs of progress

Swackhamer made a point of noting signs of hope and progress on Minnesota water issues, including:

  • Changes in the Department of Natural Resources’ approach to permitting for groundwater withdrawals, with more perhaps to come.
  • A recognition that water-management decisions need to be made at the watershed level, since water doesn’t respect political boundaries, and growing interest in integrating land-use and water planning within watersheds.
  • A good possibility, in her view, that the St. Croix River may come off the impaired-waters list in the next few years because of phosphorus reduction.

* * *

Swackhamer’s subject was so large, and her talk was so wide-ranging, that I’ve only been able to cover some of the main points here. For a video of her full 50-minutes presentation, plus an hour of Q&A with an engaged audience, you could go here.

Tuesday’s talk was at the Minnesota Zoo, as part of its World Speaker Series.

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Comments (10)

Thanks for this really

Thanks for this really informative piece. People view what's happening in CA and assume that we're immune from these issues, what with our 12,000 lakes, rivers, and more frequent rainfall. But those aquifer level graphs are sobering...

Amen

…to Dimitri's comment. My framework is Colorado, where quantity is more of an immediate issue, but obviously it's going to become an issue here, as well.

nice article but...

"But there’s no limit on how much they can use, nobody to say they're using too much, and it’s cheap insurance to make sure their crops will grow."

This is exactly what anyone who knows nothing about agriculture always says. It is not cheap at all and not looked at as insurance either. The more a person puts on the more expensive it is since the benefit of it is reduced. Farmers know this already and don't like to keep putting on fertilizer if they are not seeing a cost effective benefit from it.

The pie graphs are way too simplistic to be useful. Of course the majority is coming from agriculture but that is also because there is much more agriculture land. Check out the discovery farms study to see what I am talking about. The amount coming from the farm land is greater but careful analysis shows how terrible water coming from the city is and when compared apples to apples the city looks far worse. Other sources of pollution may be easier to correct also. Cities and businesses discharge all the time and there are numerous articles about it. I'd also like to know why there is no mention of mercury in this article. Mercury is the number one reason the majority of our waters are impaired. Not nitrogen or phosphorous but the article makes no mention of it.

I realize the buffers would do some good in places but still have a problem requiring them where the land slopes away from the waters. Makes no sense to me at all.

Agriculture is dependent upon

Agriculture is dependent upon several "free" inputs--light and water being the most prominent.

In the recent year when drought has been prevalent during the summer, the use of pivot irrigation units has increased and spread into areas that formerly were adequately served by natural rainfall.

It is the amount of water pumped in the irrigation that remains a big question, and there really is no good answer out there--even in areas with significant water table drought. There is no oversight or even reporting of the amounts of withdrawal and there really is no overall monitoring of groundwater resources.

Who knows how much and how many years of drought before groundwater resources are severely limited? And given the non-uniform aquifer matrix, some areas may fail sooner than others and redistribution may not occur as fast as one would want.

water pumping

There is oversight. DNR has oversight of irrigation and does monitor amounts of withdrawal. In fact the DNR is cracking down in one county on usage over what was permitted in MN. The DNR has the experts to tell us how much water can be taken out of aquifers so I will trust them to know what they are doing. It is pretty unfair of you to characterize irrigation as being unregulated when it clearly is watched closely. No need to cry fire when there isn't even smoke.

The DNR has publically staged

The DNR has publically staged that it does little to crack down on rampant over-pumping-- there was a good MPR story last year, found here:

http://www.mprnews.org/story/2013/02/27/environment/water-use-permitting

Monitoring without enforcement seems pretty unregulated, to me. From that piece:

"But violators face few consequences for these misdemeanor violations. Even in a two-year drought, DNR officials admit they don't spend much time enforcing permit limits."

enforcement

"The DNR's water permit data show the vast majority of the state's more than 7,000 permit holders stay well under their maximum allotment."

Direct from the article you linked. Over pumping is apparently not as rampant as you would like everyone to assume. That said, there are some that do overpump and enforcement or lack thereof has more to do with budgets, politics, and man power. I would question if the new permits are issued based on the permitted amount of pumping or actual amount of pumping so they are not over permitting pumping of aquifers.

joe-- my point was that

joe-- my point was that pumping is not as regulated as you implied in your post. To then shift to an argument of "well most people pump their allotted amounts" is a distraction from the original point: when people break the rules, are their consequences? You implied yes. I pointed out that that's not true.

link

I'm not sure I'd put too much faith in your linked article. Why would the nursery in spicer pump from a river some 50-60 miles away when most businesses in the spicer/willmar area have other much closer places to pump from? Much of the article seems to be not very current information.

Great article on water supply sustainability

The USGS and Met Council studies strongly indicate the greater metropolitan Twin Cities needs to go back to the use of surface water, i.e. the Mississippi River, for our.drinking water. 50 years ago our drinking water was 70% from surface water & 30% from well water. Today our drinking water is only 30% from surface water and 70% from well water. The result is a lowering of our aquifers. White Bear Lake is the "canary in the coal mine" on the health of our aquifer. Our legislature needs to mandate a switch back to surface water as the primary source of drinking water if we want water for our grandchildren.