The Nitrate Commons

P1140132Over the past three weeks, we’ve visited a cluster of three northwest Iowa counties: first Calhoun (Twin Lakes WMA), then Buena Vista (Storm Lake Marsh), and last week it was Sac County (Kiowa Marsh). The center of that cluster is about 90 miles (145 kilometers) due northwest of the state’s capitol (and largest city), Des Moines. It might be more useful, however, to measure the river miles—how far water flows downstream from those counties. And therein lies the tale of a serious nitrogen pollution problem, recent legal action, and a glaring example of our collective environmental commons.

This concept of The Environmental Commons was explained by Garrett Hardin in a classic 1968 paper in the journal Science entitled The Tragedy Of The Commons. That article is about human population growth, but the premise of the Commons itself works for any shared resource. In the article, Hardin presents a parable of a shared grazing space (a village green), called The Commons, and presents the choice faced by any user of a commons (e.g., sheep herder):

…The rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another; and another… But this is the conclusion reached by each and every rational herdsman sharing a commons. Therein is the tragedy. Each man is locked into a system that compels him to increase his herd without limit–in a world that is limited. Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons.

The tragedy, of course, is that everyone acts rationally, until the Commons (shared resource) is “ruined” (depleted). Every user of the Commons only takes a little bit, and never intends to cause harm. And yet overall, harm is the result. This certainly has happened with overgrazing on shared public lands in the United States, a giant “village green” if you will.  However The Commons can be ANY shared resource, such as harvesting  from ocean fisheries. Little  by little, through innocuous individual actions, populations crash, and a shared resource (commons) is ruined.

dsc_0810Now, let’s think about water pollution. A common form of nitrogen (nitrate, NO3) is found in Iowa’s waters: rivers, lakes, groundwater. Its presence is normal and natural. Adding just a little bit from a pipe or through runoff over the land surface is to be expected, and not a problem. Organisms in ecosystems, such as found in an Iowa stream, can and will use/process/transform the nitrate. In fact, nitrogen is a fertilizer: it helps plants grow. This is not inherently a problem.

However—at some point, the individual contributions add up, and we collectively add so much nitrate that our water bodies become degraded. This affects the stream or lake ecology (they become “impaired” in the regulatory sense), and the nitrate flowing downstream joins the Mississippi River, where it eventually reaches the Gulf of Mexico. Down in the Gulf, it contributes to hypoxia, the infamous Dead Zone.

The nitrate problem isn’t just ecological, however. Some water suppliers draw from surface water bodies, or shallow groundwater connected to surface waters. Their customers will then drink the high-nitrate water. For example, the Des Moines Water Works supplies domestic (drinking) water to half a million residents in central Iowa. The Water Works draws from the Racoon River whose large drainage area (watershed) lies to the north and west. Nitrates within the watershed are carried to the river flowing downstream and then affect the water quality, raising levels of nitrates above the legal limit (10 parts per million of nitrate-N). Nitrate levels exceeding the limit happens several times a year, and forces the Water Works to use an expensive nitrate-removal process.

As a result of this added operating expense, the Des Moines Water Works then sued three public drainage districts located in upstream counties. Those are the counties featured in the last three weeks on this blog.

Note that nitrates are added to water in many ways: effluent from wastewater (such as septic systems or a city wastewater treatment plant), animal waste, runoff from farm fields or golf courses, and the very lawns at our residence—literally, our own back yard. They can all add nitrates, and they are all implicated in our common nitrate challenge.

The Water Works lawsuit was dismissed, and that isn’t surprising. Too large an area of watershed, with too many sources of nitrates, are contributing to the river’s water pollution—it would be quite difficult to assess damages against a few particular entities. The watershed, and its ability to safely process nitrates, is a shared resource–a commons. We all own it, we all are effected by it, and we all contribute to a common nitrate problem.

dsc_0168What then shall we do?? I believe there are three parts to this challenge:

First, we should have an honest conversation. It’s long past time pretending that no problem exists, or that it will solve itself. When I arrived in Iowa in 1998 and learned of ongoing legal battles about nitrates in water, I never dreamed we’d be fighting about it all these years later. We need to acknowledge the multitude of evidence, consult with the people who have worked hard on this problem, and commit to finding solutions.

Second, we must strategize about the possible solutions. Knowing how nitrates get into the water, and what acceptable levels (water quality standards) should be, we can talk about ways to account for the sources and how to reduce the inputs.

Third, we must implement well-planned measures to get the job done. This is where economic and political reality comes in—what strategies will be widely supported, and workable? What is cost-effective and achievable in a timely manner? We should think about buffer strips and cover crops, and better wastewater treatment, and bioreactors, and many other great ideas.

Oh…and wetlands. As discussed many times on this blog, wetlands “clean the water,” including removing nitrates. Preserving and protecting our existing wetlands, and building or restoring others, will surely help us save our Nitrate Commons. Let’s get to work!


Author: Paul Weihe

Associate Professor of Biology at Central College, traditional author (Textbook of Limnology, Cole & Weihe, 5th ed.; Waveland Press), and now...blogger!

3 thoughts on “The Nitrate Commons”

  1. The N problem is a huge one and has layers of complexity that touch all of us whether personally acknowledged, or not. From disruption of historically conserved biogeochemical cycles, resultant shifting of ecological community structure (flora and fauna), epidemiological impacts on communities from chronic exposure, and innumerable other considerations. Ecological consequences and the disruption of services, never mind intrinsic rights to existence, need to be part of our societies decisions. Short of that we might as well destroy our own homes.


  2. Greatly-stretching the metaphor above, suppose we had a extremely-overgrazed village-green commons on which three-quarters of the sheep were owned by one large extended family. And while that family expressed willingness to reduce their sheep numbers, they insisted that they be able to do it on their own schedule, which turned out to mean removing one sheep every twenty years.

    Yes, Iowa’s nitrate problem belongs to all of us. In our state, however, because of land-use patterns, conventional agriculture is the biggest source of nutrient pollution. That fact, based on scientific research, is acknowledged and discussed in the Iowa Nutrient Reduction Strategy, and Iowa farm groups have agreed that the science in the Strategy is valid.

    One huge watershed where major progress on nutrient pollution is being made is the Chesapeake Bay watershed, where all the people in the watershed, including farmers, are being required to take action, and where there are standards and deadlines. One huge watershed where progress is extremely slow, at best, is the Mississippi River watershed, where standards and deadlines are lacking and where agricultural nutrient reduction is almost entirely optional.

    I’ve been following Iowa water politics for almost forty years, starting back when State of the State addresses sometimes included an offhand short boast about Iowa’s “clean air and water” compared to other states. That phrase was used even though Iowa conservationists who were paying attention to water quality knew full well, even then, that Iowa’s surface waters were not clean.

    Interesting stories could be told about water-politics shenanigans in this state and why we’ve been so slow to even face our water problems, let alone address them. But that, as the old saying goes, is water under the bridge.

    At this point, we need to acknowledge that climate change is playing a significant and growing role in the agricultural-pollution problem, as jaw-droppingly-big rain events increasingly overwhelm conventional farm conservation structures. And all of us are contributing to climate change.

    A reasonable compromise now would be for Iowa taxpayers to pony up a lot more money to help pay for much better farm conservation. Ouch. And farmers and landowners, in return, would agree to do that conservation on a non-optional basis, with every farm required to do its share. Ouch.

    Both sides of that compromise would be painful. But it would allow serious progress to be made in Iowa over the next three decades, not the next three centuries. Which is a lot more than can be said for continuing the status quo.


  3. Thanks to you both for these thoughtful comments. I do have educated guesses about which approaches might be most workable, but I certainly want to hear about options. And like it or not, we’ll have to consider several constraints simultaneously, as you wisely note. Are we ready to (finally!!) take this on…?? I hope so…


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