A study recently published in Science suggests that eutrophication throughout the American Midwest is set to increase – an alarming fact given the already abysmal state of surface water quality in Iowa.
Eutrophication - a state of low oxygen levels in waterbodies - is caused by high concentrations of phosphorus and nitrogen compounds, the nutrients necessary for plant growth. These compounds make handy fertilizers, however, heavy rains can carry these nutrients from corn and soybean fields into waterbodies where they spur algal growth. This algal growth consumes the dissolved oxygen in the water while simultaneously blocking out sunlight for aquatic plant species, damaging aquatic ecosystems. Eutrophication is universally acknowledged problem in Iowa, which consumes over 5 times the national average of nitrogen (usually in the form of anhydrous ammonia), however, programs that have been developed to reduce farm runoff have had little impact, while lawsuits and legislative action have been fruitless.
So how bad is eutrophication in Iowa? A 12-year survey of 130 lakes performed by the Iowa Geological Survey found that all but 9 were eutrophic or hypereutrophic. In a 2012 review required by the US Clean Water Act, the Iowa Department of Natural Resources found that 78 percent of streams and rivers and 66 percent of Lakes and Reservoirs are classified as potentially impaired or impaired.
Usually when you hear about eutrophication it’s in an environmental context: it disrupts ecosystems and reduces biodiversity. These effects can make water-bodies unfit for recreational actives, such as swimming and fishing, damaging local tourism and lowering water-front property values. Additionally, the cost for treating water goes up – the treatment cost of relatively clean drinking water is approximately $2 USD per thousand cubic meters of water, while highly eutrophic water can cost upwards of $10 per thousand cubic meters. If not treated properly water with high levels of eutrophication pose a public health risk through ingestion of algal toxins or high nitrate concentrations, which are associated with miscarriages, types of intestinal cancers, and blue baby syndrome.
This is bad news for Iowans, but the buck doesn't stop there. All the nutrients flowing down the MIssissippi have created a dead zone in the gulf of Mexico measuring 8,776 square miles, costing the U.S. seafood and tourism industries an estimated $82 million a year.
Des Moines Water Works vs. the Drainage Districts
In a state where agribusiness reigns supreme, preventing or reversing eutrophication is a political issue. This politicization was put on display in 2015, when an Iowa water utility, Des Moines Water Works, sued 3 rural county drainage districts over high levels of nitrates in the Raccoon River, a drinking water source to over 500,000 people. Des Moines Water Works claimed that high levels of nitrates cost the utility $1.5 million in 2015, and expect to invest $15 million in the coming years to expand capacity in order to handle treatment of the high nitrate load.
The suit was dismissed by a federal judge in March 2017. The dismissal was two-fold: 1) as a nonpoint source of pollution, drainage districts in Iowa do not require a permit under the Clean Water Act, and 2) under Iowa law, drainage districts are immune from damage claims. The decision passed the buck back to the Iowa Legislature which failed to pass a series of bills aimed at improving water quality this session. Instead, the Legislature cut the Iowa Department of Natural Resources budget by $1.2 million, a cut that reduced funding for a volunteer water quality monitoring program by 75 percent.
Iowa's Nutrient Reduction Strategy
Despite recent failures, the Iowa State Government does have programs working to reduce nutrient loading. The current active initiative is Iowa’s Nutrient Reduction Strategy (NRS), in which farmers volunteer to adopt sound land management strategies in exchange for monetary incentives. Essentially, taxpayers are paying to prevent pollution, rather than the state requiring those who pollute to pay. The voluntary nature of the program means many farmers are not even aware of its existence. In a 2015 NRS Farmer Survey, 28 percent of respondents indicated that they were knowledgeable or very knowledgeable about the program, while 30 percent answered that they were not at all or only slightly knowledgeable.
Given the voluntary status of the program, it is unsurprising that it has failed to reach its goals. The Iowa Nutrient Reduction Strategy Annual Progress Report from May 2016 states that baseline nitrate levels were 307,000 tons in 2011. The program’s goal is to eliminate 125,870 tons of nitrate from waterbodies throughout the state using strategies targeting nonpoint sources, but they haven’t even come close. In 2015 the program estimated the reduction of nitrates from nonpoint sources to be 3,830,000 pounds or around 1.5 percent of the program’s goal.
To the north, the state of Minnesota has taken a regulatory approach to nonpoint source pollution. The ‘Buffer Law’, passed in 2015 and which establishes buffer zones of perennial vegetation around water bodies, is a great start. An interactive map of buffer widths required by the law can be viewed here. The buffer law was passed in 2015 with an implementation deadline of November 1, 2017, so it is too early to draw any conclusions about the effectiveness of the law. As of late May 2017, only 18 percent of counties have compliance rates lower than 60 percent. Including some mandatory measures such as a buffer zone along side voluntary programs like the NRS would benefit Iowa's water quality.
Action or Stagnation
The abysmal state of water quality in Iowa combined with political paralysis on the issue should make Iowans more alarmed about the recent findings published in Science. There is a wide body of literature that suggests a link between global warming and eutrophication – it makes sense: when temperatures increase, chemical reaction rates increase as well. This study, however, draws the link between higher temperatures and an increase in the quantity of nutrients entering waterways. Stronger and more frequent rainfall resulting from higher temperatures is likely to cause more agricultural inputs to run off into streams and lakes, and more nutrients mean more eutrophication. The study’s modeling predicts that total nitrogen loading under a business-as-usual scenario will increase between 5 percent and 33 percent, solely due to increased precipitation. Compare that to the reductions seen by the NRS program and you can see that the current strategy isn't getting Iowans anywhere.
This isn’t a doomsday scenario by any means; however, with global warming potentially speeding eutrophication through more than one mechanism, it’s time for Iowa to get serious about its water quality. If the predicted increase in nutrient loading is accurate, a voluntary program like the Nutrient Reduction Strategy is not going to cut it. Taxpayers will continue footing a growing bill, both in through the NRS program and higher water treatment costs, while business-as-usual continues and eutrophication worsens – unless, of course, policymakers demand change.