Iowa Wetland

Iowa’s Waterbodies & Water Quality | Guest Essay

Dec 21, 2018

Iowa’s Waterbodies & Water Quality

Guest Essay by Cornelia F. Mutel and Larry J. Weber

December 21, 2018

Biking or driving through Iowa on a hot summer day, your gaze cannot help but linger on the rivers and creeks you are crossing, the farmstead ponds and reservoirs you pass. Nostalgic memories of cooling summertime dips or tubing down rippling rivers may float through your mind – and if not these, then at least the image of a chilled glass of sparkling water. Water – it’s essential to life. And much of the time, Iowa has had just the right amount of it: enough to foster abundant crop growth and meet the needs of thirsty people, livestock, cities and industries, while steering clear of floods or drought.

However, modern changes to the water’s flow over the land have created some of today’s most critical environmental problems. Drainage ways cut like knives down slopes and through farm fields, the flowing water then deepening steep-sided creek beds in valley bottoms. Iowa’s fast-flowing water washes away Iowa’s “black gold” – its precious topsoil that’s among the richest in the world and the natural resource at the base of our agricultural economy. Gushing water washes the fertilizers, pesticides, and manure from land into streams and rivers, along with microorganisms, antibiotics, and other waste from confined animals. Cities add their own chemical brew: urban debris and wastes, and also cleaning agents, animal and industrial wastes, and a growing mixture of trace elements such as caffeine and pharmaceuticals. Iowa’s water has become among the most polluted in the nation and is increasingly flood-prone.1

These problems result not from nature, but instead from how we have handled our land and water. To understand this statement, let’s look back 200-plus years at how Iowa’s land handled water before Euro-American settlers arrived.

A Historical Perspective

At that time, water and soil formed an integrated unit, with soil capturing and holding vast amounts of water like a gigantic sponge. Indeed, soils that were waterlogged at least part of the year covered about one-quarter of Iowa, forming bogs, fens, ponds, flooded oxbows, and a variety of additional wetland types.
Much of this tightly held water was absorbed by deep, dense plant roots and passed back into the air, only to fall again as rain. But some managed to creep slowly downhill until it emerged in manners fitting the local topography. In hillier southern and northeastern Iowa, for example, well-developed streams and rivers, fed in part by hillside seeps and springs, might run through waterlogged bottomlands and forested floodplains. The flatter expanses of northern Iowa in contrast boasted abundant poorly-drained depressions such as prairie potholes, larger lakes, vast sedge meadows, and marshes.

A drop of Iowa’s lazy, lingering water could require years to flow to the Mississippi River and then to the sea. These leisurely flows did not erode the soil; instead, the soils cleansed the groundwater. Iowa’s perennial creeks and rivers once transported crystal-clear water. And, because water’s slow, steady, gently pulsing flows rose and fell sluggishly, they moderated both floods and droughts. Soil, water, and sky created an interacting unit, each shaping the others and moderating extremes, producing a sustainable landscape of abundance and integrity.

This variety of wetlands and interspersed drier lands created a great diversity of habitats for plants and animals. The complex landscape, with its standing and flowing, mucky and clear, large and small wetlands housed a vibrant, bountiful, noisy, sometimes smelly mixture of mammals, frogs, insects, and other resting, feeding, migrating, and reproducing animals, each with its own needs. Iowa’s north-central marshes emerged as a veritable “waterfowl factory” for ducks, geese, marsh and shorebirds, and cranes.

Humans Bring Change

Today, Iowa’s racing rainwaters reach our streams and rivers in minutes or hours rather than years, causing flash floods and gathering pollutants along the way. These problematic flows are the the result of processes begun by early settlers. These settlers needed to drain the soils if they were going to plant crops, and dry up muddy bottomlands that might trap their grazing cattle. They set out to separate water from soil and speed up its flow, dewatering the land by digging drainage channels, straightening and deepening creeks and rivers, and inserting long slotted tubes (drainage tiles) into croplands. Their intent was to replace slow, soil-held flows with surface waters rapidly flowing to the sea. The rich, diverse wetlands and their residents started to disappear. Today intact native wetlands are rare; modern water bodies include constructed farm ponds, dammed lakes and reservoirs, and channelized streams.

The early settlers’ actions intensified as hand shovels were replaced by massive steam engines scooping out straight wide ditches, as short clay drainage tiles were supplemented by today’s endless coils of plastic pipes, and as fencerow prairie remnants were plowed under when small, diversified farms were replaced by expanses of corn and beans and mammoth confined animal feeding operations.

The conversion of Iowa’s prairielands to croplands, towns, and roadways, accompanied by new patterns of flowing water, have brought many benefits. Iowa farmers built an agricultural economy and culture that have nurtured their lives and fed millions of others. But this land conversion has also created the problems of soil erosion, water pollution, and more frequent and severe flooding, and it has robbed our land of its resilience.

These problems are now affecting Iowa in a major way. Since the plow first bit into prairie sods, the average depth of Iowa’s topsoils have dropped to less than half of their original 16 inches. With topsoils thinner and less absorbent, the incidence and damages of flooding have risen dramatically. Between 1988 and 2016, Iowa placed fourth in the nation for the number of flood-related Presidential Disaster Declarations. Flood damages garnered Iowa $1.7 billion through the FEMA Public Assistance Program between 1999 and 2016, placing Iowa seventh in the nation for states receiving such funds.2

Finding Solutions

In the meantime, Iowa’s water quality has continued to degrade. One example is the synthetic nitrogen fertilizers and manure of confined animals that are applied to Iowa’s farmland in tremendous quantities. Despite efforts to keep these fertilizers on the land, more and more runs off to pollute our rivers and streams each year. From 2003 to 2017, the 5-year moving-average nitrate export from Iowa increased 77 percent.3 These nitrates flow rapidly down the Mississippi River to form a massive and growing dead zone, devoid of fish or other animal life, in the Gulf of Mexico. Closer to home, Des Moines continues to spend millions to construct and operate sophisticated facilities for cleansing drinking-water supplies of harmful agricultural nitrates.

How can we address these problems? How might we reduce the erosive power of gushing surface flows and moderate flash floods? How could we reduce the growing quantity and diversity of pollutants?

One approach embraces slowing the water’s surface flows and encouraging water to enter and flow through the soil, as it did in the past.4 Doing so begins with adding organic matter back into the soil, for example with continued use of crop rotation and cover crops, and refraining from tilling croplands each fall. Such actions, which increase cropland soils’ health and water-absorption abilities, also can raise per-acre farm profits.5

Another approach addresses the flow of water and its pollutants within each field. Research has shown, for example, that converting 10 percent of cropland to interspersed plantings of native perennial plants reduces soil erosion by 90 percent and nitrogen runoff by 85 percent, while simultaneously providing habitat for pollinators and other beneficial insects.6

And lastly, consider larger actions that can help reduce flows between fields and across the broader landscape.7 Research demonstrates that restoring native plantings along creeks – buffer strips of trees, shrubs, and prairie plants – can produce amazing results, cutting sediment in surface runoff by 90 percent, nitrogen and phosphorus runoff by 80 percent, and increasing soil organic material as much as 66 percent.8 Other forms of rural land retirement, wetland reconstruction, and floodplain restoration and management that increase the extent and health of deep-rooted native plantings can be similarly beneficial for reducing soil erosion, water pollution, and flooding. Cities also can play their part, encouraging water to enter and build soil by maximizing and restoring interspersed urban drainageways and native wildlands, and installing permeable pavement, bioswales, raingardens, and any other structures that absorb and hold precipitation.

Iowa’s water-related problems developed over many lifetimes; they will not magically disappear or be solved rapidly. But if we work with a sense of urgency, even as we adopt a long-term view, we could significantly renew Iowa’s soil health and simultaneously reduce flooding and water pollution. Positive actions will require compacts between rural and urban residents and land-managers as well as agricultural corporations. These partnerships, combined with political will and the will of the people, could transform Iowa within our generation.

Generating visions of a healthier future will energize our efforts. Consider an Iowa where clean stream banks invite both wildlife and people to relax and enjoy, where children play safely in clear unpolluted water, where flooding is moderated. An Iowa where rivers flow freely through wild natural areas that wind across the land, these strips of nature and all its beneficial services renewing and tying remnants of Iowa’s prairie heritage into a landscape that nurtures life, health and spirit.

Many communities and organizations are already working toward more resilient and sustainable waters and landscapes in Iowa. What is being done in your community? How could you contribute to these efforts?

Additional Information

  • “Iowa Flood Center,” ongoing, IIHR-Hydroscience & Engineering website, The University of Iowa, https://iowafloodcenter.org
  • Mutel, C.F. 2008. The Emerald History: The History of Nature in Iowa. University of Iowa Press, Iowa City IA. 319 pp.
  • Mutel, C.F. (Ed.) 2010. A Watershed Year: Anatomy of the Iowa Floods of 2008, University of Iowa Press, Iowa City IA. 250 pp.

Sources

  1. Data from the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, https://water.usgs.gov/nawqa/digmap.html ; increasing floods: Data compiled by the Iowa Flood Center, IIHR-Hydroscience & Engineering, University of Iowa College of Engineering, and accessed September 14 2018.
  2. Data compiled by the Iowa Flood Center, IIHR-Hydroscience & Engineering, University of Iowa College of Engineering, and accessed September 14 2018. ($1.7 billion is in 2016 dollars; Disaster Declarations are made by county. Iowa had 951 Presidential Disaster Declarations from 1988 to 2016.)
  3. Jones CS, Nielsen JK, Schilling KE, Weber LJ, September 2018,“Iowa stream nitrate and the Gulf of Mexico.” PLoS ONE 13(4): e0195930. https://doi.org/10.1371/journal.pone.0195930 . 2017 data, personal communication from CS Jones.
  4. American Society of Agronomy, May 27 2015, “New Planning Toolset gives Farmers More Options for Improving Water Quality,” Phys.Org website. https://phys.org/news/2015-05-toolset-farmers-options-quality.html
  5. Monast M, Sands L, Grafton A, September 2018, “Farm Finance and Conservation: How Stewardship Generates Value for Farmers, Lenders, Insurers and Landowners,” Environmental Defense Fund website. https://www.edf.org/sites/default/files/documents/farm-finance-report.pdf
  6. Schulte Moore L, ongoing, “Farming with Prairie Strips,” Iowa State University – STRIPS website. https://www.nrem.iastate.edu/research/STRIPS/
  7. Weber LJ, Muste M, Bradley AA, Amado AA, et al. 2017. “The Iowa Watersheds Project: Iowa's prototype for engaging communities and professionals in watershed hazard mitigation.” International Journal of River Basin Management, DOI: 10.1080/15715124.2017.1387127
  8. Leopold Center for Sustainable Agriculture, 2013, Funding Impact Brief #5: Bear Creek Riparian Buffer Project, Leopold Center Pubs and Papers 52, Iowa State University digital repository, Ames IA.
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