Iowa fields are eroding at an unsustainable rate, study says


Agricultural runoff in Iowa (Lynn Betts/Flickr)
Agricultural runoff in Iowa (Lynn Betts/Flickr)

The rate of soil runoff from Iowa fields may be many times higher than previous estimates, according to a recent study.

The report, released by Environmental Working Group, shows that Iowa fields are eroding at unacceptable rates, depleting Iowa’s rich topsoil and sending sediment and chemicals into streams and rivers. Between 2002 and 2010, many fields consistently lost more than the sustainable rate of five tons of soil per acre from storms and other erosion events. A single storm in May of 2007 eroded up to 100 tons of soil per acre.

Much of the soil is carried away by gullies that are increasingly appearing in Iowa fields. These low channels are a telltale sign of high erosion, and are often refilled with soil only to be emptied again with the next storm.

High erosion creates high agricultural and environmental risks by carrying away Iowa’s rich topsoil and by polluting waterways with sediment and chemicals. An effective means of curbing this is to plant grass and trees along the edges of fields and in areas where gullies are likely to form. A series of buffers implemented in various fields reduced sediment, nitrogen and phosphorus by more than 90 percent in 2009.

Sediment buildup accelerating in Iowa


Photo by docentjoyce, Flickr.
Photo by docentjoyce, Flickr.

An Iowa State University study has found that sediment buildup in Iowa’s lakes is accelerating.

This is occurring despite soil conservation efforts in the state.

According to the study, the sediment is building nearly six times as quickly as it did back in 1900.

Read more here.

2011 Iowa DNR projects reduce sediment reaching our waterways by 20,000 tons


Centennial Bridge over the Mississippi River in Davenport, IA. Photo by ercwttmn, Flickr

Projects funded by the DNR in 2011 will keep over 20,000 tons of soil out of Iowa’s waterways each year. Additionally, these conservation projects will reduce the phosphorous and nitrogen reaching the waterways by 27,164 pounds per year and 41,881 pounds per year respectively.

Since 2004, DNR funded projects have reduced sediment reaching Iowa’s waterways by 175,867 tons.

These conservation projects include creating wetlands, ponds, terraces and buffers.

Read the full press release from the Iowa DNR here.