Skip to Content

The Science of Improving Iowa’s Water Quality

Billions and Billions

Posted on November 16th, 2017

On February 27, I posted here about the estimated 2016 state-wide stream nitrate-N load ( My colleagues and I used multiple sources of data to estimate Iowa streams delivered 1.04 billion pounds of nitrogen to the Mississippi and Missouri Rivers during 2016. As we go about our regular lives, a billion of anything seems like […]

Climate Change and Stream Nitrate

Posted on July 17th, 2017

Pulitzer Prize winner Art Cullen recently published an interesting article about climate change and stream nitrate in the Storm Lake Times (link). I like this article. I always think a person could not have farmed in Iowa over the last 50 years and not know that things have changed–a lot. Maybe not so much with […]

Raccoon River nitrate: Jan-Jun vs Annual

Posted on July 12th, 2017

Load is the total mass of a pollutant transported by a stream over a defined time period. The graph below shows Raccoon River nitrate loads (metric tons) from January through June (blue bars) versus the annual load (red bars). The years are arranged according to the magnitude of the Jan-Jun load. You can see where each year was […]

April Historical Nitrate: Raccoon and Des Moines Rivers

Posted on June 8th, 2017

  Just posting some graphs of recent data here of the last two months and historical perspective.            

Economics of reducing nitrate loss

Posted on May 26th, 2017

More than 90 percent of the nitrogen transported by Iowa streams is in the form of nitrate (NO3-N). Three separate but similar methods have recently been used by me and others to estimate the amount on NO3-N exiting Iowa in its major streams draining to the Missouri and Mississippi Rivers during 2016. These methods have […]

Morgan Creek Oxbow Restoration

Posted on May 18th, 2017

Oxbow Restorations Benefit Habitat, Ecosystem <!– by jstolze –> Posted on May 18th, 2017 <!– No Comments –> Oxbow restoration in progress at Morgan Creek in Linn County, Iowa. Aleshia Kennedy (arms outstretched) of the U.S. Fish and Wildlife Service and IIHR graduate student Bryce Haines (far right) talk with employees of the earth-moving firm […]

#Nitrate is Trending

Posted on May 10th, 2017

It is really tempting to talk about water quality trends. Sometimes the direction water quality is going (i.e. better, worse, or the same) seems more important to the discussion than the current condition itself. Certainly any degradation of a very high quality stream or lake is cause for concern. Unfortunately, this is not something we worry about much, simply […]

Raccoon and Des Moines River 1st Quarter Nitrate

Posted on May 1st, 2017

First Quarter nitrate levels in the Raccoon and Des Moines Rivers (at Des Moines) were above average in 2017 compared to the historical record. First quarter Raccoon nitrate-N concentration was 16th highest out of 43 years (1977-present), while total load was 8th highest. In an average year, 16% of the Raccoon N load occurs in […]

January and February nitrate loads: Raccoon and Des Moines Rivers

Posted on March 6th, 2017

Raccoon & D.M. River Nitrate: Historical Nuggets

Posted on February 12th, 2017

My detailed data sets for the Raccoon and Des Moines Rivers at Des Moines go back to 1974 and 1982, respectively. Here are some interesting nuggets from that data:   Largest Nitrate-N Loading Years Raccoon Des Moines year N Load (kg) Year N Load (kg) 2015 47,456,365 1991 68,891,857 1993 36,559,570 2016 65,197,500 1991 35,032,826 […]