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The Science of Improving Iowa’s Water Quality

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 […]

Iowa Statewide 2016 Stream Nitrate-N Load Calculated

Posted on February 2nd, 2017

Note: the original post was edited 2/27/16 to reflect updated data:   During 2016, IIHR Hydroscience and Engineering along with USGS had 14 real-time nitrate sensors deployed in locations that captured water quality conditions for 82.5% of the water leaving the state of Iowa. From this measured data (average of 217 days per site), I […]

Is January river nitrate a predictor for the entire year?

Posted on January 30th, 2017

January is only one of 12 months, but in fact it is not a bad predictor of where the annual average Raccoon River nitrate will settle 11 months from now. This January, nitrate levels have averaged about 6.7 mg/L. When January nitrate was between 6 and 8 mg/L in the period of 1974-2016, annual nitrate ended up between […]

Summary of 2016 Nitrate: Raccoon and Des Moines Rivers: Corrected 2016 Loads

Posted on January 6th, 2017

    I first posted this last week, and made some mistakes in process. I used English Tons units for the load instead of my tradtional metric tons. Thus the 2016 loading numbers were about 10% higher than what they should have been. This made 2016 at the Des Moines River (at 2nd Ave in Des […]

Climate change and stream nitrate

Posted on January 1st, 2017

What might climate change mean for stream nitrate loads? In the Raccoon River watershed, precipitation has increased about 25% since 1916. This, coupled with land use change (artificial drainage and conversion of native perennial plants to annual crops) has increased average streamflow (discharge) in the river about 250% over the same time period (Figure 1). […]

November Nitrate, Raccoon and Des Moines Rivers

Posted on December 5th, 2016

This year the story continues to be the large loading on the Des Moines River. There is an outside shot that 2016 will be the largest year ever for N loads on the Des Moines. However cold weather in the forecast will likely result in 1991 continuing to be the largest, followed by 2016 and then […]

Raccoon and Des Moines River Nitrate: October and YTD (10/31)

Posted on December 3rd, 2016

A little late with this, but October summaries here. Looks like this year the story is going to be the Des Moines River. I will be looking at some discharge and rainfall data for this basin soon.  

Cedar River Hydrograph-Nitragraph animation

Posted on October 27th, 2016

My last post discussed how Cedar River nitrate loading responded to flood of late September. This post builds on that with some excellent animations created by my colleague, Antonio Arenas. The text below refers to the animation that can be watched here: https://www.youtube.com/watch?v=-qjrvQd95To&feature=youtu.be. In watersheds with a lot of tile drainage, nitrate concentrations and loads […]

Nitrate Loads Associated with Cedar River Flood

Posted on October 11th, 2016

Cities along the Cedar River and some of its tributaries just experienced an historic flood over the past two weeks, with river stages reaching their 2nd-highest level ever only eight years after the devastating 2008 deluge. The flood also delivered a lot of nitrate-nitrogen to the stream network, where it then reaches the Mississippi River […]