Nutrient and sediment concentrations and corresponding loads during the historic June 2008 flooding in eastern Iowa

Journal of Environmental Quality
By: , and 

Links

Abstract

A combination of above-normal precipitation during the winter and spring of 2007-2008 and extensive rainfall during June 2008 led to severe flooding in many parts of the midwestern United States. This resulted in transport of substantial amounts of nutrients and sediment from Iowa basins into the Mississippi River. Water samples were collected from 31 sites on six large Iowa tributaries to the Mississippi River to characterize water quality and to quantify nutrient and sediment loads during this extreme discharge event. Each sample was analyzed for total nitrogen, dissolved nitrate plus nitrite nitrogen, dissolved ammonia as nitrogen, total phosphorus, orthophosphate, and suspended sediment. Concentrations measured near peak flow in June 2008 were compared with the corresponding mean concentrations from June 1979 to 2007 using a paired t test. While there was no consistent pattern in concentrations between historical samples and those from the 2008 flood, increased flow during the flood resulted in near-peak June 2008 flood daily loads that were statistically greater (p < 0.05) than the median June 1979 to 2007 daily loads for all constituents. Estimates of loads for the 16-d period during the flood were calculated for four major tributaries and totaled 4.95 x 10(7) kg of nitrogen (N) and 2.9 x 10(6) kg of phosphorus (P) leaving Iowa, which accounted for about 22 and 46% of the total average annual nutrient yield, respectively. This study demonstrates the importance of large flood events to the total annual nutrient load in both small streams and large rivers.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Nutrient and sediment concentrations and corresponding loads during the historic June 2008 flooding in eastern Iowa
Series title Journal of Environmental Quality
Volume 40
Issue 1
Year Published 2011
Language English
Publisher American Society of Agronomy
Publisher location Madison, WI
Contributing office(s) Iowa Water Science Center
Description 9 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Environmental Quality
First page 166
Last page 175
Country United States
State Iowa
Other Geospatial Mississippi River