Date of Degree
MS (Master of Science)
Civil and Environmental Engineering
Weber, Larry J.
First Committee Member
Second Committee Member
Conservation practices are needed to reduce nitrate loss across the Midwest. Different riparian wetland designs have been investigated, but the physical, chemical and biological processes controlling nutrient cycling in restored oxbows are not well understood. A restored oxbow’s influence on nutrient cycling was investigated by studying the hydrogeology and water quality at a recently reconstructed oxbow site adjacent to Morgan Creek in Linn County, Iowa. Over a one-year period, the lentic oxbow’s nitrate loading was found to be dominated by flood pulses. Nitrate concentrations in the stream ranged from 7.38 – 12.95 mg l-1, concentrations were consistently low in the oxbow ranging from < 0.10 – 5.35 mg l-1, and the lowest nitrate concentrations were detected in the groundwater ranging from 0.10 to 3.4 mg l-1. Following a spring flood event, an in-situ sensor measured the nitrate concentration in the oxbow. Nitrate retention efficiency was estimated to be 0.30 g N m-2 d-1 or a 74.2% reduction efficiency. The observed nitrate reduction was compared to a first order denitrification model. The observed nitrate reduction measured in the oxbow followed a linear decay rather than an exponential decay suggested by first order kinetics.
Floodplain Restoration, Nitrate Reduction, Oxbow, Oxbow Restoration
Includes bibliographical references (pages 90-98).
Copyright © 2017 Bryce Jordan Haines
Haines, Bryce Jordan. "Characterization of hydrology and water quality at a restored oxbow : ecosystem services achieved in year one." MS (Master of Science) thesis, University of Iowa, 2017.