Journal article
Long-term nitrate-nitrogen reductions in a large flood control reservoir
Journal of hydrology (Amsterdam), Vol.620, 129533
05/2023
DOI: 10.1016/j.jhydrol.2023.129533
Abstract
•Riverine NO3-N concentrations and loads were reduced in a large flood control reservoir.•Lake Red Rock reservoir reduced NO3-N an average of 7,379 Mg per year or 12.4 % of the reservoir inputs.•Annual NO3-N reductions in flood-control reservoirs are a function of water retention time.•Manipulating reservoirs for longer residence times may reduce downstream impairments.
Flood-control reservoirs are common in the U.S. and several are located in highly agricultural regions of the Midwest. In this study, a mass balance of annual and seasonal NO3-N concentration and load reductions was calculated for Lake Red Rock, a large flood-control reservoir located on the Des Moines River downstream of the City of Des Moines, Iowa. Utilizing rare long-term upstream and downstream NO3-N monitoring records extending back in time 42 years and combining this with estimates from tributary inputs, Lake Red Rock reservoir was found to remove an average of 7,379 Mg NO3-N per year, representing 12.4 % of the NO3-N inputs to the reservoir. Annual variations in NO3-N loss rate varied considerably (-2.9 % to 41.3 %) and were significantly related to annual reservoir water retention time. Combining study results with literature data, annual NO3-N reduction in Midwestern flood-control reservoirs was logarithmically related to average annual water retention time. Although flood-control reservoirs are designed primarily for flood protection, manipulating the reservoirs to achieve longer water retention times, particularly during periods of high NO3-N concentrations and loads, could be a strategy to alleviate impairments at downstream water suppliers and help state and federal agencies meet NO3-N reduction goals.
Details
- Title: Subtitle
- Long-term nitrate-nitrogen reductions in a large flood control reservoir
- Creators
- Keith E. Schilling - Iowa Geological Survey, University of Iowa, Iowa City, IA 52242, United StatesElliot Anderson - IIHR Hydroscience & Engineering, University of Iowa, Iowa City, IA 52242, United StatesMatthew T. Streeter - University of IowaChuck Theiling - U.S. Army Engineer Research and Development Center
- Resource Type
- Journal article
- Publication Details
- Journal of hydrology (Amsterdam), Vol.620, 129533
- Publisher
- Elsevier B.V
- DOI
- 10.1016/j.jhydrol.2023.129533
- ISSN
- 0022-1694
- eISSN
- 1879-2707
- Grant note
- DOI: 10.13039/100006505, name: US Army Corps of Engineers Engineer Research and Development Center; DOI: 10.13039/100006752, name: U.S. Army Corps of Engineers, award: W912HZ2120023
- Language
- English
- Date published
- 05/2023
- Academic Unit
- Earth and Environmental Sciences; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984400160102771
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