Journal article
Distribution and mass of groundwater orthophosphorus in an agricultural watershed
The Science of the total environment, Vol.625, pp.1330-1340
06/01/2018
DOI: 10.1016/j.scitotenv.2018.01.035
PMID: 29996430
Abstract
•Groundwater orthophosphorus concentrations were higher in floodplains than in uplands.•OP loading rates beneath floodplains are approximately three times higher than in uplands.•Eight years is needed to flush out existing OP mass present in shallow groundwater.•Conservation focused on floodplain areas may have disproportionately large water quality benefit.
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Orthophosphorus (OP) is the form of dissolved inorganic P that is commonly measured in groundwater studies, but the spatial distribution of groundwater OP across a watershed has rarely been assessed. In this study, we characterized spatial patterns of groundwater OP concentrations and loading rates within the 5218ha Walnut Creek watershed (Iowa) over a two-year period. Using a network of 24 shallow (<6m) monitoring wells established across watershed, OP concentrations ranged from <0.01 to 0.58mg/l in all samples (n=147) and averaged 0.084±0.107mg/l. Groundwater OP concentrations were higher in floodplains and OP mass loading rates were approximately three times higher than in uplands. We estimated that approximately 1231kg of OP is present in floodplain groundwater and 2869kg is present in upland groundwater within the shallow groundwater zone (0–5m depth). Assuming no new inputs of OP to shallow groundwater, we estimated it would take approximately eight years to flush out existing OP mass present in the system. Results suggest that conservation practices focused on reducing OP loading rates in floodplain areas may have a disproportionately large water quality benefit compared to upland areas.
Details
- Title: Subtitle
- Distribution and mass of groundwater orthophosphorus in an agricultural watershed
- Creators
- Keith E. Schilling - University of IowaMatthew T. Streeter - University of IowaThomas M. Isenhart - Iowa State UniversityWilliam J. Beck - Iowa State UniversityMark D. Tomer - National Laboratory for Agriculture and the EnvironmentKevin J. Cole - Agricultural Research ServiceJohn L. Kovar - National Laboratory for Agriculture and the Environment
- Resource Type
- Journal article
- Publication Details
- The Science of the total environment, Vol.625, pp.1330-1340
- Publisher
- Elsevier B.V
- DOI
- 10.1016/j.scitotenv.2018.01.035
- PMID
- 29996430
- ISSN
- 0048-9697
- eISSN
- 1879-1026
- Grant note
- DOI: 10.13039/100005825, name: National Institute of Food and Agriculture
- Language
- English
- Date published
- 06/01/2018
- Academic Unit
- Earth and Environmental Sciences; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984383293102771
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