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Sea Won Kim - VASP Brown Bag - "Use of Water Quality Surrogates to Estimate Total Phosphorus Concentrations in Iowa Rivers"

Event Type
vasp brown bag
Center for East Asian and Pacific Studies
101 International Studies Building (910 S. Fifth Street, Champaign)
Oct 31, 2017   12:00 - 1:00 pm  
Sea Won Kim, Principal Researcher, Water Resources Research Center, K-water Research Institute, K-Water, South Korea
Originating Calendar
Asian American Studies

Accurate measurement of TP concentrations in rivers is needed to quantify loads and evaluate the progress of nutrient reduction strategies. We evaluated the relation of water quality surrogates, turbidity, ortho-phosphorus (OP), chlorophyll a, chloride and discharge to TP concentrations at 43 different river monitoring sites over a 15-year period. New hydrological insights for the region: TP concentrations were highly correlated to turbidity (0.78 ± 0.20) and OP (0.69 ± 0.13) across all sites and less correlated to chlorophyll a (0.07 ± 0.15), chloride (−0.10 ± 0.24) and discharge (0.41 ± 0.23). When the regression models included OP as a variable, the mean r2 for all 43 sites was 0.90 ± 0.08 and ten of the 43 sites had r2 values greater than 0.95. When OP was excluded in the regression model, the overall mean r2 values decreased to 0.72 ± 0.14 and for six of the river sites, the r2 value decreased by 50%. Other variables (discharge, chlorophyll a, chloride) were included in the regression equations on a case-by-case basis. Including OP in the regression models was critically important for rivers draining the tile-drained Des Moines Lobe region.

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