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Nutrient Fluxes in the New River, NC:. The Dark Side of Hog Farms. Rae Mooney Hydrology May 1, 2007. New River Watershed. 1,436 km 2 Fisheries Economy Recreation Home to 138 CAFOs July 1995: Holding pond ruptures on New River 25 million tons of hog waste. Mallin et al., 2005.
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Nutrient Fluxes in the New River, NC: The Dark Side of Hog Farms Rae Mooney Hydrology May 1, 2007
New River Watershed • 1,436 km2 • Fisheries • Economy • Recreation • Home to 138 CAFOs • July 1995: Holding pond ruptures on New River • 25 million tons of hog waste Mallin et al., 2005
Map of Study Area M52 172
Effects of Hog Farms and other Agriculture • Increased Eutrophication • Waste ponds overflow • Spray waste on fields – “overapplication” • Now, LESS farms w/ MORE HOGS • TOXIC and harmful to humans • Discharge – more than waste • Harmful Algal Blooms • Secrete toxins • Seafood – toxic to eat
LOADEST: Load Estimator • Estimates constituent loads using Linear Regression • Input: daily streamflow, data variables, monthly constituent concentrations • Output: daily constituent concentrations, residuals, z-scores, regression statistics from models
Stats and Models Normal Distribution: MLE – Max Likelihood Estimation AMLE – Adjusted MLE (less biased) PPCC – not normal distribution: LAD – Least Absolute Deviation
Conclusions • Must be careful to use BEST model • User-friendly • sometimes • Overall useful tool since continuous sampling impossible
Tomorrow… • For comparison • Chat w/ scientist at N.C. Division of Water Quality • Sampling from Hurricane Floyd • Look at effects of new wastewater treatment plants in 1998