The Confounding Effect of River Discharge on Estuarine Response to Nutrient Loading. Craig A. Stow NOAA Great Lakes Environmental Research Laboratory Ann Arbor, MI.
The Confounding Effect of River Discharge on Estuarine Response to Nutrient Loading
Craig A. Stow
NOAA Great Lakes Environmental Research Laboratory
Ann Arbor, MI
Borsuk, M. E., C. A. Stow, and K. H. Reckhow. 2004. Confounding effect of flow on estuarine response to nitrogen loading. Journal of Environmental Engineering, 130: 605-614.
Additional Insights and Inputs provided by Conrad Lamon and Song Qian
Vollenweider Cross-Sectional Lake Nutrient Loading Model
Brazenly stolen from:
Vollenweider, R.A. 1976. Advances in defining critical loading levels for phosphorus in lake eutrophication. Mem. Ist. Ital. Idrobiol., 33:53-83.
River discharge highly variable – even on relatively long time-scales
Drives Nutrient Load Variability at this scale
Concentration:Flow relationships idiosyncratic: positive, negative, or non-monotonic
In the Neuse the relationship was negative
Data Provided by:
NC DENR DWQ – nutrient concentrations
USGS – daily flow
Water Quality Station
Chlorophyll a Model
(Bayesian multilevel piecewise lognormal model)
Estuarine N Concentrations vs. Annual N Load
Estuarine P Concentrations vs. Annual P Load
Nonlinear chlorophyll, flow (~ load) relationship on short time-scales
Relationship differs systematically along spatial gradient
Maximum differs systematically along spatial gradient
No relationship between nutrient load, concentration on medium time-scales
This may differ among systems
Mississippi River Flow – Seasonal Trend Decomposition Using Loess
April 2006 - U.S. Court of Appeals District of Columbia Circuit ruled that EPA-approved plan to limit pollution into Anacostia River contrary to Clean Water Act requirements to set "total maximum daily loads" of pollutants.
January 2007 -- United States Supreme Court let stand lower court ruling requiring limits on pollution allowed in Anacostia River each day.
Upper Trophic Level