Solute transport into Shark River Slough Troy D. Hill 1 , Kevin Kotun 2 1 National Park Service, Department of the Interior 2 United States Geological Survey, Department of the Interior
Solute transport into Shark River Slough
Troy D. Hill1, Kevin Kotun2
1National Park Service, Department of the Interior2United States Geological Survey, Department of the Interior
2
1. Application of WRTDS to stations at ENP northern boundary, 1992 - 2017
2. Trends in nutrients (TP, TKN) and geogenic solutes (Ca, Mg, Na)
Outline
3
> 5000 sampling locations
4
S151
S333
S12A S12BS12D
S12C
5
Why model concentrations?
Sampling events may not be representative
6
C-Q relationships are not uniform
WRTDS – WTF?• Weighted Regression on Time, Discharge, and Season (EGRET)
• Allows time and discharge relationships to vary• Estimates raw and flow-normalized concentrations
• What are the trends? How confident are we?• Do trends differ by season? By discharge magnitude?
7Hirsch et al. 2010; Hirsch et al. 2015
8
TP time series for S333
- estimated· observed
TP (m
g·L-1
)
9
· annual mean conc- flow-normalized conc (FNc)
TP a
t S33
3 (m
g·L-1
)Bootstrapped trend in FNc 1992-2017
Dens
ityComparison
10
Water quality trends: 1992-2017
11
TP at different flows (S333)1987 - 1991 2015 - 2019
TP (m
g·L-1
)
12
Ca+Mg at different flows (S333)1987 - 1991 2015 - 2019
Hard
ness
as C
aCO
3(m
g·L-1
)
13
Conclusions
• WRTDS is a promising tool
• Water quality gains more dramatic for nutrient concentrations vs. fluxes
• Concentrations of geogenic solutes are also declining – less groundwater
• Nutrient reductions more dramatic at low flows
DataForEver data requests: [email protected]
S151 S333 S12A
S12B S12C S12D
TP (m
g·L-1
)