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
&3
&3
&3
"/"/
"/ "/
"/"/ "/ "/
"/"/Legend
"/ UNCW-Sampling Sites
&3 StreamGages_NewRv
NHDFlowline_NewRv
flowlineattributesflow.MAFLOWU
0.00088 - 13.06333
13.06334 - 47.97963
47.97964 - 97.81542
97.81543 - 272.71247
272.71248 - 489.09477
NHDwaterbody_NewRv
NewRiverSubbasin
LULC
Value
Developed
Forest/Scrub/Grassland
Agriculture
Wetlands
M52
172
Percentages of LULC
LULC in the New River Estuary
7%
44%
15%
34%Developed
Forest/Scrub/Grassland
Agriculture
Wetlands
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
Input Files
Output Files
Stats and ModelsSite-Constituent
Model-based on AIC PPCC
NH4-M52 2 0.9901
NH4-172 9 0.9971
NO3-M52 7 0.9907
NO3-172 9 0.9473
PO3-M52 9 0.9919
PO3-172 7 0.9919
Normal Distribution:
MLE – Max Likelihood Estimation
AMLE – Adjusted MLE (less biased)
PPCC – not normal distribution:
LAD – Least Absolute Deviation
Hurricane Floyd (500 yr Storm) – September 9-17th, 1999[NH4] 9/99 at site M52
-50000
0
50000
100000
150000
200000
250000
9/1/1999 9/9/1999 9/17/1999 9/25/1999
Time (days)
[NH
4]
kg
/da
y
0
2000
4000
6000
8000
10000
12000
Str
eam
flo
w (
cfs
)
AMLE MLE
LAD Streamflow
[NO3] 9/99 at site M52
-2000
0
2000
4000
6000
8000
10000
12000
9/1/1999 9/9/1999 9/17/1999 9/25/1999
Time (days)
NO
3 C
on
cen
trat
ion
(k
g/d
ay)
0
2000
4000
6000
8000
10000
12000D
isc
ha
rge
(c
fs)
AMLE MLE
LAD Streamflow
[PO3] at site M52, 9/99
-500
0
500
1000
1500
2000
2500
9/1/1999 9/9/1999 9/17/1999 9/25/1999
Time (days)
PO
3 C
on
cen
trat
ion
(kg
/day
)
0
2000
4000
6000
8000
10000
12000
Dis
char
ge
(cfs
)
AMLE MLE
LAD Streamflow
[NH4] for site 172, 9/99
-2000
0
2000
4000
6000
8000
10000
12000
14000
16000
9/1/1999 9/7/1999 9/13/1999 9/19/1999 9/25/1999
Time (days)
NH
4 c
on
ce
ntr
ati
on
s
(kg
/da
y)
0
2000
4000
6000
8000
10000
12000
Dis
ch
arg
e (
cfs
)
AMLE MLE
LAD Streamflow
[NO3] 9/99 at site 172
-20.00
0.00
20.00
40.00
60.00
80.00
100.00
120.00
9/1/1999 9/9/1999 9/17/1999 9/25/1999
Time (days)
[NO
3]
(kg
/day)
0
2000
4000
6000
8000
10000
12000
Str
eam
flo
w (
cfs
)
AMLE MLE
LAD Flow
[PO3] 9/99 at site 172
-200
20406080
100120140160180200
9/1/1999 9/9/1999 9/17/1999 9/25/1999
Time (days)
[PO
3]
(kg
/day)
0
2000
4000
6000
8000
10000
12000
Ste
am
flo
w (
cfs
)
AMLE MLE
LAD Streamflow
Hurricane Floyd
[PO3] M52 & 172, 9/99
-200
0
200
400
600
800
1000
9/1/1999 9/9/1999 9/17/1999 9/25/1999
Time (days)
PO
3 C
once
ntra
tion
(kg/
day)
0
2000
4000
6000
8000
10000
12000
Str
eam
flow
(cfs
)
M52 172
Streamflow
[NH4] at M52 & 172, 9/99
-5000.00
0.00
5000.00
10000.00
15000.00
20000.00
25000.00
30000.00
35000.00
40000.00
45000.00
9/1/1999 9/9/1999 9/17/1999 9/25/1999
Time (days)
NH
4 C
on
ce
ntr
ati
on
s
(kg
/da
y)
0
2000
4000
6000
8000
10000
12000
Str
ea
mfl
ow
(c
fs)
M52 172
Streamflow
[NO3] 172 & M52, 9/99
-2000.00
0.00
2000.00
4000.00
6000.00
8000.00
10000.00
12000.00
9/1/1999 9/9/1999 9/17/1999 9/25/1999
Time (days)
NO
3 C
on
cen
trat
ion
s (k
g/d
ay)
0
2000
4000
6000
8000
10000
12000
Str
eam
flo
w (
cfs)
172 M52
Streamflow
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
Questions??
