Predicting Acid Neutralizing
Capacity for the Mid-Atlantic
Highlands Region
Brett Kellum
Jennifer Hoeting
N. Scott Urquhart
Colorado State University
September 21, 2002
FUNDING SOURCE
• This presentation was developed under the STAR
Research Assistance Agreement CR-829095 awarded by
the U.S. Environmental Protection Agency (EPA) to
Colorado State University. This presentation has not
been formally reviewed by EPA. The views expressed
here are solely those of its authors and the STARMAP
Program. EPA does not endorse any products or
commercial services mentioned in this presentation.
Introduction
A. What is Acid Neutralizing Capacity
(ANC)?
B. Remotely sensed model predictors
C. Data source: EMAP - Mid-Appalachian
Highlands Region Assessment
Histogram of Acid Neutralizing Capacity
40
20
0
# of observations
60
80
N = 238
0
1000
2000
3000
ANC
4000
5000
6000
Distribution of ANC by Geologic Class
ANC
5000
3000
1000
-1000
Argillace
Carbonate
Felsic
class
Mafic
Siliceous
ANC Sites by Available Geology
NA
Argillace
Carbonate
Felsic
Mafic
Siliceous
Unclassif
Location and Magnitude of ANC in MAHA region
Predictors Considered for Model
• Elevation
• Bedrock Geology (with 5 classes)
• 13 Thematic Mapper Imagery Classifications
• Alber’s Projection Coordinates
• Strahler Order
Final data set contains 238 sites
Final Predictors in current “best” Regression Model
(Transformations)
Response:
Predictors:
Acid
Neutralizing % Probable Row Crops
Capacity (log) % Pasture (log)
% Urban – High Density (log)
% Emergent Wetlands (log)
% Woody Wetlands (log)
% Quarry
Elevation
Model Summary
Carbonate Bedrock
2 = 0.58
R
Felsic Bedrock
Overall p-value <.0001
0.4
0.2
0.0
Correlation
0.6
0.8
1.0
Omnidirectional Correlgram of residuals
0.0
0.5
1.0
Euclidean distance between points
1.5
0.4
0.2
0.0
Correlation
0.6
0.8
1.0
Directional Correlogram of residuals
50 degree angle, 10 degrees span
0.0
0.5
1.0
Euclidean distance between points
1.5
2.0
V. Areas of Further Research
A. More work in the area of
anisotropic spatial models
B. Including interaction terms in the
model
C. Weighted Least Squares
D. Predictive ability of models in
other areas of MAHA
-1. 5
-0. 5
Resids
-0. 5
-1. 5
Resids
0.5 1.0
Plot of Resids vs. log(Pasture)
0.5 1.0
Plot of Resids vs. Probable
0
20
40
60
-6
-4
Probable
0
2
4
log(Pasture)
-0. 5
-1. 5
-1. 5
-0. 5
Resids
0.5 1.0
Plot of Resids vs. Elevation
0.5 1.0
Plot of Resids vs. log(Urb.hi)
Resids
-2
-6
-4
-2
log(Urb.hi)
0
2
200
400
600
800
1000
1200
Elevation
Tue Sep 17 12:26:51 2002
-1. 5
-0. 5
Resids
-0. 5
-1. 5
Resids
0.5 1.0
Plot of Resids vs. log(Emergent)
0.5 1.0
Plot of Resids vs. Quarry
0
5
10
15
20
25
-6
-4
Quarry
0
log(Emergent)
-0. 5
-1. 5
-1. 5
-0. 5
0.5 1.0
Plot of Resids by carbon and felsic geology
0.5 1.0
Plot of Resids vs. log(Woody)
Resids
-2
-6
-4
-2
0
2
0
1
log(Woody)
Tue Sep 17 12:26:51 2002
-1. 5
-0. 5
resid
-0. 5
-1. 5
Resids
0.5 1.0
QQ plot of Residuals
0.5 1.0
Plot of Resids vs. Fitted Values
6.0
6.5
7.0
7.5
Fitted values
8.0
8.5
-3
-2
-1
0
1
2
3
Quantiles of Standard Normal
Tue Sep 17 12:26:51 2002
150
100
50
0
# of observations
200
250
Histogram of Acid Neutralizing Capacity From Full MAHA Data
-2000
0
2000
Acid Neutralizing Capacity
4000
6000
Coefficients:
Value
(Intercept) 7.8
pasture
0.0361
probable
0.0133
row.crops 0.0102
decid
-0.0025
mixed
0.0554
evergreen -0.0210
urb.hi
0.0437
urb.low
0.0247
emergent
0.0559
woody
-0.0468
transition -0.0030
quarry
0.0113
water
-0.0110
elev
-0.0007
carbon
0.4408
felsic
-0.2392
arg
0.0356
silic
-0.0211
ord2
-0.1206
ord3
-0.1471
X
-0.0841
Y
-0.0846
X^2
0.0058
Y^2
-0.1141
X*Y
0.1067
Pr(>|t|)
<.0001
0.0169
0.0184
0.5017
0.3589
0.1624
0.1991
0.0713
0.1898
0.0160
0.0203
0.8109
0.4649
0.5110
0.0006
0.0302
0.2233
0.8480
0.9144
0.1630
0.1355
0.1223
0.0649
0.8951
0.0155
0.0748
Multiple R-Squared: 0.6394
Overall p-value is <.0001
Coefficients:
Value
Pr(>|t|)
(Intercept) 7.4355
<.0001
probable
0.0119
0.0008
pasture
0.0529
<.0001
urb.hi
0.0686
0.0002
emergent
0.0446
0.0369
woody
-0.0694
0.0003
quarry
0.0260
0.0750
elev
-0.0005
0.0007
carbon
0.5215
<.0001
felsic
-0.2935
0.0040
Multiple R-Squared: 0.5784
Overall p-value is <.0001
0.4
0.2
0.0
-0.2
yp
0.6
0.8
1.0
Directional Correlogram of residuals w / X and Y
50 degree angle, 10 degrees span
0.0
0.5
1.0
xp
1.5
2.0