xv
List of Figures
known to have low ANC, which are represented as dots on
the map. Streams having ANC less than 0 μeq/L are coded
in black; streams having ANC between 0 and 20 μeq/L are
coded in white.
154
Figure 5.12 Critical load simulated by the Model of Acidification of
Groundwater in Catchments (MAGIC) to protect streams
in Shenandoah National Park against acidification to
ANC below 0 (top panel) and 20 μeq/L (bottom panel)
by the year 2040 is plotted as a function of 1990 ANC.
Stream sites are coded to show differences in geology.
This approach yields a predictive equation with which to
estimate the model projected value (in this example of
critical load) for a specific stream based on the measured
value of ANC in that stream.
156
Figure 5.13 Some example trend analyses of ANC in lake and stream
waters, based on data from EPA’s Long-Term Monitoring
(LTM) program. These examples illustrate that
interannual and intra-annual variability can sometimes
be larger than the change over time in the variable of
interest.
157
Figure 5.14 Relationship between lake size and lake ANC in the
Adirondack Mountains.
160
Figure 5.15 Nitrogen outputs in soil water or stream water versus N
deposition inputs throughout Europe.
161
Figure 5.16 Example patterns of NO 3
− concentration in surface
water at four sites at various stages of watershed N
saturation.
162
Figure 5.17 Schematic representation of data normality.
164
Figure 5.18 Plot, with regression line, of SO 4
2− concentration in Deep
Run, Shenandoah National Park, over the period of
monitoring record through 2002.
165
Figure 6.1 Design for the reachwide benthic macroinvertebrate
sample.
183
Figure 6.2 Modified D-frame kick net: (a) schematic drawing (not
drawn to scale); (b) photograph showing EMAP crew
sampling macroinvertebrates with modified D-frame
net in Utah.
189
List of Figures
known to have low ANC, which are represented as dots on
the map. Streams having ANC less than 0 μeq/L are coded
in black; streams having ANC between 0 and 20 μeq/L are
coded in white.
154
Figure 5.12 Critical load simulated by the Model of Acidification of
Groundwater in Catchments (MAGIC) to protect streams
in Shenandoah National Park against acidification to
ANC below 0 (top panel) and 20 μeq/L (bottom panel)
by the year 2040 is plotted as a function of 1990 ANC.
Stream sites are coded to show differences in geology.
This approach yields a predictive equation with which to
estimate the model projected value (in this example of
critical load) for a specific stream based on the measured
value of ANC in that stream.
156
Figure 5.13 Some example trend analyses of ANC in lake and stream
waters, based on data from EPA’s Long-Term Monitoring
(LTM) program. These examples illustrate that
interannual and intra-annual variability can sometimes
be larger than the change over time in the variable of
interest.
157
Figure 5.14 Relationship between lake size and lake ANC in the
Adirondack Mountains.
160
Figure 5.15 Nitrogen outputs in soil water or stream water versus N
deposition inputs throughout Europe.
161
Figure 5.16 Example patterns of NO 3
− concentration in surface
water at four sites at various stages of watershed N
saturation.
162
Figure 5.17 Schematic representation of data normality.
164
Figure 5.18 Plot, with regression line, of SO 4
2− concentration in Deep
Run, Shenandoah National Park, over the period of
monitoring record through 2002.
165
Figure 6.1 Design for the reachwide benthic macroinvertebrate
sample.
183
Figure 6.2 Modified D-frame kick net: (a) schematic drawing (not
drawn to scale); (b) photograph showing EMAP crew
sampling macroinvertebrates with modified D-frame
net in Utah.
189