Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-1 September 24, 2010

APPENDIX I.

Documentation of the Reduced Sensitivity to Load Reductions at Low Nonattainment Percentages

The Chesapeake Bay water quality criteria adopted by the four Bay jurisdictions into their 

respective water quality standards (WQS) regulations provide for allowable exceedances of each 

set of DO, water clarity and chlorophyll a criteria defined through application of a biological or 

default reference curve (U.S. EPA 2003). Figure I-1 depicts this concept in yellow as allowable 

exceedance of the criterion concentration. In order to compare the Chesapeake Bay Water 

Quality Model results with the Bay jurisdictions WQS, the model results for each scenario and 

for each modeled segment are analyzed to determine the percent of time and space that the 

modeled DO results exceed the allowable concentration. For any modeled result where the 

exceedance in space and time (shown in Figure I-1 as the red line) exceeds the allowable 

exceedance (shown in Figure I-1 as the yellow area), that segment is considered in nonattainment. This amount of non-attainment is shown in the figure as the area in white between 

the red line and the yellow area and is typically displayed in model results as percent of nonattainment for that segment. The amount of non-attainment is reported to the whole number 

percent. The yellow area below the blue reference curve reflects the amount of „allowable‟ 

criteria exceedance. The area between the blue reference curve and the red CFD curve is the 

amount of „unallowable‟ criteria exceedance, defined here as the „red area‟

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

Percent of Space

Percent of Time

CFD Curve

Area of Criteria 

Exceedence

Area of Allowable

Criteria 

Exceedence

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

Percent of Space

Percent of Time

CFD Curve

Area of Criteria 

Exceedence

Area of Allowable

Criteria 

Exceedence

Source: USEPA 2003.

Figure I-1. Illustration of the application of a reference curve to the cumulative frequency distribution to 

assess Chesapeake Bay water quality criteria attainment.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-2 September 24, 2010

Figure I-2 below displays Chesapeake Bay Water Quality Model results showing percent nonattainment of the 30-day mean open-water dissolved oxygen criterion for various basin-wide 

loading levels of the Maryland portion of the lower central Chesapeake Bay segment 

CB5MH_MD.

0

0.2

0.4

0.6

0.8

1

1.2

1 2 3 4 5 6 7 8 9 10 11 12

9% DISSOLVED OXYGEN NON ATTAINMENT 

324TN

24.1TP

309TN

19.5TP

248TN

16.6TP

200TN

15TP

191TN

14.4TP

190TN

12.6TP

179TN

12.7TP

170TN

11.3TP

141TN

8.5TP

58TN

4.4TP

85TN

5.7TP

113TN

7.1TP

0%

1%

2%

3%

4%

5%

6% MODEL RESULTS CB5 - MD

BASIN WIDE LOAD (MILLION POUNDS PER YEAR)

Source: Appendix O.

Figure I-2. Example of dissolved oxygen criteria non-attainment results from a wide range of nutrient load 

reduction model scenarios.

As can be seen in Figure I-2, there is a notable improvement in the percent non-attainment as the 

loads are reduced until approximately 1 percent non-attainment. At a loading level of 190 million 

pounds per year total nitrogen and 12.7 million pounds per year total phosphorus, the 1 percent 

non-attainment is persistent through consecutive reductions in loading levels and remains 

consistent until a loading level of 58 million pounds per year total nitrogen and 4.4 million 

pounds per year of total phosphorus is reached. While this is one of the more extreme examples 

of persistent levels of 1 percent non-attainment, this general observation of persistent nonattainment at 1 percent is fairly common to the Bay Water Quality Model results as described 

and documented below. 

This empirical observation is likely based on the geometry of the time and space-based 

assessment of the Bay WQS. An initial reduction made in the nutrient loads would be associated 

with an increase in attainment of the WQS as shown in the green line in Figure I-3. As 

reductions move toward attainment, they move toward the area of allowable criteria exceedance 

as shown by the light green line in Figure I-3. Note that even though the reduced nutrient loads 

under the scenario represented by the light green line continue to reduce the time and space of 

WQS nonattainment, different rates of improvement exist at different portions of the curve. In 

this hypothetical example, the scenario represented by the light green line has reduced the time 

of exceedance well below the area of allowable exceedance, but the space component still 

showed a very low level of non-attainment.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-3 September 24, 2010

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

Percent of Space

Percent of Time

CFD Curve

Area of Criteria 

Exceedence

Area of Allowable

Criteria 

Exceedence

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

Percent of Space

Percent of Time

CFD Curve

Area of Criteria 

Exceedence

Area of Allowable

Criteria 

Exceedence

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

Percent of Space

Percent of Time

CFD Curve

Area of Criteria 

Exceedence

Area of Allowable

Criteria 

Exceedence

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

Percent of Space

Percent of Time

CFD Curve

Area of Criteria 

Exceedence

Area of Allowable

Criteria 

Exceedence

Figure I-3. A graphical representation of how the persistent 1% nonattainment may arise in the criteria 

assessment of the Chesapeake water quality standards.

The observation of a small, yet persistent percentage of model projected dissolved oxygen 

criteria non-attainment across a wide range of segments and designated uses, all of which are 

responding to nutrient load reductions, is an outcome of the criteria assessment methodology. 

Given that this has been observed in a wide variety of different segments across all three 

designated uses—open-water, deep-water and deep-channel—non-attainment percentages 

projected by the Bay Water Quality Model rounded to 1 percent were considered to be in 

attainment for a segment‟s designated use for purposes of developing the Chesapeake Bay 

TMDL. Clear evidence of small, yet persistent percentage of model projected DO criteria nonattainment across a wide range of segments and designated uses is documented within this 

appendix.

A separate validation of the findings described above was undertaken to confirm that 1 percent 

was the correct percentage below which the designated use-segment could be considered in 

attainment and is provided within this appendix.

Reporting of Criteria Non-Attainment Percentages

Chesapeake Bay modeling results for dissolved oxygen, chlorophyll a and water clarity criteria 

non-attainment percentages are rounded to whole numbers. This is a common scientific practice 

and principle for conveying data to the public and is fully consistent with how many others 

report modeling output. 
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-4 September 24, 2010

Documenting Attainment for 1% Non-Attainment Dissolved Oxygen 

Criteria Values

The Chesapeake Bay water quality criteria adopted by the states and the District of Columbia 

into their respective water quality standards regulations already provides for „allowable‟ 

exceedances of each set of dissolved oxygen, water clarity and chlorophyll a criteria defined 

through application of a biological or default reference curve (U.S. EPA 2003). What is being 

addressed here is how to address 1% non-attainment dissolved oxygen, water clarity and 

chlorophyll a criteria values assessed using the CFD-based criteria assessment procedures in the 

face of clear evidence: 1) for persistence over large simulated load reductions across numerous 

segments and designated uses; and 2) reduced sensitivity to load reductions at and below the 1% 

non-attainment level. 

Evaluation of Residual 1.499 Percent or Less Non-attainment Values

There is clear evidence for a „residual‟ of 1% non-attainment across a large span of modelsimulated load reductions across a number of tidal Bay segments and designated uses (Table I1). Within the Bay TMDL document and supporting appendices, the reported criteria attainment 

values already account for the allowable exceedances documented in each Bay jurisdiction‟s 

respective Chesapeake Bay water quality standards regulations. These reported criteria 

attainment values also account for any restoration variances adopted by the Bay jurisdictions into 

their water quality standards regulations. All the values that are colored green denote full 

attainment of the respective criteria, dissolved oxygen in this case.

For illustration purposes only, as observed in the dissolved oxygen „stoplight plot‟ spreadsheet 

dated May 24, 2010 shared with members of the Chesapeake Bay Program‟s Water Quality Goal 

Implementation Team, there were 21 designated use-segments where the recorded model 

scenario-transformed monitoring data non-attainment values between 0.0% and 1.5% across a 

range of model scenarios. (Please note all the values reported in Table I-1 would round to 0% or 

1%.) These model scenarios had loading levels which spanned 9 to 151 million pounds of 

nitrogen and comparable ranges of phosphorus loading levels (Table I-1).

Table I-1. The range of dissolved oxygen criteria non-attainment percentages across different 

model simulated nitrogen load ranges for 21 Chesapeake Bay segments-designated uses

Chesapeake Bay 

Segment

Designated Use Criteria Nonattainment Range1

(%)

Model Simulated 

Nitrogen Load Range 

(million pounds/yr)

CB7 Open-water 0.5-0.0 200-141

CHOMH1 Open-water 0.1-0.0 254-179

CSHMH Open-water 0.8-0.1 342-309

DCATF Open-water 1.2-0.1 191-179

PAXTF Open-water 1.0-0.6 190-179

DCPTF Open-water 0.6-0.2 309-254

MAGMH Open-water 1.3-0.3 342-191

MOBPH Open-water 1.0-0.0 342-200

PIAMH Open-water 0.1-0.1 191-179

TANMH Open-water 1.5-0.1 342-309

YRKMH Open-water 1.0-0.4 191-170

CB3MH Deep-water 0.6-0.0 254-179

CB5MH Deep-water 1.5-0.0 254-141
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-5 September 24, 2010

Chesapeake Bay 

Segment

Designated Use Criteria Nonattainment Range1

(%)

Model Simulated 

Nitrogen Load Range 

(million pounds/yr)

CHSMH Deep-water 0.5-0.4 170-141

EASMH Deep-water 0.8-0.2 200-170

MD5MH Deep-water 1.5-0.1 191-141

MAGMH Deep-water 0.5-0.5 170-141

PATMH Deep-water 1.1-0.1 200-190

VA5MH Deep-water 0.7-0.0 254-179

CB3MH Deep-channel 0.2-0.1 200-190

EASMH Deep-channel 1.3-0.0 190-170

1. Each 0.0% value in this column is colored in red in the original May 24, 2010 ‘stoplight plot’ 

spreadsheet, denoting a very low percentage of non-attainment was recorded below 0.1%.

Source: The dissolved oxygen criteria attainment detailed stoplight spreadsheet dated May 24, 2010 

presented to the Chesapeake Bay Program’s Water Quality Goal Implementation Team during the 

Team’s May 24, 2010 conference call.

The observation of a small, yet persistent percentage of dissolved oxygen criteria non-attainment 

across a wide range of segments and designated uses, all of which are responding to nutrient load 

reductions, is an artifact of the criteria assessment methodology as described above and 

illustrated in Figure I-1. The entire analysis system can all result in such small non-attainment 

percentages over a range of scenario loading levels. The analysis system includes the following 

steps: 

calculate the model output differences between the scenario and the base calibration 

use differences to develop the regression 

apply regression to transform monitoring data to reflect scenario differences in water 

quality 

interpolate transformed monitoring data 

develop cumulative frequency distribution using interpolated data 

compare with the biological or default reference 

produce a non-attainment percentage—can all result in such small non-attainment 

percentages over a range of scenario loading levels.

There is not comparable evidence of persistent percentages of dissolved oxygen criteria nonattainment above 1% across a wide range of segments and designated uses for segments 

responding to nutrient load reductions. There were several open-water segments where the same 

percentage non-attainment persists across a wide set of nutrient loading reductions—e.g., 

Gunpowder River (GUNOH) at 5% from 342 TN to 85 TN, Wicomico River (WICMH) at 5% 

from 191 TN to 85 TN, several segments in Pocomoke River at 5% from 179 TN to 85 TN (see 

Appendix O). However, all these segments have been identified as having poor local responses 

to load reductions in the Bay Water Quality Model scenarios based on poor regressions. Other 

lines of evidence, separate from the model generated outputs were used to determine attainment 

and develop the respective Bay segment TMDL (see Appendix N). The cause for these persistent 

percentages is different from small, yet persistent percentages being addressed in this appendix. 
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-6 September 24, 2010

Analysis of D.O. Criteria Attainment Sensitivity to Simulated Load 

Reductions

A separate validation of the findings described above was undertaken to confirm that 1% was the 

correct percentage below which the designated use-segment could be considered in attainment. 

This analysis involves plotting the change in unallowable dissolved oxygen criterion exceedance 

or “red area” under the reference curve (see Figure I-1) per loading unit against the starting “red 

area”. The change in red area between two scenarios is divided by the change in load. For this 

analysis, the changes in nitrogen (N) and phosphorus (P) loads are combined into a single 

measure, load units, enabling the calculation of change in red area per change in load:

load units = (N + 10*P) /2) Equation L-1

This single measure, when plotted against starting red area, allows a direct comparison of 

sensitivity of the analysis system1to load changes across different levels of non-attainment. To 

get a true sensitivity, calculations involving scenarios that attained the applicable dissolved 

oxygen criteria were not included. Twelve scenarios were used with eight 3-year periods for a 

total of 88 possible sensitivity assessments per designated-use segment, decreased by the number 

of assessments that attained the applicable dissolved oxygen criterion.

This analysis was not amenable to tidal tributary segments as the loadings are bay-wide and not 

specific to an individual tidal tributary. Further, some of the existing scenarios used for this 

analysis have varying levels of reduction between different tributaries. 

The CB7PH open-water segment provides a clear example of a decrease in sensitivity to load 

reductions as non-attainment approaches zero. The highest sensitivity to load reductions is with 

the highest red area, but there is still considerable sensitivity to load reductions through 

approximately 0.2% (Figure I-4). Another example is CB2OH open-water, where there is a sharp 

drop off in sensitivity to load reductions near 1% (Figure I-5).

 

1 The analysis system referred to here is the combination of the Chesapeake Bay Water Quality/Sediment Transport 

Model, the procedures for using differences in Bay model scenarios outputs to transform Bay water quality 

monitoring data, and the EPA published Bay criteria assessment procedures.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-7 September 24, 2010

CB7PH Open Water

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

0.0012

0.0014

0.0016

0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0%

Red Area

Load Sensitivity (red area per load)

Figure I-4. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB7PH open-water.

CB2OH Open Water

0.0000

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0% 0.5% 1.0% 1.5% 2.0% 2.5% 3.0% 3.5% 4.0% 4.5% 5.0%

Red Area

Load Sensitivity (red area per load)

Figure I-5. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB2OH open-water.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-8 September 24, 2010

A counter-example is CB5MH open-water, where the sensitivity to load reductions is relatively 

constant throughout the model simulated range of load reductions (Figure I-6). 

There are a large number of segments that could be analyzed (see Table I-1), but it is most 

appropriate to focus on those designated-use segments most important to the Bay TMDL—those 

requiring significant basinwide nutrient reductions in order to come in attainment with the 

respective dissolved oxygen criterion. These designated use-segments are CB3MH, CB4MH, 

CB5MH for deep-water and deep-channel and POTMH for deep-channel.

The CB3MH deep-water segment has consistently reducing sensitivity to load reductions and no 

high sensitivity examples above 1% red area (Figure I-7). The CB4MH deep-water designated 

use-segment shows relatively consistent sensitivity across a wide range of red area (Figure I-8). 

The CB5MH deep-water designated use-segment (Figure I-9) and the POTMH deep-water 

designated use-segment (Figure I-10) are relatively constant across wide ranges but have a clear 

reduction in sensitivity to load reductions around 1%.

The deep-channel designated use-segment plots are similar to the deep-water designated usesegment plots. The CB3MH deep-channel designated use-segment also shows a consistent range 

of sensitivity throughout multiple ranges of red area, but has low sensitivity to further load 

reductions at 1-1.5% red area (Figure I-11). The CB4MH deep-channel designated use-segment 

shows a clear drop-off in sensitivity to load reductions at 1% (Figures I-12 and I-13). The 

CB5MH deep-channel designated use-segment has no basis to make the judgment as there are no 

red area values less than 15% (Figure I-14).

Although there is some discretion involved in the judgment of exactly when sensitivity to further 

load reductions becomes low, there is a general decrease in sensitivity when the red area is low. 

One percent is a relatively consistent level at which sensitivity decreases significantly across 

many of the principal designated use-segments used for decision-making in the Chesapeake Bay 

TMDL (Table I-2). At the non-attainment values of 1 percent (or less), there is a significant drop 

off in the sensitivity—further reduction in dissolved oxygen criteria non-attainment—of these 

designated use-segments to further load reductions. The analysis system is not sensitive to the 

effects of further load reductions at the 1% or less non-attainment level. This finding is fully 

consistent with findings from the parallel analysis summarized in Table I-1 for a wider array of 

designated use-segments.

Application in Development of the Bay TMDL

Given these findings have been observed in a wide variety of different segments across all three 

designated uses—open-water, deep-water and deep-channel—and confirmed through an 

independent analysis, non-attainment percentages rounded to 1% are considered in attainment for 

that Bay segment‟s designated use for purposes of developing the Bay TMDL.

For those designated use-segments for which a jurisdiction has adopted a restoration variance 

that sets attainment at a percentage of the non-allowable criteria exceedances, the 1% nonattainment described above does not apply to assessment of the restoration variance percentage. 

For example, Maryland‟s designated use-segment CB4MH deep water has a restoration variance 
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-9 September 24, 2010

of 7%. Chesapeake Bay Water Quality Model-based criteria attainment assessment results 

showing 8% non-attainment would be considered in non-attainment.

The results of numerous dissolved oxygen criteria assessments are used here to illustrate and 

diagnosis the reasons behind the persistent low levels of non-attainment. However, the 

documentation of attainment for 1% non-attainment applies to dissolved oxygen, water clarity, 

and chlorophyll a criteria given each are assessed using the same set of CFD-based criteria 

attainment assessment procedures, the source of the persistent low levels of non-attainment 

(USEPA 2003).

Literature Cited

U.S. Environmental Protection Agency. 2003. Ambient Water Quality Criteria for Dissolved 

Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries. 

EPA 903-R-03-002. Region III Chesapeake Bay Program Office, Annapolis, Maryland.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-10 September 24, 2010

CB5MH Open Water

0.0000

0.0001

0.0001

0.0002

0.0002

0.0003

0.0003

0.0004

0.0004

0.0005

0.0% 0.5% 1.0% 1.5% 2.0% 2.5% 3.0% 3.5% 4.0% 4.5%

Red Area

Load Sensitivity (red area per load)

Figure I-6. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB5MH open-water.

CB3MH Deep Water

0.0000

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

0.0009

0.0010

0.0% 1.0% 2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 10.0%

Red Area

Load Sensitivity (red area per load)

Figure I-7. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB3MH deep-water.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-11 September 24, 2010

Table I-2. Summary of findings from the analysis of red area with low sensitivity to load reductions 

for the Chesapeake Bay designated use

Chesapeake Bay 

Segment

Designated Use Red Area with Low Sensitivity to 

Load Reductions (%)

CB3MH Deep-water 0.2

CB4MH Deep-water 0

CB5MH Deep-water 1

POTMH Deep-water 1

CB3MH Deep-channel 1-1.5

CB4MH Deep-channel 1

CB5MH Deep-channel N/A

Sources: Figures I-7 through I-14 in this appendix.

CB4MH Deep Water

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0% 35.0% 40.0%

Red Area

Load Sensitivity (red area per load)

Figure I-8. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB4MH deep-water.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-12 September 24, 2010

CB5MH Deep Water

0.0000

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

0.0009

0.0% 1.0% 2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 10.0%

Red Area

Load Sensitivity (red area per load)

Figure I-9. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB5MH deep-water.

POTMH Deep Water

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

0.0012

0.0014

0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0%

Red Area

Load Sensitivity (red area per load)

Figure I-10. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment POTMH deep-water.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-13 September 24, 2010

CB3MH Deep Channel

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% 16.0% 18.0% 20.0%

Red Area

Load Sensitivity (red area per load)

Figure I-11. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB3MH deep-channel.

CB4MH Deep Channel

0.0000

0.0010

0.0020

0.0030

0.0040

0.0050

0.0060

0.0070

0.0080

0.0090

0.0100

0.0% 10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 70.0%

Red Area

Load Sensitivity (red area per load)

Figure I-12. Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB4MH deep-channel.
Draft Appendix I – Chesapeake Bay TMDL for Nutrients and Sediment

I-14 September 24, 2010

CB4MH Deep Channel

0.0001

0.0011

0.0021

0.0031

0.0041

0.0051

0.0061

0.0071

0.0081

0.0091

0.0101

0.0% 1.0% 2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 10.0%

Red Area

Load Sensitivity (red area per load)

Figure I-13. Expanded view of the Figure 10 focusing down on the 0-10% red area for segment CB4MH deepchannel to illustrate the drop off in sensitivity at the 1-1.5% of red area.

CB5MH Deep Channel

0.0001

0.0011

0.0021

0.0031

0.0041

0.0051

0.0061

0.0071

0.0081

0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0% 35.0% 40.0% 45.0% 50.0%

Red Area

Load Sensitivity (red area per load)

Figure I-14 Load sensitivity (unallowable dissolved oxygen criteria exceedances per load unit) vs. red area 

(unallowable dissolved oxygen criteria exceedances) for designated use-segment CB5MH deep-channel.