Chesapeake Bay Program Water Quality Standards Coordinators Team Final Responses to Comments on the July 3, 2001 Working Draft Chesapeake Bay Tidal Waters Designated Uses Document

December 20, 2001
Chesapeake Bay Program Water Quality Standards Coordinators Team
Final Responses to Comments on the July 3,2001
Working Draft Chesapeake Bay Tidal Waters Designated Uses Document

From Denise Hakowski, EPA

1. I'm a little confused. According to the summary page and Julie's message, we were
supposed to receive the working draft versions of the Bay specific criteria and the refined
tidal water designated uses. When I sat down to review, I realized I only had the refined
designated use piece. I am actually more interested in Chapters m, IV and V. Am I
missing something?

Response: Copies of the July 3, 2001 draft criteria for dissolved oxygen, clarity and
chlorophyll (chapters III, IV, and V) were posted on the Chesapeake Bay Program
web site.

2. I did look at the refined tidal water designated use piece, and I only have one significant
comment: In all of the designated use boundary delineations, it should be discussed if these
delineations are based on historic observation or present day. You touch on this in the
"shallow water" delineation section, but it needs to be addressed in each piece. This will
make a difference in developing the UAAs and what 131.10(g) factors will need to be taken
into consideration.

Response: More specific text has been added to the revised draft designated use
documentation to make it clear as to the basis of the delineations in terms of historical
or current day observations.

From Tom Gardner (see more of his comments at the end)

3. Can you insert the following sentence: In addition to the requirements of the Clean Water
Act, refined designated uses may also:

"The process of refining designated uses will meet the requirements of the Clean Water Act
and it's implementing regulations, including use justification based on naturally occuring
conditions, or on human caused conditions that cannot be corrected or that correcting would
cause substantial and widespread economic and social impacts."

This would go below the list of five considerations on page 2. I guess this sentence can be
combined with "the resultant conceptual..." to form one paragraph.

Response: This recommended sentence has been added to the text of the revised draft
designated use documentation.

From Joe Beaman, Maryland Dept of the Environment

4. A discussion of the interrelationship of the water quality parameters and their significance
to the specific use designation(s) may be useful. Should be incorporated into the
background section of the document.

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Response: Additional text has been added to the background section discussing the
interrelationship between each of the three Bay criteria-dissolved oxygen, water
clarity, and chlorophyll a-and each of the designated uses.

5. Assuming that the seasonal "anoxic" zones occurring in the subpycnocline have precisely
delineated boundaries, it seems to me that the criteria to maintain the Deep Channel
designated use should have both numeric and narrative criteria. The goals of this criteria
should be two-fold:

* No addition of anoxic conditions due to anthropogenic inputs. Refine the criteria to limit
the incidence of anoxia to delineated regions within seasonal limits using solid historic
data (cores, historic D.O. measurements).

* Decrease the incidence of anoxic "creep" - belts of low D.O. intruding on shallow shelf
areas with waters containing sufficient D.O. to support designated uses under normal
conditions, but the increase in anthropogenic inputs are causal in the occurrence of this
phenomenon.

Response: The two sets of bulleted text in the above comment have been incorporated
in an edited form into the deep channel designated use rationale section to better set
the stage for the seasonal anoxic region. The rationale text has also been expanded to
include more specific documentation on the monitoring data-based estimated area and
extent of the seasonal anoxic region as of and since the 1975 time period, with
recognition of yearly differences in river flow. The deep channel designated use
language has been edited to include specific text describing the living resource
communities utilizing the seasonal anoxic region during mid-summer. The seasonal
anoxic zone has delineated boundaries based on specified depth contours.

From Scott Stoner, NYSDEC

6. page 1 (background) the sentence at the bottom of the page that continues onto page 2 —
very unclear about "too generic to warrant more than very general water quality." What is
meant by this - and by "very general water quality" ? Water quality is good or bad or in
between due to many factors only one of which are designated uses. Please revise this
sentence!

Response: The subject sentence has been edited.

7. page 2, the first of the five "considerations" replace "publically" with "publicly" (correct
spelling)

Response: The correctly spelled word has been added.

8. page 3. Migratory spawning and nursery, first para. Is "balanced indig. pop. of ecol. rec.
and com. important...fish...: defined anywhere? Is it clear and defendable, what it means, in
case it is challenged? What are "tidal fresh resident fish" ?? Does this designated use apply
only during the Feb 15 - June 10 time period? Is it "to" or "through" June 10 (inclusive or
exclusive of June 10?) Under Des. Use boundary delineation, 2nd par. (last par. on page 3)
states that the delin. for the mig. spawning and nursery use directly matches the shallow and
open water uses.

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Response: "Balanced indigenous population" for migratory spawning and nursery
habitats has been defined, in part, through the Funderburk et al. 1991 reference
"Habitat Requirements for Chesapeake Bay Living Resources-Second Edition"
through the identification and listing of target species. A listing of example tidal fresh
resident fish (e.g., largemouth bass, pickerel, various sunfish species) has been added
to the revised draft designated use documentation to illustrate how the "balanced
indigenous population" term applies to the tidal fresh habitats. The migratory
spawning and nursery designated use is applied inclusively from February 15th
through June 10th. During the June 11th through February 14th time period inclusively,
the shallow water and open water designated uses apply. Text has been added to make
these same points more clear within the revised draft document.

9. page 5, Shallow Water first par. same concern re definition as above.

Response: "Balanced indigenous population" for shallow water habitats has been
defined, in part, through the Funderburk et al. 1991 reference "Habitat Requirements
for Chesapeake Bay Living Resources-Second Edition" through the identification and
listing of target species. The species used in derivation of the applicable dissolved
oxygen, water clarity, and chlorophyll a water quality criteria provide further
documentation in terms of the community of living resources composing a "balanced
indigenous population" within these designated uses.

10. p. 6, applic. bay water criteria..3rd line "...water clarity apply..." ?? is a word missing?
perhaps clarity criteria or clarity requirements??

Response: The word "criteria" has been added.

11. P. 6, under "Open Water", first par same concern as above re the definition.

Response: "Balanced indigenous population" for open water habitats has been defined,
in part, through the Funderburk et al. 1991 reference "Habitat Requirements for
Chesapeake Bay Living Resources-Second Edition" through the identification and
listing of target species. The species used in derivation of the applicable dissolved
oxygen, water clarity, and chlorophyll a water quality criteria provide further
documentation in terms of the community of living resources composing a "balanced
indigenous population" within these designated uses.

12. The map (Figure A-6) does clarify the area of this use.

Response: No change made to the text.

13. p. 7, deep water, same comment as above re definition.

Response: "Balanced indigenous population" for deep water habitats has been defined,
in part, through the Funderburk et al. 1991 reference "Habitat Requirements for
Chesapeake Bay Living Resources-Second Edition" through the identification and
listing of target species. The species used in derivation of the applicable dissolved
oxygen water quality criteria provide further documentation in terms of the
community of living resources composing a "balanced indigenous population" within
these designated uses.

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14. General comment: the terms upper and lower boundaries appear to refer not to water depth
but to horizontal position ; this should be clarified as I was initially confused.

Response: The text has been edited to place emphasis on horizontal position.

15. For all the designated uses: The first paragraph under each of the uses includes some
language about a balanced indigenous population of ecologically recreationally and
commercially important species... How is this defined? Do you know what species this
means? How will it be implemented? Are you prepared to explain what this means if the
language is challenged?

Response: The "balanced indigenous population" for the different designated use
habitats has been defined, in part, through the Funderburk et al. 1991 reference
"Habitat Requirements for Chesapeake Bay Living Resources-Second Edition"
through the identification and listing of commercially, recreationally, and ecologically
important target species and their supporting prey species/communities. Text has
been added to each designated use section providing this reference as the source of the
existing definition of "balanced indigenous population".

16. The terms upper and lower as used in the text and figures sometimes mean vertical
boundaries and sometimes mean horizontal extent. This is confusing and needs to be fixed.
Response: The use of the words "upper" and "lower" has been edited in each of
designated use boundary delineation sections to focus more explicitly on vertical and
horizontal descriptors.

17. Are the five "designated uses" really "uses" of the water or are they locations or areas of
water that we are defining as having certain uses? I think the latter is more appropriate, and
habitats? The language is not consistent in the figures - some locations are described as
uses and others as habitats. To me, a designated use or best use is a USE of the water, not a
LOCATION of the water. This should be carefully considered and addressed in both the
text and the figures.

Response: The use of the terms "migratory spawning and nursery", "shallow water",
"open water", "deep water" and "deep channel" refers to both the location of habitat
within the water as well as the defined uses of that specific habitat. These short hand
terms are only used as part of the presentation materials and to illustrate the
connection between the designated uses and the applicable Bay criteria. The
designated uses are the actual language describing the indicated use of these defined
habitats. The text and figure legends have been edited to be consistent in the use of the
terms "use" vs. "habitat".

18. top of page 3. delete "artificial" in the second line. It is sufficient to say jurisdictional
borders.

Response: Word has been deleted.

19. page 3, designated use rationale ( for migratory spawning and nursery) refers to a list of
target species, then lists 7 species. Are these the only species on the list? Does this list
equal and wholly comprise the "balanced indigenous population of... in the paragraph above
it?

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Response: The text has been edited to reflect that the seven named species are only a
representative subset of species comprising a "balanced indigenous population".

20. page 6. top half, applicable bay water quality criteria [ref to shallow waters], for
chlorophyll-a, refers to spring as Mar-May and summer as July-Sept. What about June?

What season is it included with? Same issue - first full paragraph on page 8 re: where does
June fit in?

Response: See the chlorophyll a criteria chapter for documentation on the rationale
for not including June in the criteria application of spring and summer time periods
(it's a transition month during which phytoplanktonic communities during some year
can be composed of summer oriented species and spring oriented species during other
years depending on temperature, river flow conditions, etc.).

21. page 8, last paragraph, suggest "human" rather than "man's" influence.

Response: Change in words has been made in the revised draft text.

22. page 9, designated use boundary delineation. What if there are two pycnoclines - what is
the boundary if there are 2 pycnoclines? Check throughout for any clarification that may be
needed to boundaries if there are two pycnoclines.

Response: Text has been added to be more specific in describing how the upper and
lower boundaries of the pycnocline are determined, even in the case of two
pycnoclines.

23. Generally, the figures A-l through A-10 are useful and help the reader understand the
boundaries of the waters for each designated use.

Response: These figures has been further refined to help the reader.

24. For all the figures that show the map as one would view if from above, (not the
cross-sectional ones), it would be valuable to identify some of the cities, states, waters, etc.
to better orient the areas demarked on the maps.

Response: Well known geographical landmarks and waterways have been added to the
revised draft maps.

25. Figure A-3 - why is it included? How does it differ from A-2? A figure should stand alone;
if A-3 is not going to be deleted, please give more explanation with the figure as to what to
means and about the count of overlapping habitats.

Response: Figure A-3 was originally added to illustrate how the final set delineation of
the migratory spawning and nursery designated use boundaries were made. This
figure has been dropped to prevent any confusion.

26. Figure A-4, is the 2 meter bathymetry contour defined as where the depth is exactly 2
meters or where the depth is less than or equal to 2 meters? The map and legend indicates
the latter. Is this correct?

Response: The legend for Figure A-4 has been corrected to describe the shaded areas
on the map as being depths equal to or less than 2 meters.

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27. Figure A-6. Is the pycnocline here a single line or does it have thickness, with an upper and
lower boundary? The caption refers to the upper boundary of the pycnocline and implies
that it has thickness with an upper boundary and lower boundary. Is this intended?

Response: The legend and illustration on Figure A-6 has been revised to better
illustrate the lower vertical boundary of the open water designated use is the upper
boundary of the pycnocline.

28. Figure A-7 is confusing. It's title is unusual for a figure - a sentence rather than a title.

Suggest" "Influence of ocean exchange on sub-pycnocline waters." More clearly show and
label the pycnocline on the figure. Identify the designated use for the sub-pycnocline waters
where the flow is restricted.

Response: The figure title has been changed as recommended and the figure as a whole
has been modified to more clearly illustrate the complex message trying to be
communicated through this graphic.

29. Figure A-8 caption - correct spelling "tandem"

Response: The correctly spelled word has been added.

30. Figure A-9 s in the caption describes upper and lower boundaries of the pycnocline. On the
figure itself, do the terms "upper" and lower" refer to the boundaries of the deep water
designated use or the pycnocline or both? The figure needs to be clarified re this. Show
and label the pycnocline in the figure.

Response: Changes been have been made to Figure A-9 to address the confusing labels.

31. Figure A-10. Show and label the pycnocline.

Response: Appropriate labels have been added to Figure A-10.

From VAMWA and MAMWA

Clifton Bell — Malcolm Pirnie, Inc.

Will Hunley — Hampton Roads Sanitation District

32. The appropriate southern boundary of the deep water use is currently unresolved.

Response: The revised draft designated use appendix includes a revised draft figure
and supporting text and technical documentation for setting the general location of
designated use boundaries in the southern mainstem Chesapeake Bay. Setting the
exact boundaries and coordinates of the designated use are the responsibility of
Virginia working with its stakeholders through its water quality standards adoption
process.

33. To address these issues we have developed graphical and statistical methods to evaluate
potential means to establish a defensible southern boundary on the basis of the monitoring
data (refer to attached hydrographic graphics and report entitled "Statistical and graphical
comparison of vertical DO gradients in the Lower Chesapeake Bay"). The idea was to
quantify the definition of the line of demarcation consistent with "proximity to the mouth of
the Chesapeake Bay allows for continuous replenishment of subpycnocline waters with
oxygenated ocean water".

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Response: The Water Quality Standards Coordinators Team has reviewed the
submitted hydrographic graphics and report (see attached copy of graphics and
report) and factored its findings into the revised draft set of general boundaries for
designated uses in the southern mainstem Chesapeake Bay. The submitted graphics
and interpretation provide some basis for attempting to determine how far up the Bay
the subpycnocline waters are supplied with oxygenated oxygen water under existing
water quality conditions and nutrient/sediment loads through a strict comparison to
water quality at the mouth of the Bay. The general boundaries for draft refined
designated uses in the southern mainstem Bay are based on analysis of the existing 16
year record of Bay water quality monitoring data as well as model simulated water
quality conditions under additional nutrient and sediment reductions compared to the
draft dissolved oxygen criteria applied to the different designated uses under
consideration. These designated uses must be protective of potential uses in addition
to existing uses. The revised draft designated use appendix contains edited and new
text further documenting the revised draft set of general boundaries.

34. Our results support the designation of an open-water-to-bottom use south of a line extending
from the Back River on the York-James Peninsula to the mouth of Cherrystone Inlet on the
Eastern Shore. These results also indicate the need for reconsideration of the southern
boundary of the deep trench use designation.

Response: The results provided in the attached graphics and report are strictly based
on a comparison and a determination of statistically significant differences between
existing water quality conditions measured at the Bay mouth and conditions observed
at stations further up the southern mainstem Bay. Setting the boundary for the
designation of the open water to bottom use south of this line would ensure immediate
compliance with the draft open water Bay dissolved oxygen criteria. Further analysis
of the existing record of Bay water quality monitoring data indicates more extensive
regions of the southern mainstem Bay could currently attain the draft Bay dissolved
oxygen criteria or reach attain under further nutrient/sediment reductions, principally
undertaken by basins to the north of the lower Virginia tributary basins.

35. It is our present understanding that additional analyses are planned by VIMS and others to
evaluate other aspects of the issues. However, we are unclear on the details. It is our
recommendation that an ad hoc workgroup be assembled to address these issues for
resolution. We would also like to participate and continue making contributions towards
this important issue.

Response: Work on the designated uses will continue to be directed by and
coordinated through the Chesapeake Bay Program's Water Quality Standards
Coordinators Team. Anyone is welcome to actively participate in the team's
activities-notices of all meetings, conference calls are posted in advance on the
Chesapeake Bay Program's web site. All interim and draft materials discussed by the
team are also posted on the team's web page at www.chesapeakebay.net/wqsctg.htm.

From CBF

36. Overall, our main concern is that the refined designated uses and criteria as drafted cannot

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advance the efforts to improve water quality of the Chesapeake Bay if they merely aim to
meet existing or easily attainable conditions. While the result of such efforts might "de-list"
the Bay, the question remains whether the Bay could honestly be considered "clean". A
truly restored Bay requires the goals to be set at levels that do not, at present, widely exist in
the Bay. This does not imply that we must work toward unrealistic goals, such as those that
existed centuries ago, but certainly we should strive for conditions present prior to the Bay's
decline.

Response: The combination of the working draft designated uses and working draft
criteria supportive of those individual designated uses do not describe existing water
quality conditions in the Chesapeake Bay or its tidal tributaries. The draft uses and
criteria were not delineated or derived to make attainment of required water quality
conditions "easy", but they were derived based on decades worth of information on
influence of stratification on dissolved oxygen dynamics, close to a 50 year record of
juvenile fish distributions, and so on. The revised designated use appendix document
clearly describes the basis for each individual use and the basis for setting general
boundaries.

37. CBF is intrigued with the theory of refined designated uses based on different habitats, but
we have several concerns with the practicality of these designated uses. Response: See
responses to comments 38-43 below.

38. We support additional protections for migratory spawning and nursery habitat set forth in
this designated use, but want to be sure that the refined designated use will truly protect
those areas. The draft designated use document does not sufficiently explain how the
beginning and end dates of the more stringent seasonal criteria were determined, unless they
were based merely on two particular species, the yellow perch and striped bass. Even if this
is the case, it is not clear that striped bass juveniles will be protected by the June 10th end-
date, as it reflects "the time when many striped bass juveniles are heading down river/down
Bay beyond the lower boundaries of the designated use." (emphasis added) This implies
that many juveniles are still in those areas and could benefit from the additional protection.
Furthermore, we question whether there may be other species that spawn after the June 10th
date; if so, the end-date should be extended. In addition to the seasonal dates, CBF is
concerned that the geographical extent of the designated migratory spawning and nursery
areas is not broad enough to be truly protective. This concern is exacerbated by the
statement that "(e)ven though juvenile striped bass can be found throughout a broader range
of Maryland and Virginia tidal waters, the highest concentrations of early juvenile life stage
striped bass are found in the primary nursery areas... " (p.4) If there is evidence that
juvenile life stages are found beyond the designated areas as drafted, then the areas should
be extended to provide adequate protection.

Response: The February 15th through June 10th time frame for application of the
migratory spawning and nursery designated use was based on the composite of the
timing of spawning and nursery life stages for the listed target species. Yellow perch
was the earliest spawner and striped bass juveniles were the latest nursery habitat life
stage. The designated use and the applicable dissolved oxygen criteria were
established to fully protect egg, larval and very early juvenile life stages. See the
dissolved oxygen criteria for more details. After June 10th, striped bass juveniles will

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be full protected by the applicable shallow water/open water dissolved oxygen criteria,
which were derived in part using juvenile and adult striped bass low dissolved oxygen
effects data. Again, see the draft dissolved oxygen criteria chapter for more details.
The text has been revised to make these points.

39. The shallow water designated use has been delineated to the two meter depth contour based
on grass bed distributions in the past 30 years, as opposed to historical depths of underwater
grass beds at "three meters or more." While a depth of three meters would seemingly be
more difficult to attain, it does not necessarily mean that historical benchmarks should be
disregarded. Rather, the designated use boundary should be set at a level which constitutes
the historical depth, as opposed to a less stringent level that can be more easily attained.
Response: The shallow water designated use was delineated out to the two meter depth
contour based, in part, on observations of underwater grass beds back as far as the
1930s. See refer to the revised draft water clarity criteria for documentation on the
specific application depths for the water clarity criteria within the shallow water
designated use. Note that the shallow water designated also extends across
unvegetated habitats, e.g., Calvert Cliffs region of the northern mainstem Chesapeake
Bay, where for physical mixing and sediment substrate reasons underwater grasses are
likely to never grow. Shallow waters are an important designated use to be protected
beyond the presence of underwater grasses.

40. The lower boundary of the open water designated use, as currently stated, is the upper
pycnocline boundary or bottom sediments, and where the pycnocline does not represent a
barrier to oxygen replenishment, then the lower boundary extends down to the bottom
sediments. While this may be theoretically appropriate, we are concerned that the actual
determination of this boundary will prove to be very difficult. Moreover, the scale at which
these areas will be delineated is unclear in this document. Use of historical data and the
Chesapeake Bay Water Quality Model as mentioned in the document implies a large scale,
whereas there may be a need for site-specific information to be reflected in permits.

Response: The lower vertical boundary of the open water designated use has been
delineated using long term averaged pycnocline depths derived from Chesapeake Bay
Water Quality Monitoring Program data. Where applicable, a set of upper and lower
pycnocline depths have applied to each individual Chesapeake Bay Program segment
to balance the need to be make application of criteria to the open water vs. deep water
vs. deep channel straightforward to apply at a region specific scale with the need to
reflect actual conditions in the estuary and the strong influence of the pycnocline on
observed dissolved oxygen conditions. This level of specificity directly addresses the
need for local region determination of criteria attainment and assessing reasonable
potential for the purpose of establishing permit limits.

41. CBF questions whether the deep channel designated use should be divided into two distinct
functions - refuge for over-wintering species (October through April) and food propagation
for bottom-feeding fish and crabs (May through September) - with two different criteria.
Assuming a relatively stable temperature regime in the deep channel, it may be possible that
some bottom-feeding fish and crabs would feed at those depths year round, although they
may not be protected by the criteria as drafted.

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Response: The designated use description for the October through April time frame
has been edited to also include support for bottom feeding fish and crabs during those
months. The applicable dissolved oxygen criteria during the October through April
would provide full protection for bottom feeding fish and crabs in the deep channel.
See the dissolved oxygen criteria document for more details.

42. Further explanation should be given as to how the end of April was selected as the
distinction between these two timeframes — that date seems too early (this comment applies
to the deep water criteria as well).

Response: By the May time frame, a combination of water column stratification and
increased water column temperature causes a natural loss in the ability of the Bay's
waters to hold oxygen in the deeper waters. These natural conditions are specifically
reflected in the designated use through application of these two groupings of months.
Text has been added to the revised draft designated use appendix to make this point
more clear.

43. With regards to defining the seasonal anoxic region, it is critical that the analysis be
scrupulously careful in differentiating anthropogenic effects from naturally-occurring
physical conditions. Writing off a large section of the Bay should not be done lightly; for
this reason, anthropogenic effects must be non-existent in regions defined as seasonally
anoxic.

Response: The seasonal anoxic region has been delineated in the revised draft
designated use appendix using the best available information on the past extent given
natural forcing factors-strength of water column stratification, river flow, etc. Water
quality data dating back to the 1950s has been used to help inform decisions regarding
delineation of the seasonal anoxic region. With 15+ million plus people within the
Chesapeake Bay watershed and existing buildings, homes, and roads, anthropogenic
effects on Bay water quality will never be non-existent. The final delineation of the
seasonal anoxic region will need to be a balance of the need to restore this
volumetrically small, yet still ecologically significant habitat with what nutrient and
sediment reductions are feasible (technically, economically, and socially) in the coming
decade to decades against continued increases in basin population. Achievement of
this balance will be worked out with the Bay watershed partners and public
stakeholders through the use attainability analysis.

From Virginia DEQ

44. The exact boundaries of the impaired waters that EPA identified for inclusion on Virginia's
1998 303(d) list are still unclear, and this issue has already come up several times during
public briefings on the draft criteria and designated uses. Therefore, EPA needs to
accurately delineate the 303(d) impaired waters (re. 5/10/99 EPA letter to DEQ) because
this is vital information to be used in the geographic application of the new criteria and
designated uses, and determining where the de-listing process will apply.

Response: Response to this comments is the responsibility of EPA, not the Chesapeake
Bay Program's Water Quality Standards Coordinators Team. No change made to
text.

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From Maryland DNR

Accommodating Multiple Designated Uses

45. New designated uses would need to be overlain with current uses. In Maryland, the current
designated use for the Chesapeake Bay "proper" is Use II (Shellfish harvesting). In many
cases, the tidal tributaries are Use I and Use II in the lower portions of the tributaries, with
exceptions specifically listed. Shellfish harvesting incorporates all of the Use I criteria and
requirements, but is more stringent with respect to bacteria.

Probably the best analogy for handling multiple designated uses in an area is the drinking
water use in which a dual use is attributed to some waters such as Use m-P which is Trout
support and drinking water supply. In such cases all of the basic requirements of Use I
apply, plus more stringent temperature and oxygen requirements for Use m, plus drinking
water requirements such as the human health toxic requirements.

Recommendation

New draft, as well as existing, designated uses should be mapped with a GIS system with
separate layers for each use to see how multiple uses and appropriate criteria would apply
geographically to all areas of the Bay.

Response: Once the designated uses and their general delineations have been agreed to
by all the watershed partners, the Chesapeake Bay Program Office's GIS Team will, at
the specific request of each jurisdiction, work directly with Maryland, Virginia,

Delaware and the District of Columbia on developing a state specific set of separate
GIS layers as recommended.

Definition of Time and Space Scales

46. In the current form, designated uses are not sufficiently well defined for regulation
development. From a regulatory perspective, it will be critical that all boundaries, both
horizontally and vertically be well- and unequivocally defined.

Recommendation

It is recommended that the next drafts and final publication of this document include
adequate resolution and definition in the use boundaries. In addition to horizontal
boundaries, it is recommended that the pycnocline (which separates Shallow from Deep
Water uses) be defined, using the Bay Program's working definition developed for its
monitoring program or some comparable objective calculation. It is also recommended that
specific language be provided to how the pycnocline calculation would be applied when
there are multiple pycnoclines or when the pycnocline is temporarily disrupted (mixing by
storms, changes in freshwater runoff, ship passages) or for pycnoclines existing outside of
the defined seasonal bounds.

Response: The revised draft designated use appendix provides the specific delineations
and definitions requested.

It is also recommended that EPA provide technical support to assist States in defining and
additional use boundaries that may be needed for State regulations.

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Response: EPA staff in the Water Protection Division in Philadelphia and Chesapeake
Bay Program Office in Annapolis are committed to providing the states with the
requested support.

Effects of Variations in Freshwater Flow

47.	Freshwater flows to the Bay are not addressed in the definition of designated uses, however,
natural flow conditions can affect the success of a spawn as well as the spatial extent of
designated use areas such as the "Spawning/Nursery Area Use".

Recommendation

It is recommended that the appropriate workgroups of the Water Quality Steering
Committee examine the influence of freshwater flow at least in the definition of the
"Spawning/Nursery Area" designated use and, if it is determined to be an important factor,
then the Committee should consider how to integrate flow conditions into the these use
definitions.

Response: The revised text recognizing the influence of year to year changes in
winter/spring freshwater flow on the down Bay/down river extent of viable spawning
and nursery habitats (generally defined by a combination of salinity and temperature).
The migratory spawning and nursery designated use was delineated on the basis of
long term averaged information on the extent the seven listed target species spawning
and nursery habitats to reflect the cumulative effect of year to year variations.

Obstacles to Achieving Attainment

48.	Natural conditions that prevent the attainment of criteria in certain areas should be
considered in detail in the Use Attainability Analysis (UAA) and to some extent in the
designated use document. There are natural areas identified by draft designated use
definitions where existing and/or proposed criteria will not be met, including tidal wetlands,
blackwater tributaries, coastal ponds, poorly flushed tributaries, and turbidity maximum
zones. In fact, natural conditions will probably be the primary basis for justifying the Deep
Channel Use as less stringent the CWA §101(a) requirement to protect fish and aquatic life,
in that it will not allow for most life stages of most species to live there. These factors will
play very heavily into the economic analysis required for the UAA. If areas where criteria
achievement is not possible are not explicitly excluded, it could undermine the credibility of
this new regulatory approach.

Recommendations

Because defining in detail areas where criteria will not be met, either by natural conditions
(listed above) or man-made conditions (tidal ditches, canals, dredge spoil islands, managed
wildlife areas, shipping channels) will be politically and technically difficult for the Bay
Program and States, it is recommended that the process to make these determinations be
defined as soon as possible. EPA's final publication should explicitly address these areas
and define what criteria do apply in these instances.

Response: The revised draft Bay criteria document contains a new chapter on
implementation guidelines which explicitly address natural and anthropogenic
conditions that need to be directly considered and factored into determination of
criteria attainment for the three Bay criteria applicable within the five designated

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uses.

Defining Attainment of Designated Uses

49.	In 2010, and at points along the way, the States and EPA will have to determine if the
designated uses have been attained, i.e., whether the criteria continue to be violated or if
defined uses are not attained.

Recommendation

It is recommended that future drafts and the final version of this document provide clear
definitions of designated uses and examples of narrative criteria in addition to specific
numeric criteria under development to provide as much clarity as possible about how water
quality standards will be implemented, including the degree of attainment (e.g. no more than
10% of monitoring values in exceedence of criteria). As part of assessing the attainment of
designated uses, it is recommended that the Water Quality Steering Committee determine
what our attainment capabilities are using existing monitoring technologies and programs.
If attainment of designated uses cannot be sufficiently assessed using existing technologies
and programs, then enhancements to existing monitoring programs and improved
technologies should be identified and recommended for implementation.

Response: The revised draft Bay criteria document contains a new chapter on
implementation guidelines which explicitly address natural and anthropogenic
conditions that need to be directly considered and factored into determination of
criteria attainment within the five designated uses. The Chesapeake Bay Program
partners have an effort underway currently to design a tidal monitoring network that
include specific modifications and enhancements to the existing tidal water quality
monitoring program to direct monitoring toward assessment of Bay criteria
attainment.

Application of Designated Uses Beyond Chesapeake Bay

50.	Although it is outside of the Water Quality Steering Committee mission, from a state
regulatory perspective, it would be very advantageous to have consistent defined uses for
estuarine waters that would address both the Chesapeake Bay and other coastal embayments
such as the Coastal Bays. While Deep Channel (possibly Deep Water) uses clearly would
not apply for these waters, other uses (Spawning and Nursery Areas, Shallow Water, Open
Water) could be applicable.

Recommendation

It is recommended that EPA provide technical support to applicable National Estuarine
Programs and State agencies to possibly redefine designated uses in these waters, based
upon the findings for Chesapeake Bay and to determine any UAA needs of these additional
estuarine waters.

Response: This is outside of the scope of the objectives of the subject designated use
appendix as they apply specifically to tidal waters within Chesapeake Bay and its tidal
tributaries.

Because spawning habitat of key anadromous fish species included among those targeted
for the Migratory and Spawning Areas also extends to non-tidal freshwater areas, it is

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recommended that this document acknowledge the importance of these habitats to relevant
species and the need to protect these non-tidal habitats through a similar regulatory process.
Response: Text has been added to make this point in the migratory spawning and
nursery designated use section.

From Pennsylvania DEP

We have no comments on the designated uses and dissolved oxygen criteria documents at
this time.

Response: Thanks!

From Tom Gardner (these were faxed)

51. Should we have more discussion in the "Background" section of how existing uses (40 CFR
131.3 (e) will be protected? (I can help with this).

Response: Text has been added to the background section making this point.

52. Suggest discussing "boundary" before discussing "rationale" under each refined designated
use.

Response: These respective sections of text have been switched in the order they are
presented in the revised draft text.

53. Page 2, last sentence of first paragraph: instead of a "restored" Bay water quality conditions,
substitute "desired"

Response: Wording change has been made.

54. In the bulleted section: discuss what is the basis for these - where did they come from?
Response: These five considerations were developed and applied by the Chesapeake
Bay Program's Water Quality Standards Coordinators as the driving principles
behind the set of five designated uses presented.

55. In each of the bullets on page 2, the designated uses "should," not "need to" or "must."
Response: Suggested wording changes have been made.

56. Last paragraph, page 2: the syntheses are of physical chemical (not water quality), and
biological habitat requirements. Also, target species and communities "in the Bay" (add
underlined words).