HomeMy WebLinkAboutSummaryEcological
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Ecological Flows Science Advisory Board (EFSAB)
Meeting Summary June 18, 2013
Stan Adams Training Facility, Jordan Lake, Chapel Hill, NC
FINAL Approved for Distribution
Attendance
Members
Hugh Barwick, Duke Energy
Mark Cantrell, USFWS (online)
Bob Christian, East Carolina University
Tom Cuffney, US Geological Survey
Linda Diebolt, NC League of
Municipalities
Chris Goudreau, NC Wildlife Resources
Commission
Jeff Hinshaw, North Carolina State
University
Amy Pickle, EMC, Duke Nicholas School
Sam Pearsall, Environmental Defense
Fund
Judy Ratcliffe, NC Natural Heritage
Program
Jay Sauber, NC Division of Water
Quality
Bill
Swartley,
NC
Division
of
Forest
Resources
Fred Tarver, NC Division of Water
Resources
Division of Water Resources
Tom Fransen
Harold Brady
Alternates
Rebecca Benner, The Nature
Conservancy
Sarah McRae, US Fish & Wildlife
Vann Stancil, NC Wildlife Resources Commission
Tom Thompson, Duke Energy
Guests:
Jim Mead, Environmental Defense
Fund
Kimberly Meitzen, The Nature
Conservancy
Jennifer Phelan, RTI
NCSU Facilitation Team
Mary Lou Addor, Natural Resource
Leadership Institute (NRLI)
Christy Perrin, NC State University
Nancy Sharpless (NRLI)
The purpose of the Ecological Flows Science Advisory Board: The Ecological Flows Science
Advisory Board (EFSAB) will advise NC Department Environment and Natural Resources (NCDENR)
on an approach to characterize the aquatic ecology of different river basins and methods to determine
the flows needed to maintain ecological integrity.
Presentations, reports, and background information of the EFSAB are available at: www.nc-
water.org/sab
WebinaResponse: If you cannot attend the meeting in person but would like to join us via the webinar, you
can watch the presentations and listen to the live streaming audio of the meeting by going to
https://denr.ncgovconnect.com/sab/ and typing your name in the space labeled "guest."
NOTE: The EFSAB will meet July 16-17, 2013, 9:00am until 4:15pm
at the Stan Adams
Training Facility, Jordan Lake Educational State Forest Center Chapel Hill, NC
(see page 54 for meeting agenda topics and directions to location).
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June 18, 2013:
Summary of Decisions/Recommendations and Proposed Actions
Decisions and Recommendations:
1. Distinguish in the Report (Draft 1) Outline from the EFSAB to DENR/DWR that the research
assumptions are currently limited to the RTI and USGS research as well as some sections of
the Recommendations like the protocol conclusions; that the Report will eventually include a
comprehensive view of what has transpired and a more comprehensive set of
recommendations..
2. The EFSAB came to full consensus that the following recommendation should be
included in their final report:
T&E subcommittee review suggests that flow-habitat relationships for these species are
broadly addressed by the PHABSIM approach. Rather than further evaluate the
developing research on T&E species' flow requirements, the SAB recommends that
specific, potentially more limiting, flow needs for resident T&E species should be
considered on a project specific basis by the DWR in addition to the more generic
recommendations offered by the SAB. For planning purposes, portions of basins (e.g.,
nodes) that include listed species should be treated by DWR as needing additional
analysis.
Proposed Actions
1. The EFSAB was asked to email any comments, questions, or proposed edits to Mary Lou
Addor before the next EFSAB meeting scheduled for July 16.
2. The EFSAB has asked if the Coastal Ecological Flows Work Group can provide a trial balloon
(a series of proposed recommendations) for the July 16 and 17 discussions.
3. Hugh Barwick and his subgroup will analyze PHABSIM data on 5 or 6 sites using 20, 30 and
40% of mean monthly flow by season.
a. See how that relates to flow-by.
4. EFSAB asked for RTI/USGS to conduct one or more examples of applying eco-deficit and
benthos condition ranking using site specific data for a river and projecting out for 50 years
(looking at how it impacts a current good-fair relationship was suggested).
5. EFSAB asked RTI/USGS to conduct a log-linear model for the benthos flow-biology
relationship so it can be more comparable to fish, and so that the curve is not as flat
6. Based on their discussion, it appears that EFSAB members need to make a decision about
whether they should recommend the approach or also determine the threshold that constitutes
significant impact to ecological integrity. This has not been decided yet.
7. If our recommendation is based on PHABSIM results run using natural conditions, we need to
understand what the implications are when it’s used in a model with a SIMBASE current and
SIMBASE future condition. This would need to be done on a basin-by-basin basis.
Table of Contents
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I. Executive Summary……………………………………………………………………………..p.3
II. June 18, 2013 Meeting Orientation and May 14, 2013 Meeting Summary Approval…….p.9
III. Presentation: Introduction of Preface Section of the EFSAB Report to DENR………………...p.10
IV. Presentation:
Report
on
Work
of
the
Endangered
Species
Subcommittee………………………………………..p.
11
V. Coastal Ecological Flows Work Group: Progress Report………………………………………...p.14
VI. Presentation: Report Back on Comparison of SIMBASE and PHABSIM Unaltered Flows….p.19
VII. Presentation: Biological-Environmental Classification (BEC) Project Update…………………p.25
VIII. Presentation: A Trial Balloon—20/30/40% or 30/40/50% of Annual Mean Flow or Monthly
Mean Flow……………………………………………………………………………………………..p.40
IX. July 16-17 Meeting Agenda………………………………………………………………………….p.51
X. Information on Next Meeting………………………………………………………………………...p.54
Appendix A: Report Outline from EFSAB to DENR/DWR (DRAFT 1)…………………………………..p.55
I.
Executive Summary
TITLE: Presentation: “Recommendations” Subcommittee’s “Preface” document
Presenter: Mary Lou Addor
Mary Lou Addor introduced the Preface (Draft 1) developed by subcommittee members Chris
Goudreau, Amy Pickle, Fred Tarver, Sam Pearsall, Jim Mead, and Ian McMillian (and distributed to the
EFSAB on June 10,2013). The subcommittee met twice to draft the Preface. In addition to the Preface
(Draft 1), the subcommittee drafted a section titled Research Assumptions and Protocol Conclusions,
followed with the subcommittees’ previous work on Recommendations, the Proposed Framework of
Recommendations, Summary, and Conclusions. Reference Appendix for a copy of the latest copy of
the Draft Report.
The preface was envisioned to introduce the Report that the EFSAB will submit to DENR. The Report
will include research assumptions, recommendations, and conclusions that represent the EFSAB.
Currently the Report and the outline is limited to a portion of what has been accomplished by the
EFSAB.
Major Discussion items/concerns/questions: In the first paragraph of the Preface (which describes
how the report to DENR will be organized), this section does not clearly state whose research
assumptions and recommendations are listed. The section on the research assumptions does not
include a comprehensive list of the organizations and groups that have advised the EFSAB but rather is
limited to the RTI and USGS research. The recommendations section does clearly state whose
recommendations are listed.
Decisions Made: Distinguish in the Report (Draft 1) that the research assumptions are currently limited
to the RTI and USGS research as well as some sections of the Recommendations like the protocol
conclusions and that the Report will eventually include a comprehensive view of what has transpired
and a more comprehensive set of recommendations.
Proposed Actions or Identified Decisions to be made: The EFSAB was asked to email any
comments, questions, or proposed edits to Mary Lou Addor before the next EFSAB meeting scheduled
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for July 16.
TITLE: Report on Work of Endangered Species Subcommittee
Presenter: Judy Ratcliffe
Presenter: Judy Ratcliffe
Judy provided the list of fish species that are host for various federally listed mussels, went through and
lined up which fish species were riffle-run, pool species, then cross tabulated with the mussels to see
which habitat guilds are being covered by the fish species. Chris G. helped develop a spreadsheet to
display the results, which was shown to the group. Riffle run guild is very well represented (by fish
hosts), as are pool run and riffle. The subcommittee believes the results suggest that using the guild
approach could adequately address concerns for freshwater mussels, at least for their fish hosts. The
exercise did not consider species that were petitioned for federal listing, which the subcommittee
provided as a tab in their spreadsheet. They needed to know if the EFSAB wants them to do additional
work to evaluate those species. After discussion, the EFSAB decided to develop and test consensus
on a recommendation for their report rather than conducting additional analysis.
Major Discussion items/concerns/questions:
• If the BEC is not recommended or used, there would likely be additional work needed to
determine if threatened and endangered species are being adequately addressed by a different
method
• A lot of additional work would be required to crosswalk the petitioned species with the guilds,
including determining which species are flow-dependant.
• The relevant species in the swamps and riparian systems shouldn’t disappear from the
petitioned list
Decisions Made:
The EFSAB came to full consensus that the following recommendation should be included in
their final report:
T&E subcommittee review suggests that flow-habitat relationships for these species are broadly
addressed by the PHABSIM approach. Rather than further evaluate the developing research on T&E
species' flow requirements, the SAB recommends that specific, potentially more limiting, flow needs for
resident T&E species should be considered on a project specific basis by the DWR in addition to the
more generic recommendations offered by the SAB. For planning purposes, portions of basins (e.g.,
nodes) that include listed species should be treated by DWR as needing additional analysis.
Proposed Actions or Identified Decisions to be made: NA
TITLE: Coastal Ecological Flows Work Group: Progress Report
Presenter: Bob Christian
Bob introduced the latest progress report of the Coastal Working Group and the results of the groups’
second meeting. Comprised of 12 scientists, 3 are members of the EFSAB: Bob Christian, Fritz Rhode,
and Judy Ratcliff. Six of the members attended the June 17meeting. The group is focused on NC
Coastal Waters downstream of DWR’s OASIS Basin Models, an area well represented in the state in
terms of the number of streams in the coastal plain. The second meeting of the coastal ecological
flows working group included several learning objectives.
Assess applicability of previous coastal work
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o Other states
o Greenville
Hone stream classification framework based on Scott’s efforts and previous discussions
o Identify key classes to consider based on importance of environmental factors and potential
for flow modification by human activity
Advance modeling effort
o Consider maps of potential areas of concern
– Other?
Major Discussion items/concerns/questions: The Coastal Ecological Flows Work Group is working
on a three-pronged approach to link stream typology (origin with slope) to a potential Ecological Flows
determinant such as discharge and habitat, downstream salinity, and overbank flow.
Decisions Made: None
Proposed Actions or Identified Decisions to be made: The EFSAB has asked if the Coastal
Ecological Flows Work Group can provide a trial balloon (a series of proposed recommendations) for
the July 16 and 17 discussions.
TITLE: Presentation: Report Back on Comparison of SIMBASE and PHABSIM Unaltered Flows
(to better inform modeling results of 80% flowby)
Presenter: Tom Fransen
During Tom Fransen’s presentation at the May, 2013 meeting, the EFSAB had asked him to compare
analyses using natural conditions (such as had been used in the PHABSIM work evaluated by the
EFSAB previously) versus analyses using current conditions (SIMBASE) at PHABSIM sites and to
compare 80% flow-by (using natural flows) with natural flows and SIMBASE. Tom presented these
comparisons. His major conclusions for the PHABSIM comparison using one site were:
• The majority of reductions in habitat are associated with “Deep Fast” guilds where half or nearly
half of months fall below 80% threshold.
• Deep Slow” guilds have 1 or 2 month breaches of 80% threshold.
• Another Deep species (Golden Redhorse Juvenile), with nearly half of months below threshold,
had habitat values <500 by month.
• The SIMBASE and 2060 projection include wastewater treatment plant return flows, which tend
to offset dam alterations.
• Seasonal calculations (Summer) tended to exclude breaches for marginal months when using
Index B (mean of habitat events between 10 and 90% exceedance).
• Most of the impacts occurred between Natural and Current Conditions.
• Little to no addition impacts between Current Conditions and projected 2060 scenario
conditions.
Major Discussion items/concerns/questions:
1. In the watershed evaluated, the difference between current and projected 2060 demands were
not substantial, whereas in some areas, like the Triangle, the differences could be much more
substantial.
2. If the EFSAB chooses to use an 80% flow-by approach based on PHABSIM results that used
natural flows, it would be important for DWR to do this analysis within each basin. The
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difference between natural and SIMBASE and between SIMBASE and SIM60 is going to vary
basin to basin.
3. The question is still out there: if our recommendation is based on PHABSIM results run using
natural conditions, even if it’s not 80% flow-by, we need to understand what the implications are
when it’s used in a model with a SIMBASE current and SIMBASE future condition.
4. It’s hard to capture what the impact is of using a different baseline flow if it’s going to be
different for each basin.
5. Do we have any idea how these deficit figures compare to the deficits that RTI calculates? Is an
80% flow-by equal to 20% deficit, or do we not have any idea of that yet? RESPONSE: It's a
challenge because eco deficits are how big is the area under a curve, so that percent doesn’t
translate directly to these types of percentages.
Proposed Actions or Identified Decisions to be made:
1. The question is still out there: if our recommendation is based on PHABSIM results run using
natural conditions, even if it’s not 80% flow-by, we need to understand what the implications are
when it’s used in a model with a SIMBASE current and SIMBASE future condition. This would
need to be done on a basin-by-basin basis.
Decisions Made: none
TITLE: Biological-Environmental Classification (BEC) Project Update
Presenter: Jennifer Phelan, RTI & Thomas Cuffney, USGS
After continuing with the classification analyses as they said they would do at the last meeting, it was
determined that nothing was gained by splitting rivers into pre-exiting classes (EDU for fish and
Omernik Ecoregions for Benthos) - the most robust flow alteration – biological response models were
statewide. Additional work was completed to create flow-biology relationship graphs. The ad hoc
research group including: RTI, Tom Cuffney (USGS), Chris Goudreau, Fred Tarver, Jim Meade, Mary
Davis and Sam Pearsall recommend: use state-wide flow-biology relationships for fish and benthos
(based on RTI flow-biology methodology) to support determination of ecological flows. For biological
response, use fish species richness of riffle-run guild, normalized by 90th percentile value for each basin
and benthos EPT Richness, normalized by the 90th percentile value for each Omernik Level III
ecoregion. For flow alteration, use change in eco-deficit based on a comparison of flows under
Potential Natural Vegetation (PNV) condition and current (2006 NLCD land-cover + instream flow
withdrawals, discharges and impoundments). Jennifer explained the methods and showed graphs to
illustrate the relationships.
Tom shared with the group a method for how to equate percent change in benthic biological condition
to DWQ benthic site condition (IBI) ratings of excellent, good, good-fair, and poor. A proposed way to
determine a threshold for ecological integrity could be when an eco-deficit moves a site from one rating
to a lower rating (for benthos). This method may not be as easily applied to fish due to concerns that
fish NC IBI collection methods were more complex and less consistent than benthic IBI. In addition, the
fish IBI would have to be adapted for the riffle-run fish guild. Benthic IBI is based on EPT.
Major Discussion items/concerns/questions:
• How to determine how long it takes species to recover- the lower you set the bar for the insult,
the more likely it will recover. That information can be conveyed in the report.
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• It would be good to have similar IBI-based biological condition classes for fish (same as benthic
IBI classes) to proas to the rankings for benthos to help provide a framework and thresholds for
changes in biological condition. However, the complexity (fish IBI based on multiple factors)
and inconsistency (fish IBI method varies by location within the state) makes the development of
a fish IBI biological class system less feasible
• Trying to understand the relationship of PNV to unaltered flows and SIMBASE in OASIS
• Whether EFSAB should recommend the approach or also determine the threshold that
constitutes significant impact
• In the legislation, there was a clear decision to use a definition different than DWQ’s definition
for biological integrity- EFSAB should keep that in mind while considering using DWQ ratings.
• How to highlight acute (extreme short term events that may highly impact benthos) as well as
chronic eco-deficit impacts during planning
• How to express a level of comfort that changes are affected by flow and not other variables
• Some questions were submitted to the ad hoc research group after the meeting- those
questions and responses are at the end of the summary for this item
Proposed Actions or Identified Decisions to be made:
• EFSAB asked for RTI/USGS to conduct one or more examples of applying eco-deficit and
benthos condition ranking using site specific data for a river and projecting out for 50 years
(looking at how it impacts a current good-fair relationship was suggested).
• EFSAB asked RTI/USGS to conduct a log-linear model for the benthos flow-biology relationship
so it can be more comparable to fish, and so that the curve is not as flat
• Based on their discussion, it appears that EFSAB members need to a decision about whether
they should recommend the approach or also determine the threshold that constitutes
significant impact to ecological integrity. This has not been decided yet.
Decisions Made: None
TITLE: Presentation of a Trial Balloon: 20,/30/40% or 30/40/50% of Annual Mean Flow or Monthly
Mean Flow
Presenter: Hugh Barwick
Hugh
Barwick
presented
a
trial
balloon
that
he
developed
in
cooperation
with
fellow
Board
members
Jeff
Hinshaw,
Linda
Dieboldt,
Tom
Thompson,
and
Jaime
Robinson.
They
developed
this
trial
balloon
in
response
to
concerns
they
have:
• Biological-Environmental Classifications (BEC) does not appear to be a viable tool for stream
classification.
• Biological data used in the BEC were from wadeable streams.
• Potential for future water withdrawals appears greater for streams larger than those sampled and
analyzed in the BEC.
• 80% flow-by appears overly protective.
Their objectives were:
• To present an alternative method of developing ecological flows somewhat based on a water-
withdrawal permitting program currently used in SC.
• To suggest how these flows might be used by the NCDWR for planning purposes.
They divided the state into 4 physiographic regions: Lower Coastal Plain, Upper Coastal Plain,
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Piedmont, and Mountains. They did not address the Lower Coastal Plain in their proposal, and made
the following recommendations for the other physiographic regions:
Upper Coastal Plain Streams (Anadromous fish)
• High flow (Jan-April) – 50%*
• Transition flow (May, June, and Dec) – 40%*
• Low flow (July-Nov) – 30%*
Piedmont Streams (Cyprinids and Catostomids)
• High flow (Feb-April) – 40%*
• Transition flow (May, June, and Jan) – 30%*
• Low flow (July-Dec) – 20%*
Mountain Streams (Trout)
• High flow (Dec-April) – 40%*
• Transition flow (May, Oct, and Nov) – 30%*
• Low flow (June-Sep) – 20%*
The asterisks indicate that the percentages would be of Annual Mean Flow (cfs) or of Monthly Mean
Flows.
Hugh showed graphs for each physiographic region showing how the recommended flows would
compare with the mean monthly flow and a drought of record at each site.
Major Discussion items/concerns/questions:
1. Although the biota might be able to survive equivalent flows during a drought, they would not be
able to withstand those levels over multiple years.
2. Even if you set up a floor, you still have to come up with some way to say how often and how
close do you have to get to that floor before some flag goes up.
3. Two of the gages you plotted here are below reservoirs that tend to make the average flows
during wet times lower and average flows during dry times higher because that is the way they
are supposed to operate. If you set your threshold or your floor based on monthly means and
you are doing it off a gage record that has a big reservoir upstream, we need to be aware of
that, and maybe think about do we want to use the regulated hydrograph, or do we want to use
from the model an unaltered hydrograph.
4. I think philosophically, as a planning tool, what you want is something that raises flags earlier
rather than later.
5. I think everybody in this room realizes that this planning tool may eventually morph into a
permitting tool.
6. What South Carolina ended up with and those numbers were a policy decision. It was not really
based on the science, solely. We need to be careful about understanding what those numbers
are based on.
7. An approach like this has some value, has some merit because it is simple, it is straightforward,
it is easily understood, but before I could endorse an approach like this, I have to be able to look
at the graphs and say I see something there that reassures me that ecological integrity as
defined in the Act will not be violated by using this approach.
8. You talked about balancing the needs for humans and aquatic resources and that is a good
thing and DENR needs to do it. But our job is to figure out when ecological integrity is violated
and when it is not.
9. How do we tie this to biological impact?
10. Part of the simplicity of this approach is the use of monthly mean flow as opposed to percent
flow by. I think that, in and of itself, may be something the currently regulated entities are more
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familiar with or are already used to thinking of usage in terms of that. Is that one aspect that
makes this a simpler approach?
11. How much time would it take and is it feasible to re-run PHABSIM for a handful of Piedmont
sites using 40, 30, 20 as a threshold and tell us what happens to our guild habitats?
RESPONSE: They are already done, but not exactly like this. They were run with 30 all year,
20 all year, 40 all year. You have to pick from the different columns and recombine them.
RESPONSE: You would have to do them by season.
12. The reports this was based on were from a minimum flow perspective, not from the perspective
of maintaining ecological integrity.
13. If the goal is to not be at that minimum too frequently, then you are already taking a step
towards just using a flow-by approach.
14. With an 80% flow by, drought years are worse [than a minimum flow].
15. It would be interesting to see how using this kind of approach would match up against the
calculated impact of a flow-by. Just to use these kinds of numbers to set the level, and then see
and calculate the percent deficit or whatever you want to call it at that point so we can get an
idea of how it works. But it is a far simpler way to evaluate it, I think.
16. If we chose to recommend that our strategy should be to prevent increasing eco deficit by more
than a certain percentage, minimum flow thresholds and flow-by targets are both viable tools for
achieving that goal`. These are not mutually incompatible strategies. It may be that minimum
flow is not the best strategy for attempting to maintain eco deficit below some threshold, but it is
a potential tool for doing that.
17. The reason why we moved away from these flows, these thresholds to begin with when we first
evaluated them was that we were seeing impacts, in general, that we felt were not going to
meet the ecological integrity objectives of the legislation.
18. The surficial simplicity of this actually leads to a greater complexity because you have to have a
pretty complex system of if/then statements [to avoid being at too low a flow for too long]. We
move quickly away from simplicity.
Decisions Made: none
Proposed Actions or Identified Decisions to be made:
1. Analyze PHABSIM data on 5 or 6 sites using 20, 30 and 40% of mean monthly flow by season.
a. See how that relates to flow-by.
II.
June 18, 2013 Meeting Orientation and May 14, 2013 Meeting Summary
Approval
Members and alternates of the Ecological Board Science Advisory Board introduced themselves and
their affiliations. Guests in attendance and the facilitation team also introduced themselves. Everyone
was reminded to sign-in who attended the meeting.
A brief orientation was conducted of the meeting facilities (restrooms, concession) and available
technology (webinar). Members and alternates are encouraged to sit at the main meeting table and
guests at tables away from the main meeting spaces. During discussions of the members and
alternates, guests may comment once members and alternates have completed their comments and
questions. During small group work, guests can also participate in small group discussions but may
not dominate the time. Everyone is asked to ensure that space is created for others to engage. From
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time to time, the facilitators will conduct a straw poll to determine the current level of support for an
idea or what additional information is needed, not necessarily for a final decision.
The EFSAB approved the May 14, 2013 meeting summary, and it has been posted to the NC
Water.org website.
Presentation: Introduction of Preface Section of the EFSAB Report to
DENR
Presenter: Mary Lou Addor, NC State University
Mary Lou Addor introduced the Preface (Draft 1) developed by subcommittee members Chris
Goudreau, Amy Pickle, Fred Tarver, Sam Pearsall, Jim Mead, and Ian McMillian (and distributed to the
EFSAB on June 10,2013). The subcommittee met twice to draft the Preface. In addition to the Preface
(Draft 1), the subcommittee drafted a section titled Research Assumptions and Protocol Conclusions,
followed with the subcommittees’ previous work on Recommendations, the Proposed Framework of
Recommendations, Summary, and Conclusions.
The subcommittee met May 30 to determine an outline for the Preface and to assign sections of the
outline to the writing team; the subcommittee met again June 30 to review the drafted content and
complete subsequent edits of the Preface (Draft 1) for incorporation into the EFSAB report.
The outline of the Preface (Draft 1) contains three primary sections:
1. How the report from the EFSAB to DENR is organized
2. DENR mandates in legislation
3. DENR’s actions establishing the EFSAB
The first paragraph of the Preface describes the Report Outline from the EFSAB to DENR as follows:
The Preface describes the ecological flow provision contained in the basin modeling statute, the
Department of Environment and Natural Resources’ (DENR) effort -- with the Division of Water
Resources (DWR) taking the lead role -- to establish the Ecological Flow Science Advisory Board
(EFSAB), and the activities of the EFSAB. The Research Assumptions describes the guiding
principles of the ad hoc work group that advised the analysis efforts of Research Triangle Institute
(RTI), and the U.S. Geological Survey (USGS). The research was to assist the EFSAB in providing
a foundation for their recommendations to DENR. The Recommendations includes the recommendations
as well as supporting information. The Summary and Conclusions provides additional context
for understanding the recommendations supported with maps, a flowchart, and insights from “lessons
learned.”
The EFSAB members asked additional questions about the Preface and offered specific comments.
Comment: In the first paragraph of the Preface (which describes how the report to DENR will be
organized), it is not clear whose research assumptions and recommendations those are. Are you
presenting the assumptions and recommendations on behalf of the subcommittee or are you presenting
these assumptions and recommendations from RTI and USGS on behalf of the Advisory Board. As an
Advisory Board, we’ve solicited specific input from a large number of different groups and
organizations, not just RTI and USGS. I think we need to be very clear to distinguish whether the
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recommendations that follow in our Report are coming from the subcommittee or from the entire
EFSAB. However we put the REPORT together, we need to be clear where we’re drawing our
recommendations from and who they represent.
Subcommittee Comment: The preface was envisioned to introduce the Report that the EFSAB will
submit to DENR. The Report should include research assumptions, recommendations, and
conclusions that represent the EFSAB, not just the subcommittee. The subcommittee was offering the
best effort of what we believe has been accomplished to date.
Comment: We need to indicate this in the first paragraph since it is not that clear. We looked at a
whole range of research and recommendations that the EFSAB did not directly solicit, that provided us
with research accomplished by other scientists and researchers. However, only the latest research is
mentioned rather than presenting a comprehensive view of what has transpired. If we can make it clear
that the recommendations will be put forward by the EFSAB and not simply two groups that recently
conducted research, this will clear it up. It’s still early in the deliberation process.
Subcommittee Comment: Agreed. As we move forward, the report will be expanded with additional
comments and recommendations. In fact, the final version of this preface may not include research
assumptions at all or it may include research assumptions that guided whatever the final
recommendations are.
Facilitator: I will indicate this in the Draft 1 version.
Question: Can someone explain the last sentence of the third paragraph on page 2, which starts out,
“Second, it was agreed that the EFSAB is recommending scientifically based methods or approaches of
flow requirements which may be numerical but not site specific.” I believe “site specific” in this case
means specific for a project at a site but certainly the numbers we’re getting are site-specific in the fact
that we’re trying to determine what flows might be at some node within Oasis or some position within a
river or reach of a river. We’re not setting up permitting requirements; what we are doing is setting up a
planning tool that is certainly site specific from that perspective.
Facilitator: So it seems like project-specific is a better term. Is that right?
Research Assumptions Section from the Subcommittee’s Report (this discussion occurred in
the afternoon following the BEC update from RTI/USGS)
Mary Lou Addor asked the EFSAB to turn their attention to the subcommittee’s June 10 report. She
reminded the EFSAB about the Research Assumptions section. This section describes the guiding
principles of the ad hoc work group that advised the analysis efforts of Research Triangle Institute
(RTI), and the U.S. Geological Survey (USGS).
The subcommittee had intended for the EFSAB to review this section as it related to June 18 RTI and
USGS presentation. The ad hoc water research group plans to revise these assumptions given the
results of today’s presentation. Given this new development, the group would like to postpone the
review and discussion. In the meantime, you have the original document that was submitted to you on
June 10, and I have hard copies to provide to you today (if you would like a hard copy).
The EFSAB was fine with tabling this discussion until the ad hoc group had time to revise their
Research Assumptions for a future presentation.
The subcommittee was thanked for their additional time and effort in developing sections of the report
that the EFSAB can consider moving forward. The EFSAB was asked to email any comments,
questions, or proposed edits to Mary Lou Addor before the next EFSAB meeting scheduled for July 16.
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IV.
Presentation:
Report
on
Work
of
the
Endangered
Species
Subcommittee
Presenter: Judy Ratcliffe
Judy reported on the work of the Endangered species subcommittee, which included Judy Ratcliffe,
Chris Goudreau, Mark Cantrell, and Sarah McCrae. The group has worked mostly through email.
Previously, Chris got help from Brynn Tracy and Fritz Rhode, went through textbooks and assigned
habitat guilds to the list of species in the DWQ database. They assigned guilds to adult, juvenile and
spawning stage. For this exercise, Judy provided the list of fish species that are host for various
federally listed mussels (from an Ohio State publication), went through and lined up which fish species
were riffle-run, pool species, then tried to cross tabulate with the mussels to see which habitat guilds
are being covered by the fish species. That’s what the boxes on the bottom are (referring to an Excel
spreadsheet that is now posted online).
Species name of federally listed mussel is on far left. Riffle run guild is very well represented (by fish
hosts), as are pool run and riffle. This goes forward with recommendation that if we go with the most
flow sensitive guild species, try to establish if using the guild approach adequately addresses concerns
for freshwater mussels, at least for their fish hosts.
The subcommittee didn’t know how much further analysis the Board wants them to do. There is a
petition list that may be included in the future (species that USFWS is or will be evaluating for
endangered or threatened status). The list is included as a tab in the spreadsheet. It includes crayfish
species, dragonflies, additional mussel species, fish, and amphibians. It would be possible to look into
the literature and determine how well the species needs may be addressed by the current guild
approach as well. The subcommittee needed guidance about if/how much more the Board wants done.
USFWS is currently considering these species in NC for listing. This requires species assessment and
threat assessment before determining whether to list or not. Many if not all have some level of state
recognition as threatened, special concern, significantly rare, etc., through the NCWRC or NC Natural
Heritage Program.
QUESTION: How do you envision using the information? That would help us decide how far you
should go.
RESPONSE: Listed fishes and mussel fish hosts- this crosswalk is directly related to whether or not we
use the BEC, since BEC is using the guilds as part of their analysis. If the Board moves forward with
using BEC, we could assess the confidence of the EFSAB in using the guilds as representatives of
endangered and threatened species.
QUESTION: So you envision using it to put more or less emphasis on a particular habitat and how
important it is?
RESPONSE: In the case of a lot of the mussel fish hosts- there are host species for across the board,
across the guilds. But there is significant use in the riffle run and pool run. As we add species to this
list it could spread out more, or it could become more apparent that riffle run is a critical guild for fish
hosts. We have seen from a previous presentation that riffle run may be more sensitive to habitats.
We’re trying to help the Board determine if we may be able to address the endangered species of
mussels with fish hosts through the guilds. It does seem like this suggests that we may be able to
adequately address those needs through this approach. I’m not suggesting that BEC is the way to go,
but if it is, then some of the federal species questions may be addressed.
QUESTION: Can you please send the Excel file for us to look at?
RESPONSE: Regarding the petitioned species list in the file, I got the list from Sarah, and took out
terrestrial species. But I’m not sure if all the species are flow dependent. This is a draft; there may be
species on the list that should be taken off, like some herptiles (amphibians and reptiles).
RESPONSE: Our committee has been away and has not thoroughly reviewed this draft. We’d like to
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take a week to review it and then send it out to you as a draft.
COMMENT: Coastal group is in part focusing on overbank flows into swamp forests. I wouldn’t want to
see any of those relevant species in the swamps and riparian systems disappear from the list. Like
crayfish- I see them there, but would want to see amphibians and plants.
RESPONSE: I can have our botanist check the plant list to look at habitat needs in riparian and flood
plain areas.
COMMENT: If looking at overland swamps then ground-nesting birds and butterflies would be there.
COMMENT: They’re waters of the United States, right?
COMMENT: We’ve determined that a lot of the petitioned species are flow dependant.
QUESTION: Would the petitioned species need to be cross-walked with the guilds?
RESPONSE: I don’t think it would need to be done if the Board moved away from considering the BEC.
Can we bring this up for questioning the Board at end of day? I haven’t considered how the
endangered species would be addressed with other scenarios.
QUESTION: I assume the habitat requirements for those that have been listed, are going to be
proportional to the petitioned species habitat? We’re considering expanding the list under
consideration based on the presumption that the proposed species for listing will be protected through
the same habitat. Is that represented there? If majority require riffle-run habitat, you’d like to know of
those guilds’ habitat…
RESPONSE: Not necessarily, if you look at species that wouldn’t have been collected by DWQ or
elosa species.
COMMENT: In your synoptic analysis at the bottom, you may need to put the % of each habitat type,
to clarify. You have a huge list of petitioned species, then a smaller subset that already has
protection…those that are currently protected- are they represented, or are their requirements
proportionally represented by the habitat (riffle run habitat for example) there compared to those that
are proposed to be listed? Before we draw conclusions on this information it would be good to look at
proportionality. Are we putting too much emphasis on one thing when maybe we should be looking at
something else?
RESPONSE: The first tab of this spreadsheet contains species collected by NCDWQ, and is what the
guild data is build on. That represents habitat use for fishes in wadeable streams, it doesn’t matter
whether it’s endangered or threatened.
QUESTION: To simplify the question, you could take the listed species, run through the analysis and
look at the guilds, their requirements for habitat, just on the ones already listed (RESPONSE: that has
been done). That does not include the petitioned species?
RESPONSE: no.
QUESTION: Then do proposed listed species require the same types of habitat as the listed species?
RESPONSE: We can only confidently tell if we run the petitioned species through the crosswalk.
COMMENT: That would be a lot of work.
COMMENT: If we go through the process and there is environmental flow that is established that is
protective of the guild or habitat needs, we (USFWS) may not need to add them to the list because it is
protected by the environmental flow. A lot of these critters are facing issues due to flows- not all but
some.
QUESTION: How hard would it be to separate those that might require just that type of protection?
RESPONSE: Usually they are imperiled for multiple reasons. Aquatic systems are impaired for
multiple reasons- impervious surfaces, many ubiquitous threats.
COMMENT: I’d like to see and spend time with it. But we only have 5 months left. I could see us
debating whether endangered and threatened fits into “eco integrity”. To move in a more expedient
way, we could have a comment in our recommendation like “specific flow needs for resident T&E
species should be considered in addition to the more generic recommendations…”. We don’t have
time to deal with petitioned species. We should focus on the more generic targets for this group,
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though I would consider it important to make reference in our recommendations.
COMMENT: Our cursory analysis shows we are addressing T&E species, but there are other
considerations. We could add a second “flag tripper” that says if you have listed species then further
analysis is needed. That could be a recommendation of the Board without getting into more work.
The group discussed how to develop language, suggesting at first that the facilitators write it up as part
of the meeting summary, but then deciding that they wanted to consider something for consensus in the
June meeting.
The T&E subcommittee developed a proposal for the group to consider and test for consensus, then
brought it back to the group later in the meeting:
T&E subcommittee review suggests that flow-habitat relationships for these species are broadly
addressed by the PHABSIM approach. Rather than further evaluate the developing research on
T&E species' flow requirements, the EFSAB recommends that specific, potentially more limiting,
flow needs for resident T&E species should be considered on a project specific basis by
NCDENR, in addition to the more generic recommendations offered by the EFSAB. For
planning purposes, portions of basins (e.g., nodes) that include listed species should be treated
by NCDENR as needing additional analysis.
QUESTION: Regarding the last sentence, is that not covered automatically with SEPA (State
Environmental Protection Act) regulations when a withdrawal is requested?
RESPONSE: The previous sentence covers that- project specific basis. What I was trying to get at
was the planning phase- so when DENR runs OASIS, there would be an overlay of listed species in the
basin. If there are listed species related to a node in the model, then that also raises a flag. I was trying
to distinguish between the planning phase and site-specific analysis.
Consensus to include this language in the draft EFSAB report was tested using the5-finger
scale- all 1s and 2s. The EFSAB was in consensus agreement.
V.
Presentation: Coastal Ecological Flows Work Group: Progress Report
Presenter: Bob Christian, ECU University
Bob introduced the latest progress report of the Coastal
Working Group and the results of the groups’ second
meeting. Comprised of 12 scientists, 3 are members of the
EFSAB: Bob Christian, Fritz Rhode, and Judy Ratcliff. Six of
the members attended yesterday’s meeting. The group is
focused on NC Coastal Waters downstream of DWR’s
OASIS Basin Models, an area well represented in the state
in terms of the number of streams in the coastal plain. The
second meeting of the coastal ecological flows working
group included several learning objectives.
Assess applicability of previous coastal work
o Other states
o Greenville
Hone stream classification framework based on Scott’s efforts and previous discussions
o Identify key classes to consider based on importance of environmental factors and potential
for flow modification by human activity
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Advance modeling effort
o Consider maps of potential areas of concern
– Other?
The working group was interested in the geomorphology and some of the hydrology of the system.
Using Fred Tarver’s October 2012 presentation, the working group looked at how Ecological Flows (EF)
was addressed in different states and how they handled the coastal plain. The working group looked
specifically at the City of Greenville and their planning work on the effects of what future withdrawals
may do to the Tar.
A stream classification framework was
introduced. Scott Ensign, a consultant from
Morehead City with a lot of experience in the
Coastal Plain streams came up with a typology
of the streams and the coastal rivers. The
working group has worked with the typology to
figure out what would be valuable and useful to
the working group.
The deliberations resulted in the following
thinking: look at the origin of the streams and
their location with respect to the upper and
lower coastal plain, and then essentially looking
at three stream types that would be freshwater
streams – those with a medium gradient and
non-tidal, low gradient non-tidal and those that
were wind or lunar driven tidal freshwater systems in which essentially stage has nothing to do with
discharge and it’s stage is driven by the tide. This represents a situation that’s quite different; one can
think of these as not simply three blocks but really
three Venn diagram circles where there’s overlap.
There are snags and mud too. There are riffles in
the medium gradient streams, but they tend to
disappear in the low gradient streams. There is
development of swamp forest in the low gradient
streams, which carry over into these lunar or tidal
dominated streams. The working group focused
on these three different classes as having enough
differences in their hydrology, geomorphology, and
potentially their ecology that they can and should
be treated separately.
Eban
Bean and a graduate student (Mike Griffin)
in the Coastal Resources Management PhD
program at ECU put together some maps
largely based on state data and other data
as a sort of a preliminary to the kinds of
mapping the working group could do. The
map demarcates the upper and lower
coastal plain within the state. Next, the
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group looked at the slopes of these different types of streams in trying to start to
characterize those that would have steeper slopes or at least median gradient streams
versus lower gradient streams. The problem is, there isn’t really a classification out
there that identifies those tidally driven streams and the non-discharge driven streams
that are freshwater. Thus, the state delineates tidal streams but they’re all with salinity.
What the working group is interested in is freshwater streams.
The working group has developed a trial balloon (a scheme) to
address which of these areas may in fact have these freshwater
tidally dominated streams. Basically there’s a model that was
developed for the coastal plain of North Carolina in which surface
areas of the watershed have been related to the depth at bank full
of these coastal streams. The working group is considering using
Lidar to get the elevation of the surface of the flood plain and then
use this model to figure out where the bottom of the stream is
relative to sea level. If the bottom of the stream is at or below sea
level, these should be tidally dominated. Thus the goal would be to
go in and map those tidally dominated streams and then
everything north of that or west of that would be either these low
gradient or medium gradient streams, and the working group could
define those non-tidal streams. The working group is headed in
that direction to try to map out where one could delineate each of
these three classes.
The working group also reviewed swamp and non-swamp waters versus swamp waters in the coastal
plain. Thinking about how other states have handled coastal systems and what happened in the
Greenville study, the working group believes that they can look at three different ways of characterizing
the ecology of these systems and relating it to flow
change. For some of these, where there is a
relationship between discharge, stage, and habitat,
the working group should be able to develop some
kind of discharge habitat or stage habitat
relationship. What is more commonly used – what
has actually turned out for Greenville – is looking
at downstream salinity as a measure and looking
for how change may affect the position of a certain
salinity downstream of the withdrawal. And then
finally, in some of these cases where there is a
significant riparian system, we could look at
overbank flow as an indicator of how flow
changes might affect the ecology of the
system and the ecological integrity.
The working group has this three-pronged
approach that it has not addressed in any
depth at this point. The working group plans to
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meet before the July meeting with scientists who study anadromous fish and begin to look at some of
these issues by pulling from some of the Coastal Habitat Protection Plan (CHPP) work. Bob reported
this is where the working group stood following two meetings.
A group discussion followed Bob’s presentation:
Comment: I got the swamp/non-swamp but is that based on DWQ information? [Yes]. Then
a caveat is to keep in mind that the DWQ classification system of swamp and non-swamp is based on
the Environmental Management Commission actions, and not characteristics of the actual streams.
For example, in the Chowan river basin, where the Great Dismal Swamp is located, those streams are
not classified as swamp streams. The classifications are bureaucratic classifications and not ecological
classifications.
Question: Where can the working group locate this definition? Is it on the DWQ website?
Response: The classification is neither a definition nor an ecological label; it’s a process label.
So depending on whether it’s swamp or non-swamp, DWQ uses different strategies for determining
water quality.
Question: Jay, does DWQ have a data set that would help map swamp ecological characteristics? Is
there data that DWQ collects that would help collect that?
Response: Not that I’m aware of. The definition of swamp is generally along the lines of low velocities,
and those sorts of things. I’m not aware of any legal definition that we’ve actually implemented that
would also be consistent with our ecological definition for this particular group.
Comment: There are swamp waters on the Roanoke all the way up to Big Squash. They may not be
classified as such.
Bob: The working group spent time talking about brown water versus black water and whether that was
an important distinction to make. It may be when the working group gets into actually relating flow to
ecology or stage to ecology.
Comment: Don’t hang too many hats on that.
Bob: The group won’t; maybe the National Wetlands Inventory would be a better map for this.
Facilitator: Any other questions about what you heard or that you would like Bob to bring forward to
the coastal ecological flows working group?
Comment: Maybe a comment to bring back to the working group is the point of staging a habitat
relationship for some and not for others. The question that comes to mind is the work that’s been done
by others and presented to this group up to this point (like the RTI and TNC work), it would be good to
see if the working group has a feeling for whether those are applicable? could be expanded? how
could they be expanded? And if so, could they be expanded to the medium gradient streams as an
approach? There is an interest in the working groups’ feedback.
Bob: That’s a very good point. We may have the opportunity within the coastal working group to bring
non-EFSAB members up to speed and thus could consider it.
Comment: I think something that would be helpful is to extrapolate work on the part of the coastal
working group to develop a better idea of the actual slope or the sort of low gradient to medium
gradient. I am not looking for a hard boundary dividing line but a range. Perhaps we could provide
gradient classes that we’re using and then you could determine if that is too steep or not.
Bob: That would be wonderful because the first time I saw these slopes was yesterday, and, in fact,
they weren’t really slopes. They were changes in elevation over the reach of the stream. We need to
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develop that a little more and any advice that you would have, any contribution would be really
appreciated.
Comment: I will contact Scott and ask for clarification about the cutoffs that we’re looking at.
Question: Bob – do you believe that the Costal Ecological Flows working group will have some type of
draft recommendation for this group to consider by the July meeting?
Bob: We are hoping but it will depend on whether we meet a week before the July meeting or the day
before. Meeting a week before will provide time to advance something that can be formalized in some
fashion. We are hoping that a few key points can be made to move us beyond, “Let’s look at the
literature,” when it comes to the coastal plain. That’s our goal.
So far we have discussed the physics of the coastal plain and expect to get into the biology of it. In
the meantime, the Albemarle-Pamlico Nationally Estuary Program (APNEP) is committed to ecological
flows for the region so they’re going to continue our efforts beyond the EFSAB; they don’t have the
limitations of the legislation so they can really broaden their objectives.
VI.
Presentation: Report Back on Comparison of SIMBASE and PHABSIM
Unaltered Flows
Presenter: Tom Fransen
This power point presentation can be found here.
DWR
had
time
to
run
only
one
comparison
with
the
PHABSIM
versus
the
80%
flow-‐by.
They
looked
at
the
Kings
Mountain
node
that
they
had
used
earlier.
They
did
three
analyses:
SIM
(SIMBASE—which
is
basically
current
conditions)
versus
unregulated
or
natural,
SIM60
(which
is
the
projected
2060
scenario)
versus
the
unregulated,
and
then
what
people
were
interested
in
was
the
SIM60
versus
the
current
conditions.
DWR
used
the
Index
B
approach
(mean
of
habitat
events
between
10
and
90%
exceedence).
Interestingly,
SIM/UNREG
and
SIM60/UNREG
came
out
the
same.
Basically
one
guild
out
of
eleven
shallow
guilds
dropped
below
that
80%
threshold.
The
2060
versus
current
is
not
shown
because
it
didn’t
have
any
guilds.
When
they
ran
this
seasonally,
all
three
analyses
had
zero
guilds
that
were
below
the
80th
percentile.
If
you
look
at
the
deep
guilds
[slide
4],
it’s
showing
a
little
bit
more
impact.
Half
of
them
were
below
the
80th
percentile.
The
2060
versus
current
was
still
zero.
The
only
seasonal
impacts
were
in
the
summer.
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Fred
had
compiled
a
list
of
major
conclusions
from
the
analyses:
• Majority
of
reductions
in
habitat
are
associated
with
“Deep
Fast”
guilds
where
half
or
nearly
half
of
months
fall
below
80%
threshold.
• Deep
Slow”
guilds
have
1
or
2
month
breaches
of
80%
threshold.
• Another
Deep
species
(Golden
Redhorse
Juvenile),
with
nearly
half
of
months
below
threshold,
had
habitat
values
<500
by
month.
• The
Simbase
and
2060
projection
include
wastewater
treatment
plant
return
flows,
which
tend
to
offset
dam
alterations.
• Seasonal
calculations
(Summer)
tended
to
exclude
breaches
for
marginal
months
when
using
Index
B
(mean
of
habitat
events
between
10
and
90%
exceedence).
Fred added that he thought that for the deep/slow there were one or two months that were below. He
went on to say that he had not created tables that Jim had included in earlier presentations of
PHABSIM, indicating 1’s and 0.1’s where he was showing those that were greater than 1,000 weighted
usable area versus those that were less than 1,000. Fred indicated that he could provide those if
desired. He noted that some of these guilds like the Golden Red Horse had a fairly small amount of
weighted usable area.
QUESTION: The over 120% isn’t represented. What I would see there, if I could see that, is whether
the deep fast is transitioning into an increase in the riffle habitats. Do you see what I’m saying--like a
significant increase in the shallow fast or shallow slow--what became of the deep fast?
RESPONSE: My recollection is that none of the comparisons showed greater than 120%.
Tom: Part of the driver for doing this analysis was to compare—where I was doing everything on
current conditions, looking forward, there was some concern how much potential degradation had
occurred between the natural versus current. As one of the non-ecologists in the group here, my
conclusions after taking a look at these were that what we saw with the PHABSIM is that most of the
impacts occurred between the natural and the current conditions, and we were not really picking up, at
least with PHABSIM on this one node, any additional impacts from current conditions up to the
projected 2060 scenario.
Tom tried to do the same type of thing with the 80% flow-by. He modified what he did last time. He
used the full record—the full hydrograph—last time. This time he used the index B approach where he
was only looking at
the flows between
the 10th and 90th
percentile,
dropping off the
extremes, which is
comparable to
what you do with
the index B
approach. Looking
at slide 7, the first
column shows
natural flows as
the baseline
compared to
current conditions
or SIMBASE. The
second column
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shows natural flows and compares them to the 2060, and the last column is basically what Tom did last
time, taking SIMBASE and current conditions and comparing them to the 2060. One interesting thing to
note using this approach is that most of these nodes are coming out with zero days because most of
them are actually looking at it during low flow range, usually less than 2nd percentile, so we’re ending
up with 12 nodes that were showing 1 or more days that are now zero days, dropping off the ends. It
seems The Kings Mountain node is probably a worst-case scenario, at least based on this analysis. For
the Kings Mountain node, which is what Fred did with the PHABSIM, we’re showing quite a few days
that are dropping below that 80% threshold for both, when you’re using the natural flows. Before we
were looking at impacts in the range of 1-2% as the highs; when you go back to natural, you’re starting
to see 34 to over 40%. So there is a difference—we are seeing some differences here. Of those 5
nodes that were showing 1 or more days, most of them are down at the lower end of the river system
and below large reservoirs [slide 8].
Tom included slide 9 to help show
what’s occurring, why we’re picking up
so many days. It shows the duration
curve for the natural flows then the
duration curve for the 80% of that, of
natural. Then it shows the duration
curve for SIMBASE. He highlighted
anytime the SIMBASE duration curve
for a particular percentile was less
than the 80%. So you’re seeing for
this node that it’s in that 10 to 35%
range or a good 15-35% range, which
is showing why we’re getting so many
days, With most of the other nodes we
were seeing the difference, when we
had them, in usually less than 1%, 1-
2%. So they were not being picked up with this modified approach.
One of the
questions that
came up last
time, since Tom
just showed the
full period of
record, was
how does the
analysis break
down by month
or season.
DWR modified
the analysis
approach so
that you can
now see the
break down for
a month [slide
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10], using seasons the
same way as defined in the
PHABSIM analysis or the
full period of record.
Tom did not think it is
surprising that most of the
impacts occur in the
summer months. Your
overall deficits are not real
huge. Tom’s conclusions
about the 80% flow-by using
an Index B approach were,
1) like the PHABSIM, most
of the impacts occur
between the natural and
current conditions; 2) this particular technique is picking up a few additional impacts between the
current and the 2060 (Tom noted that he thinks that goes back to a question he has, in spite of having a
lot of experience interpreting PHABSIM, about if you have one or two days, is that an impact or not—
he’s still trying to figure out how to interpret whether that really is an impact); and 3) using the Index B
approach, 85% (22 out of 27) of the nodes in the model really weren’t showing any impacts.
QUESTION: Tom, would you remind us what the 2060 projection was?
RESPONSE: The 2060 projections are our planners using the local water supply plans and other
information to set up a scenario based on our best estimate of what conditions would be like in 2060.
So we’re putting our projected 2060 demands in if we know of new sources coming online, changes in
reservoir operations, anything like that. That’s our best guess of what the basin would look like in 2060.
QUESTION: So it’s a projection of how management would change?
RESPONSE: Management, demands, and those types of things.
QUESTION: And in this watershed, were those 2060 projections substantial?
RESPONSE: There are some changes, but you’re not going to see huge changes like you would over
here in the Triangle. If you look at the Triangle region, you’re going to see more changes than what
we’re seeing over in the Broad.
COMMENT: What I’m trying to figure out is when there’s very little impact detectable between the
current situation and the 2060 projection, whether that’s an attribute of the sensitivity to the model, or if
there just aren’t any significant changes projected.
RESPONSE: There were a couple of municipalities that were projecting changes, but not many. Most
of them were not much. That’s probably something I should have pulled in here is to show what those
were.
QUESTION: In following up on Sam’s point, if I can jump in, I had the same question, but also noting
that the PHABSIM site, on which fast and shallow, deep slow and shallow fast guilds were evaluated, is
downstream of the Kings Mountain wastewater discharge. Is this due to the fact that the difference
between unregulated and current is much more than between current and the projected 2060, and was
that due to the fact that there’s not much difference in the amount of water being taken out between
current and projected 2060? Or is it because that wastewater discharge offsets more being taken out
in 2060. Maybe it’s a little of both.
RESPONSE: I think it’s a little bit of both.
COMMENT: Yes, that’s why I was kind of surprised when you compared natural to SIMBASE and the
60-year projection that you saw the 50% difference because I thought the wastewater return would sort
of mitigate some of those impacts. But I guess the return wasn’t enough to offset the impacts of the
reservoir.
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Tom: Well, I mean it is a little bit because this line here actually is the release from the dam, the one
that shows the greatest. So you’re seeing the impact from the dam. The next one down is the 610 to
650 where the wastewater gets added back in. So you’re seeing that wastewater is mitigating some of
what’s gone on upstream, but not all of it.
RESPONSE: So instead of 34%, it’s 20%.
Tom: 20%, yes. It hasn’t mitigated all of it, but it did half of it. That’s one of the things that I liked about
this approach is that I can look at the upstream and downstream to see how things are kind of
changing. You know, whether I’ve got a cumulative impact or—
better or worse. This example does actually show it out. You expect something at the dam, and you
would expect an improvement from the wastewater there.
QUESTION: I don’t want to be repetitive, but can you give me a quick refresher on where the natural
flows number came from in this case? What is that?
RESPONSE: When we create the model, we have to create an inflow record to drive it. The technique
that we use is to start with USGS gage data, and we have collected the historical withdrawals and
discharges and as much historical information about reservoirs as we can. So that we’re not doing
double counting in the modeling if we have a withdrawal, we add it back to the record. If we have a
discharge, we subtract it out of the record, and we do the same type of thing depending on whether
you’re either gaining or losing storage in a reservoir. So by doing those additions and subtractions, to
the best that we can find historical records, we come out with what we’re calling an unregulated or
natural or unencumbered flow. These are all terms that we use. It’s not perfect, but it’s better than
doing no adjustment.
COMMENT: So bottom line, just trying to go back and look at the questions from last meeting, the
question was, essentially, what’s the difference between using SIMBASE versus unregulated as your
denominator in your calculations for PHABSIM, for example. And the answer is…
COMMENT: About 50%.
Tom: I thought you were going to give me the answer.
RESPONSE: What’s the take home message here?
COMMENT: Well you do have to temper it a little bit because in those percentages if the guild had one
month versus 12, it was counted in or out. There might have been one month where it didn’t meet the
criteria. Whether you consider that a significant impact versus one that all 12 months doesn’t meet the
criteria, there does have to be a little bit of tempering. When you look at 50%, there’s that.
Tom: I’ll go back to the driver of this whole thing. I think part of this was the question of trying to figure
out what’s your baseline to use, and the statute says prevailing conditions. I think the question that
came up was how has prevailing conditions already changed from natural. At least on the one node we
looked at, which is the worst one by a couple of different measures here, there are significant
alterations. But the statute still goes back to prevailing conditions so I’m not sure where that leaves you
as a group to figure out what your final recommendation is going to be.
COMMENT: One clarification on that though: Your percentage reduction of flow, it seems like the
largest one that I saw on your list was just under 11%. Is that correct? You have the average deficit
percent difference; the largest number there is 10.7%. I know that if it’s your habitat that’s being lost,
you’re not that concerned if it’s 10% that wipes you out. I just want to make sure I’m not misinterpreting
what that deficit percent difference means. Can you explain to me?
Tom: The deficit—I was just looking at what we’ll call the baseline, the 80%, and any time I drop below
that 80%, I made it a positive, so that’s saying, okay, in this case the average for those times that were
below 80% are that many CFS. I also tried to put that number in context, and I also did it as a
percentage over the natural flow. The three cfs deficit would translate back to the 10% of what the
natural flow would have been. I know the magnitude by itself gets misleading because you don’t know
if that three is at a time when you only have six in a river, versus 500. So that’s why I tried to normalize
the data by using a percent difference.
QUESTION: So the natural flow would be about 35? Is that what that’s saying?
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RESPONSE: Yes.
QUESTION: CFS?
RESPONSE: When that occurred, yes.
COMMENT: Even though you have got a high percentage of just days that are below your 80% flow by,
the habitat results were not as—correct me if I’m wrong here—the PHABSIM weighted usable area
impacts were not that significant, not as much as just the day count. And one reason for that is that the
deviation below that 80% is not very large.
Tom: Right. We were seeing that in the PHABSIM results, too where we went to seasonal, because a
lot of those were just under the 80% and when we group the months together, we actually ended up
with not having that trigger for us. Now is this a good basin to do this on? I don’t know. We’ve had
such small changes, but it’s the one we had to use.
COMMENT: So I think this is an important assessment to do within each basin. Rather than try to
make an assumption that there is a minimum impact based on this analysis. It seems that it would be
heavily driven by the amount of anticipated change between SIMBASE and SIMBASE 60. So it’s highly
relevant within each basin that this type of analysis be run because the shift in natural to SIMBASE
could be greater in other basins, as well. Or it might be less. And so without doing this type of analysis
within each basin model, you wouldn’t really be able to appreciate cumulative change and then
characterize the additional withdrawal relative to its cumulative impact. It doesn’t seem to be in this
case that the SIMBASE to SIM 60 is going to be the straw that breaks the camel’s back because we’re
fitting pretty well within the 80%. But there may be a scenario, there may be a basin in which even a
small change that’s represented in SIM 60 to SIMBASE could be a cumulative straw that breaks the
camel’s back if the cumulative change between natural and SIMBASE is so substantial, you see what
I’m saying?
RESPONSE: Yes, I understand what you’re saying.
COMMENT: The results here can’t necessarily be applied in the Cape Fear, and you already made
that point, or in the Chowan. But it’s within each basin. If you conduct this analysis, it’s very
meaningful so that you can understand the cumulative flow change and then also add in your
anticipated changes to see if that’s really going to throw you into a lot of deficit.
RESPONSE: We’ve tried to set this up so that it would be easy to use as we move forward. As you
can see, I have an analysis set up. I can do all of the nodes in the model, once I get that one script set
up, in one shot. The interesting thing is that it takes longer to run the analysis than it does to run the
model. But that’s not uncommon doing these post-processors. Did you have any other questions that I
could try to answer?
COMMENT: I was just trying to remember what we talked about a month ago.
Facilitator: You referenced this concern already but the concern was that if you go with one of these
recommendations, for example that were in the trial balloon that Fred presented which was 80% flow
by, if DWR uses SIMBASE instead of the baseline that was used in the habitat simulation that Jim did,
are you really recommending 80% flow by or are you recommending something different because
baseline has changed. Tom did these additional analyses to try and clarify if there was a big difference
between the natural flows that Jim used and the SIMBASE that DWR’s using moving forward with the
basin planning. So I guess the question is, how much more do you need, or do you need more at all?
RESPONSE: Well I think Judy just said it; it’s basin specific.
RESPONSE: So would we need to recommend that to DWR? Would that be a potential
recommendation, that this type of analysis would be appropriate?
Tom: If 80% flow-by is what comes out in the end, and I’m not saying it is or isn’t, what we’re going to
need from the Board whether it’s 80% or something else, is here’s our recommendation, this is how you
implement it and how you interpret it. That would be ideal but the less you give me, the more flexibility I
have to make up how I want to interpret it, too. Just going through this internally, we’ve had quite a bit
of discussion. What does the 80% flow by mean, how could we implement it, what does it mean in
terms of modeling and planning? And what you’re seeing here is kind of what came out of those
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discussions.
Facilitator: Are there any other reactions to this? Does this bring up any other thoughts for you or
concerns?
Tom: I can do some follow-up summaries, if you need. Right now we only have the one PHABSIM, it’s
kind of hard to compare.
COMMENT: All I want to say is that I think there is something really profound in these results, and it is
hard for me to even know, having just seen it, what exactly my response is going to be. But I think that
question is still out there, if your PHABSIM recommendation, even if it’s not 80% flow by, but if there’s a
recommendation that’s based on the PHABSIM work that was done, and it was based on naturalized
flow, or unregulated flow, we need to understand what the implications are when it’s used in a model
with a SIMBASE current and SIMBASE future condition.
Facilitator: It’s almost like you could have a caveat to a recommendation saying the equivalent of
SIMBASE, right? If it’s a difference? That would be something they would have to look at in the other
basins, it sounds like. Is that kind of what you were thinking?
Tom: Well, like I said I apologize we didn’t get it out so you could look at it and think about it before so
when you get working on your next agenda, if somebody feels like they need a follow-up discussion to
clarify something that either Fred or myself have done, we would be glad to come back and do that.
COMMENT: I think one of the issues that Judy brought up though is that we’re looking at one basin,
and in a way, it’s hard to capture what the impact is of using a different baseline flow if it’s going to be
different for each basin. You’ve got some basins that already have a lot of water use development, and
others that don’t—some that are projecting to have a lot more than others in the future, so without
seeing this kind of scenario on different basins, to me it would be a little difficult to move ahead and say
okay this is the impact of using SIMBASE versus the naturalized flow. Okay, if we’ve only seen one
basin, I accept your estimate that it’s going to be different in others makes a lot of sense, but how much
different.
Tom: That’s really going to vary from one to the other, because I can tell you some basins we’re
working on right now and we’re having dramatically different wastewater discharge scenarios and
different water supply alternatives with what the current condition is. So I would expect that you’re not
going to see 22 out of 27 of the nodes showing 0 change.
QUESTION: Do we have any idea how these deficit figures compare to the deficits that RTI
calculates? I mean is a 80% flow by equal to 20% deficit or do we not have any idea of that yet?
QUESTION: Are you talking about eco deficits?
RESPONSE: Yes.
RESPONSE: I think we have had that discussion.
RESPONSE: It's a challenge because eco deficits are how big is the area under a curve, so that
percent doesn’t translate directly to these types of percentages.
COMMENT: Yes. This is a daily, an instantaneous, in a sense, issue versus a summation.
Tom: Right. I mean they’re slightly different approaches to this. I think that’s part of the problem of all
this. We talk about percentages, but we’re talking about percentages of different things. So it’s kind of
hard sometimes to compare them. If you think about it, and somebody feels that they need us to come
back and summarize this slightly differently or have a follow-up discussion, we’d be glad to come back
at the next meeting.
QUESTION: So, Tom, just for my own understanding, if you were to run the other basins, how much
time would that take?
RESPONSE: I don’t think for me to run some of the other basins is meaningful unless we’ve also got a
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PHABSIM site for comparison. I can run the numbers and see, probably the Neuse and the Tar I could
do—probably would take me maybe a day, maybe a couple of days to set up the initial analysis, and
I’m probably talking maybe for both of those maybe 3 or 4 days’ work, total. But like I said, I’m not sure
it’s going to help you if I don’t have some PHABSIM sites in there to compare against.
QUESTION: Tom, I have a question for you and Jim. Would that work we did in association with the
Harris coal application be applicable for comparison, where we used PHABSIM?
RESPONSE: That was on Buckhorn Creek, and that was one of the nine PHABSIM sites.
RESPONSE: Yes, and we did Cape Fear River as well.
RESPONSE: Cape Fear would not work probably because remember we had side channels, and it
doesn’t really represent. At Buckhorn Creek, that was one of the nine PHABSIM sites. There, the
difference between unregulated and existing is phenomenal because of the creation of Harris Lake.
Even if the additional units were put in and the reservoir were raised, and I’m not sure that the 2060
projection would include that or not but even if it did, it would be, I suspect, a lot smaller than the
difference between no Harris lake and Harris Lake.
RESPONSE: You probably will see some there because if you actually go with the scenario of the new
units and changing the size of the lake, you’re going to see some changes.
RESPONSE: But as part of that would be adding a minimum release to Buckhorn Creek, which the
current situation does not have.
Tom: Right. So add all of those together—that’s why we have the models because there are too many
variables to get a good handle on what would be the final answer.
COMMENT: I guess, again, the use of the river stations just wouldn’t be applicable because we were
restricted to that small two-mile study area.
RESPONSE: I think so, yes. I mean it had a very specific aim, and all but a couple of the transects
there were off on little side channels because that’s where we thought most of the impact would be.
And also just workability, too.
COMMENT: That’s where the most diverse habitat was.
Right.
COMMENT: But thinking about the Buckhorn Creek thing, that’s another reason where when for the
nine sites that we did the PHABSIM analysis for, over the course of this group’s meeting, we used
unregulated as a baseline and then some flow regime, whether it was flow-by, percent average flow,
7Q10, etcetera. None of those included the presence or the operation of a reservoir because each
reservoir is different. Trying to come up with some sort of approach that could be applied broadly, and
we’ve talked about this before, we’re looking more at just withdrawal types of changes in flow and not
big reservoirs, or even smallish reservoirs and how they change flows because each reservoir has its
own unique characteristics in terms of how much storage, how big of a stream is it on, how is it
operated. Plus every reservoir has to go through its own separate permitting and environmental study
process that we didn’t want to try to replicate or shortcut. So even though Buckhorn Creek has
reservoirs sitting upstream on it, we treat it as if someone just had a lower spot withdrawal on Buckhorn
Creek that was letting some amount or more go downstream.
RESPONSE: Right.
VII. Presentation: Biological-Environmental Classification (BEC) Project
Update
Presenter: Jennifer Phelan (RTI) and Tom Cuffney
Jennifer provided an update on the BEC work, followed by Tom providing an update on the fish
classification portion of the work. This has been a joint effort between RTI and USGS. We acknowledge
funding sources of EDF, NCDENR, and NC WRC. They provided feedback to make it a strong
collaborative effort.
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At the last meeting, 2 main presentations were given, one by Philip Jones on stream classification.
Then I did one to share products of our RTI Internal research development project, specifically a
method to test on developing flow- biology relationships. As a reminder, we presented that there was
no obvious winner with respect to stream classification associated with biological assemblages. No
stream classes…we suggested 2 approaches (see slide Last meeting for the 2 options)
1) Do multifactor response models offer better predictions of biological response? (other attributes
besides flow metrics)
2) Do a priori regional classifications improve strength of flow-biology relationships? (Like
Omernick ecoregion or EDU)
Since then we’ve pursued the 2 options of the BEC classification system pairing those results with RTI
IRD work. We’ve come up with recommendations for flow-biology curves. Recommendations are
based on going as far as we can with the class approach and given time and resources, best available
data for flow-biology curves.
Before jumping to curves, I’ll give a brief overview of methods. Similar models were developed by Tom
and presented by him. We did similar analyses with fish. Response metric- species richness of riffle-
run since it is most responsive so far for flow changes.
Muti- factor response models?
• NC fish (species richness of riffle-run guild)
• Flow metrics:
o Summer Eco-deficit - chosen because summer eco-deficit represents magnitude
o decreases in Annual 30-day Minimum Flow- chosen because it represents both
magnitude and duration
• Best model fit- We included a variety of predictive variables based on Tom’s recommendations,
and could be applied across the state (mapped):
o Flow metric
o Ecological Drainage Unit (EDU) regions- a strong predictor variable
o Slope
o % Forest Cover (highly correlated with flow metrics)
o Average Temperature -only a good predictor for annual 30 day min flow
These results we found for fish were similar to results for benthos (forest cover/flow metrics,
Ecoregion(Omernick) worked best for benthos, EDU for fish, which makes sense since EDU was
developed for fish.
A priori regional classification improve strength of flow-biology relationship?
• NC fish (species richness of riffle-run guild; RTI flow-biology methodology – normalized by
basin; response of 90th percentile data)
• Flow-biology relationships developed for each EDU
• Results:
o Flow-biology relationships were not consistently strengthened by splitting up by EDU
o only 4 of 10 EDUs had significant flow-biology relationships
o only 1 EDU had a better model fit than the state-wide model (Albemarle Pamlico
Piedmont EDU)
We didn’t gain much by splitting up by EDU. There weren’t always a lot of observations within each
EDU, some had 4, 2, 9. If there were more monitoring data results it could change but can’t do that.
Normalizing by EDU, found only 1 EDU had a stronger model fit than statewide model. We’re not
gaining anything by splitting by EDU. Best approach is a statewide model.
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Recommendation (from the ad hoc research group including RTI, Tom(USGS), Chris, Fred)
Use state-wide flow-biology relationships for fish and benthos (based on RTI flow-biology methodology)
to support determination of ecological flows
o Biological response:
o Fish
Species richness of Riffle-run guild
Normalized by basin by 90th percentile value for each basin
o Benthos
EPT Richness
Normalized by Omernik Level III
o Flow metric:
o Eco-deficit
QUESTION: Remind us what EPT is?
RESPONSE: Includes mayflies, stoneflies, caddisflies (insect orders Ephemeroptera, Plecoptera, and
Trichoptera). It has for a long time been a very sensitive method, and one that DWQ uses as
procedures for establishing site condition.
QUESTION: Summer or annual eco-deficit? Both.
Eco-deficit definition: It’s a calculation not as simple as a daily flow value. Eco-deficit is a measure of
the reduction in volumetric water availability
20% eco-deficit = 20% reduction in volumetric water availability (over a defined period of time)
It can be
expressed
daily,
monthly,
seasonal, or
annual
basis. A
relationship
between
flow
duration
curve during
baseline
condition
(can choose
that (and current condition, and looking at difference under the curve. Results in a calculation of either
a surplus- increased flows, or a deficit, meaning flow is reduced. Red is decrease, blue is surplus.
These graphs (above) show the rate of how the deficit or surplus will change based on amount of flow
per second. These are NHD catchments in Roanoke. We find more often than not that this is what the
relationship looks like. You have a consistent decrease in flows, but a little bit of surplus in the higher
magnitude of flows. Occasionally you have something like this happen; sometimes you have an
increase in flows. You have a whole variety of what these look like when you examine on a catchment-
by-catchment basis, which makes sense when you think of the changes. This one, when I scroll down
the plots you’d see this was a common trend (the one on left).
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QUESTION: The expectation for slide on right, where current exceeds unaltered, that’s expected to
occur where you have a low flow requirement,
or changes in land use where you have
flashiness of a discharge?
COMMENT: A dam, or wastewater discharge
could cause that.
QUESTION: For the graph on right, if
calculating eco-deficit for that one, you’re
taking the eco-deficit you have right now,
subtracting surplus from it and that would be
your eco-deficit?
RESPONSE: No, just taking the eco-deficit.
Only calculating this value, not doing net
change…
QUESTION: When calculating eco-deficit
over time is it a cumulative calculation or is it
an average for that time period?
RESPONSE: These flow duration curves are
done over a time period, so you determine
what period you want to do eco-deficit for
based on what period of record.
QUESTION: 20% measurement over entire
period, summed?
RESPONSE: Yes, so keep in mind whether it is annual, seasonal, daily or monthly. It doesn’t make a
lot of difference in results.
Now we’re getting to the curves themselves. This graph shows annual exceedence for fish. As a
reminder, normalized fish species richness is normalized by 90th percentile value as denominator for all
monitoring (max biological condition). So you take the 90th percentile value of species richness for the
basin, use that as denominator for all monitoring stations in that basin. Anything less than that is less
than your maximum biological condition. These are a best-fit curve to the upper 10% of the data, either
linear or non-linear based on the best model fit.
Q Why did you choose upper quantile?
RESPONSE: Potomac did ground breaking work; they used upper quantile approach. They found that
there was so much variability in the data, there seemed to be an upper response limit. They used
quantile regression approach to hypothesize that the top 10%, the upper quartile, of data was showing
the upper response, the ceiling of response that could be attributed to flow alteration.
COMMENT: If you look at the dot that says 16, what it tells me is that a 16 percent increase in annual
eco-deficit will result in a 30% reduction in biologic condition.
QUESTION: I understand the 90th percentile decision though it seems arbitrary. Equate that to
definition of ecological integrity put forth by legislation.
RESPONSE: We haven’t done that. That is up to EFSAB. Argument could be made (by biologists)
that a reduction of any number of species, any species loss in the system violates integrity. We’re not
saying that. We’re saying EFSAB needs to determine where that violation occurs, where to draw the
vertical line. We’ll have to have that debate here.
COMMENT: The point I’m wrestling with, when legislation was enacted and DWR negotiated, there
was a crystal clear decision to use a definition different than DWQ’s definition for biological integrity.
I’m hoping EFSAB can avoid making the judgment decisions, and make our recommendations so that
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allows a lot of flexibility. I’ll hold off until Tom makes his recommendations.
Jennifer continued her explanation of the graph- This is the bio-flow response relationship with best fit
curve based upon data. All we’ve done here is to put into context of changes in biology we’ve plotted a
10, 20, 30, 40, and 50% reduction in biological condition, saying for this incremental change of
biological condition, it is associated with the 7,11,16, 21, and 28% eco-deficit for fish.
QUESTION: Specific for riffle run guild? If you’re looking at riffle run guild, and the site you’re looking
at is on a riffle, you will already have much higher amount of riffle run guild than if it were sampled at a
pool. Have you accounted for the habitat at the site? One might show up as low in a riffle run guild, it
may be because of the individual habitat site…
COMMENT: Regarding how they were sampled, it’s a 600 foot length of stream. The question is
pertinent since it is a site-specific assessment, hopefully we’ll capture a diversified habitat for the reach
we’re trying to evaluate. We can provide the SOPs but in actuality there is variation in the sampling.
It’s a good reason for why to use the entire database rather than narrowing it down.
RESPONSE: Right. The hope would be because of the sheer volume and number of data points, that
would help reduce error.
COMMENT: Because of DWQ program and resource constraints, the entire data set for fish is not very
big. Not as big as the benthos.
RESPONSE: Riffle run guild is 858 sites, then take into account tidal zone, restricted sites- we got 600
sites for riffle run, ~650 for pool guild collected between 1990-2010, the most recent measurements for
each site.
COMMENT: If riffle run guild was not present in sample, site was not included in analysis (
RESPONSE: correct). Not a determinant; won’t see a lower value of sites simply because of sites
without riffle run.
RESPONSE: Right. 90-95% of sites that have riffle run guild present were almost exclusively in
piedmont and mountains, and had at least one observation of riffle run guild species, whereas Pool had
representation in coastal, piedmont and mountains.
COMMENT: Calculation of species richness when predicting effects of eco-deficit on richness, is that
accomplished by using either sequential observations on the same site with different flow patterns, or is
it calculated based on an estimate of reduction versus natural flow conditions?
RESPONSE: The latter. All the data points here represent single time measurements, most recent at
a biological monitoring station (even though measured every 5 years). Kimberly did more of a time
series analysis which she’ll present next time. As far as flow alteration was concerned, it was
comparison of flow under PNV, no flow alteration, vs current condition (2006 NLCD with current
withdrawals, discharges). We used same climate period (1967-2006) for both land cover conditions to
isolate effect of human influences.
COMMENT: Every site has a current eco-deficit, which is the baseline.
COMMENT: Your numbers are based on you calculate natural flow versus current flow at most recent
sample.
COMMENT: We have to treat current condition as baseline. If you add additional eco-deficit, how many
additional species do you expect to lose?
RESPONSE: Some sites have had a lot of alterations based on current land use, where some have
had relatively little alteration.
Q; When you enter data, take species richness data from a site and it has categorization as riffle run or
pool, it seems logical that at some point if it has significant eco-deficit (20% or more) then that the site
may have been a pool site.
COMMENT: No, each site includes multiple habitats.
COMMENT: But Jen used current guild species…
RESPONSE: In last meeting I showed a map of NC with fish monitoring sites, it showed overlap of
which ones had riffle run species- the majority in mountains and piedmont.
COMMENT: The site description is from guild species present at sampling, not from looking at the site.
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RESPONSE: correct.
Moving on to Benthos- we did
the same analysis. Benthos in
response to eco-deficit
normalized by EPT richness.
50% reduction is not on this
curve.
Then look at them on the same
graph- the blue is benthic, black
is fish. Confidence interval is
shown.
COMMENT: A stronger
response demonstrated in
fishes
RESPONSE: yes, as according
to best fit curve normalized with
90th percentile
COMMENT: with the best we
could do with data we could
find, these 2 graphs based on
fish and bugs, tell us how biological condition reacts to increases in eco-deficit. We used the most
sensitive/most representative guild, second most sensitive guild, came up with these 2 curves. One
option is to give the 2 curves to DENR and say it is up to DENR to decide how much degradation is
tolerable. Other possibility, charge in legislation prefers this, I think we can in this room on the basis of
science, only on science, try to decide where the state should declare ecological integrity exists on the
graph. There is no regulatory function reflected in this graph. We don’t need to think about balancing
needs of stakeholders, we need to think as scientists, where does eco integrity fall apart. Ecological
integrity is defined in act as species richness and ability to recover species richness and disturbance,
and ecosystem services. I think we’re at the point where we need to consult colleagues, literature,
each other, to make science based decision about where on this graph eco-integrity probably lives. I
don’t think it will be easy.
QUESTION: Based on this graph, is there any way in which this can reflect on recovery?
COMMENT: if you go to literature and ask how much can species richness decline before it can
recover you may find answers. That’s the only way to answer that question.
Jennifer continued with the rest of her presentation.
Annual ecodefict combined slide: With respect to duration, here it presents the metric by annual,
seasonal (annual shown in graphs). Seasons correspond with PHABSIM months in seasons. These
values correspond to 10, 20, 30%
reduction in condition. Values
correspond to changes in flow.
You can see in comparison of
annual to seasonal there is not
much change. You could adopt
season-by-season or annual.
QUESTION: To interpret the
table, an 18% increase in annual
eco-deficit gives you a 20%
reduction in EPT richness?
RESPONSE: yes. These
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thresholds have been calculated for all 23 flow metrics. They all show a similar trend, there’s not much
variation between metrics.
COMMENT: The big issue for me is because the benthic curve is so much flatter than fish curve,
you’re looking at making decisions that could be skewed in either direction, the difference between 20
and 30 depending on which curve you use.
RESPONSE: Last time we showed pool as well, pool guild showed a similar response to benthos.We
only analyzed 2 of the 6
guilds determined by fish
biologists. We chose
contrasting guilds. The
data supported our
hypothesis that riffle-run
guild is more responsive
(sensitive), the pool guild
less so.
COMMENT: There are a
lot of things going on.
Benthic ecologists would
indicate that community
structure of fish is much
more related to habitat.
Benthic incorporate water
quality and other things
more so than fish. The
difference between the 2 is not as wide as I thought.
RESPONSE: Remember these are 2 different models. Invertebrates do not use a log-linear model. It
may be worthwhile to do this, even if it is not the best fit, it may be a more comparable and better
model. That’s why it’s flattening out.
COMMENT: EPT are not necessarily categorized by their guild. There may be some that may not be
so flow sensitive, some will be. They are bound together right?
RESPONSE: Right. Usually EPT is used because a large amount of them are sensitive. In doing this
we looked at 140 some metrics. We used this one because of response and because it’s applicable to
things that have been going on for a long time.
QUESTION: Can you guess what the log-linear relationship would look like?
COMMENT: It may be worthwhile to do that, because of the fact we don’t have many samples out at
the other end, that place where it is flattening out is not well defined.
QUESTION: For comparison purpose, how does your PNV flow compare with the unaltered flows
showed this morning? They use different method of calculating unaltered flows. It would be good to
see comparison.
RESPONSE: It may be good to compare.
COMMENT: Not sure that comparison can be made. OASIS strategy is to remove all human
alterations of flow, and OASIS ignores land use change over period of record. WaterFALL compared
PNV flows with current flows and avoided all human modification of flows in baseline condition.
RESPONSE: PNV flows in comparison with current condition which is 2006 land use cover and
instream alterations (in 2006).
COMMENT: What you started with in 2006 would be more comparable to the unaltered flow that was
presented this morning (SIMBASE).
RESPONSE: In WaterFALL you could start with 1970s and use it as baseline and compare with 2006
as another option.
QUESTION: Your current condition model we’d hope it is similar to SIMBASE. The question is, is PNV
similar enough to their unaltered flow so eco-deficit could be a part of the conversation of how it goes
into OASIS. If PNV were very different from unaltered regime, we’d need clarification moving forward
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with a recommendation about eco-deficit.
COMMENT: SIMBASE in OASIS is the current state of affairs. Take SIMBASE and remove all human
alterations of flows-outfalls, withdrawals, dams. If you have 100 years of data in OASIS, every year
represents the land cover that year. There is no PNV point in an OASIS model.
COMMENT: Right, in order to use the eco-deficit in relationship to model DWR has, we need to
understand relationship between PNV and what DWR uses as unaltered flows.
COMMENT: To rephrase, what we’ve done with waterFALL is characterize current rate of affairs as
how much eco-deficit already exists. Then DENR with OASIS can calculate future eco-deficits based
on future management and can determine future additional eco-deficits, then we can look at how that
may affect species richness.
QUESTION: That relationship is there when comparing difference in flow. Whether it’s due to
vegetation, climate change, human use is beside the point.
COMMENT: Your denominator is based on current flow and difference you’ve projected between
natural flow and current condition. Magnitude is what is used to calculate effect on species richness
and where that fits on the curve, correct?
RESPONSE: Yes, but it is that change starting from today into the future. You don’t have to go back to
model PNV.
COMMENT: DWR will use model using SIMBASE regardless.
RESPONSE: As long as you are calculating deficit in the same way, same area under the curve
calculation.
COMMENT: You’re saying its not the difference, its where your starting point is.
RESPONSE: Yes, PNV has only been used to develop this relationship,it does not have to be used in
putting this into management.
COMMENT: Oasis can be used to calculate future eco-deficit. That’s the point.
RESPONSE: Depending on where you fall on the curve, how much further degradation are you willing
to accept? Your prescription may be different if you are on one part of the curve as opposed to the
other, maybe.
QUESTION: I have concerns with eco-deficit metric, think its important to look at guild that you’re
using. Hypothetically since calculating eco-deficit with high and low ends of flow range, you’re saying
with a riffle run guild it will respond the same to changes in a 75th percentile flow as to a 25th percentile
flow, but in reality literature says riffle run guild is most likely to change in response to the 50th down to
the ) or 10th percentile, which is when they will be sensitive to the metric. I feel like the result of eco-
deficit could be artificially exaggerated by putting an eco-deficit at that higher end. I think it’s important
to have a better link between the flow metric and the guild that is used.
RESPONSE: Good point…that’s a concern when you see a bias of a deficit or surplus in one part of
your curve vs another. But more often and not we found the graph on the left as a trend- an even
spread, a general reduction in the curve. It’s not quite as biasing. You also have to be concerned that
this is an annual thing that gets rid of your periodicity. Versus if you want to do it on a seasonal or
monthly basis. You have to be cognizant of these when looking at the results.
COMMENT: Also important in the difference of how the fish and benthics respond.
Tom Cuffney presented the rest of the slides.
As Sam alluded, when you start looking at plotting the 10, 20, 30% reduction, we’re faced with issue of
putting in relevant context to interpret it.
Depending on the current condition of a stream, how much degradation in the biological condition is
EF-SAB (NCDENR) willing to tolerate?
To make this work relevant: Need to link ecological responses (e.g., EPT richness) and flow deficits
(i.e., quantile regressions) to ecological condition.
DWQ has established invertebrate condition classes based on EPT taxa richness. DWQ uses EPT
richness as one means of establishing condition classes:
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Mountain Piedmont Coastal Plain
Excellent >35 >27 >23
Good 28-35 21-27 18-23
Good-Fair 19-27 14-20 12-17
Fair 11-18 7-13 6-11
Poor 0-10 0-6 0-5
DWQ has condition rankings for most sites and
dates used in EF-SAB analyses.
Therefore, we can:
• Calculate 90th Percentile for Condition
classes in each ecoREGION
• Standardize for 90th percentile Condition
in each condition class within each
ecoREGION
• Derive state-wide Condition classes
based on average standardized values
It gives us some context as how much change
has occurred. From the invertebrate
perspective, we have advantage that DWQ has
used them to rank sites by condition. The numbers aren’t important but the concept is what is
important. With DWQ data we have condition data, rankings, for the sites.
Because quantile is dealing with 90th percentile, we can calculate 90th percentile for each category of
condition class for piedmont, coastal plain (atlantic and southeastern plains combined), mountains (see
graph).
Based on EPT taxa richness the curves are different, particularly for coastal plain. We can normalize
those dividing by excellent condition, from 1 to 0. The excellent condition reflects reference. We can
get average curve for state- we’ve got one curve to deal with. Could also take midpoint between
classes and develop table (see table above).
EPT richness classes are based on proportion rather than percentage. We can go back to the quantile
regression and plot where the excellent condition would be, good, good-fair. WE can go to eco-deficit
and see it may be fair, not excellent. If you change it, maybe it goes to poor. So we can use it as a
screening criteria to see if a planned water withdrawal will result in a flow deficit that it pushes site into a
lower condition class. Then if that
occurs you could go into site specific
flow study. This takes advantage of
what state has done for condition
classes and in order to get a feel for
whether the change is significant, this
is significant if it jumps into a different
condition class.
Graph shows statewide condition
classes based on 90th percentile.
Advantages of approach- takes
advantage of best data we have. A
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data-driven approach for establishing ecological flows.
• Relates back to NC DWQ concept of biological condition classes
• Uses state-wide flow-biology relationships for fish and benthos (based on RTI flow-biology
methodology) to support determination of ecological flows
• Guards against further degradation, while taking into account of current conditions
• On-going process (adaptive management)
COMMENT: Remember that DWQ’s definition of biological integrity is based on reference condition
and not on prevailing condition. It’s unimpacted comparison, not prevailing comparison.
QUESTION: how many sites?
RESPONSE: ~900 sites. There were 1700 invertebrate sites but RTI couldn’t model them all for flow.
We did not restrict sites used to certain conditions (good-fair etc)
We don’t have expectation a fair site to be good or excellent. It’s an ongoing process, the invertebrate
model is an exponential decay model, we need to decide if we want to use a different model even if not
as good a fit. It may be good for us to say “here is a way to proceed in the future”, we won’t get to a
final end point during the EFSAB process.
Tom ended his presentation. Questions, comments, responses:
QUESTION: Most of this data is based on wadeable streams. What are pros and cons of trying to use
this data to say anything about larger rivers where most of your withdrawals will come from?
RESPONSE: I think there is overlap with streams where there are water withdrawals, the Eno for
example. These are percents of flow, if you’re saying it is not related to large rivers, and large rivers
are responding to flow differently than other river systems, I’d say it’s not true. Some large rivers may
be more sensitive to it, particularly ones where benthos are dependent upon snag habitat (coastal
plains streams). I wouldn’t throw it out, I’d say this is the best we have to deal with. If we don’t try to
incorporate this, then what other basis are we standing on? I like data.
QUESTION: About fishes, because IBI (index of biotic integrity) also has excellent, fair, good, will that
be run along same concept?
RESPONSE: It would take additional work to see if riffle guild info and IBI coordinate.
COMMENT: We (DWQ) continue to work on refinements to IBI to address issues. The IBI is an
adaptive process itself. In some places it’s not working well- small mountain, sandhill streams for ex.
Fish uses more metrics used than EPT, which makes it more challenging.
QUESTION: Using riffle-run guild, you’d have different one for fish and for benthos based on different
sensitivities.
RESPONSE: Instead of using 10, 20, 30 % reduction arbitrarily, he’s equating it with an existing
condition classification scheme to enable you to use a framework to determine when you are crossing
an ecological flow threshold.
COMMENT: DWQ draws line in sand between fair, and good to fair, calls fair to poor waters impaired.
That is a threshold we use.
QUESTION: How much of the difference in richness indicator here would you attribute strictly to flow
as opposed to other factors?
RESPONSE: It’s a small portion looking at the entire state. That’s one of the reasons for going with
the quantile regression. The 90th percentile is a statistical estimate of upper ceiling based is on flow.
RESPONSE: Data points are color coded based on site condition ranking of benthos. More or less the
excellent provides the excellent data (blue) followed by the good (green), then good-fair (mauve)…it’s a
nice gradient, doing what you would expect with your site conditions.
COMMENT: If good-fair is acceptable condition, than your eco-deficit is pretty far out there.
COMMENT: We haven’t made the call that good-fair constitutes acceptable condition. Lots of
variables influence species richness is stream, flow is without question the most difficult of those to
characterize because flow changes a lot seasonally and inter-annually. What I think RTI and USGS
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team has done is close to best job humans can do in figuring out how species richness responds to
flow variation, filtering out other variables and giving us something close to the truth. I don’t know what
we’ll do with this, but I feel strongly that it is a powerful tool for us to consider using.
COMMENT: At a bare bones minimum it will provide us with some educational tools to share with folks
who have not been sitting at the table. I also think it provides us an opportunity to talk about other
issues, impacts on ecology, biology, flow durations, frequency and magnitudes. Another way to
express annual eco-deficit in terms of a recommendation, it could be changed to our comfort level or
confidence in making a recommendation. I need time to digest this and think about it. I like making
decisions based on data.
QUESTION: For sake of argument, could you take this relationship, using good-fair rating, establish
eco-deficit with that. Take projections for a river basin and look at it in 50 years to see as an example?
RESPONSE: Right, and not just look at magnitude, also whether it changes water quality rating class.
It would be a good screening tool. To get to hard facts PHABSIM would probably need to put site
specific data in it.
QUESTION: A math question, it seems that if the denominator were at 90th percentile, than the
intercept would be about 111% but it seems to be around 120%?
RESPONSE: I don’t have the equation here, it is a non-linear relationship. Lauren would be more
familiar with the statistical model.
COMMENT: I think she used 90th percentile for excellent rather than 90th for maximum biological
condition. That may be why it’s low.
RESPONSE: We’ll look at that together with the log linear model to see how that changes it.
QUESTION: This is interesting. Jay hit on the difference between fish and EPT, if you could establish
this sort of relationship/graph with fish it would be interesting how it compares.
RESPONSE: A graph with both fish and invertebrates were shown in this presentation, but fish does
not have the site condition classification. We would have to do the same thing with fish with IBI, rather
than arbitrarily using 10, 20, 30% etc. reduction in biological condition.
Facilitator: The faciliators think we’re still in information gathering phase today and we’re winding that
down. Sam brought up that we need to address frequency, duration, magnitude, and the need to
discuss the threshold and whether to set them. We think it would be best to complete the information
gathering. We have another trial balloon today, and the TNC report in July, then let’s start assessing
the various trial balloons and questions to answer. What I’ve taken from today’s discussion- there’s
some desire to do log-linear model for benthos to finish fleshing out this work, comparison of unaltered
by Tom Fransen, crank through some examples with site specific data to see if condition switches, and
to look at fish condition similar to benthos method. Other suggestions?
RESPONSE: RTI can do log-linear model.
COMMENT: I think it can wait until we decide if we may make decision about eco-deficit, then we’d
want to see if it is transferable to OASIS (regarding the comparison of unaltered).
Facilitator: What about doing site-specific examples? Is that something that could be done?
COMMENT: Using projections of one of the rivers to project out and see what it would show us, using
the benthos with DWQ site rankings, see if it jumps class.
COMMENT: Keep in mind that good-fair class is not the way the legislation is done. It is a comparison
to reference condition not to prevailing conditions.
COMMENT: But it’s a characterization of the prevailing condition relative to the reference condition, it’s
not making a judgment call about impairment. You could still use it to anticipate whether there will be a
change.
COMMENT: Right.
COMMENT: It’s just an exercise to better understand the impact of this model.
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COMMENT: I find the classification from fair-good to fair, whatever, misleading in that it is strictly flow
related. If you are saying you are only going from good to fair good, when in reality you may be going
to poor conditions due to water quality. It’s misleading to characterize using these terms to define the
system. I think you will confuse people like me.
COMMENT: In the end, legislation says tell us what changes in flow produce reductions in ecological
integrity. All changes in flow produce changes in eco integrity- there is not point on the lines where it is
flat. The question for this group becomes what constitutes a significant change. What Tom did by
using the DWQ classes is handy, something that many people understand. When we started I
dreamed that we would find stream classes, and they would be sensitive to flow changes but that didn’t
work. So now I think we have the challenge of looking at curves that relate flow and richness (these
worked the best), and determine what constitutes a significant change from current to future condition.
I want to say any loss of species is significant, but I imagine not everyone will agree so I think at some
point we’ll have to decide what is significant.
COMMENT: Legislature doesn’t require that.
COMMENT: Is that a policy decision?
COMMENT: For DWR, we’re developing planning tools. In terms of a planning tool, annual eco-deficit
is something you can work with. If I want to suck all the water out of a creek, I could still have a darn
good annual eco-deficit. What is your minimum duration and frequency elements you’d need to work
with to do the kind of planning you would normally do? In acute situations, planning is not very good.
C(DWR): If you talk about drought, if I have a run of river scenario I’ll look at worst case scenario,
worst day. If a reservoir I’ve got more flexibility. That’s what we’re hoping you can help us define the
time frame we should look at. I’ve got daily data- we can look at by day, group by month, by season.
Tell me how I have to group it, we can figure out how to analyze it. We’re it looking for you to tell us
what is significant from an ecological viewpoint.
COMMENT: If it is an acute (one day no flow- invertebrates may be toast, fish may be able to hang out
in a pool and come back), if it’s a chronic situation, like eco-deficit looks at, it could be a similar or
maybe worse effect. There are 2 times to deal with. Extreme one day changes in flow are very
important.
C : Eco-deficit is a kind of average, it gets at tendency. If DENR was in regulatory mode (though they
won’t be) if they said to a municipality that they couldn’t increase eco-deficit by >10%, the municipality
has flexibility for when it takes water, etc to meet that over a year. The other point is that suppose
DENR does say that 5% additional eco-deficit is threshold, question is how often and how long can you
violate that. If annual eco-deficit is violated once every 4 years, DENR would probably use that as
prevailing condition.
COMMENT: If you suggest natural cycle of drought is an acceptable prevailing condition, I would say
that for an example drought in the mountains, trout were not recoverable in a reasonable span of time.
They only through stocking and rehabilitation and some have not returned.
COMMENT: If we or DENR picked a number of acceptable degradation (example 10% loss of bio
condition), you see what the corresponding eco-deficit is, you can look at period of record to see what
happened around that number. If species were there during that number, then you know the eco-deficit
is not going to cause significant degradation.
COMMENT: I’m with you but the question is we haven’t defined how long it takes to recover.
COMMENT: Would we even be able to get to that point? Seems like we’re wrapping our predictions
into this eco-deficit. Resiliency, recovery are related more its position in landscape than to how flow
relates to resiliency and recovery. As long as flows address eco-deficit question, the flow part,
assuming it will be taken care of, then the resiliency and recovery will vary by site. I don’t see how to
tie recovery and resiliency to flow.
COMMENT: I wish legislation had included your opinion, it’s in the definition.
COMMENT: Wherever we set the eco-deficit reduction point, it could be conservative to reflect the
recovery ability. If we set 50% then it would be less likely to recover than 10% reduction.
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COMMENT: Right, we could express if we are less confident, more confident that recovery will occur at
different points.
COMMENT: We’ll have to do the best we can given definition given in law. Definition in law does not
give us a way to report back on the variable given. We can report back on species richness based on
data.
COMMENT: The lower you set the bar for the insult, the more likely it will recover. We can relate that
even if not related to a parameter.
Facilitator: It sounds like there is an inclination by some to use these curves to answer some questions
in the legislation. Is there additional work that would provide more comfort in using these. If so, the
researchers need to know this now.
RESPONSE: We won’t come up with additional data. If there are additional analytical methods or
presentation strategies that RTI can do to help this group, we can discuss this tomorrow when ad hoc
group meets and we’ll see if we can get them done.
COMMENT: Would it be more productive for us to provide that there is a way to proceed in general
terms, and here is an example using annual eco-deficit. Or are we saying we want to pick a number (for
example maximum 10% annual eco-deficit)? Do we have the time and ability to get that level of
resolution?
COMMENT: The more refined our recommendation, the easier for DWR to implement it. The broader,
the longer it will take them to get a workable solution. If we have capacity we should try to get a refined
recommendation.
COMMENT: I think the legislation says we need to tell how biology responds to flow. I think we need
to give DWR more than an example.
COMMENT: Are we going to tell them how to use it? Or let them know how we think they should use
it?
Facilitator: I don’t think you can decide that today. There is some question about level of comfort with
using this method. Do people have questions about this, or do they want to see it analyzed a different
way? Sam would need those today.
COMMENT: My question- I like the way benthic EPT proposal was laid out and how we could make
recommendations. I don’t have as equal a grip on how the fish curve could be implemented. It would
be helpful to see some scenarios of how fishes and the riffle guild piece could be implemented.
RESPONSE: Do you feel comfortable choosing like how much biological condition are you willing to
accept a reduction in (5%, 10%, 15%, etc)? If group feels comfortable coming up with a threshold
value associated with change in riffle run guild, you could.
COMMENT: So it would be a change in the riffle run guild? (RESPONSE: yes) So for every reach/node
analyzed that does not have riffle run guild, how would we apply this? There is a subset that is not,
coastal?
RESPONSE: You could potentially apply riffle run guild to every wadeable monitorable stream. Then
you might do something like pool guilds or other guilds for coast. Then have to think how do you deal
with benthos vs fish? Do you go with the more sensitive of the species in an area? Again, the question
is how do you mark the threshold condition for your comfort zone. Benthos could use a preexisting
condition. We don’t have an equivalent in fish but could choose a % reduction in biological condition as
an option. This was presented as a strawman as a way to start talking about fish.
QUESTION: Is this going to be sent to us in hard format for us to consider?
COMMENT: We need time to review this before sending thoughtful questions. Until Friday.
RESPONSE: Ad hoc committee meets tomorrow, we can see if they can meet again.
COMMENT: Maybe you don’t need to meet, but the question could go directly to the person in the
group. It doesn’t necessarily be a new analysis, but answer questions.
RESPONSE: A lot of time and energy went into producing these. We’re presenting the jewels at the
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end of these roads. Its not that we don’t want to further meet your needs but we have to keep time in
mind.
COMMENT: It would be interesting to run a couple examples through the Cuffney method, looking at
projected changes in 2060.
C (ad hoc team member): we can do that.
COMMENT: Slide- state-wide condition classes- that shows the only -2 classes represented due to
data available. It could not do a jump from class based on this data
QUESTION: Somebody mentioned the chronic vs acute issue, that eco-deficit represents chronic
conditions, (inaudible) seemed to be intercorrelated. Is there any acute metric that would be inherently
different than this?
COMMENT: The metric wouldn’t be any different. Even if you had daily values.
RESPONSE: the metric we used as the smallest time step was…and correlation between 30
day…found a high correlation between…(inaudible- not recorded)
COMMENT: Those are all magnitude. In my mind you get to acute by dealing with a duration type of
variable.
RESPONSE: Have we done that with the 1, 3, 7, 30, 90 day flows
COMMENT: That’s an average one day flow. Duration is how long a certain flow lasts- number days
below certain flow.
COMMENT: We’ve looked at IHA stats and others, to our surprise some of the stats we thought would
be most powerful weren’t. Eco-deficit turns out to be most powerful statistic. You can vary flow quite a
bit as long as you maintain the ecoedficit.
COMMENT: One of the issues is perhaps the correlation between flow and other variables that results
in measures, such as land use, other factors. It’s not that we’re saying were looking at another
indicator, how can we reach a point where we can say this is a result of flow reduction. How do we
tease that out?
COMMENT: I believe that’s included in our charge. If flow causes variations in temp and DO, and
biology is responding to flow, and some is related to temp, DO, I think all we need to know is that flow
changed and biology responded. If flow is caused by a suite of other variables. Our charge is flow-
biology. The place where we have to worry about is where changes in biology have nothing to do with
flow. I think we’ve done good job of isolating flow and response.
COMMENT: I think some of it is integrated in there, but getting back to where the numbers came from.
Perhaps the change in biological condition is due to flow change. If we can assign a proportion of
likelihood change due to flow. I’d like a comfort level that it is flow primarily.
COMMENT: I’m open to suggestions about how to do this.
COMMENT: If you can restate the use of the 90th percentile and how it helps us focus on flow?
RESPONSE: Take for example 30 on eco-deficit. That value represents the best condition of all those
sites. If you say what is the best condition, everything else is not affecting that flow parameter. It’s not
a partial regression, what your doing is saying here is my very best if everything else except flow does
not change. If it were 50th percentile, you’re saying other things affecting it.
COMMENT: What that indicates to me is that we can spend a lot of time refining, but perhaps a more
appropriate use would be if these were the trends, pick a comfort level with where the steep part of
curve is, etc. without redoing the calculations.
COMMENT: Depends on your recommendation, if you have enough confidence in these curves today,
the EFSAB could say “don’t increase annual eco-deficit more than 10%” for ex. I feel like we’ve beat it
to death. I’d Like to hear Hugh’s pitch.
The following questions of clarification for the ad hoc research group were submitted and
answered after the meeting:
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QUESTION: Slide 3: How did the annual 30-day minimum flow statistic results turn out? Can these be
circulated to the group? What led the research team’s preference for eco-deficit as the
recommendation?
RESPONSE: We decided not to use annual eco-deficit, because it was disguising important seasonal
differences. We will now compare seasonal eco-deficits and 30-day minimum flows to see how they
effect biological condition. We should have the results of that comparison for the July meeting.
QUESTION: Slide 5: Recommendation is to use statewide flow-biology relationships…with this
recommendation where can we to meet the legislative directive for a classification of streams? Would
we instead “classify” the streams by the current eco-deficit? Group streams by their current condition
annual 30-day minimum flow statistics?
RESPONSE: We tried several different strategies for stream classification, and none was robust,
meaning none of the classes could be counted on to be ecologically distinct from their nearest
neighbors in multivariate space. The clusters were too close together and too fuzzy. So now we are
using a statewide, unclassified approach, with the important distinction that fish data are normalized by
basin and benthos data are normalized by Omernick region. These a priori "classes" seem to be doing
the trick for making it possible to compare one basin or ecoregion with another. Species in the
mountains and species in the piedmont tend to respond about the same to eco-deficits and 30-day low
flows, even thought these are different species and they are responding to changes in wadable streams
of different sizes.
As I recall, the legislation does not require classification, but does require characterization. But even if
it does require classification, our normalization strategies qualify. We're still on target.
QUESTION: Slide 6: What change in flow (cfs) results in a change in the eco-deficit from 10% to 20%.
Slide 6 indicates that 20% eco-deficit = 20% reduction in volumetric water availability; will the reduction
in flow (cfs) be relative, depending on basin characteristics? I want to better understand how
“significant” a shift in eco-deficit could be to habitat availability as described with the concepts of the
PHABSIM models where we are presented with % change in habitat availability in relation to change in
flow (cfs). Is it possible to cross-walk these concepts?
RESPONSE: Eco-deficit is kind of hard to understand. Increasing the eco-deficit from 10% to 20%
does not mean reducing flow by 10% overall or at any given time. Eco-deficit is a kind-of-average (cool
term, huh?) value that represents the gross (not net) negative area between the stream in undisturbed
condition without management and with natural vegetation and the measured flow today or at some
future time. So essentially every stream has a current eco-deficit, and we would measure the percent
change in the eco-deficit from that baseline if flow is changed in some way(s) by management or
climate.
In a general sense, eco-deficit is the difference between two scenarios – baseline and managed. The
baseline is not necessarily natural vegetation, but in our instance comparing current to natural
vegetation gives us a sense of how much things are already altered.
PHabSim investigations determine the reduction in a guild's habitat based on changes in flow. They
remain the investigation technology of choice for individual sites. But we're trying to use a statewide
database to develop ecological condition response curves for actual organisms, based on actual data.
That is, not local reduction in habitat, but local reduction in species, based on a statewide model
without a local PHabSim study everywhere to lean on.
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Meanwhile, remember, habitat area is not necessarily the same thing as species presence, and
species presence varies differently per area for all species. This is the standard criticism of PHabSim.
QUESTION: Slide 7: What is the range of riffle-run guild species richness included in this
analysis…what is the maximum richness? In the piedmont? in the mountains?
RESPONSE: Riffle Run species were chosen because they are the most representative species, found
in the most samples, and they are the second most sensitive species guild, after riffle species.
However, there are never very many of them at one site, a problem we're struggling with all the time.
The most at any one site in the Neuse is 4, and the most in the mountains is 14. The total number is
18. {I think these numbers are correct; if not, someone please correct me}
In the DWQ database of species collected in their samples, there are 51 species in NC we classified
as riffle-run. RTI used all the riffle-run species classified that were in the latest NC samples at sites
with repeated sampling. That number ended up being 42 species. The drop from 51 species is not too
surprising since some of the riffle-run classified fish were pretty rare in the data (0 to 1 occurrences at a
sample location since 1990).
We are exploring the Shannon-Weaver index which takes into account both species richness and
abundance, but the SW index is also hard to explain to non-specialists, and the legislation does
explicitly refer to species presence as relevant to ecological integrity. I would say that the choice
between species richness and the SW index is the most thorny problem we currently face.
QUESTION: Slide 18: Does a 100% change in eco-deficit translate to 100% reduction in volumetric
water availability(as described in Slide 6)…if so that sounds like a catastrophic change, yet, this 100%
reduction does not result in the good-fair to fair reduction in Benthos condition pointed out in the slide
and also by Tom and Jennifer…does this suggests that the Benthos may not be“sensitive” enough to
the eco-deficit metric. Perhaps the log-linear fit will demonstrate a greater sensitivity?
RESPONSE: The DWQ condition classes are wide enough that a large change in benthic species
present does not necessarily force a class change. It's like the class boundaries are 20 units apart, and
sometimes a change of 15 units is entirely inside a class. We are considering an alternative approach
in which, rather than looking at class changes, we look instead at the total change in ecological
condition, such that a change of 15 units will always be more important than a change of 10 units, and
so on. I predict we will come out with that approach, but then the question is, how many units of
change does it take to raise the flag?
The RTI and USGS team members have been losing sleep and missing meals to come up with some
way we can use real data to tell the story of how aquatic ecosystems, the second most ephemeral
(after aeolian) of all kinds of ecosystems to my knowledge, respond to flow variation, the second most
capricious and highly variable of all the physical parameters (after weather) that define aquatic
ecosystems. And amazingly, they've done it. All the species x flow response curves look about the
same. They all have about the same shape. We're struggling with two things, basically: Which curve
tells the story best, in language that others will understand; and given whatever our favorite curve is,
what change(s) in the y-axis variable (ecological condition) can be said to violate ecological integrity.
I have more confidence now than I ever have that we will have cogent recommendations for x-axis and
y-axis variables and acceptable values for y-axis deltas. We were hoping to have an official trial
balloon at the July meeting, but I am not at all sure we will. August is more likely.
I am also absolutely confident that our answers will only be approximate, and we will have to
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recommend strongly to DENR that more data be collected, with the specific aim, and format required, to
make our recommendations better.
VIII. Presentation: A Trial Balloon—20/30/40% or 30/40/50% of Annual
Mean Flow or Monthly Mean Flow
Presenter: Hugh Barwick
For this power point presentation go here.
Hugh Barwick presented a trial balloon developed in cooperation with Jeff Hinshaw, Linda Dieboldt,
Tom Thompson, and Jamie Robinson. Hugh noted that this subgroup represents on the Board those
that use water. They wanted to make this presentation because they have some reservations about
the BEC as a viable tool. The data that were used in the BEC were from wadeable streams. These
EFSAB members are concerned that you cannot take the information for wadeable streams and just
transfer it completely over to non-wadeable streams. They think that is important because a lot of the
future withdrawals in this state are going to be from streams that are larger than those sampled to
produce the data analyzed in the BEC. The 80% flow-by approach proposed is a big concern to this
subgroup of the EFSAB. They think it is overly protective; it will restrict a lot of things that the water
users in this state might need to do in the future. Hugh expressed that he wanted to walk the EFSAB
through this subgroup’s trial balloon objectives and to present an alternative method of developing
ecological flows, somewhat based on a withdrawal-permitting program that is currently used in South
Carolina. That program was developed back in the 1980s and was put into permitting mode in South
Carolina in 2011. It took them a long while to go from developing an ecological flow, and they do not
necessarily call it an ecological flow. They use more of a minimal flow there. Hugh indicated that his
group wanted to offer a few suggestions of how DWR might use some of this for planning purposes.
Hugh noted that he has listened a lot to what is needed for a desirable ecological-flow planning tool.
The EFSAB has talked about specific physiographic regions. The EFSAB has said it needed to
account in some way for the needs of the aquatic resources; the ecological flow needs to be somewhat
based on specific stream biota, although he noted that maybe in some of the information heard today,
that may not be quite as important an issue as it was. He noted that the EFSAB’s recommendation
should be relatively easy to understand and to use and provide some balance between the needs of
humans and aquatic resources. So those are the things that this subgroup thought about when they
were developing this tool. The physiographic regions are pretty simple. The state breaks out into the
lower Coastal Plain, upper Coastal Plain, Piedmont, and Mountain streams. This subgroup did not
address lower Coastal Plain streams. They are going to leave that to Bob and his group. This
subgroup focused on the upper Coastal Plain, Piedmont, and Mountain streams.
In Upper Coastal Plain streams, anadromous fish are the species of importance: sturgeon, river
herring, hickory shad, American shad, and striped bass. The importance of these upper Coastal Plain
streams is primarily for spawning in the spring of the year. We need higher flows during those periods
of the year when they would be using these streams to get them easily upstream. Hugh proposed:
• High flow (Jan-April) – 50%*
• Transition flow (May, June, and Dec) – 40%*
• Low flow (July-Nov) – 30%*
The asterisks indicate using either percentage of annual mean flow (cfs) or percentage of monthly
mean flows.
QUESTION: You are saying these are minimum flows or how much could be taken out?
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RESPONSE: No. It is just a percentage of the mean annual flow, and I will elaborate on that a little
further, or a percentage of the monthly mean flow.
QUESTION: Well you are suggesting that for the months of January to April, 50% of the annual mean
flow should be considered a minimum flow?
RESPONSE: Yes.
COMMENT: So they are minimum flow figures.
What does that really look like when you go to the river? Hugh picked Neuse River in Goldsboro [slide
7 in the power point, shown on next page]. South Carolina uses 20%, 30%, and 40% of annual mean
flow; they proposed 20, 40, 60. Hugh took the difference between 40 and 60 and made it 50. In slide 7,
the green line represents those percentages (20, 30, and 50, depending on season) of the annual
mean flow. That is kind of a flat line. The black line indicates monthly mean. Hugh also wanted to
know what it did during a drought year. How close was this planning flow or ecological flow, depending
on what you want to call it, to drought conditions? At this site, Hugh used the 2011 drought. You can
see that it represents this 30, 40, 50 percent annual flow relatively well. There are some periods when
it is below, some that are at it, some at above, but it is not too bad a fit. Slide 8 shows percentages of
the mean annual monthly flow. They took a 30, 40, 50% of that flow and plotted it here, looking at
somewhat the minimum that we would allow during those seasons, based on what we have seen
historically for this period of record. Hugh noted that it is not a very long period of record there for a lot
of these stations but that is what
they had and that is what they
used. Again, he superimposed
the drought of 2011 on there just
to see how this minimum flow or
ecological flow might compare.
This group is proposing that
DWR, if they get a request for a
withdrawal, take their models
and predict what this would look
like at that particular location.
They would calculate the 30, 40,
50% monthly mean flows for
that, then they would do their
model predictions, and hopefully
that flow would be between the
green line and the black line. If it
was, then maybe for planning
purposes, you could say okay we
have sufficient water over the next 50 years
for them to have that withdrawal, and you
do not have to
go any further. If, however, it starts to look
like its getting closer to that line, you might
say well that is a red flag. This group is not
proposing that these are absolute numbers
here by any means. They are saying this
just for example purposes. This is for
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planning purposes. These are planning flows. What they are trying to do is preserve sufficient water in
the river to allow anadromous fish to complete their life cycles in freshwater and to preserve the other
species of fish in the river. If we maintain that for them during these periods of the year, the young are
adapted to this period and other fish as well to these lower flows. This group is calling that their
ecological flow, and they would not think that the ecological integrity of the Neuse River at that station
would be impacted as long as flows stayed above this minimum.
QUESTION: So if anadromous fish experienced the drought of 2011 every year, would they do okay?
RESPONSE: Well I think they always recover from previous droughts.
QUESTION: But they recover from previous droughts by having non-drought years, right?
RESPONSE: Well, yes, that is right. But this does not mean that this is going to be the flows every
year. Flow is going to be dependent on the rainfall that occurs. Through the modeling, I think—and
you correct me if I am wrong, Fred—that you would be able to predict how frequently flows approaching
this level might occur, and then you would look at the duration, the frequency of that before you made a
determination as to whether a site specific study was needed there or not.
QUESTION: So you are not proposing those metrics of what actually is the frequency of excursions
into that realm there? In other words, what you just said was you can model that, but how often you go
into that is not...
RESPONSE: I am not presenting—I am not making a recommendation for that.
RESPONSE: Okay.
Hugh: That is something either this group or Division of Water Resources would have to decide.
COMMENT: Hugh, I think what you want to say is do you want to look at that in terms of how often and
frequent are those flows going to approach that lower end of that range.
Hugh: That is right.
COMMENT: And if it looks like they are going to be approaching the lower end of that range outside of
what you would see normally, then that is your warning flag, that is your—that is where you need to
worry.
Hugh: That is right. Other questions?
QUESTION: I have a question; it may not be for you; it may be for DWR. If withdrawals are permitted,
are you able to change them year-to-year? If you were going to assess that this is sort of what you are
left with, or sort of this excess capacity, and you are going to look at it and say it seems to me like over
time that you are going to be sort of pushing that lower threshold and then you get to the question of is
there ever a chance then for it to get to some sort of a natural, or a more…
Hugh: It would, but then there are other things that would have to be considered. There would have to
be low inflow protocols. And I think that is something that might be required. Offsite storage or off
stream storage might be a way, or withdrawals from the groundwater for makeup water if you were
getting down into this level. So you may have to require, or industry may have to impose on
themselves, a way to moderate their impact on this flow. Those are just some ways to do it. The other
option is that that intake does not go in at the location they prefer; maybe it would have to go into an
existing reservoir.
COMMENT: This conversation seems to be about a regulatory program.
Hugh: No, sir.
RESPONSE: Well you are talking about—let me revise my question. How can I look at that graph and
tell what the effect of flow moderation is on ecological integrity?
RESPONSE: Well based on the science that went behind producing these flows, based on what they
did in South Carolina and what I have seen in some other studies in North Carolina, that 30% is going
to generally protect the fishery resources; 40 will, and 50 will.
QUESTION: Is that based on the Tennant method?
RESPONSE: Yes. Well, that is one method they use.
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RESPONSE: Which was known originally as the Montana method?
Hugh: That is it.
QUESTION: Why don’t we let Hugh continue before we get too far,,,
RESPONSE: Oh, I am sorry. Okay.
Hugh: Yes, you are going to see similar proposals for other streams. Okay. Piedmont streams. Here
again we are targeting your riffle run dwellers primarily, with the high flow period right at February and
April where we are looking at 40% of the flow, transition flows in May and June, possibly January
gearing up for this higher flow period of 30, and low flows in July to December of 20%.
QUESTION: For us non-fish squeezers, that is sun fish and—
RESPONSE: That is shiners and suckers.
RESPONSE: Thank you.
COMMENT: Not sun fish.
RESPONSE: Not sun fish, but
shiners.
Hugh: And these are the ones that
we think are most sensitive, and we
talked about that. These are the
riffle dwellers that are most sensitive
to changes in flow in these
Piedmont streams. The Deep River
was one of the sites I selected. If
you look at the annual mean, 20, 30,
40% of the annual mean, based on
this flow at this Deep River site, it is
flat-lined primarily [slide 10]. This
slide also shows the mean monthly
and compares this to the 2001
drought. This is what they use in
South Carolina, and in some
respects, Hugh’s group did not think
that this method produced a
planning flow or an ecological flow
that was similar to what we normally see on our mean monthly flows at these stations. So, again, that
is why they tend to go to the mean monthly flows [slide 11] and then that gives a little more simulation
of what the monthly mean flows look
like there. Again, here we are looking at the
drought and you can see that protects the
period of the year when those fish would
traditionally be spawning there and then as
lower flows the rest of the year, which we
think those species are readily adapted to
enduring. So we are looking at this as being
the ecological flow and again, Fred would
use that similarly in his modeling and for
flows that were approaching this, would
certainly raise a red flag in the predictions of
the 2060.
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In Mountain streams, we are primarily focusing on trout. There are some mountain streams that
probably should not even be considered for any withdrawals, some of the higher elevation streams.
There is probably no need for withdrawals from some of those streams. This trial balloon concentrates
on high flows during the spawning season for trout, and depending on the species, they would be
spawning in this December to April period and we are looking at a 40% flow there. Transitional flow
period, November getting them into the riffles where they spawn in December and allowing those young
to hatch and move out of the riffle areas in May going into the low flow period in June and September.
This trial balloon would suggest maybe 20% was appropriate there. We looked at Linville River flows
[slide 13]. You have the annual mean of 150, and this is what South Carolina uses. This slide shows
the monthly mean—and a 1988 drought. The flows for the annual mean flows were lower than what
were noted for the drought. That appears to be maybe too low. If we look at the mean monthly flows
[slide 14], again, it simulates what we normally see at this particular location on a seasonal basis is 20,
30, 40 and again it is a little lower than what we saw in the drought. So there may be some tweaking
that is necessary here in some of these
mountain streams. I do not know, we
would have to look more closely at that.
But that is what it would look like at the
Linville River site. Hugh closed by saying
that these percentage-based ecological
flows presented here appear to provide
adequate protection for aquatic
resources when compared to drought
flows, which we see naturally. Hugh
acknowledged that we do not want those
every year for the fish to respond to.
Hugh noted that this approach appears
to somewhat balance the needs for
humans and the aquatic resources, and
he thinks it might be easy to incorporate
it into the models that DWR currently
uses. He does not think it will preclude
any site-specific studies.
QUESTION: You chose three different drought
years, 2011, 2001, and 1988; is that because
those were the droughts of record for those—
Hugh: Well they were pretty close to the lowest
I could find in say the last 10 or 15 years.
RESPONSE: So those were the droughts of
recent record for those three systems.
RESPONSE: Yes.
RESPONSE: Okay.
QUESTION: I guess what I am trying to get my
head around is you refer to not being at those
minimums all the time; you do not want to do
that every year.
Hugh: Right.
QUESTION: I guess for me the $64,000 question then becomes well, if you set up a safety net or a
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floor—
Hugh: Basically, that is it. That is what we are talking about.
QUESTION: You still have to come up with some way then to say how often and how close do you
have to get to that floor before some flag goes up and that is where I am a little shaky. In terms of what
do we do there and do you set it as some sort of naturally occurring frequency that you do not want to
get down to that floor or... and that is certainly preferable then saying well, this is a minimum and
whether it is that way in one year in five or five years in five, it does not matter because that is just the
flat minimum. Because that is not what I am hearing you say.
Hugh: Right. To be honest with you, I do not know. I thought about it, but I really do not know what
that frequency should be. If you look at the flow record, is that a way to determine how frequently it has
occurred historically and maybe that is what you would shoot for going forward? I do not know, I really
do not. You are right, that is the hard—
COMMENT: I think what you talked about earlier was looking at maybe modeling those drought years
when they occur based upon your period of record, how often they occur and try to model how often
flows get down in that range and is it significantly different in some statistical fashion from what you
would normally see naturally.
QUESTION: So the question—is there a predictable drought cycle in the period of record and does
adding in withdrawal drive the system to that drought condition more frequently?
RESPONSE: That I do not know.
Hugh: Yes. I am sorry, we do not know. But it is something to look at.
COMMENT: Then just another observation: with two of the three gages you have plotted there, the
Deep River and the Neuse River, those are—well, the one at the Deep River is pretty recent and they
have Randleman Reservoir now. And Neuse obviously has Falls Reservoir since the early 1970s. So
the effects on those reservoirs tends to be, on an annual basis, there may not be a whole lot of change
in terms of average annual flow. But they tend, just because they are built to operate that way, to make
the average flows during wet times lower and the average flows during dry times higher, just because
that is the way they are supposed to operate. So if you set your threshold, your target, your floor—
whatever you want to call it—based on monthly means, and you are doing it off a gage record that has
a big reservoir upstream, we need to be aware of that, and maybe think about do we want to use the
regulated hydrograph, or do we want to use from the model an unaltered hydrograph. I think the
Tennant method, forgetting for a moment that it was started out in the Western part of the country, but I
think they used unregulated gages when they were first developing their percentages and deciding
what level of protection each percentage provided. It was based on gages that had no reservoirs or
alterations to hydrology.
Hugh: But it is awful hard to find gages that do not have reservoirs upstream.
RESPONSE: Well, on big rivers—
Hugh: On big rivers, it is hard to find those, and I did not want to go into great detail here before I
presented it in case you thought it was a terrible idea and we just toss it out and go home. If it has
some merit potentially, it is an option we want to explore further, we can certainly do that. But we did
not want to spend a tremendous amount of time and effort trying to work out the details on this if this
concept was not something that was even worth considering by the Board. So we are presenting it
simply as a concept, simply to be used for planning and it is what it is. That is where we are.
QUESTION: Hugh, how long has this been in place in South Carolina?
RESPONSE: Since 2011. So it is fairly recent.
COMMENT: So that is not a lot of time, but what is the perception of business and industry?
Hugh: Well, business and industry like it, obviously. Some of the resource agency people fought going
down to the 20, 30, 40. But in the end they were able to kind of resolve their differences and agree on
20, 30, 40. And that is for Coastal streams and Piedmont streams. They do not have anything
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proposed for mountain streams simply because there are not that many mountain streams.
QUESTION: Was there heavy input from the South Carolina Chamber of Commerce technical
committee on this?
RESPONSE: That I do not know.
COMMENT: A couple of responses: one of your earlier slides talked about the other approach that we
have been talking about for a number of months, the 80% flow-by, is overly protective. Whatever the
numbers are, I think philosophically, as a planning tool, what you want is something that raises flags
earlier than later, so I think we need to deal with that.
RESPONSE: I think everybody in this room realizes that this planning tool may eventually morph into a
permitting tool.
RESPONSE: Well, that is the elephant in the room. On the other hand, what South Carolina ended up
with and those numbers were that policy decision. It was not really based on the science, solely, and I
think that is where we need to be careful here and not jump right to the end and say well this is all we
will be able to get through. As far as the specific numbers about using mean monthly flows, we did talk
about that early on with all of Jim’s zillions of graphs and tables and so on. If we want to talk about that
and the specific numbers, I think that is certainly viable and open for discussion. What I think we need
to be careful about is understanding what those numbers are based on. I am trying to go through the
South Carolina report now, but it has been years since I looked at it. But it seems like it is a
combination of Tennant stuff, wetted perimeter stuff, and maybe some PHABSIM stuff. We have, at
least for several streams here, and I guess Fred is going to have some more to bring forward to us next
month, that whole suite of numbers, of percentages for North Carolina streams. And so to me, if we
were going to go with that kind of approach, we would want to make sure that it is grounded with some
data that is—you know, what is going on in North Carolina not—some generic kind of stuff so I just
wanted to throw those ideas out there.
QUESTION: My question is an easy one. Didn't you state at the beginning of the presentation that
South Carolina has been using this for a number of years prior to its going to a permitting program, is
that correct?
RESPONSE: Not that I know of.
COMMENT: Their surveys are from the 1980s is what you said.
RESPONSE: The concept was developed in the 1980s. It did not reach the permitting level until 2011.
But I do not know that they were using it for planning purposes between then and 2011.
COMMENT: I think I am going to restate what Chris said in my own unique way. An approach like this
has some value, has some merit because it is simple, it is straightforward, it is easily understood, but
before I could endorse an approach like this, I have to be able to look at the graphs and say I see
something there that reassures me that ecological integrity as defined in the Act will not be violated by
using this approach.
RESPONSE: I fully endorse that.
COMMENT: Because our question is not how do we balance water use requirements—
RESPONSE: That is right, that is right.
COMMENT: --between fish and people. That is not our job, That is DENR’s job. Our job is to answer
the question how much water does it take to maintain ecological integrity in rivers and streams,
explicitly in North Carolina rivers and streams? And if we could answer that question and come up with
something as simple and straightforward as this, I would be partying all night.
RESPONSE: And I will go with you.
COMMENT: And I am buying. Getting to that question is where we have to go. What does it take,
how much water do we need to leave in rivers and streams, or maintain our rivers and streams, to
maintain ecological integrity in North Carolina, as well as we can figure it out from the data available.
RESPONSE: That is right. And that is what you and Jennifer and Kimberly and Tom have been—I
mean you have been beating that stuff; I mean you turned it inside out looking for that silver bullet and
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that is the elusive part in all this. What is that silver bullet?
COMMENT: In several places in your presentation you talked about balancing water usage between, it
appears to balance the needs for humans and aquatic resources, and that is a good thing and DENR
needs to do it. But our job is to figure out when ecological integrity is violated and when it is not. And if
you guys are looking for next steps, for me, it is how do we do that with this approach.
RESPONSE: Well we are just asking is there an interest in going to the next step? Does this approach
have merit for any of you? What do you think?
QUESTION: Just a question. This is not an area of my primary expertise in terms of the water
management, what South Carolina and other places have done, but how do we link this to the
biological impact? I do not want to be a broken record but what information is out there that is either
from South Carolina or other places that will give us some indication of the level of impact or
protection—
RESPONSE: Well there were the two reports that I sent out with the draft of this and that is primarily
what they used to develop these. And is there more information out there than that?
COMMENT: I think we discussed maybe a study or some evaluations that were done for permitting in
North Carolina. Is there anything we can draw on?
RESPONSE: Well I had looked at and questioned that and based upon a question I had for Jim earlier
today, I do not really think that has happened because it was a very small study area, about a two mile
stretch, that we did look at those instream flows and we looked at it for the Lillington gage and this is for
the Harris Cole project. Based upon Jim’s comments this morning, it may not really be applicable to
what we are doing here because it was a small study area. Basically, it did show that at the flows down
to about 600 CFS that you maintained about 80% of your area under the curve for most species, 80%
or better; however, again that was restricted from a small study area, and to the small side channel. So
it may not be applicable to the larger water bodies as a whole.
QUESTION: Jim—do you, Fred—know of PHABSIM work that would have any application to what we
are talking about here where we could look at flows or—
RESPONSE: Well all nine sites we have done so far you could do and there is Catawba and Pee Dee
if you wanted to look at big rivers, and Fred is going to be grinding away on the mountain ones.
COMMENT: So some of these numbers were run as part of that.
RESPONSE: Yes.
COMMENT: Now they tended to be—the biggest one was the Tar near Lewisburg, drainage area-wise,
and that was about 500 and some square miles. We do not have any on the Neuse other than a really
old one that would be impossible to resurrect.
COMMENT: And so we could actually look at these percentages of mean monthly flow and see. We
have been working out that 80% flow-by just because that seemed to show a minimal amount of impact
to most of the guilds. We can actually see what level of impact and compare apples to apples and say
this is the level of impact we see to the guilds, assuming that everybody on the Board is still interested
in the results of the PHABSIM, that those have merit. Part of the simplicity of this approach is the use
of monthly mean flow as opposed to percent flow by. I think that, in and of itself, may be something
some of the currently regulated entities are more familiar with or are already used to thinking of usage
in terms of that. Is that one aspect that makes this a simpler approach?
RESPONSE: I think so.
COMMENT: So again I just go back to the PHABSIM and look at these numbers relative to what we
have been looking at and see if the potential for impact seems to be greater. I think many of us on the
Board would think that the potential for impact is greater with these numbers because they are
representing minimums rather than some kind of optimal threshold.
QUESTION: So how much time would it take and is it feasible to re-run PHABSIM for a handful of
Piedmont sites using 40, 30, 20 as a threshold and tell us what happens to our guild habitats.
RESPONSE: They are already done.
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QUESTION: We did 40, 30, 20?
RESPONSE: Yes.
QUESTION: Like this?
RESPONSE: No. Not exacty. What we did is we did 30 all year, 20 all year, 40 all year. You have to
pick from the different columns and recombine them.
RESPONSE: Yes but we have to do them by season.
[inaudible]
RESPONSE: No more new running, just rearranging results.
COMMENT: You have results by season so if, for example, I have Eno State Park and Buckhorn here
from work he did before and if you look at the 20-50% range as a minimum flow, there are some
seasons where there was very little effect. Maybe 10-20% of the guilds or species were affected. But
there are other seasons—spring and winter—where anywhere up to 70% of the guilds were affected in
a different way. I think that is one of the reasons why we stayed away from—we started looking at that
80% flow by was that that was in an area from these graphs that had relatively little effect compared to
these 20, 30, 40, 50 as minimum flows. But it is worth revisiting, I think.
COMMENT: I would like to see—I mean I am delighted to hear—to be reminded that all we have to do
is pick some columns off of the spreadsheets and combine them. But I would love to see for a handful
of Piedmont sites, what 40, 30, 20 arranged in this way does to guild habitat. And if the answer is
positive then I am a happy guy.
COMMENT: I think one other thing that we need to take the time to go back and look at these
underlying reports that you seem to have to support this. Like I said it has been many years since I did
look at them, but my recollection is that it was from a—what is the minimum flow perspective.
RESPONSE:That is right.
COMMENT: So it was not trying to maintain ecological integrity. Whether the approach of mean
monthly flows, I said this before, is any better than percent flow by, it may not be if the numbers are
high enough where the habitat response is not crashed. I think that is kind of what Bob was saying, so
again, we just need to go do a little bit more homework on this if someone wants to continue to carry
this ball forward.
COMMENT: I was just going to offer a comment and I think I have said before that minimum flows
work when withdrawals are not large in the context of how much water is out there to withdraw from. It
is when the withdrawals grow to be a larger proportion of the flow going by that you end up spending
more and more time, more frequently and for longer durations of time, at or near the minimum. If you
start building in conditions to say well, we are going to try not to get down to the target minimum more
frequently or much more frequently than you would naturally, at some point if you build in enough little
clauses about well, here is our minimum but we do not want to get there more than x percentage of
time or for x length of time, at some point you are kind of tip-toeing up to a flow-by type flow regime
where you are saying well, we have this minimum but we are still trying to mimic so that during wet
years we have more than just the minimum and yet during dry years we do not go below minimum. I
just wanted to throw that out. If the goal is to not be at that minimum too frequently, then you are
already taking a step towards just using a flow-by approach.
COMMENT: Well and if the minimum flow is approximately drought flow, and you only go to the
minimum flow as often as you would experience a normal drought, then you cannot take any water out
of the stream because you are going to get that flow naturally anyway. The one thing I learned working
on the Roanoke all those years is that droughts are going to happen whatever you plan and whatever
their natural frequency is, they will occur.
RESPONSE: On the other side of that is, with an 80% flow-by, even during the drought years, you are
still withdrawing water.
RESPONSE: Oh, yes.
RESPONSE: Oh, yes.
COMMENT: With an 80% flow by, drought years are worse.
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QUESTION: A question and a comment—I think you started out by suggesting the context that this
would be used in and predominantly be used in those streams that were larger, that were likely to be
the sources of withdrawal. So there may be some boundaries that you might want to put on this. This
approach may not work well in small mountain streams. I think you have made that clear. It may work
fine in the Piedmont, upper Piedmont, for example, or certain lower Piedmont streams. That is one; the
other is looking at the context of how we interpret the impact, the ecological impact of withdrawals
comparing this approach to the calculation of impact using the flow-by approach, which, frankly, I do not
think it is a good way to make an estimate of an average impact. But it does not reflect the reality of
how people are going to use water. I think most facilities that do not have capacity for large offline
storage are going to want the ability to withdraw water on a reasonably broad range that is fixed. They
are not going to know what is the flow out there today, I mean, frankly from what I have heard, Water
Resources cannot tell us in most locations what the flow is today, tomorrow, the next day—you have to
do some estimates of your own to get to that point. Most facilities are not going to have that capability,
except the very largest ones in municipalities and those that might be capable of having large off
stream, or offline storage reservoirs. It would be interesting to see how using this kind of approach
would match up against the calculated impact of a flow-by. Just to use these kinds of numbers to set
the level, and then see and calculate the percent deficit or whatever you want to call it at that point so
we can get an idea of how it works. But it is a far simpler way to evaluate it, I think.
COMMENT: One last observation: if we chose to recommend that our strategy should be to prevent
increasing eco deficit by more than a certain percentage, minimum flow thresholds and flow-by targets
are both viable tools for achieving that goal`. These are not mutually incompatible strategies. It may be
that minimum flow is not the best strategy for attempting to maintain eco deficit below some threshold,
but it is a potential tool for doing that.
RESPONSE: But the number for that potential minimum would be derived from the data rather than
from your suggestion, from South Carolina’s recommendations.
COMMENT: I think South Carolina’s policy is instructive, but what we have to have in North Carolina is
science about North Carolina rivers and streams. Having that science on the table, there is nothing
wrong with having several different tools available to achieve whatever goal we decide to set. Did I
respond to what you said?
RESPONSE: I think so, to my satisfaction.
RESPONSE: Good.
Facilitator: Other questions or comments? Hugh what is our next direction, then, based on what you
find.
RESPONSE: I do not know. I think maybe we need to look at the PHABSIM data, like Sam suggested.
5 or 6 sites plotted similar to what we have plotted here and see how that compares and what do you
think, Chris, look at how that relates to a flow-by?
RESPONSE: Well, again, I think it has all been run; it is just a matter of rearranging a bunch of
numbers so it is spit out in another format.
Facilitator: And who is going to be doing that and by when?
RESPONSE: If I can get my hands on the information, I will be happy to—
COMMENT: It's public information. You just have to find it.
Facilitator: So, Fred, you would be working with Hugh to provide him with that information so Hugh
could do that.
COMMENT: Be careful when you provide that because there is a lot of look ups that refer to external
files so you have to make sure the external files stay together or it will be looking in the wrong place.
Facilitator: So do you think that this is readily something that could be produced by July? I am looking
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at Fred and Hugh and I think that—
RESPONSE: I can do my best. You know, if I can get it I will certainly try.
Facilitator: Okay. Any other questions or comments for Hugh?
QUESTION: Just in general, is there any way we can kind of reduce some of these scenarios down to
eco deficit type stuff? Put a common footing on it? Compared to what we have done with the RTI
work?
COMMENT: If you have a baseline, unregulated or SIMBASE, just run 20, 30, 40 or one of these
through and calculate your eco deficit.
COMMENT: It would be interesting to see which one, what they come out to be.
COMMENT: It is just basically the area under the curve and this is just another curve superimposed to
see the eco deficit. Now RTI has been one to calculate the eco deficits so far.
COMMENT: Calculating the eco deficit using this strategy presumes that the minimum flow is the
constant.
RESPONSE: Yes. What is the real world flow going to be under this strategy? That is something
different.
COMMENT: Basically what we got was comparisons between these strategies and the drought of
record, and in each case, the proposed strategy put less water in the river than the drought of recent
record for half or more of the year. But we are not going to take this to that level on a constant basis.
What we do not know is how often we are going to approach that level and how close we are going to
get. Those are questions that need to be answered relative to ecological integrity in North Carolina. I
think the PHABSIM data will help.
C; What Tom asked about maybe is a second step after you take a look at the PHABSIM stuff.
COMMENT: The reason why we moved away from these flows, these thresholds to begin with when
we first evaluated them was that we were seeing impacts, in general, that we felt were not going to
meet the ecological integrity objectives of the legislation. I think in order to honor your work to this
point, I am willing to look at the PHABSIM data that represents the 40, 20, 50 mean monthly flows but I
will say—and maybe I am the only one who is stupid enough to say it that I do think the implication—
what we had already seen, did not lead us in the direction of these due to the level of impacts that we
were perceiving. Before we go too far with people’s time and money, presumably, I do think that was
the general direction, why we moved away from this early on.
COMMENT: And those were with those levels being there; that was it. It was not a safety net with
some unknown frequency of being well above minimum. We have no way of really saying well what
does that really mean.
RESPONSE:I think that, though, is where the surficial simplicity of this actually leads to a greater
complexity because you have to have a pretty complex system of if/then statements. We move quickly
away from simplicity, so again, I might be the only person—
RESPONSE: That is a really good point. Again, for planning purposes, even if you used a mean
monthly flow series of numbers that vary by physiographic province and so on, in a planning tool, if you
set those high enough, it is simple for them to run and raise the flags that need to be raised. If and
when a permitting program ever comes around, there would be a whole other bunch of discussion of
whether or not those numbers get changed and to what and then what all the other complexities get
involved into the frequency and duration of excursions outside of that. I think we really need to keep
our eye on the ball as Jay has said earlier about what it is we are trying to do right now with this
process. If it is really giving Tom Fransen’s bunch something he can stick in a model, let’s keep that in
mind and not overly complicate things because we could spend another three years talking about what
all those other metrics are for how to interpret everything.
RESPONSE: That was a big deal in South Carolina going to the permitting; I can assure you that. It
was complicated; it was complex; it did not have any fistfights but there were plenty of verbal fights.
RESPONSE: Well the fistfights can come after our work is done.
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Facilitator: Hugh, thank you very much and yes, I think you and Fred are going to be working together
so hopefully you can get us something in July so thank you and your team for doing that.
IX. July 16-17 Meeting Agenda and the Timeline
Nancy Sharpless initiated a planning discussion to determine the agenda for the July 16 and 17
meeting. She pointed out to the EFSAB that scheduled for July 16 were several agenda items:
1. PHABSim mountain sites and recommendations
2. TNC Final Report and recommendations
3. Coastal Study update and recommendations
4. Barwick Updates of 20/30/40% & 30/40/50% and recommendations
5. BEC/RTI
a. Log-linear model
b. Revised research assumptions of the RTI/USGS study & recommendations
For the July meeting, the focus will be on closing the loop on presentations and to hear
recommendations from the presenters on how their presentation addresses the charge to the EFSAB.
Although trial balloons may continue to be developed (as well as new information) – where are we
now?
Several members asked questions about the July meeting:
Question: Have we seen trial balloons related to the BEC and eco deficit? I mean we’ve seen the
presentations but are we anticipating trial balloons that are directly built out from that?
Comment: What we will have from the RTI and USGS work at the next meeting is revised research
assumptions and conclusions, responses to address the questions we heard today during
the RTI/USGS presentation (this includes questions that may be submitted later this week),
and recommendations for recommendations. This will be our trial balloon.
Facilitator: Hugh – will you return with results from the additional work requested today? [Yes]. Once
we review the trial balloons, our plan was to begin to discuss remaining questions we had.
For instance, how do we deal with questions like duration and magnitude? What kind of
criteria will you all develop to help select options or recommendations for moving forward?
For July, we will have a two-day meeting. Given you will hear new presentations (TNC,
Coastal, the 20/30/40 Presentation) and information on July 16, does a back-to-back
meeting make sense? Will this give you enough time to start processing and assessing what
you heard?
Comment: If we were presented with new information on day one and then had a structured decision-
making process day two about how to use the cumulative information that we’ve seen so far,
would that not work? Even though day two may end up being a little bit nebulous, our time
constraints encourage us to move forward. Moreover, if the presenters send all proposals
ahead of the meeting, then we could review the material prior to the meeting. Postponing
any additional work until August is not moving us forward.
Facilitator: Given the month-to-month meetings, presenters try very hard to provide information ahead
of the meeting as best they can.
Question: Do the two meetings have to be on consecutive days?
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Facilitator: One reason for scheduling back to back meetings is that this allows those who travel to
reduce their travel time overall and it helps with consistency. If we split up the meetings now,
some folks might not be able to attend.
Comment: Since we don’t know what’s coming for the July 16, it’s hard to say how much we need to
digest. Perhaps you all could factor in time on the July 16 agenda to work with the materials
and/or raise additional questions. It’s hard to know how much time will be needed for
digestion.
Comment: It would be helpful if presenters would package their presentations with specific
recommendations for the EFSAB to digest and deliberate in order to determine our options.
If we could get something like this for presentation – in part or mostly drafted, then we might
be able to have structured discussions. Kimberly, for example your presentation – will you
offer recommendations in part or whole?
Kimberly: That’s my goal; to have something to provide you guys with so that you can hopefully pick
out pieces or ideas from it that you think would be useful. My recommendations will be
those that Nature Conservancy is supporting.
Comment: Since the EFSAB is somewhat familiar with Kimberly’s methodology, it will not be startlingly
new.
Comment: I think we’ve been a little bit reluctant to suggest our recommendations during our
presentations, “Here it is and now react to it.” We’ve kind of beat around the bush, which
lends itself to more questions than deliberation on how to move forward. Using this method
might finally get us to a point where we know what the gaps are and areas of agreement.
Regarding the two days - if we have them before us then it will be useful. We need
packages of information/recommendations to help us make sense of how to move forward.
Comment: RTI and USGS will produce responses to your questions, a revised set of assumptions, a
revised set of recommendations which would constitute our trial balloon at least a week in
advance of the meeting.
Facilitators: Our proposal to you all would be to review each presentation with the recommendations
and assess strengths and limitations of each, how each presentation addresses the charge
based on specific criteria, and then let those settle unless something clearly rises to the top.
We may take a straw poll but the idea is not to settle on a trial balloon- it is still too early and
you all may want to create a new trial balloon (or hybrid) (something that incorporates
aspects from each trial balloon you all agree on).
Comment: I think we have to come a lot closer to a decision about which approach we’re going to
recommend. We’re getting very close even with what was presented by the 20/30/40
subcommittee. I don’t think it’s going to be helpful to DWR if we say there’s five trial balloons
and we don’t want to hurt anybody’s feelings, and we think there’s something good in each
one of these. I would rather see trial balloons that are more fully fleshed out as opposed to
saying, “I like 80% flow by and I like eco-deficit.” I don’t think that that’s the type of
recommendations that DWR is going to be able to operate.
Comment: That is not what the facilitators are suggesting. It might be, for example, we take a wadeable
stream approach from this presentation and non-wadeable from this approach and create a
whole different package from what we have learned.
Question: When is the concept mapping going to occur of where we apply and test each package of
ideas?
Facilitator: We need to determine what you want to move forward with before tackling the next stage of
mapping and using a situational approach.
Comment: It will take several iterations and that’s when the surprises hopefully start popping out, “Oh
that thing we didn’t think was going to work has use.”
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Comment: That’s when we have to be careful that we don’t accidentally design a camel while trying to
design a horse.
Facilitator: Ok, it sounds like we will move forward with two meeting days in July. Next, are we missing
any agenda items for July?
Comment: Can I get clarification on what people want to see from the 20/30/40 subcommittee? I
believe we are not going to do any reruns but rather use previous results and rejigger the
results by these designated months. Is that correct?
Comment: Tom made a comment about the eco deficit. This is tough to address because without
assuming it’s a flat flow all the time what do you model?
Comment: The suggestion was to table this approach for now.
Question: Can the second meeting not be a consecutive day, that it’s maybe the following Tuesday
the 23rd? Or sometime that week?
Response: It’s a matter of expense for those who have to stay in a motel unless you’re willing to pay
me for my travel.
Facilitator: So you’re actually suggesting that it’s easier for the people traveling to do it on two
separate days? Suggestion – can we keep the July meeting dates as it may be difficult to
choose another meeting day now in July (especially for the facilitation team) and then
consider how to deal with the expense or move to non-consecutive meeting dates.
Question: I have a procedural question. If we’re all not here at the meeting, can we still make
decisions? I’m not sure how the charter works.
Facilitator: Each member should have an alternate to attend the meetings when he or she cannot
attend or find a way to have someone else weigh in from them during the meetings. The
other option is to participate by webinar during the discussions.
Note: For the following meeting dates:
Dec 3 will be held at the Stan Adams Center (the Archdale is not available).
Have added October 23 as a second meeting day
We will evaluate the consecutive meeting structure on July 17.
Thank you everyone!
X.
Information
on
Next
Meeting
The draft agenda for the July 16-17, 2013 meeting includes:
• PHABSIM using mountain sites
• Report back from the coastal group and recommendations
• The results of the TNC study and Recommendations
• The RTI/USGS response to the questions asked today, the research assumptions and
recommendations
• Report back from Hugh Barwick and others with PHABSIM results for 20/30/40 and 30/40/50 and
Recommendations
• Discussion of Report
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• Begin assessing proposed recommendations (trial balloons)
The next meeting of the EFSAB is scheduled for July 16-17, 2013 at the Stan Adams Educational
Center from 9:0oam until 4:15pm. Please remember to bring lunch and refreshments with you. Coffee
will be available on site and soft drinks are ($1). Webinar: If you cannot attend the meeting in person
but would like to join us via the webinar, you can watch the presentations and listen to the live
streaming audio of the meeting by accessing the link and typing your name in the space labeled
“guest”: https://denr.ncgovconnect.com/sab/
Meeting Location & Directions: The meeting location is the Stanford M. Adams Training Facility at
Jordan Lake Educational State Forest. Directions are: 2832 Big Woods Road, Chapel Hill, NC 27517.
From Rt 64 and Big Woods Road, it will be the first Forest Service sign on the right. Pass the office
building and continue on through the gate to the education center. For Map link:
http://go.ncsu.edu/stanadams
Appendix A: Report Outline (DRAFT 1) from the EFSAB to DENR/DWR
{All working documents into this document except the guidelines to aid recommendations
source document)
Note: The research assumptions enclosed are currently limited to the RTI and USGS research as well
as some sections of the Recommendations like the protocol conclusions; the Report will eventually
include a comprehensive view of what has transpired and a more comprehensive set of
recommendations.
PREFACE
1. How this report is organized
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This report is organized into a preface, research assumptions, recommendations, and summary and
conclusions. The Preface describes the ecological flow provision contained in the basin modeling
statute, the Department of Environment and Natural Resources’ (DENR) effort—with the Division of
Water Resources (DWR) taking the lead role--to establish the Ecological Flow Science Advisory Board
(EFSAB), and the activities of the EFSAB. Research Assumptions describes the guiding principles of
the ad hoc work group that advised the analysis efforts of Research Triangle Institute (RTI), and the
U.S. Geological Survey (USGS). The research was to assist the EFSAB in providing a foundation for
their recommendations to DENR. The Recommendations includes the recommendations as well as
supporting information. The Summary and Conclusions provides additional context for understanding
the recommendations supported with maps, a flowchart, and insights from “lessons learned.”
2. DENR mandates in legislation
Session Law 2010-143 amended portions of General Statute 143, Article 38 (Water Resources).
Specifically, the Session Law added language to G.S. 143-355 requiring DENR to develop basinwide
hydrologic models for each of the 17 major river basins in North Carolina. The models are to be used
to simulate flows for determining if adequate water is available in the future to meet all needs, including
essential water uses and ecological flows. Basinwide models are considered a practical approach to
water planning because site- and project-specific evaluations require considerable time and money.
However, the planning method used by DENR will not replace site specific studies needed for a specific
environmental assessment or permit review.
The statute defines ecological flow as “the stream flow necessary to protect ecological integrity.”
Ecological integrity is defined as “the ability of an aquatic system to support and maintain a balanced,
integrated, adaptive community of organisms having a species composition, diversity, and functional
organization comparable to prevailing ecological conditions and, when subject to disruption, to recover
and continue to provide the natural goods and services that normally accrue from the system.”
The statute directs DENR to “characterize the ecology in the different river basins and identify the flow
necessary to maintain ecological integrity” and to “create a Science Advisory Board to assist the
Department in characterizing the natural ecology and identifying the flow requirements.” The EFSAB
shall include representatives from: the Division of Water Resources; the Division of Water Quality
(DWQ); the North Carolina Wildlife Resources Commission (WRC); the North Carolina Marine Fisheries
Commission (MFC); and the Natural Heritage Program (NHP). The statute also directs DENR to invite
participation by: the United States Fish and Wildlife Service (USFWS); the National Marine Fisheries
Service (NMFS); individuals with expertise in aquatic ecology and habitat from organizations
representing: agriculture; forestry; manufacturing; electric public utilities; and local governments; and
other individuals or organizations with expertise in aquatic ecology and habitat.
Finally, the statute directs DENR to ask the EFSAB “to review any report or study submitted to the
Department for consideration that is relevant to characterizing the ecology of the different river basins
and identifying flow requirements for maintenance of ecological integrity.”
DENR is required to provide status reports to the NC Environmental Review Commission (EMC) on the
development of basinwide hydrologic models no later than November 1 of each year, beginning in
2011.
While the role of the EFSAB appears rather clear from the statutory language, at times there was
confusion on several issues. First, after discussion and review of the statute, it was agreed that EFSAB
recommendations regarding ecological flows are made for the purpose of water resource planning, not
water use permitting. Second, it was agreed that the EFSAB is recommending scientifically-based
methods or approaches and flow requirements, which may be numerical but not [removed site]
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project specific.
The EFSAB is not responsible for recommending how DENR responds to a water-availability issue nor
advising DENR on how to use the EFSAB recommendations and research products.
3. DENR’s actions establishing EFSAB
DWR created and hosts an ecological flow website with pages defining ecological flow and discussing
its importance. DWR also hosts pages for all activities of the EFSAB, including presentations,
literature, audio of meetings and meeting minutes.
DWR contracted with the N.C. State University’s Natural Resources Leadership Institute and program
for Watershed Education for Communities and Local Officials to assist in the development of the
EFSAB charter, lead development and organization of the agenda for each EFSAB meeting, facilitate
each EFSAB meeting, and produce written minutes for each meeting.
DWR extended 16 invitations to members of the NC scientific and technical community with expertise in
aquatic ecology and habitat to serve on the EFSAB. The EFSAB has a total of 15 primary members, as
well as alternates, from the following agencies or organizations: DWR, DWQ, WRC, NHP, MFC, EMC,
USFWS, NMFS, USGS, American Water Works Association, the N.C. Department of Agricultural and
Consumer Services, the North Carolina Forest Service, electric public utilities, local governments, and
environmental non-governmental organizations.
The EFSAB met 24 times; the first meeting was convened November 8, 2010 and the last meeting
December 3, 2013. During the initial meetings the EFSAB established a charter that included the
purpose, goals, procedural rules, and responsibilities for the EFSAB members, DWR and the facilitation
team. Decision-making by the EFSAB was based on consensus. The EFSAB used small-group break-
out sessions, brainstorming, and trial balloon techniques to discuss and clarify topics, capture individual
member’s concerns, and put forth potential methods to achieve the EFSAB’s ultimate goal of advising
DENR on its charge of characterizing the ecology in each of the river basins and identifying the flow
necessary to maintain ecological integrity.
Experts on the EFSAB and from other organizations gave presentations to the EFSAB on the early
efforts to characterize and classify NC streams based on flow patterns, evaluating aquatic habitat using
physical habitat simulation models (PHABSIM), and the history of establishing ecological flows in
various other states and in major river basins. Other presentations focused on DWR’s basin modeling
using OASIS and the vision of how ecological flows would be incorporated into the modeling effort.
Later presentations focused on coastal waters and alternative approaches for determining ecological
flows.
The EFSAB relied on copious analyses and presentations by its members as well research of outside
organizations. DWR worked closely with Environmental Flow Specialists Inc. (EFS) on the early efforts
to characterize and classify NC streams based on flow characteristics from USGS gage data. DWR
also updated nine study sites from the NC piedmont as a test for characterization and classification
similarities. RTI undertook a biofidelity analysis to verify the EFS characterization/classification
strategy. USGS also performed statistical analyses of aquatic insect samples as an initial test of the
EFS characterization/classification strategy. RTI and USGS performed statistical analyses of fish and
aquatic insect samples to examine relationships to flow variables. {next sentence is anticipated} In the
end, the EFSAB developed a framework for determining ecological flows based on available fish and
aquatic insect data without using a stream classification system.
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RESEARCH ASSUMPTIONS
All of the original research done to date supporting the EFSAB mandate, whether by RTI for an internal
research and development project or the Environmental Defense Fund (EDF), DWR, and WRC funded
investigations, has been based on the following assumptions:
• In accordance with the statute and the operating principles of the EFSAB, any approaches
recommended for the determination of ecological flows will be made for the purpose of
understanding the flow requirements of stream ecosystems and not for water use permitting.
• While it would be desirable to evaluate what happens at sites over time as flows are altered,
biological sampling data for pre- and post-flow alteration conditions is very limited. The strategy
selected substitutes evaluation of a very large number of sampling sites (649) reflecting various
levels of flow alteration and compares the results to estimate the effects of flow alteration.
• All of the consistently collected and comparable fish data came from DWQ wadeable stream
sampling sites. We acknowledge that this leaves a significant gap in our knowledge about how
the largest streams may react to flow alterations, but aside from the fact that there was no
alternative data set readily available, there are two reasons why this approach may be
adequate. RTI determined that wadeable streams make up 88% of the National Hydrography
Dataset Plus (NHD+) catchments in NC, so they do represent most of the state, and especially,
most of the mountain, piedmont, and sandhill regions. Also, wadeable streams are assumed to
be more sensitive to flow alterations, so flow-based strategies developed for protecting
ecological integrity in them will be adequate for larger streams.
• For the purposes of evaluating the level of flow alteration and determining biological responses
in the RTI analyses, landcover for the baseline was assumed to be Küchler’s Potential Natural
Vegetation (PNV). This does not commit us to using a PNV condition to describe the current
baseline for the purposes of our final recommendations. It does provide a useful metric for
knowing the degree to which the current baseline includes prior human influence. Using the
PNV to determine biological response curves also results in a larger amount of flow alteration
when compared to the existing conditions under which the biological data was collected. In turn
this improves the resolution and range of those curves.
• The EFSAB is charged with developing a statewide approach, but this does not substitute for
site-specific evaluation when that is needed.
• With respect to stream classification schemes, these are always scale dependent, so the set of
variables and the thresholds of those variables typically change when designing a classification
system at a national, regional, state, or local scale. Again, the EFSAB focus was at the state
level.
• Research could only use available data that met certain criteria (sufficiency, consistency,
validity). Thus, the research product is limited and does not include all possible indicators of
ecological integrity, especially those based on measures of ecosystem function (e.g., nitrogen
fixation) as opposed to composition.
RECOMMENDATIONS
1. Consider how to include/weave in a lit review (how to demonstrate credibility/context with the
research)
2. Describe what the EFSAB considered and why
3. Describe how the research that did not “work” taught/informed the EFSAB about how to move
forward and in what directions.
4. Describe areas of uncertainty
5. EFSAB did both analysis of current research and conducted research
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a. Experts who presented on their research
b. Experts’ publications that were reviewed/referenced by the EFSAB
c. Ad-Hoc Water Research Coordination Group
d. EFSAB members commissioned research to support/inform the effort.
Procedural Conclusions
Flow Metrics: RTI evaluated several flow metrics in their proof-of-concept evaluation of biological
response curves. These included ecological deficit and the 3-, 7-, 30-, and 90- day low flows – all
evaluated on annual and seasonal bases. Ecological deficit is the total difference between the altered
and unaltered flow duration curves, whenever the altered curve falls below the unaltered curve – also
calculated on annual and seasonal bases. The proof of concept investigation developed a relationship
between the change in biota in the run/riffle guild in response to the change in each of these flow
metrics. The response was very similar regardless of the flow metric used.
We propose to use two flow metrics [note:could change based on RTI analysis] as the work of the
EFSAB moves forward:
1. summer (July through September) ecological deficit
2. annual 30-day low flow
We also recommend that biological response curves be developed using the spring (April through
June) and fall (October & November) ecological deficits at a later time.
Our reasoning is as follows. It is desirable to retain the seasonal analysis because the seasons
identified are different from the standpoint of hydrology, water use, and life cycles of biota. Ecological
deficit does a good job of evaluating changes in flow magnitude and frequency over the entire range of
the seasonal hydrograph. The annual 30-day low flow also captures the duration of low flow events
that could be affected by withdrawals, and is a metric familiar to hydrologists/modelers and water users.
The annual 30-day low flow will fall mostly within the summer months, but calculating it on an annual
basis eliminates calculation problems with low flow events that extend into other adjacent seasons.
Guild Representation:[note: not sure how this will apply to bugs] RTI evaluated two habitat guilds
(riffle-run and pool) in their proof-of-concept research of biological response to flow alteration. We
propose using the riffle-run guild for two reasons: 1) it shows a significant response to flow changes;
and 2) it is more flow sensitive than the pool guild. The riffle-run guild showed significant relationships
whether the biological metric was fish abundance (number of individuals), species richness (number of
species), or diversity (Shannon-Weaver index).
We do not believe it is necessary to investigate the biological response of the other guilds (pool-run,
riffle, margin, backwater) for the following reasons: 1) time and funding constraints; 2) of the four
remaining guilds, three (pool-run, margin, backwater) are expected to be less flow sensitive than the
riffle-run guild; and 3) the number of riffle species and the number of sample sites containing riffle
species is lower than that found for the riffle-run guild, thus the power to detect significant relationships
is likely lower.
Biological Response MetriComment:[note:not sure how this will apply to bugs] RTI evaluated three
biological response metrics. These were:
• Abundance: The total number of fish present at the sampling site
• Richness: The total number of fish species present at the sampling site
• Diversity: Using the Shannon-Weaver Diversity Index which combines abundance and richness
through a complex formula
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As with flow metrics, there was little difference in how these three metrics responded to flow alterations.
We propose to use richness as the biological response metric. Our reasons are as follows.
• Ecological: Species richness is a much better indicator of the ecological health of an aquatic
ecosystem than is organism abundance. A system with a very large number of one or very few
species may be and in fact probably is seriously degraded. Abundance and richness tracked
each other in RTI results because very few seriously degraded sites were evaluated.
• Legal: The legislation mandates that we evaluate ecological integrity in terms of the ability to
sustain existing species diversity.
• Ease of interpretation/explanation: Affecting the number of fish species is easier for people
outside the SAB process to understand and interpret than an index of diversity. Since the two
metrics respond very similarly to changes in flow, we recommend using the simpler one.
The EFSAB relied upon the historical fish and aquatic insect collection records of DWQ and WRC,
which was fundamental to the Biological-Ecological Classification (BEC) research performed by RTI.
The EFSAB benefited from the availability of DWR’s PHABSIM data sets in the piedmont and mountain
regions as a tool to judge various flow scenarios. The availability of real and synthesized flow records
from the USGS, DWR’s OASIS basin models, and RTI’s WaterFALL model were essential for
PHABSIM and BEC. The research performed by primary authors such as LeRoy Poff and Brian
Richter; the research undertaken in large river basins—e.g. Potomac, Susquehanna, Savannah; and
the efforts by other states, like Michigan, Texas, New Jersey, have all provided a foundation for the
decisions of the EFSAB.
EFSAB Subcommittee Proposed Framework of Recommendations
Characterization—What and How
1. A classification of streams is required. That classification may be based solely on flows but should
be based on biological data and physical characteristics of the stream. Classification at the very
least should include meaningful physiographic classes. Options include Giese and Mason, 1993;
Omernik, Level IV, 2001; SALCC, 2013.
2. Characterize each class according to the record of flows and the biological or habitat response
curves for the biota most sensitive to changes in flow. This
precludes
or
goes
further
than
using
a
flat
rate
flow
minimum
strategies
(e.g.
7Q10
or
Sept
medium).
3. For each class identify reference reaches. [will
need
to
identify
the
definition
of
class
being
used
if
classes
are
used].
Treatment of Coastal Areas [pending input from Bob’s working group]
1. Recommendations for Coastal Plain:
a. DWR should emphasize new data collection in the coastal plain
b. Use the management strategies, models, and data of other agencies (e.g., Division of
Marine Fisheries, Division of Water Quality)
c. Use literature
Approaches to Determining Ecological Flows
1. A framework for DWR to use in determining Ecological flows for stream reaches should
incorporate:
a. Seasonality - perhaps differently for each class
b. Target flow regimes for each season based on available data foResponse:
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i. the biota most sensitive to changes in flow
ii. habitat for the biota most sensitive to changes in flow
iii. the prevailing flow regime and the Sustainability Boundary and the Eco-Deficit
approaches (Richter, et al, 2011; Vogel, et al, 2007).
c. Thresholds for each season depending on class flow characteristics which may be
eitheResponse:
i. acceptable deviations from target flow regimes in terms of magnitude, frequency
and duration; or,
ii. a band of acceptable variation around the target flow.
d. A procedure for situations where there is uncertainty regarding whether the threshold is
crossed (e.g., site specific evaluations).
2. Ongoing Validation - DWR should adopt/design/develop strategies foResponse:
a. validating class characterizations and ecological thresholds. Strategies should be
informed by new data or research.
b. tracking the impact of flow changes when they occur.
c. modifying classes, characterizations, target flows, and thresholds based on new data,
changing conditions, and lessons learned.
SUMMARY AND CONCLUSIONS
• Includes visual representation of recommendations
• Includes a map of classes (if there can be a map of classes)
• Includes value-added recommendations, insights, concerns
(example: other states are using flow based stream classifications. NC EFSAB tested this and
determined the paradigm was flawed, thus came up with a different approach that addressed
those flaws)