Mary_Davis(Slides 1-77)

Environmental Flow Science:  
Lessons Learned from Selected
Environmental Flow  Programs
NC Environmental Flow Science Advisory Board
November 15, 2011
Mary M. Davis, Ph.D.
Southern Instream Flow Network
“Hydrologic regimes are the master variables in 
aquatic ecosystems.”   Poff et al. 1997
Southern Instream Flow Network
Purpose ‐To facilitate
protective instream flow
policies and practices in
15 southern states by
providing science-based
resources and opening
lines of communication.
More information at:  
www.southeastaquatics.net/programs/sifn/
Presentation Overview
1. Review of science‐based methods to 
determine IF needs
2. Methods used by select states to determine 
IF needs
3. IF resources for North Carolina
Science‐based Methods to Determine 
Instream Flow Needs
•Instream Flow Incremental Method (IFIM)
•Ecologically Sustainable Water Management 
(ESWM)
•Ecological Limits of Hydrologic Alteration 
(ELOHA)
Instream Flow Incremental Method
(IFIM)
Source:  http://www.fort.usgs.gov/Products/Software/ifim/5phases.asp
0
5,000
10,000
15,000
20,000
25,000
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95
WU
A

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1
0
0
0

f
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Discharge (cfs)
ROCKY RIVER - REDBREAST SUNFISH HABITAT vs. DISCHARGE
Adult Juvenile Fry Spawning
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
HS
I
DEPTH (ft)
HABITAT SUITABILITY INDICES - DEPTH
GUILD=SHALLOW-SLOW with WOOD…
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
HS
I
VELOCITY (fps)
HABITAT SUITABILITY INDICES - VELOCITY
GUILD=SHALLOW-SLOW with WOOD…
Field Study
Physical Modeling
Habitat Modeling
Habitat vs. Flow
for each organism
Hydrologic Modeling
•Time Series Analysis
•Flow Alternatives
•Recommendations
Requires time and $
IFIM Process:  Site‐and Project–specific Evaluations
IFIM Process:  
Water management alternatives are the basis 
for a negotiated solution.
IFIM Essentials
•Well‐established methodology developed in the 
1980s and 1990s
•Applies (usually) species‐specific models at site‐
specific level
•Based on population responses to natural 
variation in velocity, depth, cover, and area
•Negotiated instream flow solutions
Ecologically Sustainable Water Management 
(ESWM)
Ecosystem
Flow
Requirements
Human
Needs
Areas
of
Incompatibility
Collaborative
Dialogue
Water
Experiments
Adaptive
Management
Ecological Conceptual Model
Source:  Susquehanna River Commission 2011
Savannah River Ecosystem Flow 
Workshop  Participants
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
4,000‐5,000 cfs;
•Sturgeon spawning
6,000‐10,000 cfs, with 6,000 cfs as baseflow
>2,700 cfs;
• Juvenile
Outmigration
>2,700 cfs               |                    >2,000 cfs              |      >2,700 cfs
>5,000 cfs;
•Sturgeon spawning
4,000‐6,000 cfs, 4,000 cfs as baseflow
>16,000 cfs; 1‐2 days, 1‐2 pulse
20,000‐40,000 cfs; 2‐3 days, 1/month
Ecosystem Flow Recommendations: Building Block Method
Augusta Shoals on the Savannah River
Low Flows
High Flow
Pulses
Floods
• Herring passage over NSBLD
• Morone egg suspension
20,000‐40,000 cfs;
2‐3 days, 1/month | 14 days, 1/month
Jan & Feb  | Mar & Apr
• Shad, striped bass, robust redhouse spawning and 
habitat
6,000‐10,000 cfs, with 6,000 cfs as baseflow
•protect spider lily from deer grazing
>2,700,000 cfs
• Resident fish habitat
• Juvenile fish out‐migration
4,000‐5,000 cfs;
4,000‐5,000 cfs;
No flood flow recommendations provided for the Shoals
20,000 cfs;
2‐3 days, 1 pulse
•Sturgeon spawning
Key
Dry Year
Avg Year
Wet Year
ESWM Essentials
•Developed in 1990s by The Nature Conservancy
•Applied at watershed level to improve flow 
regimes and restore ecological function 
•Based on existing data and expert knowledge of 
ecological relationships with natural hydrologic 
regimes
•Integrates societal values with ecological needs
Ecological Limits of Hydrologic Alteration (ELOHA)
http://conserveonline.org/workspaces/eloha
(Poff et al. 2010)
Bi
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Hydrologic alteration
Ecological Limits of Hydrologic Alteration (ELOHA)
http://conserveonline.org/workspaces/eloha
(Poff et al. 2010)
Output from The Nature Conservancy’s 
Indicators of Hydrologic Alteration (IHA)
software
Calculation of Flow Alteration
Flow‐Ecology Relationships 
from Literature
Source:  McManamay et al. 2011
Flow‐Ecology Relationships from 
Existing Data
Source:  Potomac River Commission Watershed Assessment 2011
Characteristic species
Thriving species
1.0  
0.9  ‐
0.8  ‐
0.7  ‐
0.6  ‐
0.5  ‐
0.4  ‐
0.3  ‐
0.2  ‐
0.1  ‐
0.0  
Pr
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a
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i
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 me
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Proportion of index flow removed
0.0        0.1      0.2        0.3       0.4       0.5       0.6       0.7       0.8       0.9       1.0
Adverse 
resource 
impact
Acceptable 
resource 
impact
Michigan’s Screening Tool for Ground‐Water Withdrawals
ECOLOGI
CAL
COND
I
TION
Ecological Response to Flow Alteration
ELOHA Essentials
•Newly established method (Poff et al. 2010)
•Uses existing data to develop flow‐ecology 
relationships for classes of rivers
•Based on ecological responses to flow alteration
of natural hydrologic regime
•Integrates societal values with ecological values
Presumptive Flow Standard for 
Environmental Flow Protection
(Richter et al. 2011)
Presentation Overview
1. Review of science‐based methods to 
determine IF needs
2. Methods used by selected programs to 
determine IF needs
3. IF resources for North Carolina
Approaches for 
Determining IF Standards
•Minimum flow threshold
–7Q10 (e.g., AL, LA, MS)
–Modified Tennant (e.g., AR, GA, SC)
•Statistically based standards
(e.g., FL St Johns WMD, Potomac River Commission)
•Percent of flow approaches
(e.g., FL SW Florida and Suwannee River WMDs, TN 
Presumptive WQ Standard)
Under development in SE:  TX, NC, VA
IF Methods Used by Selected Programs
•Florida
•Michigan
•Potomac River Commission
•Texas, if time allows
Slides courtesy of Marty Kelly, DirectorSWFWMD MFL Program
Florida –
Instream Flow
Protection
Policy and
Management
Programs
http://www.swfwmd.state.fl.us/projects/mfl/
SJRWMD
NWFWMD SRWMD
SFWMD
Minimum Flows and Levels
‐Florida Statutes, Section 373.042 ‐
The minimum flow for a given watercourse shall
be the limit at which further withdrawals would
be significantly harmful to the water resources or
ecology of the area
A MFL is set by the Water Management Districts for each 
of their priority streams, rivers, lakes, and aquifers.
MFLs are used in 
•water management allocation planning, 
•surface and groundwater withdrawal permit conditions, and 
•recovery plans.
•Building Block Method
•PHABSim-style methodology
•Percent of Flow Reduction Approach
•‘Significant Harm’ threshold = 15% reduction
in available habitat for most conservative
target
0
500
1000
1500
2000
2500
0 100 200 300
Day of Year
Fl
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(
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Block 1 Block 2Block 2 Block 3
SWFWMD Instream Flow Program
Physical Habitat Simulation System
Used for Blocks 1 and 2
• Depth
•Velocity
• Substrate
Floodplain
Snags
Exposed Roots
Long-Term Inundation Analysis
Used for Blocks 2 and 3
Low Flow Threshold - Wetted Perimeter
Used for All Blocks
Low Flow Threshold -Fish Passage
Used for All Blocks
0
400
800
1200
1600
2000
0 50 100 150 200 250 300 350
Fl
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(
c
f
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10%
8%
13%
18%
LFT = 67 cfs
Flow Prescription
Percent of Flow and Seasonality
of allowable cumulativewithdrawals
Day of Year
• Best Available Information
• Peer Review Process
Block
Rivers 
Upper Alafia Braden Myakka Peace Hillsborough
Hi Lo Hi Lo Hi Lo Hi Lo Hi Lo
1 (April 20‐June 24)8 10101015158108 10
2 (Oct 28 –Apr 19)815101155818811
3 (Jun 25 –Oct 27)8 13 10 19 7 16 8 13 8 13
SWFWMD MFLs
Range of Percent Allowable Withdrawals
(Significant Harm Threshold < 15% habitat loss)
Source:  http://www.swfwmd.state.fl.us/projects/mfl/
SWFWMD MFL Essentials
•MFL set for each water body (i.e., no classification needed)
•Flow requirements based on most sensitive ecological 
response to flow alteration (i.e., fish, coarse woody debris, 
floodplains, organic soils, etc.)
•Estimate habitat loss based on cumulative depletion of the 
natural daily flow regime
•MFLs for medium size, coastal rivers show a small range of 
allowable depletions.
IF Methods Used by Programs
•Florida –using similar methods as NC; finding 
similar standards within river class
•Michigan
•Potomac River Commission
Environmental Flow Standards in Michigan
Slides courtesy of Paul Seelbach, USGS 
and Richard Bowman, TNC
Spatial
framework
Reach
attribution
MI fisheries
classification
Coordination
is good
Well-established
conceptual
framework tested
and implemented
over past 15 years
by TNC, USGS
Regional Aquatic
GAP, and a few
states.
Provides for multi-
state coverage.
Zoogeographic Region (WWF)
Ecological Drainage Unit (EDU)
Aquatic Ecological System (AES)
Ecological Segment
NHD+ Reach
Michigan River Classification Approach
Spatial
framework
Reach
attribution
MI fisheries
classification
Coordination
is good
Key landscape and
riverine attributes
for every reach
came from existing
map-level data and
state-level models.
Examples: flow,
temperature, slope,
and elevation.
0 - 0.10.1 - 0.2130.213 - 0.334
0.334 - 0.468
0.468 - 0.631
0.631 - 0.826
0.826 - 1.294
Yield (cfs/sq. mi)
Spatial
framework
Reach
attribution
MI fisheries
classification
Coordination
is good
Summer temperature
Fi
s
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a
b
u
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d
a
n
c
e
Cold fishes Warm fishes
Cold
Cold
transition
Warm
transition Warm
Spatial
framework
Reach
attribution
MI fisheries
classification
Coordination
is good
Streams
Cold
Warm Trans
Warm
Lg RiversSm Rivers
Cold Trans
11 river classes based on flow and temperature
Spatial
framework
Reach
attribution
MI fisheries
classification
Coordination
is good
Simple. Familiar. Fish values.
Incredibly powerful in policy
development. “Map that
changed the world.” Map is
central to state water law. Is in
minds and language of policy
leaders and users.
Is useful to many other river
management programs. Can
drill into database for more
details.
m
river
river
am
ll river
e river
100
Ecological
targets
Statewide habitat suitability info: flow and temperature
Rank scores per normal distribution; 60+ species
0
0.05
0.1
0.15
0.2
0.25
2 3.6 5.2 6.8 8.4 10 11.6 13.2 14.8 16.4 18
Pr
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b
a
b
i
l
i
t
y

D
e
n
s
i
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y
Normal (Gaussian) Distribution
Ab
u
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d
a
n
c
e
Habitat Gradient (Flow or Temperature for instance)
Optimum Habitat
‘4’ represents ‘best’ conditions
‘4’ is ±0.5 SD
‘3’ is ± 0.5 to 1.0 SD
‘2’ is ± 1.0 to 1.5 SD
‘1’ is ± 1.5 to 2.0 SD
‘0’ is ± > 2.0 SD
Reference
flows
River
types
Ecological
response
curves
Degree
flow
alteration
Enviro.
flow
targets
Implement
program
For representative sites per river type:
Considered initial “characteristic” species
Ran withdrawal simulations and followed scores 
common shiner
white sucker
longnose dace
rainbow darter
0102030405060
44 4 3332
4 333222
33 22200
22 10000
Percent flow reduction
Reference
flows
River
types
Ecological
response
curves
Degree
flow
alteration
Ecological
targets
Enviro.
flow
targets
Implement
program
Variation in fish assemblage response curves for each of 15
representative sites within one river type. The mean response (dark
line) was used in the water management program, and policy
safeguards were used in recognition of the degree of variation.
Reference
flows
River
types
Degree
flow
alteration
Ecological
targets
Enviro.
flow
targets
Implement
programEcological
response
curves
Summaries of simulations create early warning and total 
impact curves (for assemblage)
Reference
flows
River
types
Ecological
response
curves
Degree
flow
alteration
Ecological
targets
Enviro.
flow
targets
Implement
programEcological
response
curves
Cool Small Rivers
0
0.2
0.4
0.6
0.8
1
0 0.25 0.5 0.75 1
Early warning
response
curve
Assemblage
response
curve
Pr
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i
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t
Proportion of index flow removed
Curves and target zones per each ecological river type. 
Geographies of biological response and social values.
Allowable cumulative withdrawal
(% median August)
Michigan’s Screening Tool for 
Ground‐Water Withdrawals
Characteristic species
Thriving species
1.0  
0.9  ‐
0.8  ‐
0.7  ‐
0.6  ‐
0.5  ‐
0.4  ‐
0.3  ‐
0.2  ‐
0.1  ‐
0.0  Pr
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Proportion of median August flow removed
0.0        0.1      0.2        0.3       0.4       0.5       0.6       0.7       0.8       0.9       1.0
Adverse 
resource 
impact
Acceptable 
resource 
impact
• River classification informed by fish assemblages
•PHABSim-style methodology
•Percent of Flow Reduction Criteria
Michigan Instream Flow Program
IF Methods and Approaches Used by 
Advanced State Programs
•Florida – similar standards within river class
•Michigan –river classification informed by fish 
assemblages; similar standards within river 
class
•Potomac River Commission
Middle Potomac Watershed Assessment:
Environmental Flows 
•Follows ELOHA framework
•Multistate watershed
•www.potomacriver.org
Slides courtesy of Carlton Haywood, PRC
Bi
o
t
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c
 in
d
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c
a
t
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r
Hydrologic alteration
Ecological Limits of Hydrologic Alteration (ELOHA)
http://conserveonline.org/workspaces/eloha
(Poff et al. 2010)
Hydrologic Data
Hydrologic Metrics
Hydrologic Metrics
Middle Potomac – Biological Data
Biotic Metrics
Classification
Classification
Flow‐Ecology Relationships
Flow‐Ecology Relationships
Flow‐Ecology Relationships
Flow‐Ecology Relationships
IF Methods and Approaches Used by 
Advanced State Programs
•Florida – similar standards within river class
•Michigan –river classification informed by fish 
assemblages; similar standards within river 
class
•Potomac River Commission – demonstrated 
ecological impairment due to flow alteration in 
addition to other sources of stress
Presentation Overview
1. Review of science‐based methods to 
determine IF needs
2. Methods used by select states to determine 
IF needs
3. IF resources for North Carolina and the SE 
region
Southern Instream Flow Network
Purpose ‐To facilitate
protective instream flow
policies and practices in
15 southern states by
providing science-based
resources and opening
lines of communication.
More information at:  
www.southeastaquatics.net/programs/sifn/
•Problem:The limited focus on research and funding for 
instream flows has resulted in a lack of science to support 
protective instream flow standards.  
•Objective:to highlight research needs and coordinate 
sources of funding and research to address these needs.
•Goal:to ensure that instream flow research is focused on the 
needs of water resource managers for scientifically credible 
and protective state instream flow standards and practices.
Southern Instream Flow Research Agenda
www.southeastaquatics.net/programs/sifn
1. Develop a regional river classification system
2. Identify commonalities in ecosystem responses to flow 
alterations
3. Compile regional aquatic ecology data sets
4. Develop hypotheses for regional ecological responses to 
flow alteration
5. Perform field studies to test ecological responses to 
altered flow regimes
Southern Instream Flow Research Agenda
Priority Research Topics
Integration of Instream Research Agenda Products
To  Develop Flow‐Ecology Relationships
Ec
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a
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 Co
n
d
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t
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Hydrologic Alteration
+
+
‐
‐0
Hydrologic 
Models
Ecological Condition
Assessment
Aquatic Conservation 
Priority Areas
Sources of Flow 
Alteration
River 
Classification
Hypothetical Flow‐
Ecology Relationships
Quantify Flow Alteration
Ecological
Metric
Re
s
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c
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 Pr
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t
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s
 an
d

Va
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a
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Ec
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 Da
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SE River Classification
•Utilizing existing classifications
•Hierarchical scales 
for geomorphology, hydrology, and biota
•Principals: 
John Faustini, USFWS and Chris Konrad, USGS
Preliminary SE Flow‐Ecology Relationships
Source:  McManamay et al. 2011
Compile regional aquatic ecology data sets
Multistate Aquatic Resources Information System
www.marisdata.org
Integrating State Data 
into the National Fish 
Habitat Assessment
MARIS  States (2010)
SARP Flow Alteration Assessment
Approach –Qualitatively assess sources, spatial distribution, 
and relative magnitude of hydrologic alteration from water 
consumption, impervious cover, and dams.
In conclusion:
Generally, instream flow science is progressing and is resulting in more 
protective policies and management practices.
From the case studies:  
•River classification works well where there is a clear relationship 
with biota.
•‘Flow‐ecology’ relationships help guide selection of hydrologic 
and biotic metrics
•Demonstrated ecological impairment due to flow alteration 
provides a strong basis for instream flow criteria.
If we had more time:
•Scientific certainty should be balanced with policy development.
•Presumptive standards may provide a protective option until 
more studies can be completed.